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Discussion Starter #1
Hi All,

I have now read in a few places that the R33 GTS-T has variable valve timing on one of the cams?

Is this true? If so how is it actuated, and can this be mapped with a Power FC?

Is this the big silver thing at the top front right of the block? the bit with wires running to it?

Cheers

Nigel
 

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kngp2104 said:
Hi All,

I have now read in a few places that the R33 GTS-T has variable valve timing on one of the cams?

Is this true? If so how is it actuated, and can this be mapped with a Power FC?

Is this the big silver thing at the top front right of the block? the bit with wires running to it?

Cheers

Nigel
Yes it has VVT
Yes that is the one!!

Thats all I know I am sure somebody will give more and detailed info on this.

E Regardo
Ay Corombo
 

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That's a good point, cause I heard that too. Now I driven a few Honda's in my time and you don't arf notice the VVT when it kicks in. Mine certainly does jump up a notch around 5k but I was reliably informed on a Rolling Road day that was due to an increase in boost!

So do they have VVT? If so when does it kick in?
 

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You can hear the VVT kicking it, you hear about 5k the engine note change.

Personally I wouldnt fiddle with it, it is an integral part of the ECU and workings of the engine it does its job quite well.

If your looking for a power application incrase of over 450HP the VVT needs to really be taken off as it becomes confused and unreliable. * this is what I have heard from a number of sources *

This comes on all our engines as standard, what they don't have however is the NEO which is VVT for low down timing to assist with low torque levels. This was only ever introduced on the R34 GTT engine, although it has been rumoured HKS are bringing out a VVT for the GTR engine and this should be with us shortly.
 

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Discussion Starter #6
Yeah mine too, at 5k takes off.

But the question is this, is it the exhaust or the inlet valves? Cause the silver motor looking thing is on the exhaust side?
 

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M's Factory
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exhaust valves. look at the side of the head which the VVT is on. It is the exhaust side of the head ( Turbo Side )

And so it should scream !
 

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the device on the exhaust cam at the front of the engine is the crank angle sensor, this tells the ecu when the engine is at TDC so therefore it will inject the fuel and fire the plugs at the correct time.
The VVT solenoid is on the inlet side of the engine just in front of the inlet manifold near the cam belt cover, has a electrical plug connecting power to the solenoid valve. The solenoid valve moves the cam timing approx 5 degrees advance/retard. I think the soleniod is energised at approx 4500/4750 rpm , i have tried adjusting the rpm change over point using a power fc and have found the standard changeover point is the best for power/torque.
this is my 2p worth and I may be wrong, but I think I am correct "sometimes"

Mark
 

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From what I have been able to find out, this was done to pass emissions rather than increase power. The VVT inlet cam has less duration than the previous fixed inlet cam.

The cam itself has oil passages in the end, and a spring/piston arrangement with helical splines. When a solenoid valve opens, oil pressure causes the cam pulley to rotate in relation to the actual cam. The electrical solenoid is operated by the ECU.

At idle RPM the inlet cam is retarded to remove all valve overlap. This is to give good clean idle emissions. At some low RPM (1500 ?) the cam is advanced to give better low end torque. Above 4000 RPM the cam is again retarded.

This is why the GTS is considered slightly better low to mid range than the GTR and probably why HKS have had their VVT kit for the supra for some time and the GTR one on the way

Paul
 

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As far as I can remember Apexi does VVT controller I am not so sure what its called. Thye also do vtec controller as well for honda`s.

Kind Regards
 

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NO i know why they did it. When you go to tracks they ask you to hold your revs at 4.5k dont they. well there you go then those nice little nissan men made our cars open right up after 4.7k

So they did it to make sure we can get out on the trax within the noise limits.

Mark, you do know somethings, sometimes dont you. its quite uncanny !
 

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is that your car kngp2104 in your avatar nice flames is great to see peoples faces when does that

lee
 

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So when my engine screams at 5k it's not due to an increase in boost? If this is so, then the increase in the boost on my Dyno graph would be related to the VVT. Is this correct?
 

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Lanky,
The GTS VVT affects mid range torque not balls out power at the top end.

Paul
 

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mmm still unclear.

My Dyno reading showed a increase in boost from 0.5 to 0.64 bar_g at 4700rpm.

So the boost increase and the VVT obviously kick in at the same time BUT are they completely independant of each other.
 

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there is just the second stage boost increase, the VVT is not like Honda's in any way shape or form as it there to affect mid range tourque thats it
 

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Sorry to dig up an old post, but am jsut about to map my NEO RB25 on a V4 ECU.

I'm assuming it is just an on/off system rather than PWM controlled.

To summerise, should I switch it on at say 1300rpm/4700rpm or should it be on, then switch it off above this RPM? or Should it be off, then on, then off again?

As long as its not PWM controlled and as such it wont swing the cam enough for interference I'll have a play, but just wanted to clarify really.

Cheers,
Matt @ M-tech
 

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off, on, off. blimey this is a blast from the past.

Pope
 
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