[JSPONT]

I think torque converters rob a little bit depending on what you have. A stick shift car will put a little more on the dyno, but can be slower at the track. That's why no one races dyno's. (except in the race section here! LOL)

[Formulajones]

Originally Posted by Lee

You went from one transverse system to a different transverse? What is the best ANYONE has ran with a transverse? Every time I've heard of somebody going from transverse to a quality true dual, they have gained performance.

I refer back to my testing earlier this year, documented at http://forums.maxperformanceinc.com/...d.php?t=814803
This was a very mild motor. Very low compression, mild cam, un-ported heads, Performer intake, Q-jet. HP peaked at just 4500rpm.

Yet a full 3" exhaust made a rather significant increase in both HP and TQ, I doubt my motor would break 350hp at the flywheel, yet the exhaust made a substantial difference in performance.

With a similar exhaust system to my own (and giving the EFI computer time to re-learn) I believe FunRide's car will gain AT LEAST 30rwhp, maybe closer to 50.

Little more going on there.

For starters, the PS rules dictate a stock style exhaust system must be used, with the only exception allowed is upgrading to 2 1/2" pipe.

In other words, my 70 Formula has to maintain it's transverse system.

The other factor I was getting at was the muffler itself. The Flowmaster transverse is still a large case chamber muffler, the same muffler everyone says kills HP.
The Pypes transverse is actually a dual muffler system in disguise. If you look at it's design, each pipe is a straight through design and separate from each other, with it's own packing, it's just wrapped up in a single case package. Each pipe continues as it's own. It's not even close to being like a real transverse muffler system, yet it's in a transverse package that provides excellent ground clearance on these vehicles that were really never designed to have mufflers hanging off the floor boards.

As far as how fast people have gone with it??? I've seen quite a few in the 10's at 125+ mph. It's an excellent transverse system. However at our power level (1funride and myself) it's not worth anything over the Flowmaster transverse. Been there done that.

Would it pick up with a 3" system??? Maybe, but rules dictate 2 1/2" in my case. Besides that, it wouldn't be an honest comparison between mufflers if the pipe diameter was change too. 1funride isn't going to see any gain with the exhaust system whether he sticks with transverse or a dual muffler setup, unless he increases the pipe size. My car is an excellent example of that with about the same power level.

[Lee]

^ He is not competing in any class that I know of, so no reason to NOT increase pipe size, and gain power.

[mchell]

Originally Posted by Steve C.

And two interesting articles related to the subject.....

Dyno Thoughts and HP Losses

http://www.sdsefi.com/techdyno.htm


Comparing Chassis and Engine Dynos – Racing Dynos

https://www.hotrod.com/articles/1106...-engine-dynos/



.

Bingo.......good reading

[scott70]

Originally Posted by 1funride

The engine feels strong than the numbers show. According to my 1/8th mile runs it should be high 12s in the quarter. Results of course that was a chassis dyno with 25% loss in driveline and with all the accessories and fan connected. I think they rated the old cars without any accessories.

So what was your 1/8th mile et and mph?

[prostreet64]

The op has sparked a fun discussion, and I agree with the comments that sometimes we get too hung up on the dyno #s. My 79 T/A has never been on the dyno but I might give it a go just to see what it reveals as to dyno vs track. The Olds 403 in my car is nothing fancy; stock crank and rods, hyper pistons, mild HFT cam, 226/233 with 1.65 rockers and owner ported heads. C.R. is at 9.4:1 and 93 octane is more than enough. Other details in my sig. Power steering belt stays on even for 1/4 mile passes. Anyway, car will run 12.20s in the heat and has gone 12.01 in good air. I did spend some time doing some things that I would classify as 'blue printing' but nothing beyond the basics of ring gap, bearing clearance, etc. I haven't changed anything on the car or motor for years and it just keeps on ticking. I think your combo is/ will be a blast and offer plenty of fun and performance as you tweek the variables. Good luck.

[brodad]

My brother worked at an import tuning shop and they called their dyno “the heart breaker”. I saw many people show up with import and domestic engine combos expecting big numbers and get disappointed by the results. Like it was said earlier a great tuning tool.

[Formulajones]

Originally Posted by Lee

^ He is not competing in any class that I know of, so no reason to NOT increase pipe size, and gain power.

