LT's and Prochamber


Nov 28, 2004
Well I have finally got my exhaust installed. Its Mac lt's, prochamber, with a flowmaster catback. It sounds badass, but I feel like I lost power. Going from a dead stop if I get on it the car acts like it has lost power until it hits 3k rpm's then it SCREAMS. Before the LT's and prochamber I had stock exhaust manifolds, upr x-pipe, and flowmaster catback . With my old setup it was not as sluggish from idle to 3k. After the install it did throw a rear 02 sensor code, which I have not taken care of yet. Right now I have stock gears and I feel that may have SOME to do with it. Anyone else with a similar experience? Could something be wrong? Thanks
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It is completely normal to lose down low power when doing LT's.. the reason why is because there is less restriction now. The less restriction will help you out up top though. A dyno tune MAY fix some of your problem.. it did mine at least but I was running almost 20% lean.. here's my dyno graph anyways

I lost some low end torque as well, but it really made a big differnce up top. If you want some of your low end torque back get some hi-flo cats to help with some back pressure or get yourself some gears to compensate for the lost of low end torque...
Well that makes me feel a little better, since its not just my car. I have already been out running the car hard, should I go to a dyno and get my a/f ratio checked before I do anymore driving? I already have 4.10's, I just have not gotten around to installing them. I will wait to see how that turns out. The quality of the mac lt's are fine, and the price is definitely right. I do not have any sound clips yet, but I will get some soon. It sounds bad ass. Is that dyno before and after lt's? If so thats some good gains.
I've been contemplating the Mac longtubes, but have heard too many bad things and it kinda scared me away.. were your's ceramic or HTS coated?

Not sure, but I think that dyno graph was before and after tune, with LT's on in the baseline run.. I could be wrong tho :shrug:
Mine are the HTS coated ones. I really dont care what they look like, so I got those. I have a buddy who has had the HTS coated ones for 2 years and his only have some surface rust. Which doesnt affect their function.