Rb28 Build

[HarrisRacing]

Different compressors on the gt2860 core from garrett.

I personally wouldn't go with them as they are... miss matched. Best bet is to just go -5's and get what they get. they may not give 450kw but you really aren't going to get a better pair of stock position turbos on 98. and if you ever do go E85 should get you close to the mark but you'll need to upgrade the entire fuel system of course.

I don't buy into the whole "revs less" argument from strokers. Yes its probably got a lower maximum revs but i get the impression that the valve train limits that on any possible engine configuration regardless. I went for a ride in a Spool 2.8 equipped car and it honestly seemed more willing to rev than a stock car. That tipped me over the edge on my decision, I think it was the full conterweighted crank that makes engine a lot nicer to drive.

I went for a target of 9.5:1 on mine however it will barely be run off of ethanol so that should be fine. Turbos are gtx2860's and Cams are the unigroup ones, 260/10.85, so it should go alright and make good use of the E85.

I concur completely on the "revs less". I think when leaving deck height and Rod length stock you do side load pistons more with more stroke which theoretically lowers life but again I'm not expecting more than 8500 rpms out of this setup (which I'm sure it will do).

BTW - Perfect choice on cams. I ordered mine early on (when I was planning -7s and stockish rebuild) hence the Tomei poncam A. But while I was having head machined we did relieve the head for big cams. Yours are exactly the spec I would have liked to have.

Your setup is going to be awesome. I can't wait to hear mine run. Also realize I have never driven a GT-R other than this one with a rod knock at Super low rpms from my house to the shop (8 miles). I couldn't tell you before and after as I went off the deep end on this build.

[sneakey pete]

Yep, which is why you do neither and straight up buy a complete RB34 bottom end from someone like spool. Specifically that. Yes, they have to assemble it, but my problems really come from it being assembled wrong, multiple times. If it all worked fine first go, by all means yep do it, but as soon as any variable is slightly altered the chances of something going wrong increase exponentially (in my experience!).

I would suspect guys like Spool to be building a solid product every time vs rolling the dice at the local engine builder.

I actually make full power at 4000RPM

Did think about pulling it out and putting into a GTR which has a blown engine with an adaptor plate of sorts because RB25 neo . But realistically a pipe dream when a GTR user can just save the money, buy a complete bottom end built by whoever and do that. The path less travelled can really bite badly when the stakes are engine builds.

Spool just uses a local engine builder to build their engines, as I understand it. So I just went to said local engine builder.

VCT would be nice. I ummed and ahhed about using a NEO head on mine but there was too much unknown about getting it to fit. There's a guy up here who wants to do it though so maybe oneday...

[sneakey pete]

For what its worth, i went around and made a small table of all the lowmounts that are available and somewhat popular thesedays (no greddy turbos...) You can see the different wheel sizes which may help you get an understanding of all the different options. Basically the 2871's are called '-10's' for the gtr specific housing set, but they have too much compressor for the exhaust size when used on a 2.6/2.8..

-7's and -5's are gt2860 variants with gtr specific housings. as you can see the -7's have a smaller exhaust wheel and compressor inducer. -9's are technically a gt2859 but have a compressor halfway between in terms of its flow rate. Basically -9's are your go to for ~350-370awkw and -5's are 450awkw on E85, a bit less on 98.

[XKLABA]

-5s work very hard to make 450kw, even with E85, GTX2863rs would be a better option cause lets face it 450kws can't be made from 15psi and with the correct setup with 25psi on 98 the GTXs should be inside their efficiency range and shouldn't be to far from the goal

http://homepage.ntlworld.com/tbroom/Turbos.htm

[Piggaz]

-5s work very hard to make 450kw, even with E85, GTX2863rs would be a better option cause lets face it 450kws can't be made from 15psi and with the correct setup with 25psi on 98 the GTXs should be inside their efficiency range and shouldn't be to far from the goal

http://homepage.ntlworld.com/tbroom/Turbos.htm

Seems like the front housing comes into play here with the GTX wheels. GTX wheels jammed into "- series" housings never seem to perform as well as they do in the proper garrett housings.

[sneakey pete]

That is a significantly more useful table

The gtx 2863s seem to make power just fine with GTR compressor housings, there was the white 34 that made just shy of 500kw at 33psi with 63's on E85. Not seen any results for gtx2860's so i guess i'll find out with mine when they're on there.

But again, you'd need to run some stupidly high boost for a non E85 setup.. 25psi is quite a lot on 98 isn't it?

[Piggaz]

That is a significantly more useful table

The gtx 2863s seem to make power just fine with GTR compressor housings, there was the white 34 that made just shy of 500kw at 33psi with 63's on E85. Not seen any results for gtx2860's so i guess i'll find out with mine when they're on there.

