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VVTi guys you HAVE to look at this


qaisar
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Found this on supraforums.com

 

 

2jz-gte VVT-i fully modified...A Reality...

This picture proves that the old myth about not being able to modify a VVT-i 2jz motor is just that...This engine has an HKS GT2835 kit, and is fully built. How can this be? There is now new hope of importing these engines and modifying the hell out of them....

2jz-vvti.jpg

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Guest Terry S

2835's are horrible lag monsters. Any single kit will fit a VVTi. Who said any different???

 

I am thinking about throwing a small single on the Black car in a few Months

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Originally posted by Terry S

2835's are horrible lag monsters. Any single kit will fit a VVTi. Who said any different???

 

I am thinking about throwing a small single on the Black car in a few Months

 

I was thinking that, i've just seen a dyno plot on suprastores for this kit and im not too impressed.

 

Dyno Plot of the 2835's

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I wasnt sure before because of the vvti specific downpipe needed, also with the accompanying problems like ecu and cams etc

but heres an interesting quote from the thread

 

"The GS300 that SP just finished (Sound, not Speed Pride) made 600 rwtq @ 22 lbs with a leeetle SP61GT on the VVT-i motor. That is absolutely freakish, and Lar attributes it to the variable valve timing."

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Guest Terry S

I have had turbo issues with SP and take a lot of their info with a pinch of salt. I am the UK distributor for Boost Logic. Their kits are much cheaper and better quality IMHO. The 61GT is just a pTE turbo with a GT35 hot side. Most companies can get it.

 

There is no point putting a really big single on a VVTi due to the cams, unless you want to spend a fortune on a Valcon system.

 

I am looking into all this pretty deeply guys as I now have a VVTi, so if anyone is interested PM me.

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This guy, Lex Luthor, has apparantly tuned his own vvti car (not a supra i think)

 

"my SC300 is so responsive and fast-revving with the VVT-i that even NA it would light the tyres up from a stop. My SC400 with a 4.0-litre V8 won't do that. My SP63 has a .81 A/R and still spools quicker than this turbo on a regular 2JZ running a smaller housing."

 

"the stock VVT-i cams have been proven good to over 700 rwhp (again technically TT exhaust cam but this is almost identical)...this is about all most guys (even mkiv guys) would want in a street car, especially a daily driver, so in that application it's basically a non-issue. Since that is absolutely pushing the limits of what these cams can flow, when it comes time to upgrade you still have options and this should hopefully settle it. You can use a standard HKS or JUN grind on the exhaust side as we agree, for the intake cam if you are not happy with one of the two VVT-i grinds offered by HKS (I agree the lift issue will be of concern at some point, but that's got to be north of 800hp)...you can always have Brian regrind them to the Crower specs which are pretty close to the HKS 272 specs and made almost 1000rwhp in Ethan's SC300. Yes you'll have to use lash caps, but is that a good enough reason not to utilize the variable valve timing technology? Nope, not IMO. Again no one has addressed the two VVT-i cars I mentioned and their 'abnormal' performance. It's not a question of why it isn't commonly used, but how long it will be before it's mainstream."

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Guest Terry S

I will look at the thread and see if I can contact the guy. That seems alot for a VVTicam to flow, although I can't find the lifts, Arnout said they were similar to JDM cams. Considering UK cams become a restriction above 650 it seems a lot.

 

I'll let you guys know what I find. BTW I can get a Dual Ball Bearing 61GT35 which should spool slightly quicker and maintain a bit more inertia

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"Well I think I can answer the AEM question. It can be done, pretty easily actually. The VVTi system is controlled through PWM into a solenoid valve, which then modulates oil pressure to the pulley, which then effects the total amount of advance/retard of the intake cam. So electronically, it's just a PWM signal. The AEM has a valve timing output, that runs on PWM. Hook up one wire to the AEM, turn on the valve control, and tune it with the "Valve Map." That's it. No major hurdles to overcome."

