Last Fall my car made 660 RWHP (link to the previous 660 RWHP thread so that I don’t have to repeat all of the build technical engine details ) and now it’s at 680/540 RWHP/RWTQ, still on the factory LS7 short block, 92 octane pump gas, same 257/273 112 LSA solid roller cam, Beck sheetmetal intake and single NW 102mm DBW throttle body……and the exciting news…..there will be more HP to come when I try the P.I. LSX intake in two weeks!!! Here’s the current dyno comparison below:
Peak HP is 680 @ 7300RPM and the motor has an incredible 670+ RWHP from 6800 to 7800 RPM!!! Peak TQ is at ~5900RPM and as you can see, almost table top flat! So much for “peaky” solid roller HP curves.
I finally got the HP/TQ curves smoothed out compared to last time (new plugs and wires) so the real comparison is where I have added 20/20 RWHP/RWTQ over the previous runs. This is why I included a previous 651/520 run along with the 660/501 dyno graph because the car was really making in the 520 range for torque previously but I believe the strange A/F spike at ~4500RPM caused the torque to dramatically dip for some strange reason on this particular run.
It’s too bad that all I had was my i-phone to have this video shot of the car on a typical run on the dyno rollers because the sound of the intake roar is absolutely incredible up to 7900RPM!!!
http://youtu.be/5isNgKVycwI
What did I do different this time? Just as planned, I hand built a set of custom triple stepped headers 1-7/8” to 2” to 2-1/8” w/27” long primaries dumping into 4” merge collectors, 4” dual exhaust/X-pipe, 3-1/2” diameter Magnaflow 12909 mufflers with 3-1/2” tailpipes! This is an upgrade over the 1-3/4” to 1-7/8” stepped headers that had 32” long primaries and 3-1/2” exhaust/X-pipe and 3” DynoMax mufflers and 3” tailpipes. And believe it or not, the car is even quieter than it was before…can you say ultimate sleeper!
Here are some pic’s of the headers and exhaust:
I still plan to try the Performance Induction LSX aluminum intake with my DBW NW 102mm TB on top to see if I can crack 700 RWHP…it should be REAL close! The bad news for readers is that I will be on vacation and not back in town until after the 4th of July so the intake swap will just have to keep both you and me in suspense!
To say that I am excited about this set-up now is beyond an understatement given the fact that I believe this motor combo is likely to be the most powerful N/A single DBW TB, factory stock shortblock running 92 octane pump gas LS7 on the planet….woohoo!!!
And yes, when I am finished dyno-ing the car I will find time to take it to the track since I know there are many doubting Thomas’s about this car questioning how real and repeatable the power may really be….well take a look below…..how does EIGHT back to back runs of 679+RWHP rate for consistency? The two runs topping over 680 have a minor HP spike at the end of their run due to the rev limiter kicking in so I didn’t count these as my max power runs but before the spikes…679+!
And once again I’d like to thank Steve Barker (632C2 on the Corvette Forum) for having my car on his dyno for all of the trials, tuning and R&D work, THANKS Steve!
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