Is it really worth building a head on a VVTI?

Guys,

I read up today on another forum that there isn't a any massive benefit in building a head and changing cams on a VVTI 2JZ-GTE, What are your opinion on the matter. The Fcon ECU which I am going to use can control the VVTI too.

You had a read of this build thread? I can't remember what cams he went for in the end.

http://www.mkivsupra.net/vbb/showthread.php?267466-Johnny-s-Big-Billet-Twins-Build

Personally think it depends on what sort of power you want to achieve & turbo setup.

Guys,

 

I read up today on another forum that there isn't a any massive benefit in building a head and changing cams on a VVTI 2JZ-GTE, What are your opinion on the matter. The Fcon ECU which I am going to use can control the VVTI too.

Can you link us to the other thread, please?

Firstly, whether you build *any* head depends on your goals. The 2JZ head flows well enough to produce 1000 hp without modification - but of course, porting/polishing/upgrading cams & valves will mean that you make more power for less boost. However, considering you are concerned with the VVTi head, the only extra considerations are the VVTi gear and the necessity for engine management controllability - which are not a problem these days.

Depending on how many miles are on the motor, and how well-maintained it has been, you may want to at least clean, and refresh the seals, in the head. Exhaust cam upgrades will help with breathing for a single turbo, but you may not need to upgrade the VVTi cam. My car has made over 700 whp with a stock head and 264 exhaust cam on race fuel and 31 psi through a 71 mm.

Can you link us to the other thread, please?

Firstly, whether you build *any* head depends on your goals. The 2JZ head flows well enough to produce 1000 hp without modification - but of course, porting/polishing/upgrading cams & valves will mean that you make more power for less boost. However, considering you are concerned with the VVTi head, the only extra considerations are the VVTi gear and the necessity for engine management controllability - which are not a problem these days.

Depending on how many miles are on the motor, and how well-maintained it has been, you may want to at least clean, and refresh the seals, in the head. Exhaust cam upgrades will help with breathing for a single turbo, but you may not need to upgrade the VVTi cam. My car has made over 700 whp with a stock head and 264 exhaust cam on race fuel and 31 psi through a 71 mm.

Great information, just what I was looking for...! :-)

Can you link us to the other thread, please?

Firstly, whether you build *any* head depends on your goals. The 2JZ head flows well enough to produce 1000 hp without modification - but of course, porting/polishing/upgrading cams & valves will mean that you make more power for less boost. However, considering you are concerned with the VVTi head, the only extra considerations are the VVTi gear and the necessity for engine management controllability - which are not a problem these days.

Depending on how many miles are on the motor, and how well-maintained it has been, you may want to at least clean, and refresh the seals, in the head. Exhaust cam upgrades will help with breathing for a single turbo, but you may not need to upgrade the VVTi cam. My car has made over 700 whp with a stock head and 264 exhaust cam on race fuel and 31 psi through a 71 mm.

Hi here is the link to where I read that stock VVTI cams are the best post number 2 - http://www.clublexus.com/forums/gs-second-generation/640230-going-aristo-vvti-auto-swap-in-98-gs3.html

''If you want to pass emissions, you have to have your OBD Port working, JDM Cars are not OBD Port compliant. Running a VVTI Aristo Swap, specially with a single turbo and to tune it there are only 2 ways. Either a HKS F-Con V-PRO for aristo with jumper harness and run your JDM ECU with it (Car won't pass inspection) or AEM EMS Custom parallel ECU setup by Jeffsai...PM him about more information.

You can get your self a Universal Intercooler and make custom piping. If you have extra cash import your self a Greddy Front mount kit for the Aristo.

Fuel set up, Aristo motors need return fuel set up, what i did was i ran the factory feed line as return and ran a 10AN feed line from my twin walbro 255 LPH pumps to the motor on a dual feed fuel rail with 6an on both sides.

I have a JASMA certified Down pipe, can't remember the brand...yahoo JAPAN FTW!

make sure to stay between 19-22psi maximum PSI on pump gas...if you want your motor to survive. 2JZGTE motors love more fuel!

VVTI Stock cams are the best...don't think about changing them.

USDM cars have MAF Sensor, JDM motors have MAP sensor on the intake manifold (Sensor with a vacuum line sticking out).

Every thing is easy other then wiring, i have seen lot of people run Apexi SAFC on there swaps with factory USDM computers...i don't like that at all.

Let me know if you have any more questions''

All I can say, is that if I was going to do all of this again - I'd still do it to a VVTi. Earlier spool, smoother driving off boost. It's just better. IMO.

All I can say, is that if I was going to do all of this again - I'd still do it to a VVTi. Earlier spool, smoother driving off boost. It's just better. IMO.

Cool, sold....! Which cams do you recommend me for my power goal of between 600 and 700bhp?

Titan 264's - that's what I'm currently running in mine.

I wouldn't use a VVTi head at all. it's not true twin cam control like VANOS, and the choice of cam profiles is extremely limited. Plus I am not convinced the VVTi actuator is up to controlling cams with aggressive ramp angles, hence the odd rattling from the thing when more "racy" profiles are used. I'd stick with a properly prepped used none VVTi head, (new guides, and check the bucket to head clearance on used heads) or a new casting. If you are on a budget I would most definitely not use a VVTi head, as there's a lot more mapping time with doing a full VVTi map under lots of load sites. Keep it simple, but do the simple stuff PROPERLY.

I wouldn't bother. If you insist on going there, use HKS cams.

I wouldn't use a VVTi head at all. it's not true twin cam control like VANOS, and the choice of cam profiles is extremely limited. Plus I am not convinced the VVTi actuator is up to controlling cams with aggressive ramp angles, hence the odd rattling from the thing when more "racy" profiles are used. I'd stick with a properly prepped used none VVTi head, (new guides, and check the bucket to head clearance on used heads) or a new casting. If you are on a budget I would most definitely not use a VVTi head, as there's a lot more mapping time with doing a full VVTi map under lots of load sites. Keep it simple, but do the simple stuff PROPERLY.

Thanks for the advice Chris; Is there a simple way to change the head to a none VVTI?

Just bolt it on and use none VVTi cam covers and inlet cam drive belt wheel. Block the VVTi solenoid oil feed off. Maybe other trivial bits I can't recall right now, very straightforward. Unless it's true twin cam timing adjust, or VTEC variable lift, it's not worth the hassle, in my opinion. My doubts about the ability of the stock cam position actuator to cope 100% with more aggressive profiles bugs me, too, although I have no evidence of failure or timing scatter.