Sr20ve Neo Vvl

[Onizuka]

probably SR16VE cams, that is a common upgrade i hear. I hope to one day make a RWD SR20VE hybrid and stick it in a 510, how sweet would that be!

[s13sr20chris]

nope, he had the sr16 cams but upgraged to the really bad ones. they are either the 20v cams from the new sr20ve or the sr16ve n1 cams from the limited production pulsar n1. he is kind of a trail blazer in the ve scene.

he turns all the wrenches himself, but he needs me for consult access every once in a while.

[Cyberkreig]

Someone shoudl come up with a bolton upgrade for the DET owners.

Pull off your DET head, bolt on a VE now T head. wireup a controler... wonder if you could keep DFIS..

[SilviaLuvr]

Bling.Thanks for the info.I still like Ferrari's version though, the whole sliding cam with progressively more aggressive lobes with longer duration and more lift that move with the RPM band. That's just pimp, yet so simple.

and expensive thus it's in a Ferrari. To be honest, I thought that it was Ferrari that started VVT...hmm i guess not.

[s13sr20chris]

Someone shoudl come up with a bolton upgrade for the DET owners.

Pull off your DET head, bolt on a VE now T head. wireup a controler... wonder if you could keep DFIS..

ends up being counterproductive at high power levels. only good for low boost drivability.

[Onizuka]

not true, having VVL would be very usefull with turbo setups.

[Cyberkreig]

I dont see how it would be counter productive to have more valve lift and still have a good idle?

since we are talking about an imaginary setup, with some sort of aftermarket controler i dont see why the lift couldnt be tuned just like timing and fuel.

[Onizuka]

yup, a simple RPM switchbox from summit racing and you can set the cam switch at whichever rpm you wish.

[s13sr20chris]

yes yes, very good for a street car. my line of thinking goes like this. if you are gonna get a vvl head and all the other stuff for it, you must be looking for some big hp. fine for low hp, not for max hp as the valvetrain is not the most efficient for racing. dont get me wrong, its a great valvetrain. but if you never go below 5000 then you dont need the low cams. thats what all the honda/acura race cars do. the btcc and so on nissan race cars that come stock with vvl get rid of it to race. this is not talking turbo however. the reason is the same though. i am not making this up. vtec and vvl are not for max effort turbo setups.

[Onizuka]

It works wonderfully with turbo. Tell me, whats the difference? its still just cams driving the valves, only now you have alot more adjustability, which is good for NA and turbo. One set of lobes for around town driving and one set of wicked power hungry cam lobes for when you really step on it. Race cars dont have VVL because it would be added weight and they just run the wicked cams only anyway, they dont have to go pick up their little brother from his drum lessons across town inbetween laps so there is no need for a more docile cam profile :pface

This is not the same thing as variable valve timing found on s14 and s15 SR's

[Repo Man]

Race cars dont have VVL because it would be added weight and they just run the wicked cams only anyway, they dont have to go pick up their little brother from his drum lessons across town inbetween laps so there is no need for a more docile cam profile :pface

LOL at J-Spec.

[s13sr20chris]

yes, i understand all of that. i know the difference between vvl and vtc as well. vtc does work fairly well with turbo. the prob with vvl is you cant just try a set of cams and then have some more custom 12 lobe cams made up. another thing is that lift reaches a ceiling when it stops making anymore power. then all you have is duration to play with. so you end up looking for as much duration as possible without much overlap. you can only open up so early and close so late. in my opinion you could prob find a set of cams that were well matched to your turbo without have extra lobes at all. the ideal lobe size for a street turbo will most likely not cause a bad idle either.

[Onizuka]

not true, high performance cams make your car idle like **** and you get bad gas milage. Thats why alot of race cars idle at 1500-3000 rpms and guzzle fuel like your dads old chevy. Selectable camshaft profiles are better than standard cams for street cars. Not only can do you have two sets of lobs, you can toggle each of the cams independently (ie, the intake cam switches at 4100 and the exaust cam switches at 4300, this can greatly increase midrange power. Refer to the previous dyno graph and you can see where the line jumps when the cams are switched at two points). Street trim cams suck because they limit the HP roof you can reach, performance trim camshafts suck because they ruin the idle, make the car run dirty (not pass emmisions), and use more fuel. So basically the VVL provides the best of both worlds using simple solinoid technology and some extra lobes.

