lower rpm vtec engagement???

[whitefun]

dave, is it possible to lower the vtec engagement rpm to 5000? love the car
but would like to have a wider range of vtec use. 05 gpw s2k. thanks for any advice you can give me. i suppose a higher fuel cut off rpm might also be an option although i don't know if that would be wise on the 2.2? simpler the better if that is possible. thanks phil :revto9k:

[SenderGreen]

I know you're not asking me, but you can lower the VTEC engagement point with a programable EMS or piggyback VAFC. To lower the VTEC engagement point to 5000rpm would probably not be beneficial. I think you can tinker with with it to an extent, but I don't think it is advised to make drastic changes to the tune of 1000rpm. I don't really know from personal expierience, so hopefully you'll get more feedback.
It may be worth noting that the actual engagement point of VTEC varies slightly even under OEM ECU control. I think it is dependent on at least 5 variables/conditions (don't remember off top of head).

EDIT: As far as higher fuel cut off, you could do that by swapping OEM ECU's with an 00-01 or 02-03 S2000. The 02-03 OEM ECU's run a little leaner than the 00-01 ECU's and may be more risky to run with an F22. Either would let raise the fuel cut-off/rev-limiter to around 9200rpm(maybe too much). I am sure there are other, maybe even easier or safer ways.

[gomarlins3]

^As mentioned above, a VAFC will allow you to lower your engagement point. I don't know if you would want to go all the way down to 5,000 though.

[repiv]

I think these fellas have answered the question pretty well. I'll add my 2 cents.
I've seen posts from those who have lowered VTEC on an otherwise stock engine down to about 5300 rpm. You can always try a little lower. An engine can only breath so much air and fuel at any given rpm. Lowering VTEC allows it to breath better but at lower rpms, this can be a detriment. You will begin to get a rough running engine or one that struggles to get past that rpm. Now, I've also seen VTEC lowered below this but this was in a car that was F.I. and had quite different engine management.
It would be similar to (in the "old" days) to a car with a 4 barrel carb where the secondary barrels are vacuum actuated. Some guys would mechanically rig up the secondaries to open immediately as the throttle opens. In most cases, the engine bogged terribly and the car was nearly undriveable at lower rpms.
As for raising the fuel cut on the 2.2L, the valvetrain can likely take it and survive. It's the piston speeds that you have to worry about. This is why Honda dropped the redline on the 2.2L. Because the stroke was lengthened to get the extra 200 cc, the pistons travelled exponentially faster at 9000 rpm. A reduction of 1000 rpm was deemed necessary to maintain long term reliability.

[whitefun]

thanks for the information guys. it sounds as if the benefits would be marginal at best to tinkering with vtec in either direction. if anything maybe lowering the rpm by 2/300. the car is certainly tuned very well and performs strongly from the factory. i'll work on improving my shifting/driving skills! :thumbsup: i think i will go with a new set of rear gears and leave the eng tune as is for now. thanks phil

[raymo19]

... i think i will go with a new set of rear gears and leave the eng tune as is for now. thanks phil

And so it begins (again). First the gears to get some grunt down low, then FI and engine management a year or so later. ;)

This stuff is habit forming. :D

[gomarlins3]

And so it begins (again). First the gears to get some grunt down low, then FI and engine management a year or so later. ;)

Actually it was three months later for me, hehe.

[hecash]

Having done the very first install of a VAFC into an S2000, I got a lot of time to mess around with engagement and disengagement settings both in a straight line and track scenarios. Here's what I found with an AP1 over a full season of tuning.

STRAIGHT LINE
No improvement in straight line performance by dropping below 5,500 rpm. So, the factory setting of 5,600 rpm is right on the mark.

TRACK
In an FI configuration, I found that a disengagement at 5,100 rpm and engagement at 5,300 rpm was most manageable and quickest combination. If you manage the shifting well you don't drop out after the first turn. You can run all day between 5,100 and 9,000 with a supercharger.

I'd like to hear some more results from other SC track junkies that have tuned the VTEC.

[AssassinJN]

Well I can't speak from direct experience (I have decided to wait until FI to get the aem ems) I have driven in an ap1 with vtec lowered 400rpm. I would say that while it didn't make a huge difference, it was noticibly smoother than the stock engagement point.

As far as a 9k ap2, it's been done. There are a number of people running relatively stock ap2's at or above 9k. Most say anything above 8500 has no benefit and will shorten your engines life span significantly.

[fltsfshr]

I have my vtec engaging at 4400 exiting at 4100. It work very well with my setup. Makes for a very smooth power curve. I'm using an sc larger injectors and an aem.

fltsfshr

[hecash]

I'm using an sc larger injectors and an aem.

I think that the AEM gives you a LOT of room for better tuning over the VAFC that I had. When you acurately manage spark and fuel, you have a big leg up.