3inch to 2.5 tips

[Mark42]

Re: 3inch to 2.5 tips

why would you compare this? Im very confused why we are comparing 3" single to 2.5" double

Because the muffler has ONE input, and TWO outputs.

What I am pointing out is that dual 2.5" tail pipes flow more than the 3" I pipe, so there is no point in having 3" tail pipes when 2.5 tail pipes out flow the volume of exhaust entering the muffler from the 3" I pipe.

If 3" tail pipes are wanted for looks, that's just fine. Just don't expect that they are going to give any greater performance than 2.5" tail pipes.

BTW, its reported that a 3" I pipe on a 3800 will reduce the bottom end torque of the motor. Go with a 2.5" or even the stock V8 2.75" I pipe. 3" is a waste unless you have a turbo or supercharger.

[whitdog54]

Re: 3inch to 2.5 tips

Because the muffler has ONE input, and TWO outputs.

What I am pointing out is that dual 2.5" tail pipes flow more than the 3" I pipe, so there is no point in having 3" tail pipes when 2.5 tail pipes out flow the volume of exhaust entering the muffler from the 3" I pipe.

If 3" tail pipes are wanted for looks, that's just fine. Just don't expect that they are going to give any greater performance than 2.5" tail pipes.

BTW, its reported that a 3" I pipe on a 3800 will reduce the bottom end torque of the motor. Go with a 2.5" or even the

stock V8 2.75" I pipe. 3" is a waste unless you have a turbo or supercharger.

dyno results please?

[checkbit]

Re: 3inch to 2.5 tips

BTW, its reported that a 3" I pipe on a 3800 will reduce the bottom end torque of the motor. Go with a 2.5" or even the stock V8 2.75" I pipe. 3" is a waste unless you have a turbo or supercharger.

this is a misconception. it has been discussed ad nauseam. the torque is not reduced. the torque curve moves.

[BallerMaro13]

Re: 3inch to 2.5 tips

^this.

torque isn't lost, it is moved in the powerband. my powerband went up to about 3500 rpm with my 3" exhaust but there's definitely more muscle there.

let's keep in mind that most record holding fbodies and power builds are running 3" exhausts, even n/a builds.

[Mark42]

Re: 3inch to 2.5 tips

this is a misconception. it has been discussed ad nauseam. the torque is not reduced. the torque curve moves.

^this.

torque isn't lost, it is moved in the powerband. my powerband went up to about 3500 rpm with my 3" exhaust but there's definitely more muscle there.....

Yes, agree the torque curve is moved up the RPM scale, leaving less torque at the bottom end. For the car in question, which is a stock motor with headers, a 3" system will not buy a lot, if anything over a 2.5" system. Also, the otherwise stock car will not perform as well with the torque curve moved higher. It will actually feel like the car lost power under normal driving. High rpm torque is fine for a high performance car, but not this basically stock street car.

^this.

....let's keep in mind that most record holding fbodies and power builds are running 3" exhausts, even n/a builds.

Thats true too, but I am speaking directly to the car is question which is a stock motor, not a built motor or record holder.

Next time I'll do a better job qualifying my comments. :)

[Watazz]

Re: 3inch to 2.5 tips

Im doing the 3 inch in mind of future mods. Planning on doing a turbo setup very soon. Just working on getting all of the parts together now. But from what i hear the 3 inch exhaust if prefered more over the 2.5.

[BallerMaro13]

Re: 3inch to 2.5 tips

well informed decision ^ and not saying that just because i'm a supporter of 3" exhausts for fbodies.

future mods is the key here. i did my 3" exhaust with the intentions of building the motor n/a after full bolt-ons and looking into f/i. but even without looking into a turbo, etc., i believe the 3" is the best performance minded approach.

[Watazz]

Re: 3inch to 2.5 tips

^ I agree. I didn't do the I pipe before because i was like 15 and was on a budget. Plus driving without a license in a car with exhaust. Definatley didnt want to attract too much attention

[Mark42]

Re: 3inch to 2.5 tips

Good discussion....

And good points about planning out the build of the car. Too many folks throw parts and money at the car without regard for how well the parts will work together or what the result will be. Plan is key. I have a Microsoft Project sheet listing the catagories (Rear Axle, Trans, Engine, Electronics, etc) with columns for links to the product, price, install date, odometer, MPG etc. I know exactly what I want, where to get it, and how much it will cost. Also when it was installed, and any impact to MPG. The plan helps keep me on track, and lets me see the impact to the car.

BTW, after getting the Magnaflow, I sent off an emial to pcmforless asking if the PCM needed an update for the cat-back. They responded right away, and said no, there is no need to update the PCM for a cat-back with a stock motor. Thats cool, cause it just saved me $75.

[BallerMaro13]

Re: 3inch to 2.5 tips

Mark - do you have plans to go full exhaust or look into completing it down the road? headers and a cutout would be really nice with that new catback ;)