New 3" exhaust with 2.5" Tailpipes

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CMCE

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Pypes has come out with a new 'Hybrid' X-Pipe system where the system is a true 3" up to the outlet of the muffler, then it's 2.5" tailpipes. It's designed for cars in the 600-750HP range and eliminates the fitment problems associated with 3" tailpipes. Three different mufflers are offered and the mufflers are 3" internally up to the 2.5" outlet.
Pypes - Classic Muscle Car Exhaust
 
That is a great idea and should be perfect for many applications!
Tom
 
Been running that setup for years had it custom made for the duster sounds awesume!!
 
3" All the way ... Been running this on my Cuda since the 80's



69'Cuda Unmothballed 12.1.19-1.jpg
 
There are certain models from Ford, GM, and Mopar that struggle with fitment issues when it comes to 3" tailpipes, and Pypes is the first manufacture (to my knowledge) to offer this 3"-2.5" combination. So far they've come out with 65-70 & 71-73 Mustang, 65-70 GM B-Body, 62-67 Nova, and of course the Chrysler A-Body. I'll keep you posted on any new applications that they come out with.
Classic Muscle Car Exhaust
 
Someone posted about 3” into 2” a few weeks ago. I think that is too drastic but 3-2.5 might actually help. Seems Engiine Masters did a test like this. Dont remember the results.
If air expands when hot then it makes sense the in contracts when it cools and wont require as much volume . It would be a interesting experiment to place temp sensors at various points of the exhaust to see how much it cools.
 
On my Dad's low 11 second big Pontiac wagon, he ran 2.5" tailpipes from day one with a 3" front section and at 4200 pounds, it ran 118 mph and did so very quietly. It is ball to drive on the street and the track.
 
Someone did do a test using an Infrared thermometer from the header tubes to the tailpipe. Wish I could remember the numbers but there is a dramatic drop in temperature (and density) by the time the exhaust gases reach the tailpipes. You can't touch a header tube, but you can touch a tailpipe without getting burned. I'll have to find that article, or better yet, do that test myself.
 
Actually, we did the tests and we did it with fast reacting high temperature thermocouples mounted in the pipes. Dad was driving and I was gathering data one hot summer day. We took a lot of data.

Tom

and
Someone did do a test using an Infrared thermometer from the header tubes to the tailpipe. Wish I could remember the numbers but there is a dramatic drop in temperature (and density) by the time the exhaust gases reach the tailpipes. You can't touch a header tube, but you can touch a tailpipe without getting burned. I'll have to find that article, or better yet, do that test myself.
 
i've always went 3" to the bumper but they say 3" to 2 1/2" is supposed to be better. the exhaust cools as it goes back and the smaller pipe keeps it flowing better. thats what i've read anyway..lol
 
From my draft in 2002 or so. We even tested 2.25" tailpipes

Exhaust and Tailpipe Testing


For these tests, the performance of Torque Technologies’ mandrel-bent 3.0” pipes with an H-type crossover and 3.0” inlet and outlet Walker 17773 Dynomax mufflers feeding 3.0” tailpipes was compared to 1) open headers and 2) a system consisting of the same 3.0” pipes and mufflers but with 2.25” tail pipes. The goal was to see how much the size of the tailpipe affected a typical 455’s performance. Additional tests were made of the system’s backpressure and sound. Pressure taps were installed in four locations on the system and the backpressure (in inches of water) at wide-open throttle was measured. The sound levels were measured with the engine held at 2200 rpm and the sound level meter was mounted on a tripod 25 feet away from the outlet of the exhaust. The performance tests were run at Kansas City International Raceway and all weather and track conditions were monitored to insure consistency. Temperature measurements were taken at various locations on the system to determine the effect, if any, of running the smaller diameter tailpipes. Fast reacting temperature probes were positioned in the same locations used for pressure measurements and the exhaust gas temperatures were monitored.

Exhaust and Tailpipe Test Results

Surprisingly, the smaller tailpipes did not hurt performance as much as expected. The temperature measurements taken at various locations on the pipes offered one solution. The measurements indicated that the exhaust gas was cooling significantly before reaching the tailpipes. Heat energy is lost because the large diameter exhaust pipes and mufflers (having a lot of exposed surface area) dissipate it. This heat loss causes the volume of the gas to be reduced enabling smaller diameter tailpipes and, in some cases, a smaller muffler to be used without increasing backpressure. [Insert figure. Figure 12 shows the results of temperature testing.]

To verify that the heat loss and its related volume reduction really lower backpressure, another test was performed. The Walker 17749 Dynomax mufflers were used and moved between a front and rear location. The backpressure at the collector was measured and recorded. [Insert figure. Figure 13 demonstrates how the backpressure dropped when the muffler was moved from the collector to the “traditional” location in front of the rear axle.]

[Insert figure. Figure 14 shows the results of the drag strip performance tests.] From these tests, note that the 3.0” diameter Torque Technologies system with the 3.0” Walker 17773 Dynomax mufflers produced performance essentially equal to properly tuned, open headers. The other tests demonstrate that the use of 2.25” diameter tailpipes causes only a small reduction in performance on this particular combination due to the large amount of heat dissipated from the exhaust gas before it reaches the tailpipes.
 
A was right out of the headers, B was in front of mufflers, C was out of mufflers, and I think D was at end of tailpipes.

fullsizeoutput_5197.jpeg
 
Now THIS is what I call useful information! Thanks so much for posting this.
Thanks!

If only you could find Jim Hand's Pontiac book from Car Tech, you could see all he tested and all I wrote about in the exhaust sections. Dad wore the track out testing and I miss the fun we had doing it all too.
Tom
 
Three different mufflers are offered and the mufflers are 3" internally up to the 2.5" outlet.
Pypes - Classic Muscle Car Exhaust
For these special hybrid kits, only the Race Pro is offered. It's the perfect muffler for high HP applications as it flows the best yet is also the quietest. If you have a motor that warrants this system, I doubt you want to be any louder than what you will hear from these mufflers. The Race Pro is literally identical to the Magnaflow, DynoMax ultra flow and Xlerator mufflers. Same design.
 
For these special hybrid kits, only the Race Pro is offered. It's the perfect muffler for high HP applications as it flows the best yet is also the quietest. If you have a motor that warrants this system, I doubt you want to be any louder than what you will hear from these mufflers. The Race Pro is literally identical to the Magnaflow, DynoMax ultra flow and Xlerator mufflers. Same design.
Huh? It says right on their website that there are three different mufflers to choose from and even has a drop down menu to pick which one you want.
 
Huh? It says right on their website that there are three different mufflers to choose from and even has a drop down menu to pick which one you want.

Yeah exactly. Summit lists all three versions as well.
 
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