pipe diameter

[badassmav]

I'm modifying the exhaust system on our race Maverick. I've chosen baffle-style mufflers to help provide a bit of back pressure, but am looking for advice on secondary tube diameter and configuration. The stock head pipes (which I am retaining) are 1.720" i.d. One is estimated at 36" long, and the other 12" long. I know a larger secondary pipe will give me more top end, but is 2" x .065" wall too big considering the stock engine w/no porting mod's? Will it slow the velocity down too much as not to create a low enough pressure difference for scavenging behind the exhaust pulses?
Also, space constraints make it near impossible to match the overall lengths of the 2 pipes. I am however able to "y" the 2 together briefly (for scavenging effect) just before separating them again on their way to their respective mufflers. Will this "balance" out the indifference in pipe lengths?
No guesses, please. I really need advice from an experienced exhaust man, or someone who has experience w/exhaust on the Maverick. Also, Nate from Alba told me that he rarely see's more than a 1 horsepower gain on the dyno with customized exhausts on UTV's. Boy, it sure seems like a lot of work just for 1 pony. Hell, I could've used that bulky stock catalytic converter to hold the ass end down over whoops!!!!

 

[Glamisfan]

Here's a modified Muzzy that someone posted up View attachment 10469 I like it because it looks to be equal length, and it moves it away from the CVT, which also makes belt changes faster and easier. For the od, would you use 2" on a 400hp v8? That's the same 50 hp per cylinder as we have. I wouldn't.

 

[badassmav]

Here's a modified Muzzy that someone posted up View attachment 10469 I like it because it looks to be equal length, and it moves it away from the CVT, which also makes belt changes faster and easier. For the od, would you use 2" on a 400hp v8? That's the same 50 hp per cylinder as we have. I wouldn't.

I'm a tech bookworm, so only know what I've read. Yeah, that makes sense what you said. In my short time of research on this subject, I've learned that an efficient and well designed exhaust system steps up in diameter as it progresses towards the mufflers. The smaller diameter at the exhaust port for higher velocity air flows and lower pressures behind the exhaust pulses for cavitation reasons, and larger diameters farther back for a higher volume capacity to assist in evacuating the additional amount of exhaust gasses expelled under the higher RPM's. I'm sure I am again over thinking things. Your lay-mans reply sure sounds rational. Hmmmm...

 

[dkiewicz]

Give Mark a call (760)948-1346

http://marksperformance.com/

 

[badassmav]

Here's a modified Muzzy that someone posted up View attachment 10469 I like it because it looks to be equal length, and it moves it away from the CVT, which also makes belt changes faster and easier. For the od, would you use 2" on a 400hp v8? That's the same 50 hp per cylinder as we have. I wouldn't.

Thanks for the idea, and the time you spent for your reply! For the sake of time, here is what I did for now: From the stock head pipes, I fabbed and tied the two secondary's together to assist in balancing out the two pipes, and perhaps add a bit of a scavenging effect at the same time. I used Flowmaster's (tiny) 10 series stainless, baffle-style mufflers. I took your advice and didn't go too large on the diameter (used 1.75"). I'll let you know the results when we dyno the car next week.