Amuse Boy

On the weekend, I was pratting around with my mate's EVO - we both took off from the lights nice and slow and continued to climb the revs very slowly (part throttle). Once I crossed 6k, I could could hear a very definite engagement of VTEC, onto 7k, I hear the EVO change gears, but I carried on up to 8k (part throttle) but as soon as I let off slightly, the car would suddenly jerk as if I've flicked a switch. Tried it several times on part throttle and the same thing.

Is this normal? It never happens on WOT or when I am pushing it a bit. Just when I am gradually applying the throttle within the VTEC zone or just trying to hold it steady at 7k.

Has anyone else tried this? SHould I wack the MAP sensor and do an ECU reset?

Amuse Boy

Anyone? pleeeeaaase!

Amuse Boy

RACER

I don't know of a reason to climb that high with part throttle. When I'm at high rpm, I am either on or off throttle.

It wouldn't hurt to tap the map sensor and reset the ecu.

mxt_77

What gear were you in? First, still, I assume. Engine braking is very pronounced on the S2000, due to high compression and probably many other factors. I'm guessing that this is normal.

Amuse Boy

Thanks for the response guys

Yeah, it can happen in any gear but you're right, the engine braking is very pronounced and is quite disconcerting. For example, if I'm holding the revs at 7lk in 2nd ready to enter a tunnel it can get quite off putting because the car feels as if it keeps switching between VTEC.

So, what would happen if I am taking a long sweeping bend and want to hold the revs at 7k in 2nd or 3rd - I'd be very worried of any sudden throttle changes to upset the balance.

Thanks for advice - I've wacked the map sensor and reset the ECU by disconnecting the battery for 15 minutes. Will post back with results.

RACER

I have held my rev's at about 8,900-9,000 rpm going through turn 5 in third gear at my local track. I had absolutely no problems at all. As a matter of fact, I even bounced off the rev limiter once without upsetting the balence of my car.

The higher gears are less sensitive to maintaining as well as lifting off the throttle from high rpm's in this car.

mikegarrison

In any car. Basic physics.

RACER

I was refurring to the sudden jerk Amuse Boy felt due to the S's unique characteristics.

Fongu

Basically agree with everyone above. Your probably feeling normal engine braking. It is more pronounced in lower gears because of the higher torque multiplication from the transmission. I'm pretty sure it doesn't matter if you are letting off the throttle from WOT, partly accelerating or just balancing the throttle. The amount of engine braking would be the same in the same gears. Read somewhere that zero throttle cuts fuel/spark and the engine is just "dry spinning", so ECU adjustments don't seem applicable. It's just that the transition would be bigger, bigger jerk, coming off heavy throttle. Suspect that the different feelings are due to different gears, or just automatically clutching in on WOT anticipating a gear shift.

As far as gear/rpm selection, that's more what you are comfortable with. The lower gear/higher rpm makes poweron oversteer easier and more power on corner exit. It takes a more sensitive touch on the throttle. From a racing perspective this would be preferable, but that's driving at the limit. Do you really want to do that on the public streets in variable conditions? It's wiser to have a little more safety margin, especially if you are unsure about your ability to control the throttle. It still boils down to driver skill and proper decision making.