Engine Mechanical TopicsDiscussion for motor builds, cams, head work, stripped bolts and other engine related issues. The good and the bad. If it goes round and around or up and down, post it here.
With stock heads this build would get about 90hp/ 100 tq on a average DJ250.. Numbers are a little high.. Based on the shape of the curve, drag coefficient is too high.
Add. The drag coefficient in the calcs is too high for vehicle..
Last edited by Max Headflow; 05-08-2017 at 09:39 AM.
Reason: too high
With stock heads this build would get about 90hp/ 100 tq on a average DJ250.. Numbers are a little high.. Based on the shape of the curve, drag coefficient is too high.
Add. The drag coefficient in the calcs is too high for vehicle..
I went back and checked the setup calculations and there were some issues with the gear ratios, primary and secondary ratios due to the 2006 being an odd duck in those areas. After adjusting it didn't change much, but I adjusted the vehicle weight and front end area due to only having the Duece as the available FX where those were precalculated. I can't find actual measurements for the Low Rider that would be different for the drag coefficient though. I tried lowered the drag coefficient from .73 to .50. It does change the top end of the torque curve more to what I would expect. What drag coefficient would you expect?
Here's what I got when I adjusted for weight, gear ratios, drive ratios, and adjusted drag coefficient from 0.73 to 0.55. I was getting some knocking from 3500 to 4500 RPMs on full throttle so I am adjusting AFR up in those ranges and retarding the timing by a half a degree. Will run it adjusting timing after that if the knock is still there until it is gone then run the data tracking again.
I went back and checked the setup calculations and there were some issues with the gear ratios, primary and secondary ratios due to the 2006 being an odd duck in those areas. After adjusting it didn't change much, but I adjusted the vehicle weight and front end area due to only having the Duece as the available FX where those were precalculated. I can't find actual measurements for the Low Rider that would be different for the drag coefficient though. I tried lowered the drag coefficient from .73 to .50. It does change the top end of the torque curve more to what I would expect. What drag coefficient would you expect?
Don't really know.. There are still a number of issues that make your output not comparable to a DJ dyno.. No correction for atmospheric conditions (SAE), Flatness of test track.. In some cases it you output may be more accurate than what a DJ says uncorrected. DJ drum spinning, to get HP/TQ , is not exact..
02-23-2017, 08:51 AM
