I finally got rid of the shitty basemap on my build, and gave her a street tune (for now) on Crome. I plan on going back and making a few slight changes, but would like a bit more info. BTW, I had a guy who worked with Hybrid Dynamics do the actual tuning as I gave input over his shoulder (Audi/VW guy). My motor is a GSR block, P30 pistons, B16 head out of an EM1, B16 tranny, RMF header, AEM intake, and that's about it. My compression is 11.7:1, and I am running the shitty B16 cams for the time being, with a shitty B16 stock intake manifold. We put on a stock ITR basemap, tweaked the high cam timing a bit, smoothed the fuel curve, and added a slight bit of lower end, thats really about it. I understand I do not have the ITR cams, so we tried to compensate for that. My question is, where is the most beneficial spot for VTEC to crossover. I have it set at 5500rpm now, but I feel as it should be a bit lower, 5200ish. The car pulls a helluva lot harder now, and bottom end is a lot better. It pulls strong and smooth all the way throughout, but I feel like 5kish is a little lean also. Where should I be at for fuel too. Any input is greatly appreciated.

 

With factory cams I always was told to keep the vtec engagement around the stock point.(5800-6k)I don't know of that is 100% true or not but the guy who tunes my car is one of the best tuners in the state and area so I trust what he says. I have a slightly lower compression motor (11.4:1 82mm GSR) w/ ITR cams and my vtec engages at 5800. Its very smooth, which it should be, and I feel like its at the correct spot. Earlier I feel it would be less beneficial. Every motor is diferent though, the best way to spot on the vtec is with a dyno.

 

when you raise the compression over what the factory cam was design for you usually end up needing to move the vtec point lower.

 

There are a few different things to consider when setting the VTEC switch point. Typically you will set it a bit high and do a dyno pull, then set it a bit low and do a dyno pull, then see where they overlap to give the best torque curve. With street tuning you can kind of do the same thing by looking at the fuel curves and a/f logs. With the cams/valvetrain, you don't want it way too high because the middle rocker can lose contact with the cam, and you don't want it way too low because yawr oil pressure may be too low. On a daily driver you probably don't want to cruise on the freeway in VTEC. If you really want to feel it switch over, you can set it a bit higher. So there are a few things to think about.

 

Thanks for the input guys. 93, I planned on keeping it around stock B16 VTEC engagement, but like 2k said, I figured with high cpr I should lower it a bit. Also, stock GSR is lower, so I chose 5500, and I think I could still tweak it a bit, but not sure which way to go. Hybrid has dyno day in a few weeks, and I plan to check out my progress there.

 

vtec engagement is setup specific and among other things has ALOT to do with exhaust setup

free flow = low vtec
restricted = high vtec

just fiddle with vtec until you don't feel a transition anymore

 

Well that's the thing. VTEC is very subtle, and pulls smooth to the top with a faint crossover. Idk if I should set it harder or what.

 

vtec should be a smooth switch over, you should be able to hear it, and not feel it..

b16 cams should like it around 5k.. gsr should like it around 4500-4800rpms depending on setup.. for your CR, 5k sounds about right..somewhere in there.

 

Thanks for all the help guys. Anymore input on anything will help me, I am making another identical tune to try. ALL M0T0R I can hear it, it's not rediculously loud like a B16A crossover, but then again I have the quiet World Sport exhaust, but I do not feel it. If it's at 5500 now, should I try 5200 instead of 5k first?