I agree, but that wasn't the point of my post. His concern, or maybe he's led to believe, his exhaust is really holding the combo back. I have a ton of experience with these transverse systems with my own personal testing and felt it needed to be pointed out that what he has, isn't that terrible and is enough to support his power level. The fact that I can install better flowing muffler setup along with an X-pipe and gain absolutely nothing shows that the Flowmaster system is capable of supporting his RWHP level, and then some, because mine was actually a bit more HP.

I'm actually in the low 300's for RWHP at this point and haven't touched the exhaust. I feel he'd be spending a large chunk of money chasing HP with an exhaust only to be disappointed. Especially considering 3" on a 1st gen isn't fun to fit either and opens other issues.
I'd be more concerned with straightening out the rich AFR he says it had first. Depending on how much fuel trimming is needed he may find 5-10 HP right there. But quite frankly, like I said earlier, I've seen other Pontiac 400 builds on the dyno that also were in the 270-280 RWHP range so I don't see any real big concern. Take it to the track. Depending on what it weighs (1st gens are relatively light) his HP level should give him some easy low 13's with decent conditions. That's doing pretty well with a mild 400 Pontiac.

[highway star]

Remove the flex fan & install a clutch or electric, less parasitic drag.

[steve25]

Improvements to go faster you ask?

Rotating mass wherever it's found on the car just eats up HP like it's going out of style, be it in the mass of the Rods, Pistons , Crank and flywheel , or the rims tires and brake drums on the car and is many times overlook looked for shinny new 320 plus cfm ported heads and big Carbs!

[1funride]

Working from memory but if I recall about an 8.3ish and 83 mph, my 60 foot times were terrible with wheel spin. Had a nitto 555 tire on there with posi, the tire just wouldnt do much. Best run was very 1st when the light changed and I wasnt ready, I just hit it and it actually did OK. I think the tires actually degraded past the 1st run, but of course since the first run seemed to grab I tried to load the converter a bit, that resulted in smoking the tires and having to pedal it. Then it became loading the converter some, take off and getting out of throttle when inevitable tire spin started, then back into it partially, then full throttle. I gave up on trying to get a clean pass as it just wouldnt hook up, and in some instances I spun through the first 2 gears and the car started going sideways. The tires generally restricted my passes to 80 ish mph and just wouldnt allow more power to be applied/

[prostreet64]

Those 1/8 mile #s could be 12.80s in the 1/4 and with decent traction who knows how well it might run. Nothing more frustrating than having the power but not being able to put it to the ground.

[Navy Horn 16]

Originally Posted by 1funride

I agree its time for a new exhaust any recommendations?

Doug's Header's 3 inch gate cutouts...who cares what you have behind them.

30 extra hp with a flip of a switch.

[1funride]

I am having a nasty resonance with the flow master transverse muffler at 40mph. I am thinking of changing it for just that reason, at times I like it, but most of the time now I either slow down or speed up to get past it. I seen several flow numbers for flowmaster vs other mufflers, and the flowmaster look to flow much less, in some instances less than 50%. Hard to believe it can be that bad. The ultra flows seem to flow exceptionally well, but I am a little concerned with true duals fitting without scrapping as my car sits lower than stock. I didn't know how the Pypes transverse muffler flowed with the race pro muffler, which seems to be closer to 2 single pipes in a single package. I like the ultra flow dual setup.

[Formulajones]

Originally Posted by 1funride

I am having a nasty resonance with the flow master transverse muffler at 40mph. I am thinking of changing it for just that reason, at times I like it, but most of the time now I either slow down or speed up to get past it. I seen several flow numbers for flowmaster vs other mufflers, and the flowmaster look to flow much less, in some instances less than 50%. Hard to believe it can be that bad. The ultra flows seem to flow exceptionally well, but I am a little concerned with true duals fitting without scrapping as my car sits lower than stock. I didn't know how the Pypes transverse muffler flowed with the race pro muffler, which seems to be closer to 2 single pipes in a single package. I like the ultra flow dual setup.

