I've seen the articles that mention how good this type of cross pipe is, but I've also heard that they sound is very raspy. I realy hope this refers to their sound on other motors as compared to the big Pontiacs. Anyone heard these on a 455 3" system with headers?

I've seen the articles that mention how good this type of cross pipe is, but I've also heard that they sound is very raspy. I realy hope this refers to their sound on other motors as compared to the big Pontiacs. Anyone heard these on a 455 3" system with headers?

Slobrd,
For more info on the X crossover, and exhaust systems in general, go to Eric D's Pontiac Garage at address below: Jim Hand

http://www.wauknet.com/douthitt/

Slobrd,
I have a .030 over 455 with 2 1/2" exhaust and the Dr. Gas X pipe. With no other changes,changing from an H pipe, I gained 2 tenths and 2 mph. That was without even lifting the hood. i am running Walker Race Magnum mufflers, and it has a gereat sound. I had FlowMasters before and they had a 'tinny rattle' sound.

Can you tell me more about the race magnums and the rest of the exhaust? I too am thinking about using these mufflers on a 74 bird because I'm tired of looking at big flowmasters hang under the car. They're also kinda common nowadays. I considered the flowmaster transverse muffler but it doesn't sound agressive enough.
Thanks

I was considering one of these X-pipe crossovers. Reading the Dr. Gas literature, these things work by evening out the uneven firing order in each pipe (think of the V8 as two 4-cylinder engines, each with its own exhaust pipe, but not properly synchronized because they are joined by a 90-degree crankshaft). Unfortunately, it is exactly that uneven firing order that gives a V8 that distinctive popping growl. Dr. Gas' ad says that the X-crossover makes a V8 sound like a Japanese motorcycle. Now, I love the wail of a Jap motorcycle, but I don't want my GTO mistaken for one! I think I'll give up a little efficiency in my street GTO for that V8 exhaust growl I love.

I have hedman 1-3/4 headers, 3-inch collectors, next 3 inch cutout ( the kind you can buy in Summit ), through 3 inch Dr. X crossover, in to 2 Dyno max race bullet (cans ) mufflers, 3 inch over axle, into two 3 inch 2 chamber Flowmasters under the trunk floor ( fuel cell in trunk ). 455 Th400 3:73 rear ran 13:00-104 flat off the street (zero traction). Slicks and open cutouts 12.5--107. I love the sound from the Dr X crossover. Mark L

Thanks for the comments Mark. What car is this in. I have honestly considered using a multiple muffler set up but the second gen F bodies don't have the room. I thought of running two race magnums and a transverse muffler. It may be overkill but this is the one area of the car I've reserved for an uncommon approach.
I'm sure interested in your comments on your car's sound during normal driving if it is driven on the street.

I reciently put a set of Ram Air Reproduction
Manifolds on my 79 Trans Am. Does anybody
know of an X or H pipe that will bolt on to
the manifolds?

Have one week of driving time with a new 2.5 inch "X" on the mild 400 Pontiac daily driver. New set of Dynomax 17749 Hemi Super Turbo's and 2.5 inch pipe all the way except for short pieces of 2 inch at the manifold outlets. I like it for a daily driver. It's quieter out on the road and at WOT. Still sounds plenty throaty at idle and just off-idle cruising around in the parking lot at work in the morning. When the rpm's go up the exhaust seems alot smoother and quieter than the old system. The induction roar of the Q-Jet is more noticeable even with a closed element air cleaner. It's hard to tell with such a mild 400 but there might be a slight increase in torque at WOT above 3500rpm. The real intent of this system was to make the car a little quieter and to increase exhaust system capacity for about a 325hp 462 Pontiac motor someday. (The old system was 2.25 all the way back with small case turbo mufflers.)

I have the Dr. Gas x pipe 3" system on my 70 455, with their muffers. I was very disapointed, their claim was the car would run as fast as open headers, WORNG! not even close. It's ok for idleing around untill you put your foot into it. then it sounds just like open headers. The car can be heard for
blocks

On my `66 driver I`ve got 2&1/2" pipes with an X in them, running cherry bombs (anybody remember them?). No fancy doctor anything, these were done at a local muffler shop from the stock manifolds to the rear for under $200. They sound very good, (certainly not like any rice burner I`ve ever heard!). I`ve never run the flowmasters, are they worth looking into.......and why?

I've got a '70' 400 with 2.5 aluminum and three stage Flowmasters. Sounds nice for stock engine. I had two stage Flowmasters for a day and found it to be to loud for daily commute. Convertible hardware rattled.
But there sure was a greater response and hp with the two stage from stock mufflers. And there was a noticeable difference between three stage vs. two stage, two gave more power.
This was very clear for me to recognize since I had ran with stock mufflers for 17 years. I am sure others will have more input on different brands and post.
I like mine for now but will change when tired. Look into a type that gives the performance and sound that you want. My Flowmaster three chamber's sound deep with a hint of tin.
Tilster

One thing I noticed with the X is the back pressure is not there......I remember the cherry bombs "popping" when you let off the throttle, but these are fairly smooth, even with the mild cam. When I was a kid, everybody had either thrush hush or cherry bombs. My car looks like it`s the early 70`s.........chrome reverse w/baby moons, rear up on hi-jackers....ahhh the good `ol days!

