VVT point in 20v Silvertop
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- Mr Revhead
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- Mr Revhead
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- mister2
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There are a few myths around VVT, especially to do with equating it with VTEC. Most have been addressed in this thread, but just to add my own 2c.
VVT (in 20v's) is a switched output which changes the intake cam timing by a fixed amount. When the cam is ADVANCED (on) the engine will make more power from idle RIGHT THROUGH to around 6-7000rpm. With the cam RETARDED (off) it will make more power above 6-7000rpm, and will idle smoothly.
So essentially, the only reason that VVT is off at idle and low load is for emissions, idle quality, and economy. And it switches off at high RPM because that is where the off position makes the most power.
It is pretty easy to see on a dyno, doing plots with and without VVT.
What this means though is that it is slightly more complex to think about than VTEC, where on = woohoo! You need a ECU capable of mapping the VVT output, not only a RPM-switch.
Cheers
Nick
VVT (in 20v's) is a switched output which changes the intake cam timing by a fixed amount. When the cam is ADVANCED (on) the engine will make more power from idle RIGHT THROUGH to around 6-7000rpm. With the cam RETARDED (off) it will make more power above 6-7000rpm, and will idle smoothly.
So essentially, the only reason that VVT is off at idle and low load is for emissions, idle quality, and economy. And it switches off at high RPM because that is where the off position makes the most power.
It is pretty easy to see on a dyno, doing plots with and without VVT.
What this means though is that it is slightly more complex to think about than VTEC, where on = woohoo! You need a ECU capable of mapping the VVT output, not only a RPM-switch.
Cheers
Nick
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- Loudtoy
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You may also want to try freeing up your intake and exhaust as much as possible, i found on my old facelift 101 that the less intake and exhaust restrictions i had the more power i had especially up top. Also 12btdc is far to advanced for our fuel as someone had said. Best i've found is about half that. PS if you've got a standard exhaust leave it on there get rid of the cat only and just do the intake, the standard exhaust is probably imho the best flowing and quietest sysytem for these cars.
Oh and about the vvt, if you want to feel what kind of difference it makes with it on and off you can just unplug the vvt solenoid for a short time it's down on the front side of the block on the pully side. Try it with it unplugged and see what difference it makes
Oh and about the vvt, if you want to feel what kind of difference it makes with it on and off you can just unplug the vvt solenoid for a short time it's down on the front side of the block on the pully side. Try it with it unplugged and see what difference it makes
TS Member sine 2001
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NZ Ae82 GT Liftback for gravel fun
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Big Ass Trailer to put stuff on
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Prado To tow stuff with
NZ Ae82 GT Liftback for gravel fun
Rodeo to do work stuff in
Big Ass Trailer to put stuff on
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Cheers guys, I feel like a n00b now
lol, I don't know too much about the workings of the cams etc.
My car has a 2 1/4 freeflow on and a pod filter so thats the restrictions gone (hopefully).
I'm planning on getting it dynoed once I put my oil catch can on and an adjustable fuel pressure reg to see what they pick up. My mates also building a diognostic computer device to pick up engine faults so i'll see what that picks up.
thanks for the help
My car has a 2 1/4 freeflow on and a pod filter so thats the restrictions gone (hopefully).
I'm planning on getting it dynoed once I put my oil catch can on and an adjustable fuel pressure reg to see what they pick up. My mates also building a diognostic computer device to pick up engine faults so i'll see what that picks up.
thanks for the help
- Mr Revhead
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- Loudtoy
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Mr Revhead wrote:20vs seem to like having the stock air box rather than a pod.
fit a K&N filter into the stock box.
adjustable fuel reg is not needed, your just wasting your $$ there and opening a door way for potential problems.
I disagree with the statement about the pod, so long as you do it properly and build a proper cold air box around it, have the intake pipe about 3 inch and nice madrel bend of 90 degrees leaving the pod right up behind the headlight. Will require turning the airflow meter upside down so the wires will reach and works a hell of alot better than a k&n in the standard box - about 6kw difference in my experience and thats with an el cheapo pod from a k&n panel.
Oh yeah the possible downside is you will need to move your battery to somewhere else to make room for you intake.
TS Member sine 2001
Prado To tow stuff with
NZ Ae82 GT Liftback for gravel fun
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Car no 16 in a long line of less than ilustrious automobiles
Prado To tow stuff with
NZ Ae82 GT Liftback for gravel fun
Rodeo to do work stuff in
Big Ass Trailer to put stuff on
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- Mr Revhead
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- Loudtoy
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Mr Revhead wrote:iv heard of blacktops mking a gain with open/pod filter
yours would be the first time iv heard of a gain on a silvertop
Fair to say i had a freak one, exhaust and intake only (mind you was all my own design stuff) made 84 kw sock, 87 with exhaust and standard intake and 93 with intake and exhaust. All same dyno but different days, 93 was mid summer 84 was mid winter and 87 was somewhere in the middle. Sold the car and dyno sheets went with it as the guy who brought it mates wouldn't believe that my 101 would make slightly more than his 111 on the same dyno lol. If i still had them i could have told you the temp exactly
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Prado To tow stuff with
NZ Ae82 GT Liftback for gravel fun
Rodeo to do work stuff in
Big Ass Trailer to put stuff on
Car no 16 in a long line of less than ilustrious automobiles
Prado To tow stuff with
NZ Ae82 GT Liftback for gravel fun
Rodeo to do work stuff in
Big Ass Trailer to put stuff on
Car no 16 in a long line of less than ilustrious automobiles
- Mr Revhead
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