Looking for 2.25" crossflow muffler

Steve Hoelscher said:
Ulix, one thing to remember when sizing exhaust and mufflers; stepping up the ID in the pipe after the collector is not a good idea. It stalls the velocity and raises the back pressure. Velocity is good which is why its easy to oversize the primaries and collector. There is one exception to that rule and its the Burns Stainless "merge collector". This is a carefully designed and sized expansion chamber immediately following the collector. Its purpose is to create velocity through the collector. It works well but does require careful design for the principle to work properly. http://www.burnsstainless.com/mergecollectorsmain.aspx
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Steve, you mentioned you'd gotten good torque after lots of tuning of lengths. How did your lengths compare to the Guy Croft numbers quoted here by coopertl?

I'm planning a similar project as Ulix here, but using merge collectors from Burns. Hoping to do some modeling with them soon.
 
I think I posted this a long time ago but this was my solution with a slightly modified IAP/Vicks header. Probably not useful for a 74 I guess. Pretty sure it was 2.25 out
 

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MarkF said:
I think I posted this a long time ago but this was my solution with a slightly modified IAP/Vicks header. Probably not useful for a 74 I guess. Pretty sure it was 2.25 out
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Very nice Mark. Do you recall what muffler you used ? Kinda looks smaller than the Camaro muffler most folks use...
 
rx1900 said:
Very nice Mark. Do you recall what muffler you used ? Kinda looks smaller than the Camaro muffler most folks use...
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According to my order from 2009 (!) It was an AP Mufflers 700069, intended for Camaro/Firebird among others. I found this diagram for that model and if seems about right if memory serves. I'd go measure but my X is half a state away :(
 

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Hello Ulix! Excited to see some numbers on your 1.9 with the 4-2-1. I am thinking that drive ability will improve. I am still in the process of installing my 44 DCNF's on my 1.9. I am currently running the Vic long header and noise can muffler all in 2" and will dyno again with the 44's this spring. I am thinking I need the same set up you will be running with the exception that I need a right side exit. Amazing engine as you will soon see. 136 hp on rolling road.
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Mezzanine said:
Steve, you mentioned you'd gotten good torque after lots of tuning of lengths. How did your lengths compare to the Guy Croft numbers quoted here by coopertl?

I'm planning a similar project as Ulix here, but using merge collectors from Burns. Hoping to do some modeling with them soon.
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I no longer have the notes from those tests. I saved them but they were on a computer that got stolen from my rental car several years ago. I didn't have that computer backed up. Lesson learned. I now have everything on my computer backed up via dropbox.

However.... I could go measure the exhaust. Its in my garage as I right this. :) I can probably do that this weekend. Without even looking I can tell you that the primaries are longer than those quoted by Guy. I should note that what Guy has listed is very close to what I have on my MR2. Its important to note that the MR2 engine is a much more radical build. Its a 4AGE, 14:1 static compression, JE forged pistons, Crower Rods, 300 Degree cams, TRD valve train and 43mm Individual Throttle Bodies. The motor makes power from 6500 to 9000 rpm.

The system on my X started life as an IAP header. I then bought a kit from Stahl along with a range of collectors and bends of various lengths and sizes. I learned a lot in the testing; like the IAP collector is a big restriction. About the only thing left from the original IAP header is the flange that bolts to the head. The casual observer might mistake it for an IAP but it is certainly not. Closer inspection makes that obvious.
 
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