Where should vtec crossover be set at

[projectxspeed]

Can anyone give me an intelligent response to why you should not set your vtec crossover low?

 

[projectxspeed]

???

 

[AppleSauseSi]

If you set the crossover high the engine will start to "suffocate" and lose efficiency, if you set it low the engine will have a smooth crossover and there wont be a beefy kick, it will eliminate the uncomfortable jump in the power band. Check out this article http://crx.honda-perf.org/articles/crvtec/crvtec.html it’s about a CRVTEC engine but you can see in their dyno results VTEC was set too high and they needed to lower it to get power through out the power band, if you like a big hop in power so you can feel it set it higher, but if you care about performance run some dynos and get a device to change it to how you like it.

The point of VTEC is to let the engine maintain its efficiency at high RPMs and still have a nice drivability. You could set the crossover to 250 rpm and it would be like getting a more aggressive cam but it would be less fuel efficient and you wouldn’t see all that much low end gain.

???

lame post, don't waste space.

 

[projectxspeed]

Thanks that was a good explaination

 

[GSRCRXsi]

if your engine is stock, dont change it. im talking internally stock, as in you havent changed any head or block internals. honda know what they are doing, it is already at the optimal crossover point. if its not stock, then the only way to find where to put it will be to hit up a dyno. do 2 runs. set it really high, like at redline, and then on the second run set it really low, like 500 rpms. compare the dyno readouts, and where the tourqe curves cross from the two plts, that where you want your vtec cross over point at. no one can tell you a number. especially if you dont give any info as to what engine it is or what mods it has.

 

[xj0hnx]

Originally posted by AppleSauseSi@Jun 6 2004, 02:31 AM
If you set the crossover high the engine will start to "suffocate" and lose efficiency, if you set it low the engine will have a smooth crossover and there wont be a beefy kick, it will eliminate the uncomfortable jump in the power band.

That's completely opposite, the lower I set mine the more "kick" it has, the higher I set it the smoother the changeover.

 

[E_SolSi]

mine engaged much harder when it was set at 6K than it does now at 5.5K

 

[phunky.buddha]

Mine needs to be lower for a smoother power curve, but I don't want to drive around all day in VTEC. 70mph = 4000rpm, and that's where I need my VTEC at- but that's also freeway cruising speed.

 

[Bkkfarang]

go 4500 but retune your fuel map to that crossover point, if you simple lover the vtec change the cross over point and don't re tune mostly you are shooting your self in the foot

 

[awptickes]

Mine needs to be lower for a smoother power curve, but I don't want to drive around all day in VTEC. 70mph = 4000rpm, and that's where I need my VTEC at- but that's also freeway cruising speed.

Damn. 4k for me is around 87mph.


Do the dyno readout people have told you to do. You'll be much happier, and so will your engine.