My RB25DET Nugget

[2rismo]

**Apologies if I've posted this in the wrong section.**

Just about to start tuning my new RB25DET so I thought I'd put some pics up. It has been built with drag racing in mind although it may get a bit of street driving every now and then.

I stuck with the 25 to see what could be done with one. The 3L option would make more horsepower but two of the companies that are involved in the car do most of their work and sell most of their gear to RB25/R33 owners so I thought we could use this car as an example of their expertise.

This was it when it had the stock engine in it and used to run 11.6 @ 118-120mph.



I chucked a GT35 on it and went racing again but when the gas came in, the shitty chinese manifold and 38mm gate couldn't deal with it and it saw 29psi when it was only tuned for 20psi. The ringlands on number one piston broke and I was stuck with a motor that sounded for all the world like a diesel SR20.

The rebuild began as a freshened up stocker and snowballed to an all-out engine build with new pistons, rods, cams, headwork, exhaust and intake manifolds, ecu, the list just went on and on.

I didn't want to have the oil pump dramas that lots of RB's seem to have but at the same time, I didn't want to go to a dry sump. I bought a High Energy sump pan and had it modified so the pickup joined a -12 fitting at the front of the pan. This supplies the single stage Peterson oil pump that is driven from a belt drive off the front of the crank.




The bottom end came together pretty quickly and uses .020" over CP pistons, Spool rods and quality bearings etc. The block was 3/4 filled with grout and the crank was nitrided and balanced.

I also picked up a Plazmaman intake manifold and one of their new throttle bodies. Leigh from Extreme Turbo Manifolds made the new steam pipe exhaust manifold and modified the 1.06 rear housing of the GT35 to take the wastegate.





The biggest delay was the cylinder head but the end result looks fantastic. Aaron from APM spent many hours on it to get it to the point where he was happy with it. I used a 1.5mm Cometic head gasket and half inch studs.

I then took the motor to Joe at Profab so he could make the mounting bracket for the oil pump and the drive for the front of the crank.

[2rismo]

Here's the motor with the intake and exhaust sides fitted in place.




Fast forward a little bit and the engine went in on new mounts. Joe from Profab also made the four inch dump pipe and plumbed the gate back (for now). He also modified the power steering pump to space it forward to suit the bizarre balancer (it was a prototype).





Had the radiator serviced and a new cap fitted. It was more blocked than I thought so it should be all good now. Mounted and wired up the 2 x Maradyne thermo fans using both the factory switch and a manual override so I can have them on even if the engine thinks they're not needed. Also wired up the low-oil pressure switch and light and the Tech Edge Wideband unit and display. The backlight on the display is really good and dead-easy to read.




Fitted the Autronic SM4 plugin in a standard ECU case and plugged it in - still have to wire the air temp sensor but that wasn't required to start it - something that happened last night.

Engine startup.

Gave it 5 or 6 minutes to bed cams in and then took it for the first drive in 18 months. Can't wait to get it tuned and get some racing in.

[2rismo]

Got it running a little leaner so it will idle as well as return to idle on back-off. (It was stalling left, right and centre before hand). Went for a cruise just for a bit of a laugh (it's still un-tuned and slow as shit). Pouring rain? Doesn't matter. It just washes the dial-in and workshop dust off of it


Cruising in the rain.

[Lith]

Nice one man - when does it go on the dyno? Summer is coming, keen as to hear about some awesome times being run

[R.I.P.S NZ]

Excellent, your pump seems to be driven quite fast compared to crank rpm, did you guess a starting point for pump speed or did you get a pretty good idea from someone?

Looks great, should see 9s no problem, what transmission are you running?

Rob

[2rismo]

Originally Posted by R.I.P.S NZ

Excellent, your pump seems to be driven quite fast compared to crank rpm, did you guess a starting point for pump speed or did you get a pretty good idea from someone?

Looks great, should see 9s no problem, what transmission are you running?

Rob

Thanks guys. The pump is driven slower than the crank by about 50% from memory. Mark from Godzilla Motorsport spoke to my engine builder and they did some maths and came up with the exact numbers for the CV Products pulleys but I can't remember what they are. It sees about 28 - 30psi at idle and 65psi at about 5000rpm so there's plenty there. We can see what it likes on the dyno and change it from there although I don't think we'll have to actually change the pulleys themselves.

I'm running a transbraked Ford C4 behind it.

[Dynamix]

About time you got this thing going, ive been following it on sau's for year(s).. i thought it would never get finished.. now you can go back to winning the drags..

[2rismo]

It's been off the race track for a year and a half. I'm not a rich man and all of this has to be done with what little is left over after feeding and clothing a wife and an 11 month old!

I like winning too so I'll be back out soon enough

[Andy Hornsby]

Look well cool, looking forward to seeing the numbers.

[2rismo]

You're not alone there, mate. Let me tell you!

[2rismo]

Initial tuning today and the car made 280kW at 19psi. Happy and safe on pump fuel but it's time for some boost now :-)

[garryr32gtst]

nice build. where did you get your plazmaman inlet from?

[2rismo]

Originally Posted by garryr32gtst

nice build. where did you get your plazmaman inlet from?

From the source. They're about an hour and a half drive from my place but they're right near the racetrack so I stopped by on my way. Alex an Oyay are top blokes and more than happy to answer any questions or concerns you have.

They've been a very big help to me so far and their workmanship is awesome.

Cheers,
Adrian