The X crossover both quieted and very slightly increased seat of the pants accelleration on a friends 70' GTO (400 ci, 280 cfm d-ports, 248 duration 580 lift solid cam, 1 3/4 headers, 3" exhaust out the back, Super Turbos)The sound is definently different... less rumbly??? Like an old gas dragster with the short pipes comming off each exhaust port, much quieter of course.

Lou, interesting results from your testing. Were you able to do all this testing at the same track on the same day? Did your weather conditions change or were you able to measure it throughout your testing? Can you tell me what mufflers and exhaust system you used before? Was the engine making 300, 400, 500, 600 HP? What size headers were they and what size crossover did you install? Were the pipes the same diameter all the way out to the rear of the chassis or did you neck them down? Can you email a photo to me so I can see where you located the junction? I like to keep these on file so that when people ask how far the junction has to be past the cross member, I can show them what others have done. What part number mufflers did you use? Thanks,
Tom Hand

Tom, As little as those nascar boy's know about horsepower, Yates, Hendrick, ect, I guess they have X and H crossovers on their cars by accident...maybe just for added weight?

I've competed in some close exhaust competition, and was looking for the best exhaust system. In talking to Mr Gas, I was told the X pipe system would produce more hp then open headers, NOT TRUE!! I ran their whole exhaust system, their ( Wave Trap mufflers ) The system I first bought was
their 3" X pipe cross over..... into their 3" mufflers, and 3" out..... into 3" tail pipes. What a joke, you don't need to do much testing, it's simple, you make a run with the exhaust system on, then take it off. My car slowed down 5 Tenths with their system. When I call them they said oh, you need 3½" because your collectors are 3½, your reducing them to 3" an it's killing your torque, well then, why did they sell me the 3" X over pipe system then ? I went on what they recomended. Ok", so now I buy their 3½ X pipe set up, not cheap buy the way.


After reduing my whole exhaust system ( big dollars ) I made another trip to the track, guess what ? I still went 4 tenths faster with open exhaust. I call them again, ( get this, this time, the guy tells me himself that the Walker mufflers are actually better then there's ) each time the exhaust system was installed exactly to their spec.'s. the cross over was place exactly were they told me to install it. After talking to the guys who run Heads up classes ( which closed exhaust is a must ) this is what I ended up doing, I now run 3½" pipe into 3½" Walker Mufflers with " NO CROSS OVER" the same
mufflers they said were better then theirs, the car now runs the same with open headers, as with closed exhaust, no slower or faster.....go figure, and for haft the price.

David, racing NASCAR, and drag racing are two different things, the biggest market is Pro Street,and all those closed exhaust Heads Up Classes, if their system was what the said it was, they'd all have them on their cars, don't be suck in .

Tom, I know your a big seller of their systems, and your mainly looking for what's the quietest system out there for the street, you've even offer to sponsor me with one of their systems. I think it was a great offer. So if anyone wants to inpley that I'm just bad mouthing their system I got news for you,
I'll take anything that's for free, but not if it's going to slow my car down!.

I'm not telling anyone not to run their systems, but I have many guys who have installed their systems under the impression they would run as fast as open headers, not one ever did, now if you don't care about running as fast as open headers go buy their system. One more thing this Walker set up I
have on the car now is actually quieter.... go figure.



[This message has been edited by Gach (edited 06-17-2000).]

Lou,
I do need to correct you in that I am not a "seller of anybody's parts". I work for Honeywell and have no part in any business. The benefit of this forum is that with all the facts, others can make educated selection of components.
Luckily, I have had the good fortune of being able to ask some manufacturers if they could help many folks, like yourself, willing to test things to help all find out what works and what doesn't. I am glad so many are willing to do so.
I hope you can address the questions I asked previously. What part number muffler did you have from them? They make several (as far as the catalog they just sent to me shows) and it looks as if some are vastly different. Which Walker muffler ended up being the best? Walker makes many and it good to see that you found some that are quiet enough to run. After your controlled testing, you did take into account that the weight by itself contributes to a reduction in MPH and an increase in the ET?" I imagine yours should have weighed at least 90 pounds. Is this pretty close? Can you share what power the engine has and also share some of the other contributing factors that affect the way it reacts with open vs. closed exhaust? Is it 300, 400, 500, or 600 HP? All these things matter for people that want to duplicate the system. Exhaust, like any other modification, (heads, cams, carbs, etc) are related to and affected by many other things. Unfortunately, your car did not act like most I have seen, read about, and seen tested. That is the way things go sometime. Thanks for providing the information. Can you still email the photos to me ([email protected])?
Tom Hand

