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Discussion Starter #1
i vaguely remember this being brought up before but can't seem to find it with the search... so i'll ask it here

has anyone ever tried importing a j-spec vvt-i head for the TT Supra (99+ i believe) and playing with the vvt timing/duration stuff instead of just replacing with more aggressive cams?

i remember reading that going any higher than 8500rpms is pretty useless since torque drops off so heavily after that unless you get some crazy cams, but then you lose any streetability.
 

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Whats the diff between using j-spec vvti topend? Are the cams. flow setting diff? Can they handle a higher rpm range? Give me some info Please Thanks BRett
 

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krazytaiwanese said:
i vaguely remember this being brought up before but can't seem to find it with the search... so i'll ask it here

has anyone ever tried importing a j-spec vvt-i head for the TT Supra (99+ i believe) and playing with the vvt timing/duration stuff instead of just replacing with more aggressive cams?

i remember reading that going any higher than 8500rpms is pretty useless since torque drops off so heavily after that unless you get some crazy cams, but then you lose any streetability.
Over the past couple of years, no body on the forum has got any of these-and announced it

I would assume it could be a great mod, depending upon how they are controlled and if they are adjustable viz computer or something. I know hondas can adjust their vtec so maybe these can be adjusted. That would help alot of people gettin more power out of less lag, the ultimate goal of 4 and 6 banger turbo cars:)
 
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Discussion Starter #4
btw, do j-spec VVTi heads use two cams to vary duration like celica vvt-i engines?

those are pretty nasty once the 2nd cam kicks in... my friend's celica breaks traction in 1st gear due to that. i was thinking in a supra you could run a streetable cam all the way to 6000rpm... then a LONG ass duration cam from 6000 and have it breathe well all the way up to 10000rpm.... you could get a HUGE gain in power right there.
 
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Discussion Starter #5
cuz hmm... looking at 272 cam torque curves they seem to peak right at 5750rpms - which is pretty low... theres a lot to gain from really aggressive cams. imagine running 2nd cams that peak at 9000rpm.

take jesus's car for example - he makes 706 ft-lbs. (at the wheels) max torque at 5750 (272 cams). now run some insane cams that peak at 9000rpms - 706 ft-lbs. torque at 9000rpm = 1210hp!! and thats without changing boost so not too much worrying about detonation.

it probably wouldn't make THAT much hp at such a high rpm... engine geometry might not allow for it but you could probably also play with timing to improve the VE.. and who knows that might just compensate.

or am i just out of my mind? :eek:
 
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Discussion Starter #6
ok, nevermind... only the celica has VVTL-i - the L for lift & duration... the 2JZ heads only got VVT.

anyone know if honda vtech has variable lift & duration?
 
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Discussion Starter #7
yep hondas have em there is only one version of tha vtec like toyotas vvtl &vvt butt this is very interesting, whoe knows it just might work out
 
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Discussion Starter #8
ya'll have got it figured out!!!!!!!!!

HP=TQxRPM/5252 WAAAHOOOOOOOO
 
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Discussion Starter #9
if anything you could help increase drivability, and keep the top end power, the AEM can control the VVT-i
 

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To shed alittle light on this subject the latest issue of turbo magazine listed some pro's and con's to using different heads on the 2JZ they're installing in their SC300 Lexus. They sighted a downfall to the VVTi head but I can't remember what it was.
 

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From what I've found the VVT was simply to control emissions and to bring them down in line with japans new laws... very little hp gain from just the vvt
 

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Thadius82 said:
From what I've found the VVT was simply to control emissions and to bring them down in line with japans new laws... very little hp gain from just the vvt
That's a very loose comment. Seeing though the Japanese will not quote HP over 206kw (280HP) due to the gentlemans agreement.

It made more torque (around 15 or so ft lbs) with the VVTI so there must be some benefit other than emissions - Toyota isn't *that* stupid :)
 

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Thats all out the door now... Gentlemens agreement is no longer in place.. But as i said from what i knew it was only emission control
 
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