QR25DE engine

[friday86]

How reliable is this engine and the tranny? Doesn't it have a engine with a "kick" like honda's have VTEC and toyota has VVTL-i? I think it was called CVTC, but i'm not sure?

[TeggyLS]

i dont think it really has a kick, although it does have short and long intake runners, it changes to the short or long depending of its low or high in the revs. kinda smooths out power delivery in a sense.

[chris0276]

The CVTC kicks in the lower rpms, that's why you get more torque and a wider power band. Unlike Vtec, which kicks in the higher rpms. Basically, the CVTC performs the same way at 6000rpm as a Vtec would at 8000rpm. But it takes longer to get to 8000rpm than 6000rpm, so the CVTC is already in it's torque peek when it shifts to 2nd gear, while the VTEC is still in 1st. This is why Nissan's cars are excellent for drag racing.

[friday86]

Oh.... nice one.. thankx

[blown05]

if u planning on turboing ur car than this is the best engine to do it. i turboed my sentra and response is really well. the big bottom end allows for minimul turbo lag and the power it puts out on a basic bolt on turbo kit is higher than most. mine did 315 at the wheels when i first turboed it and ita was only 8psi

[06chill]

the cvtc is constantly on and the thing you feel at 5k is the power valves opening not an extra valve or cam lobe

[nismo_pilot]

you mean secondary intake runners, nothing too eciting going on but a shorter intake path, hondas system switches to a hi-po cam at a certain point, nissans alters timing and intake lengths

[06chill]

well nissan calles them power valves but they are just another set of runners in the intake

[Spec_fishin]

The kick you're referring to are the butterflies actuating in the secondary runners. They only open at a set rpm. 5000 rpm give or take a few hundred. There is a way to control them but I can't recall since it's a pretty new method. Its on thevboard or myspecv .com CvTC is not like Vtec. The two have their differences. But generally speaking they both provide performance for the vehicle.

[nismo_pilot]

you can tap the signal that goes to the actuator responsible for opening them, and run it through a window switch for adjustability just like a nitrous system, although it wont do very much in the way of power, it could offer a few HP a little earlier

[slideways...]

yeah. the VTC is only a variable advance intake cam. no bigger lobes, just optimized cam timing linked to throttle position. helps get useable power without any real drawbacks. one of the smarter technologies invented in recent times.

[Chiquae07]

someone actually tried the butterfly thing. they removed them completely. lost a tad of power in the early rpms but had a little increase in the higher rpms for the qr. said it wasnt worth it.

im sure you can make some power out of controlling them like vtec in a way, but you would have to have some pretty expensive mods to really see a big gain out of it.

[nismo_pilot]

well the point is not to remove them, just to have control over where and when they engage, you would also have to tap the throttle position sensor as well as they only open under full throttle, or open all the way anyways, you can feel the difference when it goes over 5k when your in WOT or just partial throttle

[ProZach626]

Originally Posted by friday86

How reliable is this engine and the tranny? Doesn't it have a engine with a "kick" like honda's have VTEC and toyota has VVTL-i? I think it was called CVTC, but i'm not sure?

two words about the QR... sad to say it, but:
Time
Bomb

[06chill]

why do you say time bomb?