SC400, Lost Torque from Exhaust
07-12-22, 09:37 AM
#1
Driver School Candidate
Thread Starter
SC400, Lost Torque from Exhaust
Hello folks, it's been a few months since I've been on this forum. I've been having fun ripping on my 5spd SC400 as the weather has been permitting, but I've gotten bored enough of the thrills that I want to start fixing problems again. Here's my issue, and it relates to my exhaust. I have BFI, BTW.
I took it to a local exhaust shop to have the stock system chopped off and have a dual setup installed instead. They custom made 2.25" dual pipes, with an X-pipe roughly where the output shaft sits. 4" tips. It has no mufflers and no silencers but the shop would not touch the cats. After the install, I was immediately floored by how nasty and mean it sounded, but noticed it was a little less peppy on the lower rpms. One of the reasons I wanted a louder exhaust was to hear the motor without having to wring it out to 5000RPMs, but I found myself doing that anyway because it seemed sluggish below 3000. From what I've read, it seems like UZs like back pressure and a straight pipe might be a little bit too free flowing. I absolutely love how it sounds with no mufflers but I also want to get some of that low end torque back... I won't lie, I'm getting a little tired of having to take it past 3500rpms every time I want a little G force.
It looks like mufflers are the best way to get some of that torque back... I don't want to sacrifice very much sound though. I have been doing some research and I think flowmaster Super 10's sound super gnarly and are still loud enough for me. Given that it's a race muffler and not very restrictive, will I see the torque gains I'm looking for with mufflers like these? If this isn't a good solution, I'm totally open to other suggestions on how to get some of that low end torque back. Hoping I don't have to go to 1 7/8" duals or something.
I took it to a local exhaust shop to have the stock system chopped off and have a dual setup installed instead. They custom made 2.25" dual pipes, with an X-pipe roughly where the output shaft sits. 4" tips. It has no mufflers and no silencers but the shop would not touch the cats. After the install, I was immediately floored by how nasty and mean it sounded, but noticed it was a little less peppy on the lower rpms. One of the reasons I wanted a louder exhaust was to hear the motor without having to wring it out to 5000RPMs, but I found myself doing that anyway because it seemed sluggish below 3000. From what I've read, it seems like UZs like back pressure and a straight pipe might be a little bit too free flowing. I absolutely love how it sounds with no mufflers but I also want to get some of that low end torque back... I won't lie, I'm getting a little tired of having to take it past 3500rpms every time I want a little G force.
It looks like mufflers are the best way to get some of that torque back... I don't want to sacrifice very much sound though. I have been doing some research and I think flowmaster Super 10's sound super gnarly and are still loud enough for me. Given that it's a race muffler and not very restrictive, will I see the torque gains I'm looking for with mufflers like these? If this isn't a good solution, I'm totally open to other suggestions on how to get some of that low end torque back. Hoping I don't have to go to 1 7/8" duals or something.
07-13-22, 08:30 PM
#2
You havent lost or gained anything but sound.... it is an sound illusion .....the car just sounds like it should be going faster then it actually is
This is not a Guess or opinion. only way you would be getting less torque is if you are beating up your transmission from wanting to hear the exhaust and its going bad or needs new fluid
This is not a Guess or opinion. only way you would be getting less torque is if you are beating up your transmission from wanting to hear the exhaust and its going bad or needs new fluid
07-14-22, 10:00 AM
#3
Pole Position
I've never dyno'd one, however, I'm sure you did peak up some peak power and lost some mid-range (how much I couldn't tell you). Some of that depends on the design of the x-pipe and mufflers. If you have a nice x-pipe and throw some mufflers in you may gain some of that back. However, with smaller displacement Japanese motors the experience you're having is typically the norm. It's all a trade off!
07-18-22, 09:39 AM
#6
Pole Position
He did a little more than that but... I don't think anyone is trying to argue much with you lol.
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