Slobird,
To offer another answer to your original question, the X tends to smooth out the sound. In my opinion, it makes Pontiacs sound less like Pontiac/Buick/Old engines and more like higher winding Chevrolets. In every case we have used or seen one being used, they tended to get rid of the raspiness and choppiness and mellow the sound. Even on cars with Flowmasters that were sort of crackly, the X tended to make the sound less so. Many factors will control the sound, like compression and camshaft timing, etc., but mufflers will have a big impact. What sort of mufflers were you thinking about? We have many that have been tested over the last few years and maybe I can tell you which will do what. You are most welcome to borrow anything I might have that will fit or I can research the ones you are thinking about and see what others have experienced.
Tom Hand

Tom, when ever some one endorses a product, or offers a sponsorship of that product, in which that person has to perches the product. in order to offer a sponsorship, some were along the lines there has to be some personal gains, weather it's a free exhaust system, or money paid for writing an article. For the 2½ years I've been on this board, I've had many such offers, perhaps they feel I have some influence, that would help sell their product.

Testing is great, but it's only as good as the person doing the testing, an weather or not that person is bias towards that particular product because of some personal gains that person may have had ( the
question is how knowledgeable and what real life experience does this person have, and in what area's ) in other words do you consider yourself an expert in exhaust systems, and if you do what qualifications do you have

I've read your article's, I know there's allot of time an effort that not only goes in testing, but writing the actual article's, I also know you take great plain, making sure your results are as accurate as
possible. My guess is at the time you did your testing, other new products were not available for your testing or were not offer by that particular company. I also know you have spent allot of your time helping others with products you believe to work the best, for the particular results your trying to
achieve. As you know it's almost impossible for any one product to fit everyone's needs.

Now at the time you made your offer, I had already been a dealer for Dr. Gas, infact I was one of their first dealer's, an it was long before you were ever introduce to their product. I sold many of their systems, for many different applications, for out drag racing to street cars, I stop being a dealer after I had my expericene with their product not producing what they claim it was capable of doing.Sorry I can't an won't stand behide anything that makes false claims, I don't care how much money is involved.

We have heard many times on this board references to high dollar parts that or not needed, in my opinion their exhaust system fits that to a tee, my opinion of their system is this, it depends on what
application your intended use of the system is for , to me it's way over price. Does it work good, again it depends on what your looking for, is it the best system out there NO! it isn't. I've prove that on my own car, and on others. I stated in my response to this topic why I was unhappy with their
system, I think that's what this board is all about, giving one's personal experiences. I think its a waste of time, and board space for everyone who gives their experience to have to answer to a 3 page questionnaire, on weather or not their qualify to test some ones product ( I'm NOT their R&D man )
to me after spending the price for two of their exhaust systems, and following their instructions, it should produce results.

I'll address your questions ( what part number muffler did you have from them ? ). it was the part number they recommend, for my intended use.When that didn't work I was told that actually Walker mufflers work better. What kind of company after selling you theirs muffler, and after making claims that theirs is the best, later tells you, that it's not. I don't care how many part numbers they have in their book. I'm I surpose to believe that now some how you have all the answers. Sorry don't think so. You are also very well a were of what I make for hp, and what size my engine is, and how fast my car runs. I have answer those questions for you many times You also don't need any controlling test to know when a car will run a ½ sec. faster, imeatly after drooping that exhaust system. no one is
that dumb, taking off 90 lbs will not make a ½ sec. difference in ET. maybe 8 hundred's, but not a ½ sec. You also know by now Tom, after being on this board for two years, that I don't have to qualify myself, on weather or not I'm qualify on testing & tuning, you've seen me answer many questions.

Lou, Thanks for taking the time to explain yourself. I am glad to know that you have such a thorough background in testing and product comparison. It makes it much easier for your statements to be understood and comprehended. But, unfortunately, no, I do not know what power your engine makes nor do I know what car you tested the system on. As I stated, that is very important information to know but if you do not want to share that with others, that is quite acceptable. Thanks once again for taking the time to write the responses you did and also thanks to all the others that offered information to answer Slobrd's questions. I think when he takes into account all the facts and comments on this string of responses, he can make the decision he needs to make about whether the X-crossover makes a good sound or not on his 455 with 3" pipes and headers. Take care and Happy Father’s Day to all,
Tom Hand

Tom, we want to thank you for your expert advise in your product testing, it's well appreciated. I'm sure you've had many rewards from your testing for companies. I'd like to add one more thing on sound, our town has a local ordnance on the allowable decibel level, which is strictly enforce by our local police, who also ride around with decibel level meters. Mainly because of cars equip with loud stereo's. The Dr. Gas system would not pass, as one of the officers who describe the sound of the system said, it sounds like a jap bike going down the road.

