Exhaust Cam Gear timing RB25DET

[rev210]

Has anyone done the adjustable exhaust cam gear on their RB25DET?

If so what is the adjustment timing wise and can you use the stock ecu if you adjust timing?

I've heard somewhere a 4deg retard on the exhaust cam timing works well.

[whatsisname]

I've got an adjustable exhaust cam gear, set to 4' retard.

I don't see the stock ECU having too much trouble still running the show but some form of ECU control would see maximum results.

[rev210]

What sort of gains did you get mate?

You still haven't put that cement in the boot yet have you? I told you put the cement in the boot , so do it NOW!

[whatsisname]

I'm going off memory here....... it was 215rwkw before the gear & ~224rwkw after, however this was when I still had my Unichip/stock ECU combo & my AFM was maxing out very badly! It was a peak of ~224 but with huge dips in the power curve With a Z32 AFM or a MAP based ECU bigger gains "could" be achieved.

I'd say a 10rwkw (peak power) gain is about what you should expect. But you'll probably lose a few kw down low.

[whatsisname]

Originally posted by rev210

You still haven't put that cement in the boot yet have you? I told you put the cement in the boot , so do it NOW!

:lol: Don't need the cement anymore! I've got traction in the form of 255/40/17 RE540S's. They're no Nitto or BFG street drag radial but they sure are an improvement on the Falkens I had :uh-huh: It still will w/spin a touch but nothing like it did before!!!

[macka]

whatsisname thats a nice 1/4 mile time on that boost!

were u using the stickys to get the 2.1 60ft?

[GTS-t VSPEC]

rev210,

With exhaust gear alone I'd expect 8-10rwkw, with inlet gear about 5rwkW more, but you'll loose the NVCS. I think the settings are 2deg advance inlet, 4deg retard exhaust. Will make more difference with bigger turbo or cams, but still a decent increase for the price.

Which brand were you thinking? JustJap can get the OS Giken ones, $300 each.

See'ya:burnout:

[whatsisname]

QUOTE]Originally posted by macka

whatsisname thats a nice 1/4 mile time on that boost!

were u using the stickys to get the 2.1 60ft?

Thanks mate. Believe it or not I actually ran those numbers on my old Falken ZIEX ZE502's (255/40/17). With the extra 40+rwkw & the sticky 540's I'm hoping for @ least mid/high 12's.

I'd like to 60' in the 1.9-2.0 range with a mild launch.

Back to the topic of cam gears...... As GTS-t VSPEC mentioned, bigger gains will be had on engines with turbo &/or cam upgrades.

If anyone is wondering how the RB25DET feels minus NVCS, just disconnect the elec connector to the solenoid & go for a drive! Obviously if you're planning on a complete cam swap then a decent compromise minus NVCS can be found.

[GTS-t VSPEC]

whatsisname,

My plan is to loose the NVCS, but I will be doing cams and bigger turbo, for light to mild tunes then keeping the NVCS makes sense.

Is that the factory turbo your running? Very impressive times, the R rated tyres should gain you a couple of tenths.

See'ya:burnout:

[rev210]

Originally posted by GTS-t VSPEC

rev210,

With exhaust gear alone I'd expect 8-10rwkw, with inlet gear about 5rwkW more, but you'll loose the NVCS. I think the settings are 2deg advance inlet, 4deg retard exhaust. Will make more difference with bigger turbo or cams, but still a decent increase for the price.

Which brand were you thinking? JustJap can get the OS Giken ones, $300 each.

See'ya:burnout:

Probably get HKS from nengun for $180. I noticed the debate over cam gears and I think the bagging people were giving the HKS gears was bollocks. They use their own gears on their drag cars and I've yet to hear of a propper example of a failure and a reason related to actual design/manufacture (one that makes sense). I'll do this along with the light underdriven front pulley when I do the timing belt.

[GTS-t VSPEC]

I don't think on most cars you'll have a problem with the HKS gears, but even sub-zero who sell them said they weren't as good at the other brands. Nengun has them cheap, but by the time you add freight I can buy them just as cheap here. The HKS drag cars are hardly going to use anyone elses gears, even if they were better, but they might get replaced frequently. I think the HKS ones will be fine, I'll most likely use them on mine, if they break then I wont use them again, simple as that.

See'ya:burnout:

[whatsisname]

Originally posted by GTS-t VSPEC

whatsisname,

My plan is to loose the NVCS, but I will be doing cams and bigger turbo, for light to mild tunes then keeping the NVCS makes sense.

Is that the factory turbo your running? Very impressive times, the R rated tyres should gain you a couple of tenths.

See'ya:burnout:

I've seen a few GTS25t owners that have ditched the NVCS in favour of aftermarket cams & adjustable gears, all with good results. These cars all had bigger turbos & a host of other modifications. The JMS 300+rwkw GTS25t (standard internals) is one of these examples. It uses the earlier non-NVCS RB25DE inlet cam.

My car has a T3/T4. It's not a high flow of the standard turbo but a total replacement with bigger housings. I'm unsure of the exact specs?

The 1/4 #'s in my sig' are pre..... R tyres, Microtech LT12, custom inlet pipe work (nil AFM), cam gear & a few other minor things. No major changes but it all adds up. Oh yeah & some very good tuning too

[GTS-t VSPEC]

whatsisname,

Yes I was told to loose the NVCS for higher horsepower applications. I will be running the GT30 turbo, so I expect some good gains with the cams and cam gears.

Is the Microtech LT12 the new plug'n'play, what do you think of it?

Sounds like a nice setup, I got rid of my AFM aswell, haven't noticed any loss of fuel consumption, cause it was pretty shit before.

See'ya:burnout:

[whatsisname]

GTS-t VSPEC,

The LT12 is one of Microtech's new laptop programmable ECU's that can be configured for the GTS25t. It comes loaded with base maps to suit (like the PFC) & then plugs straight into the factory loom. There's one extra sensor that can be installed for total functionality (intake temp) but it's very simple & taps into the existing AFM wiring.

I'm really happy with my LT12 The engine is responsive regardless of throttle position or rev range, it idles nicely, makes good power & hasn't cost me all that much to get it installed & tuned. Fuel economy I don't take much notice of but it's @ least on par with the stock ECU.

[GTS-t VSPEC]

whatsisname,

Thanks for the info, it's good to see that the engine managment systems are improving and becoming competitive in price and functionality. I'm using the new Wolf, and have been equally impressed with it.

See'ya:burnout: