Posted in S2000 talk, but received little response, so copied post here:

I have MY02 with 16,xxx miles and have been experiencing some troubles when accelerating. When I am going from 1-2 WOT, my revs climb normal, but car does not feel like it has reached the VTEC "surge" (ie acceleration seems constant). When I am going between shifts in VTEC it is almost like the clutch is still engaged, because the revs remain constant between 8-9k for about 1-2 seconds rather than dropping off (to about 6k) after engagement of the next gear. At first I thought it may be the clutch but now think it has something to do with the VTEC control. Any ideas/suggestions as to what the problem is? Could it possibly be the map sensor?

Thanks

 

a couple of things i.e. temp and oil level can throw off your Vtec solenoid. Also, how fast are you accelerating? If you climb to vtec slowly the transition will be subtle, unlike the more dramatic response when you're at WOT. Also, do you have a CAI?

 

I don't have a CAI. I just recently installed a K&N air filter, but can't imagine that would be the problem. I topped off my oil level just last week, and don't really push my car until there are three bars on the temp guage. This problem occurs at WOT.

 

hmmm.... is the engine idling ok? Sometimes the ECU needs to adjust to a new filter (more air flow and thus a different air:fuel ratio). Try removing the fuse to the ECU (after disconnecting the battery cable) and see if that helps.

 

I'll try restarting the ECU tomorrow to see what happens. Hopefully that will do the trick.

 

I can't really understand what you are trying to explain, but it sounds like you are feeling less of a "kick" from VTEC. If this is the case, then it is extremely normal. Any real engine performance mod will reduce the kick that you feel from VTEC, since it will tend to smooth out the power curve (bonus). Also, we mortals have the tendency to get used to good things, which makes the transition seem weaker over time.

I think that your car just needs to have a good wash and wax to get it back to peak performance.

 

It is not only the VTEC point that is depleted, but also the RPMs between shifts. I don't think just a filter would have that much of a performance upgrade so that VTEC engagement would not be felt. If the car is shifted from 1-2 at 9k, the revs will still remain around 8-9k for a few seconds after the clutch has been released. This should not be the case, and the only problems with the car occur once VTEC is hit. I resetted the ECU this morning and will be driving around to let it "learn" all over again, so will post my findings this afternoon.

 

If you are dropping less that 1K RPM between shifts then i salute ya! On my best shifting days (without rev matching) I drop from redline to just above VTEC engagement. If I understand you correctly.

*edit* Whoops...sorry I did misunderstand!

 

We don't know how you shift. If I don't let go of my gas during a shift, my revs won't drop at at till the powertrain hooks up (although this would be a silly thing to do under normal circumstances). What you are trying to describe may not be a function of VTEC but more a function of clutch wear.

 

[QUOTE]Originally posted by xviper