Correct. The Flowmaster claimed flow from various sources never looks good compared to other mufflers, but in this case I didn't find it to have any affect. Like I mentioned I swapped to the Pypes setup and the car gained absolutely nothing at all. The Pypes transverse system is in fact a straight through design. The pipes are separated from each other inside that transverse case and have continuous flow through each pipe. If you'll notice in the design, the driver side inlet enters and exits the top, the passenger side enters and exits the bottom, they both go straight through just like their dual Race Pro mufflers. Not like a typical transverse where the inlets enter the bottom and exit the top side, so the pipes are basically intertwined and don't flow well in that style. So technically speaking, if the Flowmasters are so terrible, I should have seen some sort of gain just from the muffler upgrade, but I didn't. This tells me that at this power level it's not making a bunch of difference.
So the Pypes transverse from my experience will typically work just as well as a dual muffler system, because that's essentially what it is, and without all the ground clearance issues.

Getting back to your drone issue, I found the same thing with that Flowmaster American Thunder transverse setup. They are exceptionally loud. Years back they also offered the same thing called a "Force II" that used a quieter muffler with more chambers. I've run both systems and the Force II was much quieter and didn't drone. That's the last system I had on the bird before I switched to Pypes. Unfortunately Flowmaster cancelled that system many years ago and now only offer the American Thunder, which technically should flow a little better than the Force II I was testing with.

[1funride]

Formulajones, yeah I think your correct. It seems logical that the Pypes (RacePro) would flow better as you have a congiguous flow rather than all the changes in direction and waves/turbulance hitting one another. There is a point where all that begins to play in and you loose power, for me I think a new exhaust is needed, I dont mind it louder on outside of car but the inside droning is terrible.

I "think" the Pypes Race Pro muffler would also flow better than the Dynomax transverse muffler, as it appears the dynomax transverse muffler is similair to an X pipe and there would be some wave fronts hitting. If someone disagress with this logic and has real world experience please let me know otherwise.


Im going to throw out a few more questions in general.

* Max HP limit of Pypes Race Pro 2.5" transverse systems before it restricts, I estimate 450 simply becuase it's a 2.5" system?

* Does anyone have real world experience/opinions with the Pypes Race Pro transverse muffler as compared to a true 2.5" dynomax ultraflo system with seperate mufflers? Just not sure if I can fit a true dual system in a lower sitting Gen 1 firebird without scrapping.

* Opinion on Tom Hands prior system which I beleive was 3" out of collectors, 3" through the X-Pipe, then reduced to 2.5" using flowmaster cone reducers, then 2.5" into and out of a Pypes transverse muffler?

[Formulajones]

There are limits but I've seen several of these Pypes Transverse systems on 10 second cars. There are quite a few of them in the FAST series as well running 10's and mid to upper 120's on F-bodies.

Yes my feeling is the Pypes race pro transverse flows better than the Dynomax. I've used the Dynomax too, but no testing with it. But I do like that muffler better for it's sound qualities.

I've also run the dual muffler system in 2 1/2" as I mentioned, it was no better than the Pypes transverse. Not at our HP level anyway. However if you go changing the pipe sizes you may find something. Only problem is though, on a 1st gen, and even a 2nd gen, the 3" stuff is a tight fit. It doesn't tuck up into the driveshaft tunnel very well, which in turn makes the mufflers hang even lower, plus the muffler cases are larger because of the larger pipe diameter, then snaking 3" pipe through the leaf springs back there becomes a challenge. They almost always create tire interference as well when it comes around the gas tank. Some aftermarket gas tanks are notched here just for this purpose.

The only kit I've used that I really liked in 3" for a 1st and 2nd gen is Torque Tech. It actually fit as well as could be expected, But they are no longer in business unfortunately.

My father runs something similar to what you describe on his GTO. He runs a 3 1/2" off the header collectors, and into a Dr. Gas "X" pipe that reduces the pipe to 3" coming out of the "X". That's the best way to reduce pipe size. Then he runs a typical 3" A-body system from there with race mufflers and tail pipes from Torque Tech. Actually a very quite system in the car, no drone.

I've done other similar things. For instance on our Z I run the Pypes transverse system but I wanted a stock appearance out the back so I substituted the tailpipes for factory 69 Z tail pipes in 2". Reduced coming out of the transverse muffler. Not only did this give me a factory appearance but it did a couple other things. It freed up a ton of room around the gas tank and leaf springs, it also allowed me to use the factory tail pipe hangers, and it also mellowed the sound of the Pypes system to a point where my wife is very happy with it. Yet it's highly doubtful the change cost any measurable HP because you're at the very end of the system where pipe size isn't critical, and it's only a short section of about 1 1/2 feet of pipe with very little bend in it.
There are tons of options depending on the sound level you want and how much work and money you can tolerate. But from my experience it's not worth spending the money if only chasing 5-10 hp. Unless you jump up in pipe size and want to deal with all those issues, then I think you'll find some gain. I have tons of sound clips with examples I've mentioned but it doesn't sound like that's what you're after.

