Question on these results

[Race Grandpa I]

Today I had my engine tuned after getting the FFS on line. Here is what I learned.

1) The dyno was a Dyno Dynamics which is believed by many to be the best dyno available. The tuner said that it reads 15 to 20 percent lower than other dynos.

2) At 4800 rpm it produced 148 whp with 11 lbs boost. Adjusting for the dynos conservative readings it would indicate that other dynos would produce a reading of approximately 178 whp.

3) There was a problem with the sparkplugs that did not allow the engine run properly over 5000 rpms. It needs new sparkplugs.

Based upon the above it would seem that after putting in new plugs that I should have no problem getting 190 whp with 11.5 lbs boost. I have decided to lower the boost as a safety measure.


What do you think about these results??? :grouphug:

[Tom @ Fast Forward]

If the plugs don't do it, it might be time for coils. There seems to be a rash of weak/dead coils lately. Especially on the older cars.

[MiataMTF]

If the power drops off at high RPM could be any of several ills, including: weak coils, wrong plugs, over-rich AFR, timing, pinging (yikes!), ...

Post dyno-plot so I can see results.

[Race Grandpa I]

Thanks for your offer to diagnois the problem.

I only got a hard copy of the chart and did not ask for a PDF file knowing I would be back on the dyno soon with new plugs. He did hear some knocking and took care of that with further adjustment.

Before I go to the trouble of buying and installing replacement plugs I was wondering if there is a way to test the coils before I do this. If the plugs are not the cause of the problem, I will have to go to the dealer to get the new coils and then spend more $$$ for another dyno. I would hate to have that done and put it on the dyno to find that the coils were not the problem.

Your ideas are appreciated.

Whatever way I go I will get and post the charts.

:seeya:

When it looks good I will put it on a Dynojet to get higher numbers!!! :cool:

[Tom @ Fast Forward]

I don't know a way to test the coils. Sorry. If someone else knows, tell us. I do know that you can damage the coils quickly by doing a compression or leak-down test on the engine without dis-connecting the coils.

If the A/F was reasonably good from 5000-7000 RPM and the WHP falls off, it is most likely the coils. Put a set of BKR7E plugs in for another test run. Under $10.

[MiataMTF]

I don't know of a way to test the coils either. The static "tests" described in the Factory Manual aren't very revealing and don't show much. Again, disconnect the coils and fuel relay when doing compression or leak-down test on the engine.

Good luck with new plugs.