 

I personally have no idea what this means except the bit "it can be done pretty easily"

 

:D

 

forgot to add that guy is called AnArKey on supraforums and apparantly has quite abit of experience with AEM ecus

 

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more interesting stuff on the thread at supraforums (hope this reposting is ok with the mods, but i think its about time there was some more info on VVTi's on this forum)

 

BLKMGK (a knowlegable guy on AEM)

 

"Okay, I pinged an AEM tech. Not only have they been working on VVT but it looks like it's pretty far along. A beta I'm using now apparently has some code in it already and it was developed for the WRX's tumble valve control. Control range looks to be pretty wide too! There appears to be some sort of closed loop feedback on this too. Not understanding the technology all that well I don't completely understand all that I'm reading but it's apparent that they are working pretty hard at this. Unfortunatly this is an internal design document not ready for release so I cannot share it but when this firmware goes production it looks like the code will be there and the instructions to back it up will be provided. "

 

Also added by turbo97se

 

"There is a VVT-i (AEM call VVC) map control in the AEM software. If you look hard enough you will find it. Lex is right about the valve control, there are many paramters that makes it impossible to tune and control with just the PWM. There is an option in AEM to have active feedback control. The PWM controls a solenoid valve which controls oil pressure which determines the amount of lift in the cam. Knowing where how much lift there is at any particular time is the key. The AEM does have the ability to do this. I will be playing with this in the next few months

 

The Supra EMS is not necessarily the best EMS to run."

 

 

BLKMGK

 

"they are continuing to add new features to their existing EMS. They HAVE made some hardware changes to some platforms like an internal W/B driver on the EVO VIII boxes and the Viper box will be WAY different since it must live in the engine bay but overall no, same box with upgraded firmware. So far as I know this firmware will allow a Supra box to run VVT-i in some fashion. However I wouldn't run out and buy one until the firmware is released and this is confirmed by AEM. It appears to use more than one PWM and I'm not sure how that is done since I thought there was just the one spare. It's posisble they're doing some switching based on parameters ie you don't need a PWM meant for idle when not in the idle range but I'm NOT sure. clear as mud?

 

Bottom line - this is not for a new box, this firmware is meant for the existing box and if what I'm seeing is correct will allow for variable valve control. I do not know if it will be what you need for the Toyota VVT-i, time will tell."

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Guest Terry S

I have no problem with Derek at all. He is a very clever bloke.

 

The reason I said that is there is no PNP for the VVTi ( although I think there may be a PFC) I cant face another loom, and the car will not be that extreme this time.

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I see.

 

I reckon your VVTi will make a hell of a car with some basics and hybrids. Question is if your want to take that route again. A single would be better, but it's the mapping and getting it to run properly thats the hard bit, especially on a VVTi.

 

How much experience does Leon have with these?

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Guest Terry S

I am not sure how viable hybrids are when you can get a full kit so cheaply now.

 

The VVTi appeals to me now, although I am missing the purple car like mad. The VVTi now is a bit of a challenge. I aim just to ake a fast road car, nothing extreme, and definitely not a " no expense spared" car. The ecu will be OK on a small single. I will obviously need to do a few things to alter it but nothing extreme.

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This sounds like how the purple one started...'not too extreme, some hybrids......sod it big single........make that a bigger single... :D '

 

If reckon with the extra torque, it can make a brilliant road/race car but only with moderate power sub 500bhp. Wonder if it will be enough? If you take it further, you will be in for a lot of expense if you want to utilise the VVTi, probably first single turbo VVTi in the UK.

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Originally posted by Terry S

That's the aim between 500-550 at between 18-23 psi.

 

Trust me this one won't go further:innocent:

 

Sounds like you're aiming for what i want with my vvti, my soop is completely standard at the moment but hopefully i'll be making some basic upgrades soon exhaust decat uprated fuel pump + fse ect ect.

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