King Tut's Dyno Experience

#1

Well after Road Atlanta and some talk about some motors being stronger than others. I wanted to know for sure how healthy my original to the car 200,000 mile plus engine was doing. I decided to schedule 3 runs with air fuel ratio at a local Dynojet dyno. I then did some research and found out that the stickiness of your tires can make a difference so I made sure I was on my Kumho XS street tires. I was wondering if the other dynos I have seen on this site were done with Toyo RA1s so its possible some HP was lost due to that. Anyways these three runs were done in quick succession with the first 2 being in third gear and the last run being in fourth gear. I am really happy with how the engine seems to be running. Any comments, questions, or suggestions are always welcome:

#2

If you will email me the data files I’ll give you some feedback. Jim Levie and others will have useful comments too.

#3

No Problem, I will shoot you an e-mail now. If anyone else wants the files, I can send them as well.

#4

That is pretty good for a 200k engine. You could improve the A/F ratio below 5k by an adjustment to the clock spring tension in the AFM, Right now it is correct for a street engine, but about 13:1 is better on race engine.

#5

I didn’t think that the AFM door was an DME input at WOT, no?

#6

I didn’t think that the AFM door was an DME input at WOT, no?[/quote]
The AFM is an input to the DME up to the point that the AFM maxes out (~4500rpm). Above that point the DME only uses rpm and temp data.

#7

My testing on a dyno showed that depending on when you go to WOT depends on how the A/F is adjusted by the DME. Example: Hold at 2500 RPM and then go to WOT and the A/F will be leaner then if you hold at 3000 RPM and then go to WOT. My dyno guy figured this out when we were trying to figure out what removing the adjustable FPR did to our mixture. So in the case at point, getting the A/F good at the lower RPM’s will transfer to better at WOT.

Michael

#8

In my case I told the dyno operator to just do a pull from 2000 RPM to 6500 RPM so he brought the revs up to 2000 RPM for a real short time and went WOT. In that graph I cut the first 250 RPM where the power built up and the last 250 RPM of the run where rev limiter was hit and the power dropped to make a nicer looking graph.