I recently dyno'd my solid roller stroker in my Formula. It was down on power and peaked at only 5600rpm. I would have thought it would have peaked much higher say about 6300-6500rpm. Below is a little information about my combo....where are similar combos peaking?


My motor is a 392 ( .010 overbore and 3.875 Cola Crank). The compression is approximately 11.4. I have lightly worked AFR 190s flowing 297 at .600 Int and 237 at .600 Exh (flowed with pipe). The intake has been cut for a 58mm throttle body and has been port matched with little runner work at all.

I have a Cam Motion Solid Roller with Crane Solid Rollers...I don't have the cam sheet with me right now but the spec were something like 245/250 (give or take a degree) at .050 and .608/.611 lift with 1.6s. I am running a Comp Pro Magnums with a Comp Stud Girdle. I am running an Digital 6 and MSD wires as well.

I recently had my car dyno-tuned by Speedworks in Lewisville, TX. Started at 423 with a PCM4Less tune and ended at 431 (not sure if that says a lot for PCM4Less...or bad for Speedworks Tuning)....pretty weak and down at least 20-30rwhp. Ran cleanly, didn't really have any spikes....but plateau'd at 5600rpm and dropped power slowly from there.

Even though it did not sound like it floated the valves or had a miss, etc... is it possible the motor doesn't have enough valvespring or needs a rev kit?

Where do I find my missing horsepower?

Any suggestions or help is greatly appreciated.

Dave

 

Sounds like what I plan to build. I'm interested in this.

TTT for ya.

 

Do you know what your a/f ratio was?

 

Im sure they verified the a/f on the dyno tune..Hopefully they were checking for knock retard also..Most peps with solid rollers have to disable them because of the added valvetrain noise..Does seem like its down on power though..

Cody

 

More details can be found is this link:

Link to other Post.

Air/Fuel Ratio was close to 13.1. The dynograph I posted in the other thread has the Air/Fuel Ratio along the bottom of the graph.

Thanks,

Dave