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  • -Totenkopf-'s black SW20 (56k beware!) (p.47)
2011/11/07 17:00:03
-Totenkopf-
vvti has it merits.  It'd be great if TRD still did their VVTI cams, however, they don't.  Using a nice duration cam without the negative side effects on a forced induction motor would be wicked.   I don't know how much benefit you'll get if you are going to be running seq turbos anyway.  With a big single I would suspect you could see increases in spool of 500rpm or a little more, which is nothing to laugh about.  Obviously this is with the vvti dialed in correctly which could prove for ALOT of tuning time on the dyno.
 
I am quite confident I could get a beams head to work on a 5s bottom end with an external VVTI oiling mod.  Ferrea could do me a custom valve set and I think I found some springs and retainers that would probably work (based off installed height and preferable seat pressure).
 
 
2011/11/07 19:00:38
just_ace
not entirely sure on the logistics of oiling for VVTi, but it seems the oil feed is external standard. theres a big pipe coming from just under where the norm oil feed for a turbo is which goes up to the head.
 
i'm sure it won't require much more block alteration than what i'm already having to do for oil squirters, gen3/4 sump and AWD box fitment.
 
debating on whether i'll need new pistons or can modify my CP's. won't know until i pull the block apart i guess.
 
for your engine/car uses have you thought about a shot of NOS to bump the spool?
 
reason i chose vvti to compliment the seq turbo's is if i had 272's timed for top end it'd still be a pig to drive down low rpm even with the little gt2860.
 
hopefully i won't need such wild cams with the vvti to achieve a screamin topend rpm, also i can use much higher lift cams with the vvti heads than norm 3s.
2011/11/07 20:18:30
-Totenkopf-
Yeah, well, I guess we are both after different things at the end of the day.   The CP's probably wont be useable, the valve angles and positions are different and the combustion chamber CC is much less. 
 
That pipe isn't an oil feed, I think it may be a drain from the back of the head.  The oil feed for the VVTI is an extra gallery in the beams block.
 
IMHO, I think the real benefit in VVTI is being able to run a wilder cam then normal.  The valve open duration will be limited by the cam duration so running a smaller cam you are sort of cutting yourself short by not having the larger duration you'd want at high RPM whilst still being able to minimize overlap at low RPMs (particularly important on a turbo).  The lift is much higher, yes, I am running 11.8mm lift in my head and the vvti heads easily have another mm over this.
2011/11/07 20:27:56
just_ace
yeh, not 100%. read various things about needing to limit vvti movement when going to larger/higher lift cam's but not sure if that just when using the stock motor/pitons and valve relief aren't big enough to accommodate the extra lift.
 
i was thinking that due to the vvti movement you wouldn't need so much duration as the vvti creates the required overlap for high rpm, but maybe still not enough for 8500-9000rpm. was thinking i may get away with 264's.
 
i'm not sure how much control there is over changing vvti movement from stock settings? can you advance/retard it more than factory settings?
 
should email you about this, side tracked from your thread.
2011/11/07 21:10:21
-Totenkopf-
Yeah hit me up.  There is valve to valve and valve to piston contact you have to worry about.  Normally you need to measure these clearances using putty with the head on.  I am not 100% certain of the stock mapping but I would think it could make use of near on full advance and retard allowable by the VVTI mechanism.  As you get larger and larger cams you need to start limiting the vvti movement, which needs to be done not only electrically (through the map in the ecu) but also mechanically to absolutely ensure no contact will occur, obviously if you got deeper reliefs then factory you may be able to look at running larger advance or retard valve to valve contact allowing. 
 
With an ecu with cam control you can control the cams however you want within the stock range.  You are correct that you can tune the vvti for required overlap at high RPM, thing is, your still limited to the shorter duration.
 
I believe Toda at least make a vvti enabled cam still in the 264/268 range.  If you have a look at all the mivec evo's you'll notice that they run much more aggressive durations then an 3sgte.  >280 is quite common.  I believe the ability to run this large a cam has alot to do with the variable cam control.
2015/05/12 07:21:49
alexandre
Hello ,
Can you tell me , if you sell your intake mainfold ? Or can you give me some website where i find the same intake mainfold like you please ? 
2015/05/12 10:54:21
just_ace
Rmr have stopped making their manifolds.

Try racerX.
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