Chassis Dyno Results on 512 stroker

[joflaig]

Finally got the car on the chassis dyno. I think the results were about as expected. The fuel/air ratio was 10.5 : 1 on the first run. 12 : 1 on the second and after 6 runs and lots of fiddling with the carb and jetting I think they said the final mix was 12.8 : 1 (81 on the primary and 86 on the secondary).

I was told they left it a little fat because they didn't know what my driving habits would be. The highest HP # they saw was 409 at the rear wheels. A few months ago we dynoed at the crank at 543 hp and 612 fpt.

The results:
http://johnflaig.com/GL/dyno/chassis.pdf

This is the build:
http://www.dodgecharger.com/forum/index.php/topic,36197.180.html

And no I have not yet driven this thing, hope to do so sometime in the next week. It's getting an alignment today!

[General_01]

Very nice. It would be nice if you could keep that extra 132 hp to the rear wheels though.

[oldschool]

so you loose 25% thru the drivetrain? most people say you should loose 18-20% with a auto,and 15-17% with a manual.
i thought it was higher too. i always wanted to see a comparison between a engine and chassis dyno. good info to know.

[joflaig]

so you loose 25% thru the drivetrain? most people say you should loose 18-20% with a auto,and 15-17% with a manual.
i thought it was higher too. i always wanted to see a comparison between a engine and chassis dyno. good info to know.

Well it depends too on your gearing and torque conveter, in this case 3.54 gears and a 2800 stall - 3400 stall range. Also, different dyno machines will give different readings. I'm sure the experts can chime in on that. I was most concerned with just getting it properly tuned here.

[375instroke]

Looks like you're only starting the pull at over 4500RPM, and the waviness looks like the tires are spinning on the rollers or something.  Chassis dynos make a few assumptions when calculating power.  They don't actually measure it.  They just measure how fast they accelerate the rollers.

[dstryr]

Did you have any porting work done on your heads?  Flow #s?    I didn't read the whole 'build' thread to see.

Thanks!