Found my HP problem

[Ccmano]

Went back to Twisted Pipes today. Mike was very pleasant and willing to accomodate me. They immedeately put my car on the lift and we took a look. Long story short they installed the Mflow resonator/xpipe, had to fabricate the head pipes to connect to headers and fabricate a connection to the corsa mufflers. I supplied the reducers, connectors and clamps. So now it's 3" all the way from the header collectors to the Corsa's. Stood there and watched the whole thing. It came out very nice. They only charged me 2 hours labor, it took 3.5 hrs with 2 guys working and me supervising.

Interestingly I noted that the Mflow resonator actually has an x-pipe inside it, in addition to the x-pipe fitted on the inlet side. Strange that they would set it up this way.

In driving the car afterwards, Surprisingly I noticed that it's now somewhat quieter. No resonance what so ever. I have to say I really like the combination of Mflow x-pipe/resonator and Corsa mufflers. Problem of course is you only get these Mflow and Corsa parts as part of full systems. Really can't say I felt any more power at this point.

Next comes the Dyno. We'll see if this change made any difference at all. Third times a charm, as they say.
H

[XfireZ51]

Hans,

Are you sure that the MFlow mufflers are not available separately When I spoke with Mike last year, he told me the full system I bought was made up of components he could buy individually. In fact, I had contemplated using the MFlow Xpipe and resonator but with the B&B mufflers. As for the rsonator, I could swear that when we looked at mine before installing that
it was straight thru. But sometimes the mind plays tricks.

[Paul Workman]

Originally Posted by Ccmano

Went back to Twisted Pipes today. Mike was very pleasant and willing to accomodate me. They immedeately put my car on the lift and we took a look. Long story short they installed the Mflow resonator/xpipe, had to fabricate the head pipes to connect to headers and fabricate a connection to the corsa mufflers. I supplied the reducers, connectors and clamps. So now it's 3" all the way from the header collectors to the Corsa's. Stood there and watched the whole thing. It came out very nice. They only charged me 2 hours labor, it took 3.5 hrs with 2 guys working and me supervising.

Interestingly I noted that the Mflow resonator actually has an x-pipe inside it, in addition to the x-pipe fitted on the inlet side. Strange that they would set it up this way.

In driving the car afterwards, Surprisingly I noticed that it's now somewhat quieter. No resonance what so ever. I have to say I really like the combination of Mflow x-pipe/resonator and Corsa mufflers. Problem of course is you only get these Mflow and Corsa parts as part of full systems. Really can't say I felt any more power at this point.

Next comes the Dyno. We'll see if this change made any difference at all. Third times a charm, as they say.
H

Let's hope the dyno likes it too! Getting rid of the 2" choke points certainly didn't hurt performance, I'm sure.

Looking forward to the next FBI track day!

P.

P.

[Ccmano]

Dom,

I can not say for sure you can't get the resonator separately however, I've been all through the Mflow catalog and there are no mufflers with as long and narrow a case as this and with the pipe centerline spacing as close with 3" inlet/outlets.

As for the internal x-pipe I saw that for myself. One of the installers commented on it as well. I suspect the double x-pipe combination is engineered that way for a reason, probably to control the resonance.

H

[XfireZ51]

Hans,

As for the performance of this system and the restrictions notwithstanding,
Lgaff and I have very nearly the same setup. Both 92s with ported top end and 63mm throttle bodies. We also both have the same Watson 1 7/8" headers. Lee has an Xpipe with no resonator and Borla mufflers. I have the full MFlow system with resonator.
Lee has 4.10s to my 3.45s and a Fidanza. When he and ran heads up the last time, our trap speeds were virtually identical, 116.47 v 116.48. Just gives you an anecdotal benchmark as best as I can describe.

[Pete]

Guys here is what i remember.

Me and Al used to run 116-117 MPH with only exhust & chip.
No port work
With plenum/IH porting we were running 119-120.

So my opinion, you guys are looking for cake and eat it too.

The LT5 likes to breathe.

Heck even GM knows you can't have your cake and eat it,have you guys heard the LS7 at WOT crappy/loud from outside the car.

Also if GM went with full 3" exhaust with flappers for 500 HP why would you guys go with 2.5" and down to 2 1/4" (Corsa Tailpipe)

Think of this for a minute if your exhaust is restricted porting the heads won't be worth it you'll go from 116 to maybe 118. or from 370 rwhp to 390-400rwhp that tells me your exhaust is robbing you of 25-40rwhp.

Anyway food for thought.
Pete

[XfireZ51]

Pete

Nobody doubts either the experience you or Al have had with the LT-5 and what makes it work. Marc H. has said several times that he has seen virtually little to no difference between a 3" exhaust and a 2.5" Corsa regarding hp.
I would also think engine displacement would have something to do with the necessary size of the exhaust. By any chance, had you timed the cams when you ran 116-117 with just chip and exhaust?
At least from the dyno runs Lee and myself have done, we are in the 385-390hp range with top end porting and that's before recognizing that the Street Stuff WB may have been reading lean.
Here's a very interesting thread with excellent information:
http://www.digitalcorvettes.com/foru...hlight=exhaust

[Pete]

Originally Posted by XfireZ51

Pete
By any chance, had you timed the cams when you ran 116-117 with just chip and exhaust?

Plenum had not even come off at that time.

Al, found 19rwhp from B&B rasonator to SW X-pipe.

Pete