ET drop/Power gain with full exhaust

[VadersV6]

Given my combo and the fact I have a completely stock exhaust with a tiny non GM cat, what could I expect to gain going to a good DP/Test/Catback? What are you personal gains switching to a good exhaust system? My power falls flat at about 4500rpm. Would I see a dramatic improvement?

 

[VadersV6]

Anyone?

 

[grocerygetter]

put a dump on it and put whatever flavor of exhasut you like on it....loud or quiet. You can always dump straight from the downpipe that way it need be.

 

[Grumpy]

.2-.3 anyway :biggrin:

 

[VadersV6]

Going from a 2 1/2" DP, small Cat, and restrictive catback, to a 3" DP and dump will only net a 2-3 tenths drop? I read about some guy gaining .6 just switching to a THD over a lower quality 3" DP. Sure seems like I have alot more power on the table with what I have.

 

[Grumpy]

I would rather tell you a lower # than tellin ya you will shave off a sec .... and then not have it happen .. I don't know what else your running on a stock car your not goin to get .6 unless your stock exhaust is bent in half an not workin at all :biggrin:

 

[Grumpy]

I read about some guy gaining .6 just switching to a THD over a lower quality 3" DP. Sure seems like I have alot more power on the table with what I have.

not everything you read is true

 

[2QUIK6]

With my setup, running thru the muffs (2.5" duals with no cat) over opening my DP makes it run about 2-3 tenths slower, but thats at 25# boost too. With that much boost, the exhaust starts to get restrictive.
If your loosing power at 4500 rpm, might suspect the valve springs also...if they are original I'll bet thats your problem at lower boost levels.

 

[VadersV6]

not everything you read is true

Well it was written by a guy on this board who wasnt selling anything, so I lent him a little credibility.
I dont have the original valve springs on it. They look like Lt1 springs. But, the car did sit for 4 years before I bought it. There were likely a few valves holding open for 4 years, so that could be an issue.
Maybe my cat is blocked too. The car lets off this strong sour smell when its idling. A long time ago, I owned a Saturn that burned alot of oil, and it had destroyed the cat. That car smelled the same way.

 

[broke1]

I picked up 4#'s when I replaced my stock exhaust(ATR downpipe) with a ATR 3" single shot.Spool was also noticably increased...

 

[VadersV6]

So it was a stock exhaust with the exception of the ATR downpipe, and then you added a full exhaust? I'm not sure what the single shot is. I'm assuming its a catback. Were you running a cat or a test pipe?
Thats a pretty significant gain in boost there!
So I'm guessing that the big gains come simply from the added boost, but the 2 exhausts run at the same boost would probably net 2-3 tenths just from the added efficiency and quicker spoolup with the full exhaust....

 

[broke1]

Yes,stock exhaust with the exception of ATR dp and no cat.

Single shot is a single exhaust,in this case 3".