I also want to thank Jerry Brock, for his response on how much Dr. Gas system increase his performance, and how much he like the sound, it's like I said in my response, it depends on what application your intended use is for, obviously he wasn't after the same results I was, an is very happy with his system.

I'm sure Slobrd, is pretty enough, smart enough....LOL... to decide on his own what he's after in a good exhaust system. We have to remember though when we respond to a topic there is a wide veraity of different interest, just as Jerry an I have stated on the sound quality, and performance
level. I'm glad to see Jerry didn't take offense to my response as I didn't to his, after all that's what its all about giving your opinions, and experiences so others can make their own judgment, but we do welcome some expert advise on product testing such as yourself. Oh what's the name of your
company Tom, what other companies do you do product testing for in the performance world.
I hope in the future you don't take offense to my response, I hate having to spend hours defending my
experiences.

WOW! Nice writing Gach, a HUGE improvement!

Gach, I have been thinking about having one installed on the 77, what car did you use it on? The reason I ask is My combo is close to what jim runs (462,230/240,and 9.6 comp). I intend to run mid 11's and low 10's on the bottle. You know the cost's involved so any help would be nice. If you used it on the GTO that would make a difference to me, because that makes a lot more power than my motor does. Again, good work on the spelling, Really.

David, I've used that system on quite a few cars, and a number of 400 motors as well as 455's.. I think it's a great system for a street car and a guy who doesn't care about turning good numbers. But if your after every tenth you can possibly get then it's not what the claim. We even made the system
so they could easily be take apart with flanges for our testing. I did state in my first response that I use it on my 70 GTO, as far as I'm concern they stroke me. Oh sure there impressive on a street car that's had nothing but a stock exhaust system, that is very restrictive to begin with, seat of the paints feel is going to impress the hell out of you. My opinion on anything that's going to make hp, and especially with the bottle is FOR GET IT! don't waste your money, unless you want to have drop your exhaust every time you go to the strip.

Tom, In the Aug 2000 PHR in the Tech section, there is a question that reads to the effect of: We are building a 9 sec class car that now has to run mufflers. They advise about lenght of pipe before the mufflers then Add this: "We also recommend running a balance(crossover) pipe when ever possible. In some racing app's this can be a real pain, but the gains are worth the extra effort". Things that make you go HUMMMM!

Dave, That sure matches everything I have read in my review of literature and seen in our testing. Thanks for sharing it and for the clarification.
Tom Hand

The October 2000 issue of Hot Rod Magazine has a great series on exhaust systems, including dyno testing of headers and crossovers. The material was prepared by Ray Bohacz and Terry McGean of the Hot Rod staff.

They used a typical Chev 355 engine with Trick Flow heads, 236/236 flat tappet hydraulic cam, 750 Demon, and a Performer intake, and the engine developed approximately 400 HP. A series of headers of different primary sizes were tested but as noted by the authors, the tests favored the larger diameter sizes as the dyno measurements didn’t start until 3000 rpm. As would be expected at that rpm and above, the larger diameter pipes tended to increase HP.

The more interesting results concerned the crossover pipe testing. We had seen some gains with our H crossover, and the same is true with the Hot Rod tests. The Hot Rod test results of the X crossover mirrored just what we found in our controlled testing at the drag strip several years ago. For example, at 3000 rpm, HP jumped from 219.8 to 231.2, and torque increased from 384.67 to 404.7. Peak HP was up from 397.2 (5700 rpm) to 402.9 (5800 rpm), and peak torque increased from 419.2 (4400 rpm) to 422.2 (4300 rpm). And at the maximum test rpm of 6000, the HP increased from 388 to 394.8, while torque increased from 339.6 to 345.6. And Hot Rod saw the same thing we did some time ago with testing we did at a dyno shop in California, and that was at some rpm points, the HP is slightly less with the X crossover then without. However, when the results are averaged, the X crossover provided superior performance as compared to no crossover or the H unit.

The author of the Hot Rod crossover tests noted what he called a "testing flaw" - they did not begin the tests until 3000. Based on the very large increase in power we saw reflected in our quicker 60’ times and ET with a tighter converter at the time of the tests, we agree with the author that testing at lower rpm would likely have shown even more gains attributable to the X crossover at the lower rpm.

In conclusion, I want to compare the testing results from Hot Rod to our tests done with our car at the track: Significantly quicker to 60’, significantly quicker ET, and some minor gain in MPH with the X as compared to an H crossover. The large gains in low and mid range power (but less gain at the top) in Hot Rod’s testing shows why our car reacted in the manner it did. In summary, the test results from Hot Rod tests clearly demonstrate that the Dr Gas X crossover, and other similar X systems, do indeed meet the customer’s expectations of more power and therefore more performance.

