Why no forced induction on VVT-I 1mz? - Toyota Nation Forum : Toyota Car and Truck Forums

bvacc9 · 07-25-2011, 11:20 AM

Don't mean to beat a dead horse here as ive seen posts like this on club lexus and the solara forum but i cant help but keep wondering why there was never a S/C or turbo built for the 1mz-fe with vvt-i. I know the presence of the air scavenging in the vvt-i system makes it harder to have forced induction but surely its not impossible. If there are celica's that have been modded with vvt-i engines to run a turbo why are there no applications for the gen 5 camrys? I know the gen 5 camry isnt the best product to market a supercharger or a turbo on but why not? There was a gen 4 S/C and to my knowledge there is one for the gen 5 i4 with vvt-i? If it isnt impossible im sure it would cost a lot more then its worth but im just curious. I also saw posts way back of people saying two companies were in the process of making a turbo for the gen 5 v6 the name of them i forget.

Agent556 · 07-25-2011, 06:33 PM

turbo can be done custom, but the supercharger is a pain to try to get to work on a VVT-I head because of the way it works.

When VVT-I activates, it opens the intake valve earlier right before the exhaust valve closes so that both valves are open for a short amount of time. The exhaust air going out the exhaust valve creates a vacuum effect that helps suck in more air through the intake valve when the engine is naturally aspirated. Once you put a supercharger on, the engine doesn't need the vacuum effect, and the result of having VVT-I activate would be that the boost charge air going in through the intake port would go straight out the exhaust port due to the valve overlap

With a turbo, the boost charge would still go through the exhaust port, but since there's a higher backpressure from having the turbo already, the effect isnt as bad and it would actually work.

this video shows what im referring to

You Tube

bvacc9 · 07-26-2011, 12:18 AM

I think I understand a bit more clearly, so it isnt impossible for vvt-i. I just have some questions on what dual vvt-i is as well as the vvtL-i system which i know is very similiar to the vtec system from honda. How much do you think turboing the 1mz-fe would cost and if it makes 210hp and 225tq N/A what do you think those numbers would be turboed?

Agent556 · 07-26-2011, 03:00 AM

dual VVT-i alters the valve timing of both intake and exhaust, VVT-i alters the timing of just the intake valve, VVTL-i alters how much the intake valve opens and the timing.

as for turbo, i can't really give numbers for power and torque since that depends on your setup. cost is an estimate around $3000+ range since you'd likely have to change out the connecting rods to lower the compression ratio unless you run low boost.

bvacc9 · 07-26-2011, 01:36 PM

stock set up as of now, and if vvt-i acts as a vacuum to boost power a turbo would increase this power? and work with the vvt-i system? Im not sure how you would go about disabling the vvt-i i think without it the 1mz gets like 192hp and 209tq instead of 210 and 220 repectively with vvt-i so with that gone forced induction systems would be more practical. and i know im like 5 years late with finding this out but are you aware of the camcon vvt-i controller, its supposed to adjust the timing of the vvt-i pulley and it also changes the A/F ratio not sure how that works or how it becomes beneficial.

Donald E. George · 07-26-2011, 04:19 PM

According to the Toyota shop manual,the variable valve timing comes in at 4800 rpm.That's 2000 more RPM than this old farts V6 will ever see.These are family sedans built for comfort and reliability at an affordable price. I could disable the vvt in the time it would take me to pull the power off the oil control solenoid to each bank.Someone should try this and see if the ECM knows the solenoids have been disabled.Regards

bvacc9 · 07-28-2011, 02:41 PM

4800 rpm? was under the assumption that vvt-i doesnt kick in at a certain rpm range like a vtec system since it is constant and i dont know what toyota your talking about, but i know for a fact mine is easily capable of touching redline when needed so i'd like to know where your getting your information from

Agent556 · 07-28-2011, 04:33 PM

from what i remember, the overlap takes place at 4800 RPM because thats when the exhaust vacuum effect would be most effective due to the speed at which the air has to move in and out of the cylinders.

what he meant about his car not going to redline was that he doesnt floor the car to redline. any car will redline quickly, lol.

bvacc9 · 07-30-2011, 08:51 AM

oh hah i was confused on his redline comment, and i guess if vvt-i does kick in at 4800 a turbo wouldnt be that realistic.