250rwkw + RB20det HOW 2

[GTS-t VSPEC]

Cam gears will give you the ability to move power to anywhere on power curve with the right advancement/retard on the cams. Most people would move it to the mid or top end of the power curve.

I think I'd prefer mid-range, top-ends better for drags but mid much nicer on the road.

See'ya:burnout:

[Guest Works Auto]

Dynamic Turbo's are doing a t3/t4 combo they say spools up at 2500 on a rb25det and about 3500 on a rb20. My mate got one for his rb20 made 295 hp at wheels on 14psi ... It starts at about 3500rpm pulls strong to 8000. They use the new series garrett wheels , although not ball bearing they spool up alot quicker because of there more efficient wheel design.

[GTS-t VSPEC]

Works Auto,

Do you know how much the t3/t4 hybrids cost? It seems quite laggy on the RB20 considering only 500cc difference?

I think that this is the budget turbo of choice these days, fits onto the factory manifold and produces good useable power.

See'ya:burnout:

[Guest Works Auto]

It costs about 1100-1200 using your old turbo.

Its alot laggier on the rb20 coz they have lower compression

[GTS-t VSPEC]

That's pretty good value. Do the t3/t4 produce more power than the factory turbo hi-flowed?

The lower compression on the RB20 means that it can handle higher boost right. But 1000rpm more is still quite alot a lag, I think I'd prefer the throttle response on the RB25.

See'ya:burnout:

[skyzerr33]

that would depend on the size of the wheel used in the t4 side

[BOOSTMEISTER]

The cam gears are very strange things. The most we got in the mid range was about 4rwkw but then the top end didn't have as much. The car was on the dyno for over 8 hours that day and vitually every combo was used, graphed and then we decided on the best option. Unfortunatly every car will be different depending on turbo, exhaust etc so giving out the specs is pointless, plus the fact that it cost him soooo much to have them tuned, I don't blame him for not wanting to share those details.

[GTS-t VSPEC]

Without having done cams the gains from cam gears can be marginal. 8 hours of dyno tuning could almost get you a set of cams, I think I'd wait and do both, massive gains to be had then.

See'ya:burnout:

[Guest Boxhead]

yes gtst vspec, thats also like sayin , i wont drive it anywhere, save the money im saving for fuel to do mods.

...

[matlowth]

here here!

FYI - The RB25DET rods are NO WEAKER than RB20 rods... The only reason people say this is because the RB25 rod is longer, and hence appears to be of less solid design (and obviously not as able to rev). Have a look at a VL turbo rod - they're not much more chop, but you see them putting out 400+rwkw before the rods have had enough.

Works Auto - How many RB25 owners do you know that have bent rods?

matt

Originally posted by whatsisname

You keep mentioning the ability to run higher boost with a standard internals RB20DET, there's no need to run higher boost to make the power when you don't need to!?  I rather 250rwkw on 13-14psi than stress a "internally standard" 80-100+K engine on 18-20+psi.

I'd like you to direct me to the known facts on weaker RB25DET rods? Not that I'm doubting your claim but I'd like the "known facts".

[rev210]

Originally posted by BOOSTMEISTER

The cam gears are very strange things.  The most we got in the mid range was about 4rwkw but then the top end didn't have as much.  

Did he end up with the exhaust on 4 degrees retarded, like every other RB?

[matlowth]

Go the rb25/30

matt

Originally posted by Joe

fair enough, i dont own or know any people with r33 over 250rwkw so i cant say nothing there, but they do tend to ping pretty easy.

Most of the fast r33 that you read on the mag are rb25 head rb30 bottom end.

Why i said the rb25det gets a bigger power figure is because they have 500cc more then we rb20det owners, & can produce 160-170rwkw so easy with just a few mods.

Once you reach above 250rwkw, people tend to break things regradless or rb20 or rb25, engineers never design the engine internals to produce that amount of power.

Im a fan of the whole "RB" engine

[GTS-t VSPEC]

Boxhead,

It's not the same at all, almost all of the Skylines I know have ended up with the cam gears in almost identical positions, so why would it take 8 hours unless the tuner had no idea. It would seem like a lot of money for f#ck-all gain, I'd be pretty pissed.

I agree that you need the cam gears tuned, but for a few extra kW I think that the money would have been better spent. It's always easy to say in hind-sight but cam gears really don't make much diff on factory cams, you need to go for something like a 256/264 setup and then you notice big increase. When you do cams you'll need to retune it.

See'ya :burnout:

[Guest Boxhead]

gtst - yeh it does sound like 8 hrs is a bit too much, but i meant buying them, and not tuning them at all...

[GTS-t VSPEC]

Boxhead,

Well the do look pretty, even untuned.

I wasn't suggesting that they didn't get tuned but I think they all come out 4deg retard and 2 deg advance, so I wouldn't have thought it should take so long.

See'ya:burnout:

[BOOSTMEISTER]

And this is the exact reason I don't use a "Normal mechanic" The above specs yeld about 2rwkw in the bottom end and reduce top end power by nearly 5rwkw.....This is why you spend the dollars to have them tuned. Think about it, you do one run, stop the car get out loosen inlet gear half a degree, tighten then do another run and so one till each setting is done on the inlet, then you do the same on the exhaust onyl this time you have to remove the CAS each time you do it.

Basically if you want the job done right then you ca't cut corners. Naturally we didn't pay full price for the dyno time as our tuner realises that he is also learning and this is invaluable for him.

Cam

[GTS-t VSPEC]

So what did the advance and retard end up being?

Still would expect 2 hours from my tuner to get it done, he does them all of the time. Depends where you want the power to shift to, will be different if you want mid-range from if you want top-end.

See'ya:burnout:

[BOOSTMEISTER]

2 HOURS ???? I don't think so..... See this is where spending time with the tuner while he does his thing helps. You can't just adjust the gears without touching other things like fuel etc especially when you have an aftermarket ecu or afc for example. Oops sorry well you could but you will not get the most out of the time spent not to mention that when a car is tuned to the limit of its hardware you have far less tolerance for error so it is so important to make sure everything is spot on. Basically you can't change one thing without it making an effect on another.

[Joe]

i dont see any advantage wasting money on cams gears for the few 5-10kw gain.

To get full advantage of the cams gears are spending money on after market cams (eg. 272 degrees lift)

But they do look nice on a car

[GTS-t VSPEC]

Boostmeister,

I've been there while my tuner has done a number of these things, and 2hours is roughly right. All of the cars have aftermarket ECU's therefore adjustment to the correct advance and retard can be made quite quickly, then the fine adjustment is required.

I think it will depend on who the tuner is, if they are very experienced at doing them then the process can be quite quick with gains of between 8-10kw at the top-end.

I'm not knocking what you had done, but I don't think that other people should expect 8 hours to be the norm. You did say your tuner was learning, I think with some experience this time will be reduced greatly.

Joe, totally agree with you, a decent set of cams is the only way to get huge power gains.

See'ya:burnout: