scrambles2112

I honestly had no idea where to post this question. Just wondering what y'alls opinions were about the GSR's vtec engagement at 4500 rpm and the type r's vtec engagement at, I believe, 5600 rpm. Anyone prefer one over the other. Anyone feel 4500 is to low? Does it help having it kick in lower rather than higher? Anyways just wondering since 4500 to 5600 is quite a gap. Anyways thanks in advance.

spAdam

iTrader: (1)

Different cams, different manifolding, different engine = different engagement points. It's not really an opinion issue, it's where the crossover belongs for each engine.

hondamark35

right. and the proof is in the <s>pudding</s> dyno graph.

scrambles2112

Well I guess is there any benefits of having vtec kick in sooner rather than later is what I'm wondering?

spAdam

iTrader: (1)

The correct answer is "It depends." You may find a little bit of midrange, you may lose a lot. You'll have to put it on a dyno to find out though.

hondamark35

agree.

OP, it's a good question, but you won't find a good answer on the internet. get it on a dyno and see what the numbers say. move the engagement point around until you get as close to a nice flat torque curve as possible. it should be a relatively smooth transition from low cam to high cam.

again, if anyone tells you differently- gives you an answer other than "go to the dyno to find out" ignore them.

darrinbrewer

iTrader: (1)

way back, 13 year ago, I had a gsr, went to a chipped ECU, then added a skunk ITR style intake mani. with the ITR style manifold, and stock vtec at 4400, the car would fall on its face when vtec kicked in, then around 5500, it picked back up.

gotta remember on a gsr, vtec at 4400, with the LONG runners, then at 6000 the short runner opened up. a ITR or skunk2 mani, your on short runners ALL the time.

I found that 5300 was a typical good vtec point for most mild all motor builds that were NOT using a gsr manifold. 6000 was just too long on a wait, the power from the low cam was already falling of at that point.

This was my experience, I street tuned around 100 b series builds on crome, that's what im pullin my information from

v4lu3s

I will agree with darrinbrewer, a friend of mine had a stock gsr that worked great with stock vtec crossover. when he rebuilt with a pr3 head, pistons, aebs manifold and much better header, plus type-r cams we found that a higher engagement point was needed. Honda did a pretty good job choosing the point based on the stock setup. If you change teh manifold or cams its worth playing with to see what works best...

scrambles2112

Ok that's good to know then because it DEFINITELY will be built. Goal is 500hp so wish me luck