OilCanBoyd

I have a 98 GSR. When I hit about 5800 RPMs (or is it 4800?) I hear something opening. Same thing when the RPMS go down. I think it is around the 5800 RPM mark where I hear something close. I'm thinking this has something to do with the VTEC.

What is it that I am hearing?

Thanks for any help on this newbie question

bluetwo

i think the b18's really open up around then. Not sure...

ADRONICUS

Your hearing the cam turn into your highter lift that's the VTEC kicking in/ In a properly timed GSR it should kick in around 5500rpms. Your wheel size can change this too.

OilCanBoyd

Thanks for the help. I am running the stock wheels and I'm fairly sure it is kicking in a bit higher then 5500. Maybe 56 or 57. Does this mean I should have someone take a look at it?

Thanks

dustimus

No no and no. VTEC on a stock GSR is set at 4400 RPM, doesn't matter what wheels he has. The stock intake manifold on a GSR has secondaires that open up at 5800, that is the noise he is hearing.

From Ti.net

OilCanBoyd

Ahhhh ha! Thanks! That is the noise.... Now what does secondaries mean?

bluetwo

secondary butterflys. The little doors in the throttle body.

dustimus

In order for at least moderate power numbers for daily low RPM driving, the GSR intake manifold has narrow long runners from 0-5800 RPMS. In order to make more power from 5800-8200 the IM opens up its shorter lower runners, IE the secondaires.

worm696

ding ding ding

raiden571

could you make the longer runners stay close and the shorter ones remain open? just curious about this, never really heard to much about it