Went to the Dyno : what the hell happened? Options

[lagos]

with std correction, i made
229HP and 240TQ

with SAE crrection i made
222hp 234tq at 12-13psi ...with lots of issues.....

here is a video from the dyno
http://download.yousendit.com/D176956C4A979DBC


so i finally went to the dyno for the first time ever. on my 1st run i got a shocking surprise. the car was very lean and there was a huge drop in the power curve. what the hell happened? right before the dyno, i installed some Bosch coper plugs. the store was out of NGK and i figured, it would probably be fine. boy was i wrong. can someone explain to me how sparkplugs can make my car run lean like that?

lucky for me, the dyno owner is an mr2 owner as well. he had a fresh set of NGKs so we quickly droped them in. it seemed to cure the problem. the 2nd run did a lot better, and with the 3rd and 4th run the car was getting ritcher and ritcher, to where it should be.

then i noticed another problem. before going to the dyno, i was hitting 15psi on the street. problem is, when i got on the dyno all i was seeing was about 12 maybe 13psi, and it would start to drop off to around 10psi in the higher rpm range. this was a problem i never noticed in my car before. the only thing i can think of is that my car has a boost leak, or the mbc is not doing its job.


here is the 1st run. i was shocked when i saw that.




this is the 2nd run . you can see the a/f start to get better as well as the power curve.



finally this is the 4th run. you can see the a/f is much better



This post has been edited by lagos: May 2, 2006 - 11:40 AM

[lagos]

A few observations:

1. The first run shows massive knock response throughout the range from the plugsand a significant detonation event at 5100 rpm (again, knock response shown)
2. The third run also has a detonation event (albeit not as pronounced) at 6100 rpm
3. Why the hell would the a/f ratio be worse with different plugs???? That makes no sense to me.
4. The boost on a dyno will normally be less than the street because there isnt as much load placed on the engine. You have to turn the boost up. My guess is that if you had, the knock response would be much worse.
5. It looks like the plugs cleared up the detonation problem so thats good. Also, your a/f in that run looks much better than most afm equipped 3sgtes

Good job. Did you have fun?

jay you are correct! pretty much what aaron posted too on mr2 oc.

its crazy that the wrong plugs can really give you deotnation like that. i just cant understand why it was so lean at 1st.

5. It looks like the plugs cleared up the detonation problem so thats good. Also, your a/f in that run looks much better than most afm equipped 3sgtes

i have a feeling that most of the crazy ritch dyno sheets we see are from the USDM ecu. my JDM ecu has a very similar A/f ratio as jeffs runs did.