GenVibe - Community for Pontiac Vibe Enthusiasts

Just installed my Borla exhaust on Friday and there is a definate LOSS of torque and HP. I was under the impression that a performance exhaust would actually give me better performance, not take it away.I noticed that on Rasormans' Borla (GT version), that the muffler part looks almost in the shape of the stock. Mine, (base version) looks like a large can not even half the size of the stock. I ordered it from Performance Tuning. Any one else with a Base Vibe have similar problems or did I miss something with the instalation?I do love how it sounds, although a little louder than I imagined. And I'm hoping that the loss in torque and hp means that the engine is breathing too well which would be good for the supercharger. If that ever comes to be.

(WARNING! Technobabble alert!)This statement is likely to generate some controversy, but the fact is that 99 times out of 100, reducing exhaust back pressure will increase engine power, regardless of fuel system, number of cylinders, etc. The rare exceptions would be a carbureted car running quite lean to start with, (since reduced backpressure will usually lean out the air/fuel mixture, thus it might go so lean that a slight power loss occurred) and some all out race engines, where tuning effects can produce slightly more mid range power with say 4" bore Flowmaster race mufflers than with open pipes. (but even then, the peak power is usually better without the mufflers)It takes a lot more force from the crankshaft (and hence power) to push the pistons up on the exhaust stroke if they are fighting say 10 psi of pressure vs. 2, plus the mass of residual gas diluting the fresh intake charge will be much greater, not to mention leaving the fresh charge hotter.How do you know you've lost power Lancer? Does it just feel slower, or are you losing races to someone you used to beat or some such? (End Technobabble alert)quote:Just installed my Borla exhaust on Friday and there is a definite LOSS of torque and HP. I was under the impression that a performance exhaust would actually give me better performance, not take it away.I noticed that on Rasormans' Borla (GT version), that the muffler part looks almost in the shape of the stock. Mine, (base version) looks like a large can not even half the size of the stock. I ordered it from Performance Tuning. Any one else with a Base Vibe have similar problems or did I miss something with the installation?I do love how it sounds, although a little louder than I imagined. And I'm hoping that the loss in torque and hp means that the engine is breathing too well which would be good for the supercharger. If that ever comes to be.

lol Madbill your the man! If I got ? I am coming to you!

I drive my car all the time and I know that it feels a lot slower and shifting isn't as sharp. Had a friend rev it and didn't feel much pressure on the exhaust. Not like before the Borla. And even reving the engine is a little more 'laggy'. I even tried letting it idle for 10 minutes so the air sensor could adjust like when I installed the CAI. So do you think adding more fuel to air would 'fix' the problem (how would you do that?). Or just wait for the S/C?

Another consideration is that its a good idea to reset the ECU by disconnecting the battery, after any mod such as an exhaust or CAI, so that the computer can learn how to breathe better and take advantage of the new mods.

It's possible that as you drive it a bit, the computer will re-adjust the fuel to match. I wonder why we haven't heard any other negative performance comments? I'm sure lots of systems have been changed to Borla as well as several other brands. Plus of course, they all claim power gains, not just better sound. Perhaps a new poll is in order...

quote:Another consideration is that its a good idea to reset the ECU by disconnecting the battery, after any mod such as an exhaust or CAI, so that the computer can learn how to breathe better and take advantage of the new mods. Lancer, I would try this method first (disconnecting the battery) and see what happens.

quote:I drive my car all the time and I know that it feels a lot slower and shifting isn't as sharp. Not having enough back-pressure in the exhaust system can hurt low-end power. Mabey it is too free flowing for the car. But before you get too freaked out, try the car out at passing speeds. You may notice that the high end power is better now, but the low end torque is worse. This is a common problem with free flowing exhausts.It's a trade off.

Yup, I reset the ECU already, the same. Took off the exhaust today to check if there was 'maybe' something inside blocking air. Nothing, it's just a straight through design.It's not like I'm devistated by this since it was my plan to replace the cat and piping with something a tad larger in preporation for the S/C. It's going in for an oil change on Thursday, I'll see what the mechanics can do. All the threads I've seen in this and other forums that delt with Borla exhaust have been on GT models, except one guy that I haven't been able to get a hold of. He's got a Matrix XR.Would a higher octane gas help (I use 89 now)?

quote:It's not like I'm devistated by this since it was my plan to replace the cat and piping with something a tad larger in preporation for the S/C.The larger the piping, the more low-end you will lose. The loss of low end torque is a result in a reduction of backpressure, which is a trade-off for oomph in the higher RPMs. While it feels slower off the line, once moving it should make up for the drop in torque down low.And no, higher octane will not help.

Ok, Thank's everyone for the great input. I still love the way it sounds and the better flow will only help with any kind of forced induction I put in. Just wish that super charger would get done, Damn!

I think this is very highly unlikely. It's definitely slower if your driving normally, same with my exhaust. But, when you push the pedal all the way to the floor im sure you'll see a difference. I'm running no muffler on my vibe gt....the cat and resonator are enough, and I put on pace setter tips that have small resonators in them. To get moving in daily traffic I have to rev the engine a little higher because I lost low end torque, but when I floor the car theres a huge difference between stock and my new setup, especially when I hit lift.

that settles it I aint touchin my exhaust.

When I first had my Magnaflow exhaust installed I was surprised that I lost so much low end. It was really loud so I installed a resonater in front of the rear muffler, and that helped with the noise and gave it more back pressure. I even put back the stock exhaust to try it out but found that I got some low end back but from 3500 rpm and up it had less power than the Magnaflow. It is a compremise!

Hey Madbill, I think you were right! Yesterday I started the engine and just let it idle until it was warmed up then took it for a quick spin to return some movies. Today I took it in for an oil change and to check on the S/C. It's starting to work A LOT better now. It's now just barely noticablly slow off the line, but once it get's past 3k rpm it takes off better then before. I guess my ECU is a slow learner, only took a week to figure out the new airflow. It is even idleing back down to 650rpm. This past week it stayed around 1k rpm.Thank's, I'm a lot happier now. Fastest Vibe in town! Wait there's only 3 others (and driven by old peeps).

quote:Thermal is a good exhaust also.... Do not give up/Yeah I told my brother about it and he said dont fret they make a lot of different types that won't sacrifice your low end. If it wasn't for low end this car would be a turtle out there.

quote:Hey Madbill, I think you were right! Yesterday I started the engine and just let it idle until it was warmed up then took it for a quick spin to return some movies. Today I took it in for an oil change and to check on the S/C. It's starting to work A LOT better now. It's now just barely noticablly slow off the line, but once it get's past 3k rpm it takes off better then before. I guess my ECU is a slow learner, only took a week to figure out the new airflow. It is even idleing back down to 650rpm. This past week it stayed around 1k rpm.Thank's, I'm a lot happier now. Fastest Vibe in town! Wait there's only 3 others (and driven by old peeps). any news on the SC where you are

Here's a small pic of the set-up on a base. I'll have my own pic's taken this weekend. Thank's, I'm a lot happier now. Fastest Vibe in town! Wait there's only 3 others (and driven by old peeps).

That's great, Lancer; glad it's come alive!

wow! that's a TINY muffler... Is the exhaust TOO loud now? just curious...

It's definatly louder than stock. When just cruising around town it's just a low hum. On the highway it's a noticable hum. When you step on it roars. I don't think it's any louder than the GT that Rasermon posted. Sounds about the same.

Lancer, glad that your happy with it. If you can post a sound clip for us.