2.5 mods, power?

[crzybmxrdude]

Ive run 2.5" cat backs on my grand am and on my present car, 2.4 stratus w/ no problems at all. According to my Gtech pro comp, i gained 7 lb ft of torque at like 3500 rpm on my grand am (havent tested my strat, but I could feel a difference over all) So a 2.5L should also in my opinion take well to 2.5" also.

[capev86]

first thing - removing the stock intake setup takes away the air flow to the circuitry in the front left corner of the carner. you will burn out the sensors and stuff.

second - anything bigger than 2" exhaust pipe on an N/A engine is a no-no unless you are pumping tons of nitrous through it. a basic tbi or carb engine will loose torque. efficiency of flow (low restriction cat and muffler) is superior to amount of flow.

third - a spacer usually increases torque output, which is what the 2.5 is ALL ABOUT. swapping in an mpi setup and recalibrated turbo computer would be a good upgrade. you get more power, better economy, yet maintain a dependabilty of the non-turbo powerplant.

fourth - the 2.5 has an extremely long stroke, only the new GM big block has a longer throw. and the 2.2/2.5 have siamesed cylinders. there is no way to overbore it AT ALL without weakening the cylinder walls.

a good tuned exhaust, port matching, backcut valves, little hot rod tricks and such are your best bet without a turbo swap!

[turboXE85]

A custom exhuast shop should be able to fix you right up. I know on my daughters daytona the exhuast we put on it really helped it alot as far as breathing. It revs higher in the lower gears and pulls more on the big end. We also added an induction system on it. Soon to modify it also for better flow threw a scoop.

[Martin]

Yeah I think I will just have the exhaust shop build be a system 2.5" in to a dual 2.25 outlet muffler sound good? I want dual exhaust so I can but dual Challenger/Cuda exhaust tips into my my roll pan sort of like the old Challenger. What muffler did you use Mike Tampa and do you have a sound clip of it yet?

[turboXE85]

We got are fart cans off of airdynamicracing.com check them out. They are a sport compact site. It doesn't sound like thats the type of muffler you are looking for though. Now to sound a little like dakota .com I have an 88 dak with 360 thousand on the ol 3.9 and never really tore into. Been beat to death since day one @ 2 tenths of a mile. Only motor repair has been a water pump and 2 injectors and an alternator. She has a 2 1/2 in dual system with an H pipe into 2 thrush high flow cats, into 2 borla turbo mufflers most of it ran down 1 side to avoid the gas tank then one pipe out 1 side and the other around the spare and out the other side with 69 super bee tips. The truck has 3.91 sure grip and ram air induction and a couple of other subtle mods. It will just tear up alot of v-8's of the era and 4.3 s-10 and 4.0 fud rangers. I've posted a best 60 ft time of 2.2 sec with these mods on 235/60-15 bfg tires. She will top out at 140 red line limited and I got the ticket on the ohio turn pike to show for it. She won't run like that now but the exhuast was the best thing going on that truck. When new she was new she would red line @ 15 mph and 3 days later after the exhuast she red lined @ 35mph in 1st of course. !/4 mile times in that crate was low 16's with a best ever of 15.8 @ 92 mph. Do the exhuast.