…we made a few changes to the car in prep for taking it to the strip Sunday. We only gained ~10hp at peak up to 610RWHP and just a bit of torque (up to 532 from 529RWTQ). I’m waiting to get the graphs, but my tuner said it did pick up a good bit under the curve despite the somewhat disappointing peak #s.
What we changed:- We ditched the 85mm stock C5 MAF and went Speed Density. The Haltech intake bridge I had has a 96mm opening so we just put a filter straight onto it. Keep in mind I’m running a 102mm Throttle Body and 102mm FAST “LSX-R” Intake Manifold.- Borla straight-through 3" catback replacing the stock C5 Z06 Ti exhaust. The X-pipe unfortunately still necks-down to 2.5" just before the flange for the catback. Still, compared to the small piping of the Ti (a little under 2.25" actually) and the two 180* turns that the exhaust makes in the Ti I expected a good gain here.
I’m thinking we’re really running into the limitations of the “LS-style” intake manifold, even if it is the big 'ole 102mm. I’m just not going to do a big single plane or sheet metal intake, or individual throttle bodies. After the strip this weekend we’ll probably just put the Ti back on it and be happy w/ the 600RWHP.
Thanks. It’s less than I thought we’d do once opening up the intake and exhaust, but not too bad for NA.
Again, thanks! Let him call BS, it made the #s (and those are SAE corrected as well).
Thank you sir. And we haven’t even done every trick in the book. It’s running a pretty heavy twin-disc clutch, it’s still using a standard water pump (the electric water pumps don’t cut it on the road course), it’s a streetable cam, etc. I’m happy with the #s.
It didn’t make it out Sunday. Last minute prep on Sat it sprung both oil (there’s about a billllllion fittings) and fuel leaks. My builder hopes to have 'em tracked down and fixed by the Test 'n Tune this week (Thurs night I think). I’m back in Durkastan so I won’t even be able to see it run.
The stock Ti is known to be pretty damn good for the small size of the piping. However, back to back dyno results usually show 10rwhp on stock cube heads/cam motors, and 15+ on big cube motors. The 85mm MAF also shows pretty good restriction on big cubes. That’s why I was really expecting more than the 610rwhp. I honestly think we’ve just run up against the limit of the LS-style intake. A big single plane or sheetmetal intake on this car would be dope, and a ITB setup would be just titty. However, it already makes enough power for a road course car, I don’t want a ghey hood, and I’m happy with it.
Nice, maybe on the n2o you’ll make as much power as I do NA. J/K get that thing on the street and get a real 1/4 # for it too! It should be quick if you put a good tire on it.
600 rwhp is definitely badass. And that’s a good experiment comparing back to back with the exhaust and maf changes. It’s probably not worth investing any more in the intake. You’d get more bang for the buck with suspension, wheels, and tires for the strip.
I am using the ls7 maf right now. Just an idea if you don’t want to go speed density. The maf is $70 and the mounting bracket from gm is $13. Put all that in a 4" aluminum tube and it’s a little bigger than the 90 mm throttle body. It’s more than my engine needs - the 85 mm would be fine - but it was something different to try.
How does the Borla sound compared to the Ti? The Ti is one of the best sounding exhausts IMO.
The 610 was a SD tune. My tuner puts an entirely new OS on the PCM, and he likes it w/ SD a lot better than the LS7 MAF. He really hates the LS7 MAF actually. The straight-through exhaust is LOUD. With 1 7/8" stepped to 2" primaries on the headers, off-road X-pipe, and no mufflers in the exhaust it’s just retarded. The 12:1-ish compression really sounds mean though w/ the cam and all (248/256 or something like that). I agree 100% the Ti is the best sound exhaust out there. With this motor and the rest of my exhaust it’s actually plenty loud, in fact I won’t make sound at Laguna Seca even w/ the Ti so I need to get a catted X-pipe for there.
The car is not a drag car by any means. I have over 4 sets of stock C5Z wheels, so I did buy some of the new Hoosier DRs (in 315/30-18) for one of the rear sets just to give it half a chance of hooking. It’s not going to get a “drag” susp or more serious tires though. It’s a road course car, I just thought it’d be cool to see what it can do on the strip.
You don’t have cats right? If you do, ditch 'em. If you don’t you could do the Ti “mod” where you connect a smaller (most ppl do about 1.5" I think) pipe from the 90* that turns into the muffler straight into one of the pipes before the tip. That way a small % of the exhaust never even goes to the mufflers. It still retains the unique sound, but picks up some volume. It’s tough to find the Ti pipe and somebody that can weld it though.
I lowered a c5 a while back that had a 485hp top end kit with similar exhaust… i wanna say it had the loud mouth something cat back?? holy lord that was loud, i can only imagine yours in person!!
Last minute prep on Sat it sprung both oil (there’s about a billllllion fittings) and fuel leaks. My builder hopes to have 'em tracked down and fixed by the Test 'n Tune this week (Thurs night I think). I’m back in Durkastan so I won’t even be able to see it run.
J/K get that thing on the street and get a real 1/4 # for it too! It should be quick if you put a good tire on it.