For more information on our series of exhaust component tests, look at the Pontiac Enthusiast article on Eric D’s site at http://www.wauknet.com/douthitt/exhaust.htm
Jim Hand

Jim, Gach,
I read this thread for the first time tonight - intrigued.

Some quick hits: I tried Fowmasters for about 1 hour on my 455/[Ultradyne 255/263 with 104/104 Lobe centers]: Sounded like a Chinook on takeoff! Had the fella weld on the Walker Sup-Dyn-Turb's and then the sound was manageable.

Jim, The exhaust config we discussed earlier this year was built-out and sent to Kauffmans. Dyno said better than manifolds, not quite as good as 4:1 headers, on a 300HP motor. Early feedback from Jeff was that my 1-5/8" piping was probably too small. I agreed, as it was all I could find. Still looking for the evalation on a 550HP motor. Glad to see you are equally discerning on the exhaust requirements for 500-700HP ponchos.

I need some 2" early-Bird headers to continue the development. I think it will bear fruit.

The X-cross ought to be better than the H-cross, as long as the system needs it. Probably good for equal 4:1 headers. My guess; not show benefit for Early 421-SD manifold, Tr-Y configs, or even the Long-Branch manifolds...My header config should NOT need it as I've timed the pulses as equally as practical.
My simulations showed that the Heads' exhaust crossovers are a real problem for Big-time charge contamination; Cyl 4 contaminates cyl 6 and Cyl 3 contaminated cyl5. Need to block cyl 6 and cyl 3 and run a straight-pipe under-Intake crossover. Practically speaking we'd all fully-block the heads crossovers for cooler running heads/engines.

How many of you'z guys are running low 12's or better, with open exhaust crossovers [worse-yet with sheet metal plates blocking it?


------------------
"his peg-leg got woodworm , and broke into three"--G. Baker

In the summary of the X Crossover testing done by Hot Rod Magazine, I neglected to point out that the X was tested using 1 5/8" headers. The test results listed above reflect the differences between the X and no X using the exact same 1 5/8" headers! More importantly, Hot Rod did the X crossover testing with mufflers and approximately 5 feet tailpipes attached!

The significance of the results? The added torque and HP generated by the X came despite have to work into an almost complete exhaust system! Again the Hot Rod tests confirm what we have found in that we can run a full "out the rear" quiet "X" exhaust system and run as quick/fast or better with the full system then with only open headers! Even though our full system weighs almost 80# additional, the X system with good mufflers generates enough extra total power to offset that weight and perhaps a bit more. So, all of the test results regarding characteristics and power production posted or described in various publications by Tom Hand or the writer have been duplicated by this Hot Rod documented dyno test series. Jim Hand

Way back at the start of this post Slobird asked about the Walker Race Magnum mufflers. You might look at their #17229, I like the fit. It's only 4 1/2" tall. Length is 14" and the width is 9 3/4". It's off-set 3"in/3"out.
As on most F-bodies the mufflers tend to hang, but these are much better than previous mufflers. I have used both Walker mufflers and Flowmater, everyone to their own taste but I got tired of the flowmaster 'tiny rattle' sound.
Also switched from a h-pipe to the Dr.Gas x-crossover. No way does it have a 'motorcycle' sound, but must admit the description stated as a 'higher winding sound' could be appropriate. The Dr. Gas slightly tamed the sound level down a bit, but then my car is not real quiet to begin with. We are using headers with 3 1/2" collectors, from them the exhaust is 3 1/2" mandrel bent tubing, includind the Dr.Gas X, to the Race Magnum mufflers. From the mufflers the tail pipes are mandrel bent 3" tubing from Torque Thrust. Except for the mufflers, the entire system is Jet-Hot coated.
Going down the track the car really sounds unique and very hard to describe, never heard another system quite like it.

Muffler Man's X Style Aluminize Crossover, In a controlled test done buy Hot Rod produce 23 more hp, and 12 lbs more torque. The system used 2½" Rhino mufflers. Their claim is that this X pipe system helps scavenging, and has a larger chamber at the center of the X, that deals more efficiently with exhaust pulses, which helps both scavenging, and eliminating resonance, which makes for a rich, rumbly exhaust note. Anyone wanting more information can call The Muffler Man at
714-524-7818. For more information on Rhino Mufflers call 262-334-4466.

I've love the sound of this exhaust system, I have a couple of friends who have installed Muffler Mans crossover system, makes a great street strip exhaust. There's no doubt in my mine that it produces more hp then other brand X crossovers, with a much better sound, and is noticeably quieter in my opinion, with better quality.

[This message has been edited by Gach (edited 08-26-2000).]

[This message has been edited by Gach (edited 08-26-2000).]