[1funride]

Formulajones, I am absolutely interested in sound clips, if you have a means to share that isn't too much work that would be fantastic.

[Skip Fix]

Originally Posted by mchell

Don’t get too into trying to compare your numbers with “what others” are getting .....it’s a dyno.......every single one will produce a different number....best to get it to the track if you want to judge your real world power... the guess will turn into reality.....and frankly, that may be a disappointment as well....sound like a decent build, have fun with it

What he said same goes for engine dynos. My RAIV 400 with a 288/296 UD made 385 engine HP on a very conservative dyno through headers and mufflers and ran mid 12s @ 109 weighing 3900 lbs. My 455 made 400 rwhp and with some tuning at the track ran 10.90s @124 weighing 3750. Current pump gas 455 made 525 HP on a Stuska engine dyno runs the same as previous 455 and formulas show more like 550-570 hp engine HP.

[Formulajones]

Originally Posted by 1funride

Formulajones, I am absolutely interested in sound clips, if you have a means to share that isn't too much work that would be fantastic.

Here are 3 examples of the Pypes transverse directly behind, cruising inside the car, and from a distance going down the dragstrip in our Firebird. I used the 2 1/2" tail pipes it came with. This engine makes very similar chassis dyno numbers that your car does and ran a corrected 12.78 at 106 with a 3850 race weight. This is the car I started racing 25 years ago with the stock Gardener exhaust, switched to the Flowmaster Transverse system and picked up a half second and 4 mph, then switched to the Pypes transverse thinking the muffler and "X" pipe improvement would get me something. The car gained nothing. Like I was mentioning before, it's just not at a power level where it cares what muffler is on it. Once I upgraded from the Gardener, which was also a pipe size increase with mandrel bends, the car came alive, but after that it didn't care what brand system was on it. A pipe size increase from 2 1/2" however might gain something. But, no one makes a 3" transverse system that I'm aware of, and even if I weren't playing within rules on this car I wouldn't do 3" anyway. Especially with a dual muffler setup. The car sitting at stock ride height is low enough as is. We daily drive this and the Z, and speed bumps and driveways are knarly around here. The transverse system is a must on these cars for us.

https://youtu.be/uIFkggwDY-8

https://youtu.be/lCmw-yDq73s

https://youtu.be/er1z7PpqsnY

Here is my wifes Z. Using the exact same Pypes transverse exhaust.

This is with the 2 1/2" tail pipes supplied.
https://youtu.be/5dTNw93VPEQ

Here it is with 2" factory tail pipes from the muffler back. Tamed down the deep rumble but the most noticeable difference was inside the car.
https://youtu.be/IZ0HlEY7b74

Here we are cruising Route 66 going 65 mph and 2800-2900 rpm. Can hardly even hear the engine running. Tailpipes made all the difference in this one.
https://youtu.be/7a3lMwoM-7c

Here's a ride along in my fathers car with a custom exhaust system that consists of different manufactures. It's 3 1/2" off the collectors into a Dr. Gas "X" pipe. the "X" reduces on the back side to 3" into a pair of very small 12" long race mufflers (forget the brand at the moment) and into a pair of 3" torque tech tailpipes. Inside the car it's extremely quiet with no drone, and does a surprising job of keeping his 571 at a tolerable level.
https://youtu.be/YYoXURd5rM0

Here's a shot outside, and at full throttle it makes some noise out the back, but compared to the ride along above, it's amazing how quiet the car is inside.
https://youtu.be/Ah_LjF_Sxow

Here's another Pypes transverse I did on our Ventura with a rowdy 10:1 406. Left the 2 1/2" tails on this one. It made some noise behind the car but cruised very nice with no drone. This is the car that had a true dual exhaust system on it in 2 1/2". I didn't like how the mufflers hung below the floors so I ripped that off and installed the Pypes transverse system. There was no improvement (or loss) in performance with this car switching from true duals to the Pypes transverse system.
https://youtu.be/47HgejCVbFs