[s13sr20chris]

yeah, its great for na. turbos dont like too much overlap though. it just turns into reversion. someone adept at engineering could prob tell you just how to calculate how much cam you can have with any particular turbo setup on any particular car. you can use jwt s4 cams with turbo no prob, but a race cam that idles high and doesnt make power till 7000 is not for turbos.

[Onizuka]

you do know people upgrade their cams with turbo motors right? There are agressive and mild cam grinds for turbo just like NA and the same problems occur with both. VVL is also a solution for both. Do the cams on the NA KA have trouble spooling a turbocharger? hell no...

and you can set overlap or anything you want to whatever setting you want because the VVL system is totally adjustable (except for timing).

[Cyberkreig]

Jspec, Lets just build one; Then, Dyno it.

[s13sr20chris]

yes, i do know about upgrading turbo cams. i did mention the s4's didnt i? i agree that vvl is great. i just think its unnesessary on a turbo car. only one turbo vehicle has ever been mass produced with vvl and a turbo. thats the xtrail/vet. if it was really the way to go, porche would be all over it. heck, even if it wasnt they would try it out. the best turbo cams will not be hot enough to require smaller lobes for idle. the most you would ever need for a turbo car cam is vtc. if you need more than that, then you need more than cams. there is a point in camshaft upgrades where you start losing power. in fact i would suppose that stock sr20det big lobes are too big for a max effort turbo setup. they may make power. in fact i know they make power; i say someone do it. that same guy made more power when he switched to vet cams. the vet cams had a little more lift and a little less duration. they had almost no overlap.

[Onizuka]

there is a point in camshaft upgrades where you start losing power.

when is this point? ive seen 310 and 320 cams being sold for 4a-ge's. The more agressive the cam, the more power, there is no magical point where its like "oh it cant spool the turbo anymore" or "there is no more power to be made". But also along with the more and more agressive cams come more crappy idle and more crappy emmissions results. What if i wanted to run mild 254's for my daily driving (and emmissions testing) and 310's for when im stepping on it at the track? i would see enourmous power gains from steeping up that much in cam degree's. I understand what you trying to say in that turbos run slightly different camshafts from NA motors, but:

VVL will benifit both NA and Turbo motors. The JDM Xterra's SR20VET puts out "280" (wink wink nudge nudge skyline gtr 280) horsepower at 6400 and peak torque at 3200 thanks to VVL.

[Onizuka]

I have just confirmed that the SR20VET is infact FWD based.

[Dattebayo]

Well i dont understand how anyone could say that vvl wasn't good for turbo. I might not be mister 4000 posts but i sure can say that looking at a dyno chart can explain things... Why hasnt porshe made it yet? Maybe there is something tying up the patent office for that one. You cant just copy someone else's ideas with out accountability, and if its a multinational corporation you can be assured that its not gonna happen without a complete redesign. Maybe Nissan its just setting the president.

[s13sr20chris]

I have just confirmed that the SR20VET is infact FWD based.

how in the world did you confirm that? the xtrail is not fwd.

as to how much cam a turbo motor can take...

... just do what you like and prove me wrong. i am man enough to accept it if its clear. i personally believe that if you do choose to max out the cams on a turbo motor, you will encounter too much reversion and lose power. if you seek the most power, i think you will find that your idle is not rough and you dont really need the low cam.

as for porsche, they already have porsche valvetronic which is a continous system and works fine. they have variable intake system as well. they just dont use vvl with turbo. i think vvl with turbo is a redundancy.

[Onizuka]

how in the world did you confirm that? the xtrail is not fwd.

Transverse AWD like the EVO, my bad. I was up for 30 hours yesterday was being lazy. In other words there is no way in hell it would fit in a 240.

[s13sr20chris]

i have seen a web site of some guy with a sr20ve turbo with vet cams. he is quite happy with it. vet would be mega expensive too.