[slobrd]

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]

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

[old gto]

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!

[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.

[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.

[Tom Hand]

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

[Scott Horton]

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.

[T Hutchinson]

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.

[David Holmberg]

WOW! Nice writing Gach, a HUGE improvement!

[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).]

[Gach]

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.

[Mark Leischer]

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

[Tom Hand]

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

[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.

[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!!!

[Maurice Hood]

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).]

[slobrd]

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.

[David Holmberg]

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?

[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.

[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)