Okay .. I am geting ready to FINALLY put the exhaust system in and I have run into a slight problem.
I have the Torque Tech 3 1/2" collector, 3 1/2 x 3" Dr. Gas 'X' pipe, 3" pipes and Dynomax (Large) mufflers.
My problem is WHERE to locate the cross over. When I use the pipes as supplied by Torque Tech the cross over hits my drive shaft safety loop. Since I have to be wthin 6" of the U joint I dont have a lot of play.
Any suggestions? This can't possibly be a new problem!!!

While were on the topic of X-crossovers....
In addition to the brand Gach mentioned above there is also a 'X' style crossover manufactured by Supreme Auyomotive in Brooklyn, NY at 718-232-4646(www.members.aol.com/xforcefast).
They call it the X-Force crossover and claim crisper throttle response, smoother idle characteristics, and a noticeable decrease in exhaust noise. Here again, as with the others, they claim more horsepower to the rear wheels than true dual or even H-Pipe-equipped street machines and race cars.
Cost is around $110 each, and it's available in different sizes.
(F.Y.I. it looks just like the Dr. Gas X and probably like the Muffler Man unit that Gach mentioned)

71 Sport, They only way you can put this system in, is were you have room to fit every thing, there's not much you can do about that. I would call them first and ask were they recommend you install their crossover. Only then can you see if it's possible to install it were they recommend, you have no
other choice.

My 2 cents: Just ran at Island Dragway today.
Uncorked:12.11 @112.35
Corked with street tires: 13.30 @ 111.20
[32PSI Dunlaps spun the whole 60']
If I had known the corked MPH was going to be that good I'd have run corked with the slicks and had ET data.

Jim/Tom thanks for the Q-Jet rich-rod advise
Dgs to Ax's, and back to DGs because of the hot/humid and low barometrics at mid-day.

Next time out the first pass will be corked and slicks.

71 Sport,
I had the same problem when I installed the system on my 79 Lemans wagon. I installed the X, just behind the driveshaft loop. It is tight, but everything cleared.
My system is RamAir Restorations repop 2 1/2" manifolds, into 2 1/2" exhaust pipes, a 2 1/2" Dr.Gas X, into Walker # 17222 2 1/2" Race Magnums, and 2 1/2" tailpipes.All of the pipes are mandrel bent.
My car is a street car that I race for fun. I could easily put the car into the 11's by installing headers and removing my A/C, spare tire, jack,etc., but as Gach mentioned, taht is not why I built the car.
It is a handfull to drive on street tires, whenever you kick in the secondaries.
I drove the car to and from the track for many years (Maple Grove is just over 1025 mile round trip for me 95 and 96), until health problems prompted my wife to insist on trailering the car to the events.
I have had some lively discussions with Lou, on the exhaust system, and as he said, took no offense to his opinion. All I can say is it works for me, on my car.
Jerry

Lou, In what issue of Hotrod was that test published? What are the differences between Muffler Man's X pipe and the Dr. Gas X product? Are you saying the MM's X pipe is as good as open headers? Your latest posts seem a little contradictory to your earlier ones. Are you saying that the MM X pipe is worth that much HP increase with everything else being equal? I ( hopefully ) will be needing an exhaust system soon for the Firebird and I want what will give me the most horsepower.

------------------
Maurice

Lou, I know you're around I've seen you post on other topics. Don't you feel that you can come back and clarify some of the claims from your recent posts on this topic? Seems like a simple and fair request to me.

------------------
Maurice

Maurice,
I would like to provide the answers to some of the questions you poised above and also clarify some of the (mis)information provided in an earlier post on this X-crossover string.

To get answers to your questions, I called Rhino muffler’s technical information line and spoke to a knowledgeable gentlemen, Jay. Unfortunately, Jay was not immediately aware of any recent Hot Rod Magazine article concerning compariosns of a X-crossovers on a vehicle using their mufflers. After talking with him a few minutes, he did recall an installation done over a year ago on a 1970 Mercury Montego. Jay asked that we let him know what issue it was in so he could try to find it.

I then called The Muffler Man in Placentia, California to ask if they had information they could share with me about recent X-crossover comparison tests. I spoke to Tom, and like Rhino’s technical representative, he was unaware of any recent articles. However, he did recall the Mercury Montego article and offered to send us copies of the magazine article after he retrieved it from his files.

I spoke to Tom about the X-crossover he sells and he said that when the hole sizes in the junction of their products are similar to other manufacturer's crossovers, he would expect ALL of them to act similar. Like our past experience, Tom found that too small of a transfer hole between sides reduces the power gain and too large of a hole increases the sound level. We also compared previous test data and I told him we generally saw increases of between about 6 and 15 horsepower over H-crossover systems and he said they usually expect to see from about 5 to 12 HP increases. Tom also said that they do work on 600 to 750 HP California drag race cars and said he uses the X-style crossover to reduce the sound level and pick up the power.

