be aware that it chokes the motor significantly. This past Saturday, my car was on the dyno for a full tune, and through the full exhaust (dual 3" into a Flowmaster 2*3" to 4" Y, back into a 4" Spintech), I was only seeing 410-415 corrected HP and 380-390 corrected torque with a ported LS6 headed G5X2 cammed car (A/F was consistently 12.9 to 13.1, with no KR). Open the exhaust (read: turn downs after the collectors), and power as well as torque instantly jumped ~25-30 units. I realize that this sort of gain isn't exactly unheard of if you're uncapping a 3" catback, but I (as well as others at the dyno) felt that that kind of power loss through a 4" exhaust was excessive.

Just something to be aware of; that's all I'm saying.

 

On my first solid roller setup, I was running the 3.5" Mufflex with the Spintech muffler. I routinely picked up 15-17rwhp pretty much across the board by opening the 3.5" cutout. In contrast, the Hooker catback only cost me ~5rwhp.

How do you like your Schubeck lifters off hand?

Jason

 

I couldn't be happier w/ mine.

 

The spintech muffler doesnt look free flowing inside. Maybe you should try a straight through design like the dynomax ultraflow or magnaflow muffler.

 

Maybe this finally explains my lower than expected numbers!!!!!!

 

Wow, I'm surprised. What were your final numbers then, Jack?

 

Jason- the Schubecks seem to be doing their job, but not any better than any other performance oriented lifter (Comp R, etc...) would, as far as I can tell. It could be that since the lobes were designed with a less agressive lifter in mind, the extra stability of the Schubecks doesn't come in to play. A question that I do have, however, is regarding the lash- Joe (Schubeck) indicated that lash should be .001-.002 (cold); whatever is necessary to stay out of pre-load. What I am unclear on is whether or not that lash value will increase or decrease as the motor heats up. I know that on traditional (iron) motors the hot lash is (slightly) tighter than the cold, but it has come to my attention that the dissimilarity in metals involved in an aluminum motor (aluminum block/heads, steel valvetrain parts) may have the hot lash looser than the cold. If that's the case, then that could partially explain why my power numbers don't indicate any extra power over a more traditional lifter. What have you guys seen on your solid roller motors regarding hot vs. cold lash??

Cam- Final numbers (through dumps after the collectors) were 443/408 (torque numbers may have to do with the lack of an X-pipe). I was disappointed until I realized that it was 95*+ out with better than 80% humidity. I know that the dyno corrects for air temp/humidity, but Jeremy was saying that regardless of the provisioned timing, the IAT will pull timing out if air temp is high enough. There are still a couple of issues- Louis thinks that the collectors are leaking (I have slip-on collectors, remember), and the A/F ratio (after the exhaust was uncorked) went a little lean (13.4-13.5). So I am getting a different muffler put on (a big, nasty, straight-through Borla), and we'll see what happens. If the A/F is still a little lean, I may see if I can talk Lou/Jeremy into a little touch up to see if I can get some more power out of it. If it still doesn't make what I'd like to see, I am considering making a Louis special... a "Z" pipe... come off of the collectors, go into an X-pipe like I was running true duals, and then go back into the Y-pipe. On another side note, the TSP lid didn't make any difference at all; literally a .1 RWHP change between that and the LG lid I already had with no other changes and perhaps 5 minutes between the two runs. What was the weather like when you got your numbers, do you remember?? Did you finally get a clean run in up at Denton??

 

It was in the 80s the day we tuned/dyno'd my car.

I did get one more run in, granny shifting, but the timing shack lost my timesheet so I have no idea what I ran. After that I packed it up and went home. Gonna try Ennis on Friday night since I think I have the tranny issue figured out and fixed.

 

will this same power loss apply to the 4" exhaust, but with a flowmaster series 10 delta force muffler instead of the spintech?

 

Cam- that sucks that they managed to lose your timeslip, but it's good to hear that you have your tranny issue taken care of. The 10 degree difference between the day your car was done and the day my car was done may or may not explain the difference in power... hmmmm...

KMStevens- I'm not sure if the Flowmaster will flow any better than the Spintech or not. In retrospect, I think that Mufflex may benefit from either selling just the piping, or SERIOUSLY expanding their muffler selection.

 

should I buy a cut-out for the I-pipe or just another catback? Maybe Magnaflow

 

burnout & jason

Did you guys have cats or was that just bypassing the muffler?

 

muscrat- no cats here, all of my power gain was found by installing turndowns immediately after the collectors. As for buying a different cat-back, you may want to try simply swapping in a different muffler; it's certainly less trouble than swapping to a different cat-back. I am going with a Borla in place of the Spintech, and my next choice was an Edelbrock Victor series.

 

what other mufflers will fit the 4" inlet and dual 3" outlets?

thanx

 

muscrat- I'm honestly not sure... I forgot about the "dual outlet" option, since mine is a single 4" in and single 4" out.

 

what about installing a cut-out in the intermediate pipe? I have cats so I can't put any after the collectors

 

Bullshit. I gained only 6.2 hp through open headers as compaired to my 4" Mufflex catback with a Spintech Muffler. And I had Mufflex custom made 3" y-pipe WITH carsound cats, and a flowmaster reducer. This was on a m6 2002 t/r 224 cammed bolt on car making 386hp. SPINTECH WORK FINE. Victor

 

Vic- call bullshit if you like, but my car went from 410/380 to 438/404 with no other changes besides dumping the exhaust immediately after the collectors. My final numbers (443/408) were attained after a ~20 minute cool down. I was there, Lou Gigliotti (LG Motorsports) was there, Louis (G2 LS1) was there, and Jeremy (Godspeed) was there.

I'm not sure what the differences were in your situation vs. mine, but all I can say for sure is that the Spintech muffler was choking the hell out of my motor.

 

I'm w/ ya!

 

"and my next choice was an Edelbrock Victor series."

Very nice muffler. I run the Eldebrock RPM on my car with the true duals. Very nice sound, and compact in size.