Difference between in rb26dett

[artic84]

hey guys
a quick question. what is the difference between an rb26 from a r33 and a rb26 from a r34. sorry this is a dumb question but i was just wondering. thaks

[SkylineUSA]

Originally Posted by artic84

hey guys
a quick question. what is the difference between an rb26 from a r33 and a rb26 from a r34. sorry this is a dumb question but i was just wondering. thaks

Turbos are a little different. Cams are also a little different, other than that I cannot think of any thing.

[artic84]

any difference in hp output?

[flylwsi]

what's in the brochure, or what they really make...

[artic84]

what they really make

[SkylineUSA]

Maybe 5-10whp more in the R34s RB26, but you can get an R32/R33 RB26 cheaper, and make up the money difference with aftermarket parts and you would be well ahead in the power game.

Plus if you realy want to make power, stock turbos and cams would be the first thing to go. So the extra power in the R34s RB26 would be a mute point then.

[R33]

Originally Posted by SkylineUSA

So the extra power in the R34s RB26 would be a mute point then.

You mean, "moot"?

[SkylineUSA]

Oops, yes moot point

It's a lack of coffee I tell ya.

[RazorGTR]

Actually the R33 and R34 GTR's came with variable valve timing where as the R32 didn't. The refinements in the engine management in the R34 made a big difference in the real world performance compared to the R32. Power output was increased by quite a bit but not claimed. As much as 45hp at the wheels.

[SkylineUSA]

So, the R33 and R34 have a duration, and lift changes depending on the rpm of the engine. Can you explain how it works? I know it cannot be the cam that does it, so it has to do with?

[Moppie]

No, they only have timing changes, and if Im not mistaken its only on the exhaust cam.
(most engines run it on the inlet cam, but since Nissan run it on the exhaust cam to maximise Turbo response which has a greater over all effect on the engines performance.)


The only Nissan engines I know of with lift, durtation and timing changes are the SR16ve and SR20ve

[SkylineUSA]

Timing changes in the spark, or actually moving the cam that changes the lobe seperation?

To me variable valve timing, would be a change in the timing of when the valves open and close, which means a move in duration of some type.

[Moppie]

Timeing = Point in the cam shaft rotation that the cam lobe preforms an action on the valve. (Position of the cam lobe and/or the cam shaft relative to TDC).

Duration = Time that the valve is held open, (or closed for). (ramp length and size of the cam lobe)

Lift = Amount that the valve opens. (hight of the cam lobe)


They use a solonoid on the end of the cam shaft to change its timing relative to the crank shaft, depending on the car, engine, system used etc, it can be as much aas 10-15 degree either way.
Think of it as an adjustable cam gear, that can be continualy adjusted all the time as the engine moves through its rev range.
It simply optimizes the valve opening and closeing relative to the pistons position in the bore and airflow speeds into and out of the compustion chamber.

It is unable to effect the actual shape of the cam lobe however, which are what dictate lift and duration, but on a Twin Cam engine it will all alter the phasing of the inlet an exhaust valves and will alter the valve over lap.

[SkylineUSA]

Moppie,

My bad, I meant a move of the lobe seperation. Why the hell I put duration makes no sense.

I was unaware of the seloniod on the later RB26s. Thanks for the info.

[Moppie]

No worries mate, I did wonder why you were getting confused, and figured it was just a mis read, or a mild case of brain fade. You know as much, or more so about these things than I do.


Nissan used the same set up on the 300zx turbo as well (but dropped it after a few years production for some reason), again altering the exhaust cam timeing on each bank for better turbo response.

Im pretty sure most of the new Nissan engines use it now, Toyota certianly use it on all thier new engine range (VVTi) and Honda combine it with VTEC to get i-VTEC, Porsche and Ferrari have been useing it for a long time, along with BMW who use it on the M3. Even ford use it on the Ausie made 6cyl Falcon. Because its very cheap and easy to manufactor, and is easily fited to existing engine designs, so as long as you have an ECU and software package capable of dealing with it then variable cam timeing is well proven way of cheaply and efficantly improving an engines powercurve, with out sacrifcing its efficancy or emmisions levels.