exhaust questions

[Josh Young]

The recent talk about exhaust has got me thinking about changing mine out. I currently have a 2.5'' flowmaster sysyem- don't hate me, it was like that when I got it.:lol: I have always heard that flowmasters on these are about the worst kind of exhaust you can have. I have got several questions about exhaust, so I figured I would start a new thread. So here it goes:

1.) How much difference could one reasonably expect with a good 3 inch system over the 2.5 inch flowmasters I currently have?
2.) Is there any need to go with a 3 inch downpipe on a basically stock truck with reliability mods? Seems like I read that the stock downpipe was sufficient on a basically stock truck.
3.) Does most people go with a new catalytic converter, or just keep the stock one? The truck has never had and race gas in it, just 93 octane.
4.) I guess lastly what brand does everyone prefer, I know opinions will vary. I am just wondering what you guys think. I have seen the RPM exhaust, magnaflow, ATR... I am leaning towards an RPM cat back system, but wanted to double check with you all.

As always thanks in advance guys!

 

[SY2455]

Re: exhaust questions

So here it goes:
1.) How much difference could one reasonably expect with a good 3 inch system over the 2.5 inch flowmasters I currently have?
2.) Is there any need to go with a 3 inch downpipe on a basically stock truck with reliability mods? Seems like I read that the stock downpipe was sufficient on a basically stock truck.
3.) Does most people go with a new catalytic converter, or just keep the stock one? The truck has never had and race gas in it, just 93 octane.
4.) I guess lastly what brand does everyone prefer, I know opinions will vary. I am just wondering what you guys think. I have seen the RPM exhaust, magnaflow, ATR... I am leaning towards an RPM cat back system, but wanted to double check with you all.

As always thanks in advance guys!

You didn't say if your truck is a Syclone or a Typhoon so base on that and they are different in the exhaust. I don't know for sure, but I think the Typhoon has a single 3" system after the cat.

1. In your case you will most likely see a big increase because the stock Syclone had a exhaust system that, just after the cat it was made with dual 2 1/2" pipes into 2 Dyno-Max Super Turbo mufflers and dual 2 1/2" tailpipes.

2. The stock Downpipe has been in the 10s if I recall correctly.

3. Depending on your mileage your stock cat may be OK. If you change it you may need to make some other adjustment to advoid overboosting your engine.

4. I have the RPM and I really like it, I don't know of any other company offering a cat back anymore but them.

What ever you do, I would highly recommend that you go with a stainless steel system. That way you only need to do it once :tup:. Just my :2cents:.

 

[Josh Young]

Re: exhaust questions

It is a Syclone.

 

[Flyin Ryan]

Re: exhaust questions

http://www.theturboforums.com/mufflerswap.php

 

[ghettosled]

Re: exhaust questions

most people just install the cat back system. In your case, your cat "may" need to be replaced due to the flowmaster and the smaller then factory piping. 90% of the trucks with bad cats have restrictive exhaust like the flowmaster. It just burns them up, because there is nowhere for the heat to go. It's pretty rare to see a bad cat on a truck with a ultraflow or magnaflow muffler (or anything 3" straight through)

Stock downpipe is fine, unless you have a 60mm or larger turbo (amongst other things).

 

[vinnieTy]

Re: exhaust questions

most people just install the cat back system. In your case, your cat "may" need to be replaced due to the flowmaster and the smaller then factory piping. 90% of the trucks with bad cats have restrictive exhaust like the flowmaster. It just burns them up, because there is nowhere for the heat to go. It's pretty rare to see a bad cat on a truck with a ultraflow or magnaflow muffler (or anything 3" straight through)

Stock downpipe is fine, unless you have a 60mm or larger turbo (amongst other things).

What CAT would you recommend?? I would love to get a 3 inch cat and go 3 inch all the way back. Leave the downpipe becasue to much for me right now.

 

[Josh Young]

Re: exhaust questions

You didn't say if your truck is a Syclone or a Typhoon so base on that and they are different in the exhaust. I don't know for sure, but I think the Typhoon has a single 3" system after the cat.

1. In your case you will most likely see a big increase because the stock Syclone had a exhaust system that, just after the cat it was made with dual 2 1/2" pipes into 2 Dyno-Max Super Turbo mufflers and dual 2 1/2" tailpipes.

2. The stock Downpipe has been in the 10s if I recall correctly.

3. Depending on your mileage your stock cat may be OK. If you change it you may need to make some other adjustment to advoid overboosting your engine.

4. I have the RPM and I really like it, I don't know of any other company offering a cat back anymore but them.

What ever you do, I would highly recommend that you go with a stainless steel system. That way you only need to do it once :tup:. Just my :2cents:.

Forgive my ignorance on exhaust, but what do you mean by: may need to make adjustments to avoid overboosting. I believe I am going with the 3" RPM cat back exhaust with a high flow converter from them also. Thanks!

 

[DynaGlide]

Re: exhaust questions

Forgive my ignorance on exhaust, but what do you mean by: may need to make adjustments to avoid overboosting. I believe I am going with the 3" RPM cat back exhaust with a high flow converter from them also. Thanks!

With a less restrictive exhaust, your truck will be able to get rid of exhaust gases more easily. While this seems like a good thing (and it is), your truck may be tuned to compensate for a higher back pressure from the exhaust system. More exhaust gas exiting faster, can potentially spin your turbo faster than what is needed, thereby overboosting your engine.

This can be remedied through tuning. There have been cases of folks removing their cat with a stock tune and entering into overboost territory.

 

[SY2455]

Re: exhaust questions

Forgive my ignorance on exhaust, but what do you mean by: may need to make adjustments to avoid overboosting. I believe I am going with the 3" RPM cat back exhaust with a high flow converter from them also. Thanks!

With a less restrictive exhaust, your truck will be able to get rid of exhaust gases more easily. While this seems like a good thing (and it is), your truck may need to be tuned to compensate for the lower back pressure from the exhaust system. More exhaust gas exiting faster, can potentially spin your turbo faster than what is needed, thereby overboosting your engine.

This can be remedied through tuning. There have been cases of folks removing their cat with a stock tune and entering into overboost territory.

Sam said it very well. Fixed a few things.

 

[ImperialStormTrooper]

Re: exhaust questions

I removed my cat and went 3" all the way back through the (I forgot the brand) muffler and wound up gaining 2# of boost. Now I have to get it tuned so I dont overboost. I also left the stock down pipe.

 

[fronzoos]

Re: exhaust questions

Whats all involved with tuning?

:edit: I mean to compensate the increase boost.