After acquiring the article, I found that the power gains mentioned in the post you questioned were in reference to a complete replacement of the original single exhaust system that used log manifolds and a single 2 ¼" pipe muffler system. I’d like to share several quotes from the Hot Rod article: "Our mellow Merc still possessed the original exhaust system: 30 years in a Bay area garage had preserved it like a piece of beef jerky! While this meant factory levels of quiet in the cabin, it also meant severe exhaust-flow inefficiency- 1 5/8" manifold dumping into a single pinky-slim pipe". "We used equal length , long tube Hedman headers for our 150,000 mile 351C (1 5/8" primaries, 3" collector) and sent them to HPC in Utah, to get ceramic-coated inside and out." Hot Rod also used one of the Muffler Man’s X-crossover and Rhino mufflers. The pipe diameter was increased from the original 2.25" (single) system to dual 2.5" exhaust pipes and tail pipes. The power thus gained from this complete exhaust system change was "22 HP and 11 ft-lb of torque at the wheels". Here is another direct quote from the Hot Rod article which was printed directly under a photo of the Muffler Man X crossover: "Instead of a typical H pipe, we opted for one of the The Muffler Man’s X-style aluminized crossover pipes which was built in-house. The gentle bends of the X pipe help scavenging (no sharp corners to induce turbulence as in a traditional H-pipe system...), and the larger chamber at the center of the X deals more efficiently with exhaust pulses, which helps both scavenging and eliminating resonance. It also makes for a rich, rumbly exhaust note".

It should be noted that all X systems have a larger chamber at the junction due to the design.

Additioanlly, please note that Jim Hand commented on the expected power gain of similar X crossovers in his recent post on this subject, "In summary, the test results from Hot Rod tests clearly demonstrate that the Dr Gas X crossover, AND OTHER SIMILAR X SYSTEMS, do indeed meet the customer’s expectations of more power and therefore more performance."

So Maurice, to answer your questions, it was April 1999 Hot Rod, page 100, the "controlled test" article was about a 351C Mercury Montego with single exhaust that was changed to duals with headers, the power increase noted was gained by the complete exhaust installation, not just a specific crossover comparison, and the total power they found was a peak of 22 Hp and 11 ft-lb of torque.

I would expect the author that posted information regarding this test to answer your remaining questions. Please feel free to email me at [email protected] if you would like additional information.
Tom Hand

Tom, I want to thank you for going through all that trouble in trying to answer a question that was ask of me. You even took the time to fine the article "amazing". Nice having all that free time on your hands, I'll bet you spent some money on the phone not only with Hot Rod but with other exhaust
companies. I felt by posting those phone numbers I made it allot easier for you...LOL... hope I save you some money. Isn't it great to know there's other products out there, as Steve C. has also point out, ( Supreme Automotive in Brooklyn, NY at 718-232-4646 ) I'm really disappointed you didn't take the time to research the system Steve C, mention, but felt it important only to research Muffler Mans X crossover system.

Perhaps, I need to clarify my reason for posting my response to Hot Rods test of another brand of x crossover system. The purpose was to show that they do indeed produce more hp over stock type exhaust systems. I'm sure that anyone who has tired anyone of these systems will agree, their
perfectly happy with the performance of their system. I also agree that they do produce more hp over stock type, as well as H type systems, that has never been my argument. My other reason was to show that Hot Hot has also done articles on other x crossover systems, but what you won't see in any of those articles is the claim, that they are capable of producing more hp then running with open headers. That is the problem I had with one brand of x crossover, after a great amount of money, phone time, shipping cost, and count less hours of changing, pips, hangers, welding, jetting, timing, and track testing, under controlled conditions, it never produce any more power then open headers. I also want to state most are not looking for the same results, I was looking for, all I every did was state my experience I had with one particular brand.

Another point I want to make is this. how many times have we seen test or article's done by Hot Rod and other magazines, that are really in question, we all know by now that they tend to hype things a bit, or even have the wrong information, provided by the person selling his product or engine building
experience. My response just backs up the original Hot Rod test, and basically says that these systems are all about the same, sure out of the three systems, that were posted, I'm sure there's one that mite work better on different combinations, not any two cars are the same.

One thing that really troubles me is some of your statements you made, ooh I'm sure it was because things have been read into my post on " test results" that were taken completely out of contexts, it's under stand able if your a dealer for one particular product to try and defend what you believe to be
a good product, but I never made these statements ( recent Crossover comparison tests.) I never said it was a comparison test done to compare other crossovers systems, and I'm really disappointed that you Tom of all people would try and read into my post things that just aren't there.

As far as I'm concern this is my last response to this topic, it's gotten way beyond being petty, let people take all this information, and judge for themselves. I will not answer questions from anyone who has taken my response out of context, nor will I respond to anyone who is deliberately trying to invoke a pissing contest to help set up another response, for the sole perhaps of trying to create an argument. that in the end results is totally meaning less.

I want to thank Jim, and Tom Hand for taking time out of their busy schedule, and providing us with all this imformantion. Great job guys.

