2G Exhaust work: Excellent results!

[GV280Z]

Hey all, a little while back I had a free flow cat from Carsound installed on my 86 Si, enlarged the exhaust behind the cat to 2 1/4" from 1 3/4, removed the resonator and installed an Imco Turbo muffler.

The results friggin kick Butt!! I'm going to dyno my car soon and I won't be surprised to find that I'm up to around 135 - 150 horsepower.

The Imco turbo muffler ($70) provides just the perfect amount of backpressure so I've still got major torque in my powerband. It also sounds great but isn't overly loud or intrusive..perfect. I can still hear my intake under hard acceleration, it all sounds nice

I did have a 2 chamber Flowmaster on there for about a week and I just couldn't stand it, had to go with something more conservative and it had also decreased my torque quite a bit. Other mods include port and polish with a 3 angle valve job and short ram a.i. with 8 mm MSD wires.

Also getting very good mileage, still getting 24 to 25 mpg under hard driving / city driving. I had a local exhaust shop do the work, the tech basically formed me a new mandrel bent exhaust there in his shop. I was very skeptical about going so large in the diameter, I was ready to stop at 2", glad I wasn't in charge.

I highly recommend this exhaust mod, you'll love the results. By the end of this summer I'll have a Tri-Y header and 2 1/4" pipe infront of the cat installed with a MSD coil and 6A and I'll dyno again after that.

Once I get the first dyno ran, I'll post the results and try to upload a scanned pic of the print out. Heck, it's even a blast to drive on regular

Greg

[honda_racing101]

Umm what motor work do you have? Because stock 2nd gen Si's only had 110 to the flywheel. So good luck getting 135-150 to the wheels.

I have a 2nd gen with exhaust work too, and its still slow.

[GV280Z]

The engine is stock aside from the headwork I mentioned in my post, however that did not include any sort of milling job or anything, stock compression ratio, stock pistons rods and crank, stock flywheel. I think it's got around 100,000 (appx) miles on it. I use Royal Purple 10 - 30 and NGK V-power sparks..

I think the Si Bt/A20 is rated at 115 hp.

Then again..you and I may have a different standard of what is "slow". I think my car rocks the Casbaugh and that's all I really need to know, regardless of what the dyno says. My Lude is a hell of a lot of fun to drive

Greg

[honda_racing101]

Well thats 110/115 to the FLYWHEEL, which inturn, is about 80-90 hp to the ground. An exhaust wont change that too much.

Dont get me wrong, my 2nd gen is fun to drive but its a bore compared to my VTEC sol.

[GV280Z]

Well, I've never had a Vtec car so I don't know. I've considered getting a GSR before..I probably should. To tell you honestly, I'm really sick of hearing about Vtec everywhere and that's sad cause I know it's a superior technology.

I'm just sick of all the ricer racers everywhere in stupid looking civics and I absolutely hate the sound of most of them..what's even worse is the guy that's driving an automatic and he's got exhaust with a coffee can, you can hear his car going down the road and shifting "EEEEHHHHHHHeeeehhhhhh" and I'm just there shaking my head..you dumbass..

I bet your 1800 pound car with a 160 horse engine is pretty friggin quick! No wander you think your Lude is slow in comparison..My car is a total sleeper though, cause it's got a few dents in it and a fading paint job but it gets attention on the highway when I downshift from 5th to 3rd at 70 and blow everyone away, I'm doin 100 before I know it after shifting into 4th finally.

Every night I still just go down the highway just for the fun of it even at 3 bucks a gallon

peace

[honda_racing101]

Yeah, well VTEC is highly over rated, but for hondas its about the best there it lol.

And sols weigh around 2300 lbs, not 1800lbs. But its still pretty quick.

Yeah, fart cans are pretty bad here too. I dont mind loud, but raspy irritates me.

[GV280Z]

I'll let you know how the dyno goes and I'm confident that I've got more than 80 - 90 horsies hooves on the ground

[MazdaX]

Originally Posted by GV280Z

I'll let you know how the dyno goes and I'm confident that I've got more than 80 - 90 horsies hooves on the ground

Cat back exhaust systems really don't offer anything other than sound fuk with the exhaust velocity. If you still use a OEM Catalytic converter, You will see no gains to the wheels because the cat' is what kills the exhaust flow and cuts its velocity down. Opening it up after the cat will just increase the amount but not the velocity of the exhaust exiting the cat and shooting out the tail pipes.

I've seen people on Mazda motors non-rotary with n/a setups loose HP with catback exhaust systems because they loose the exhaust velocity. Good luck man.

[GV280Z]

Do you mean loosing back pressure? I've got high flow with good back pressure, my horsepower gains and pre-existing torque are perfectly balanced.

I do know for a fact that going a little bigger in the pipe improves top end and fuel mileage also..of which, I did see improvements on. I've definitely got a lot more ass from 3 grand all the way to redline than I did before and I'm just tickled pink about it. I can't wait to finish it all up this summer.

[MazdaX]

Originally Posted by GV280Z

Do you mean loosing back pressure? I've got high flow with good back pressure, my horsepower gains and pre-existing torque are perfectly balanced.

I do know for a fact that going a little bigger in the pipe improves top end and fuel mileage also..of which, I did see improvements on. I've definitely got a lot more ass from 3 grand all the way to redline than I did before and I'm just tickled pink about it. I can't wait to finish it all up this summer.

No. Exhaust velocity and exhaust backpressure are two different things. It'd be hard to explain just look up "Exhaust Velocity" on google and read up. Good luck man