supose you had a 93se, and where boosting 5-6psi (intercooled dim 18x7x3) would it be a good idea to grn the vtc?

 

This is your first post? What exactly about the vtc's makes you want to know if you should disengage?

 

I guess what i am trying to say/ask:
grounding the vtc (so that the timing doesnt advance when you build rpm and boost pressure)to avoid detonation.
would this be a good idea? or would just retarding the the timing and leaving the vtc alone be a better choice?

 

Seems like you could just leave the vtc and timing alone, of course I don't have experience boosting. Be advised, with a first post about boosting a VE things could get interesting
:

 

I dont think the VTC has to do with ignition timing, its involved with the cam timing I think. Ignition timing is what you are thinking of, and yes on the VE 10:1 I would think maybe a few degress retard would be optimal.

 

I agree, I'm pretty sure the VTC is Valve timing, not ignition. However, you need to find out how the relationship between the intake nad exhaust valve is altered when the VTC engages (ie overlap) Turbo engines don't like alot of overlap. In NA engines, overlap helps with the scavenging effect, the momentum of the column of exhaust gas leaving draws the fresh charge in when both valves are open at the same time (overlapping). On turbos, the cooncern with scavenging is essential gone. I'm sure it still occurs to some degree, but now you have a major pressure differential between the intake charge and the exhaust gases exiting the chamber. The pressureized intake charge needs little help getting in there, it is being rammed in by the compressor. Having the exhaust valve open too long will cause fresh charge to be blasted out the exhaust port. poor performance results with respect to power procuction, gas milage, emissions, etc. That's why turbo cams are typically lower lift (more than say, our stock NA cams, but less than an aggressive aftermarket NA cam) with less overlap.. If the VTC increases overlap (not sure if it does, but I'm sure it changes lobe seperation) at higher RPM, then diabling it might be a good idea. But the only way to know for sure how it will effect performance is to do it, dyno it, and dyno it ungrounded. Sound reasonable?

 

thanks male, I dont know why I was thinking vtc had anything to do with timing ( I replaced mine last summer)

 

just wanted to let everyone know that I have been using this board for almost three yrs ( I use search alot )I use the name prettyboymax (couldnt remember my old email, pass word just made up new name) I was working on turbocharging my ve around the same time czar was boosting his. To make the story short, I am in the military, and when the tragdy of sept 11 took place, I had to post pone the project. Well Ive been back from my mission and picked up the project from where I left off. so this really isnt my fisrt post, but back then I never posted much anyway

 

Sweet...how far along are you on the project?

 

That's good to hear. It was late at night and I saw a newbie turbo post and was wondering

 

What really holding me back is an input shaft bearing for my tranny. I already replace the flywheel with the aasco and the clutch with act. As for the turbosytem;im waiting for my exhaust piping to come in, and I have to finish welding the intercooler pipes.

 

Hmmph check your e-mail

 

Yeah, those input bearings SUCK. So you got the clutch and f'wheel in and have that noisy bearing, right. Same crap happened to me..thought it was the release bearing, so I put a clutch in it only to find it was that damned input bearing.