[Gach]

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.

[Tom Hand]

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

[Gach]

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.

[David Holmberg]

WOW! Nice writing Gach, a HUGE improvement!

[David Holmberg]

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.

[Gach]

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.

[David Holmberg]

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!

[Tom Hand]

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

[Jim 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

[Half-Inch Stud]

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?


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

[Jim Hand]

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

[Steve C.]

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.

[Gach]

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).]

[71Sport]

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!!!

[Steve C.]

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)

[Gach]

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.

[Half-Inch Stud]

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.

[Jerry Brock]

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

[Maurice Hood]

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.

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Maurice

[Maurice Hood]

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.

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Maurice