Hey guys, I had a question about the benefits of aftermarket exhaust on
near stock engines. My 305 TPI gm engine is in stock trim except for cold
air induction and dual snorkel k/n's. I know that the 305 doesn't need much
more air capacity due to the fact that airflow isn't what's really holding
back it's hp numbers, but I was wondering if an aftermarket cat-back system
would have any positive effects on torque or hp output in low, mid, and
upper rpm ranges? If I tried bolting up a 2.5 inch, non-chambered muffler,
single cat setup like a Hooker cat-back, do you think that it would be
beneficial to my engine? The reason I do ask this is because I need to know
where my money is best spent. Maybe a higher duration cam and lifters would
be better money spent for mid range torque and upper rpm hp? Thanks for any
help you all may provide me with.
It will give you more horsepower but with a 305 you dont really need it unless you a race the car
If you remove the catalytic converter you will increase the flow by quite a bit, it wont really mean an excessive power increase though :thumbs:
in the states if one removes a catalytic converter the car is undrivable as far as i know...won't pass emissions
It wont pass emissions here either, and it's far from legal, but it's perfectly drivable lol :hi:
I don't think I can remove the cat because the emmisions in california are pretty tight, so I think I just want to put on a cat-back system. I do plan to take to the track sometime to try and get a low 15 out of it, but if i could better get more power for less money elsewhere, then I would rather do that.
Why not put a straight through pipe on it when you want to race it, that's the only way you're going to significantly increase power, even then it wont be exceptional lol...or you could use it for every day use, just remember to put the cat back when you have to have the car inspected...Do you guys in the US have a yearly check that has to be carried out?
I could put a straight piping in but i don't want to hurt torque or backpressure to much, and its not a racer, i just want to take it to the track just a few times, nothing extreme. We do have inspections when getting it smogged so if i did that i definetly would have to put the stock setup back on there though.
Also, if you decide to put on a straight-through pipe, you'll have to watch how hard you push your engine in heavily-policed areas. The stricter cops will ticket you for noise pollution... :banghead:
It shouldn't be much louder without a cat though....cats dont usually deaden sound much, it's the centre silencer you've gotta be carefull of
True. I was just saying- someone I am vaguely accquainted with just got a ticket for noise pollution, and he recently had his cat removed... but the cops around here live to make teenagers' lives a living hell, too. So I don't know. Since I have no idea about California laws and the ego size of the cops there, you may want to disregard my former comment.
I guess different States vary quite a bit, in the UK, Cops dont really tend to bother with noise pollution, unless it's excessive :laughing:
a Cat-Back system will help your motor breathe better and it will be required if you plan on adding a cam/intake setup later.
but since the motor isn't modified, could money best be spent elsewhere for better torque/hp gains? or would a 2.5 inch cat-back actually help a stock 305 tpi breath better?
intake/exhaust w/ f/i helps quite a bit, so save up.
I was reading this discussion and I have a question. If you hollow out a catalytic converter on a 96 GMC Sonoma, will the performance be affected? Will it cause any problems, besides emissions?