Wonder how much power you get when you open up your exhaust???

[william]

I am running stock exhaust (cat removed) on my TII GLH. I had my tailpipe and muffler separate from the exhaust last week so it was dumping right ahead of the axle. Well, for those of you wondering if there is HP in the exhaust, yes there is. I was surprised how much it woke the car up on the top end. Now that I have the tailpipe hooked up again, a noticable decrease in power. Looking forward to going to a nice big mandrel bent system as soon as possible. Just thought I would throw that out there for those running stock TII engines wondering about exhaust.

[tryingbe]

Should be. Everytime I open my cut-out the boost goes up at least 2-3psi.

[saw wave analog]

just hack the whole thing off where the stock downpipe curves back. free power, and lots of it

[diabloed]

I just put my 3" back on tonight and notice a night and day difference!! I've been told around 10-20 HP with running just a open down pipe. Currently in the market for an electric cutout for that very reason!

[Ondonti]

When my 3.0 turbo swaps into the Duster Im not moving the 3" exhaust cause Im not sure how an AA body exhaust will fit in a P body and I dont want a crap exhaust on my spirit.....so the Duster will run open downpipe. Its really not that loud as long as there is a turbo. Great backfires too I absolutly love that. What I hate is exhaust reverb when cruising and that doesnt seem bad with the turbo.

[oldgregg]

On my 2.5 TII when I went from a stock exhaust to a 2.5" exhaust I gained at 3 psi of boost which is roughly 21 HP.

On my R/T when I hacked off the muffler on the dyno I gained a "measily" 14 HP.

[Turbo Charger]

No one said anything about torque. You may only get 10-20 by upgrading to a full 3".. but I'm betting you get at least equal torque which makes for a pretty serious 'power' upgrade.

[shelbyplaya]

Quote:

Originally Posted by ButchN On my 2.5 TII when I went from a stock exhaust to a 2.5" exhaust I gained at 3 psi of boost which is roughly 21 HP.

yeah i had the problum

[status50]

The bigger the better applies for turbo back systems. The idea is to minimize the pressure downstream of the turbine in order to make the most effective use of the pressure that is being generated upstream of the turbine. Remember, a turbine operates via a pressure ratio. For a given turbine inlet pressure, you will get the highest pressure ratio across the turbine when you have the lowest possible discharge pressure. This means the turbine is able to do the most amount of work possible (i.e. drive the compressor and make boost) with the available inlet pressure. Again, less pressure downstream of the turbine is good. This minimizes the time-to-boost (maximizes boost response) and will improve engine VE throughout the rev range.

[TurboOmni08]

On a 2.5L TII Daytona what would be the best cost to power exhaust choice? I had a 2.5in SV (89+) but it is lost somehow...I think TU might have it by accident. But anyway. Should I hunt down my 2.5in SV and do a full 2.5in w/ no cat. Or should I spring for a 3in? If one goes 3in, is the upgrade wasted if you are only using a 2.5in SV?

[t3rse]

on a 2.5 sv I put a 3 inch on my glh with a side exit and with the wastegate plugged to the turbo (min boost) I get 9 psi, so I'd say 2 psi are worth it.

[Beachbum3478]

well actually i heard you lose a little low end torque when you open it up. that is what turbovanman told me a while ago.

[Polygon]

After changing my stock exahust (TII) to a full 3" mandrel bent exhaust the clutch slips now. I couldn't get it to slip before. I can feel a big difference in power. It pulls much harder that is until the vac system gives up.

[minimoparking]

sounds like you need a new clutch. I'm running a straight thru side-exit 3" and I'm not slipping. it just breaks the tires loose instead.

Oh, and BTW, according to gary donavan's site, there'e 20-30 HP to be had from upgrading to a 3" open exhaust. Not sure how true that is.... Have to hop it on the dyno to find out i guess.

[scott_s]

mine went up 5-6psi, at 7-10whp per psi, well you can do the math. Oh, that was from the stock 88 exhaust (2.25 to 1 7/8) to 3"sv and 3" with mandrel bends.

My 88 2.2 dyno was 195whp and 213 for torque at 10-11psi. There was no before but if we take 20% for tranny loses from the factory 175hp that would be an increase of 65whp. That also included a valve job, underdrive pulley, 20 over, and self ported exhaust mani. May be a couple of extra little things I have forgotten. I attribute at least 40whp to the exhaust being open, for my case, and I suspect more.