Tom, thanks for posting the information regarding the X-pipe test. That will certainly clarify things for me when I'm ready for my exhaust system. I suspected that there was no miracle system out there anywhere. That when compared on an equal playing field they were all about the same!!!
It is refreshing to see straight forward test results posted without the extra insinuations and attempts to mislead. It is unfortunate that we have to wade through claims and allegations to get to the facts.I didn't inquire about the Supreme Automotive system as there were no unusually high HP gains claimed. If you will notice the claims for the MM-system and against the Gas-X system you can understand my confusion. Way back on post 10 it was stated that Gas-X supposedly claimed to make a car "run as fast as open headers" then on post 17 the claim changed to " make more HP than open headers". On post 32 it was stated also that " there is no doubt in my mind that it (MM-X pipe) produces more HP than other brand X crossovers". Well, I am just appreciative Tom that the record was set straight!! Thanks again. .... Maurice

[This message has been edited by Maurice Hood (edited 09-02-2000).]

To the board: there are several statements above about Jim and Tom Hand’s role in our exhaust system testing program that requires some clarification. At the time several of these comments were made, both Tom I were serving as Moderators by request of PY. As Moderators, we were asked to not respond to some of the material posted in order to maintain a good image for PY. We agreed.

However, with the change to no moderators, we have been assured by PY that we now have the same posting privileges as ALL OTHERS on this board, so I wish to comment on several selected statements that appear above in this thread:

"Tom, I know your a big seller of their systems,"

"Tom, when ever some one endorses a product, or offers a sponsorship of that product, in
which that person has to perches the product. in order to offer a sponsorship, some were
along the lines there has to be some personal gains, weather it's a free exhaust system, or money paid for writing an article."

"I'm sure you've had many rewards from your testing for companies"

"it's under stand able if your a dealer for one particular product to try and defend
what you believe to be a good product"

1. We are not nor have we ever been "dealers" for any product, exhaust or otherwise. We do have access to lower costs from several companies for test purposes, but any material we have "bought" has been forwarded to the eventual user at our cost or even less!

2. If the writer of the above was inferring that we have gained monetarily from our test program, that is pure Bull Manure. We have spent far more in wear and tear on the test vehicle, fuel costs, shipping, and telephone costs then we have ever been paid for any aspect of the test program.

3. If the writer of the above was inferring that we have gained valuable knowledge and experience from our extensive testing, that is dead accurate. We now know how most of the available products work and are able to select the best parts for our own use. Additionally, we are able to help others with their selections.

4. If the writer of the above was inferring that we have made a lot of good contacts in the exhaust industry, have access to the latest product information, and are able to make technical presentations to others with the support and knowledge we now have, that is also dead accurate.

We made a technical presentation September 10 to the Regional Meet of the POCI in the Kansas City area, and were able to display and explain a variety of exhaust products we have gathered over the years, as well as demonstrate with a real car and a real exhaust system how certain of the products sound. As a result of review of some of the recent misleading posts on this thread, we ran across a relatively new muffler, and the Mfg asked us to run them on our test vehicle to compare against presently available quality mufflers. The companies that we have worked with over the years know that we are capable of presenting accurate and verifiable test data with no bias towards any product, and they will provide new products for testing. Depending on the test results, the mufflers will then be forwarded to others for use or testing, may be kept for display for future tech presentations, or may be given away as door prizes at Pontiac events. As any exhaust product becomes useless for resale after it has been run, seldom do the Mfgs want us to return the test material although we always offer to do so.

In summary, the testing we have done and that has been presented in HPP, the Pontiac Enthusiast, and Popular Hot Rodding pretty much speaks for itself, so if any have any questions about our approach, abilities, or bias, please take a look at any or all of those technical presentations. Jim Hand

Thanks for pointing out the differences between the two magazine articles. One would expect at least a 22 HP gain going from a restrictive single exhaust to a performance level dual exhaust system. The tireless work and painstaking documentation will pay off for the Pontiac enthuisiast who wants a performance exhaust system.

Thanks for the help, unbiased technical information and comparisons.

Ron

Jim, many thanks to both you and Tom for your hard work and dedication. I'll be talking to you soon about that new exhaust system. Thanks..... Maurice

Jim & Tom,
Could you please summarize the complete, present Exhaust system on the wagon that works?
[I haven't subscribed to a glitter mag since 91, so this thread is it]
Include status of head cross-over blockage.
manifold/header type, headpipe details, X position, muffler model, length, tailpipe dia.
Thank you,
Half-Inch Stud

To Jim and Tom Hand,
Thanks for the Performance Seminar at the Show Me Region POCI Show on Sept. 9&10. It was great to see the wagon run the numbers at KCIR on Sat. and then get the tech info about the hardware/setup Sunday on the show field.

As this thread has gotten long and time consuming to access, have started a new thread called "Exhaust Systems" and have described the complete system we run. Jim Hand