But again, you'd need to run some stupidly high boost for a non E85 setup.. 25psi is quite a lot on 98 isn't it?

Simons car? It was 470. Go back through the GTX thread and have a look at what he had to say about it all. Heat, heat and more heat. He couldn't keep temps under control.

[Dose Pipe Sutututu]

But again, you'd need to run some stupidly high boost for a non E85 setup.. 25psi is quite a lot on 98 isn't it?

Really depends how cluey the tuna, I mean tuner is... You could really run that much if you balanced out EGTs vs IAT vs AFR. As you reach peak torque run considerably low timing to keep the cylinder pressure/temperatures down however this will also increase EGTs so you would need to richen it up to bring down the EGTs and also that would further more reduce cylinder temps/pressure... Then throw IAT into the mix, you would ideally need the IAT as low as possible to reduce/prevent any knock.

[GTSBoy]

Water meth.

[Piggaz]

Water meth.

on top of E85?

What about rear housing?

[Dose Pipe Sutututu]

on top of E85?

What about rear housing?

OP says no E85, 98RON only

[GTSBoy]

on top of E85?

What about rear housing?

Comment was relative to 98 / high boost worry posts immediately above. My thought was rather than doing the bandaid via tuning, which has negative consequences somewhat undoing the benefit of using the high boost versions of the turbos, use the WM bandaid, accept the consequences of needing to make sure you don't run out of water, and actually pick up power.

[Dose Pipe Sutututu]

Comment was relative to 98 / high boost worry posts immediately above. My thought was rather than doing the bandaid via tuning, which has negative consequences somewhat undoing the benefit of using the high boost versions of the turbos, use the WM bandaid, accept the consequences of needing to make sure you don't run out of water, and actually pick up power.

you'll still can make numbers up top when all the torque drops off (this is where you start dialling in the timing)... great for dyno queens and boasting about figures

[khezz]

WOW this is so much more advice then I expected. No matter what the package is, it will still be better then what I have now. Turbos are old, engine is tired and it doesnt start pulling till about 4000-4500. So some lag is not going to bother me. On the street I will rarely get a chance to use 650hp and on the track, it will rarely stay under 5000. so a bigger "laggier garrett low mounts arent going to be a problem" I am more inetersted in consitancy and reliablilty. Good cams and more displacement will oflamin mongreler lag some what also.

so far:

Spool 2.8l kit

walbro 460lph in tank pump

260-265 by 10.8 cams

1000cc injectors

GTX2860 turbos

starting to look like a plan.

had a chat to RIPS and Spool about 3.0L bottom ends. It may end up the way to go but for now, $ maths points towards a build rather then a crate. I am guessing that a few hard drives at desired power levels will show some new weak points in the car. my guess it will be the gear box first followed by diffs and may be the clutch.

[GTSBoy]

The figures I would prefer to boast about are;

• how short the life expectancy of the rear tyres is,
• How many degrees of twist the tailshaft is expected to endure.

[Dose Pipe Sutututu]

The figures I would prefer to boast about are;

• how short the life expectancy of the rear tyres is,
• How many degrees of twist the tailshaft is expected to endure.
• How early my turbo comes because it's a single turbo, unlike the twin boys

FYP

[GTSBoy]

I am guessing that a few hard drives at desired power levels will show some new weak points in the car. my guess it will be the gear box first followed by diffs and may be the clutch.

In some respects, not putting a Quaife diff in the front and a Nismo in the rear before you add this much power to the car is going to be a mistake. If you think that you will be wrecking driveline components then you should do something about them early. The front diff in particular because it makes sense to do it while it's all apart, not having to pull the engine again to do it. Nismo clutch too, and drive like you respect the gearbox.

[Piggaz]

Comment was relative to 98 / high boost worry posts immediately above. My thought was rather than doing the bandaid via tuning, which has negative consequences somewhat undoing the benefit of using the high boost versions of the turbos, use the WM bandaid, accept the consequences of needing to make sure you don't run out of water, and actually pick up power.

Oops. Two conversations going on in here lol.

[Piggaz]

In some respects, not putting a Quaife diff in the front and a Nismo in the rear before you add this much power to the car is going to be a mistake. If you think that you will be wrecking driveline components then you should do something about them early. The front diff in particular because it makes sense to do it while it's all apart, not having to pull the engine again to do it. Nismo clutch too, and drive like you respect the gearbox.

This. ALL of this. Print this out and put it in the shower.

[khezz]

In some respects, not putting a Quaife diff in the front and a Nismo in the rear before you add this much power to the car is going to be a mistake. If you think that you will be wrecking driveline components then you should do something about them early. The front diff in particular because it makes sense to do it while it's all apart, not having to pull the engine again to do it. Nismo clutch too, and drive like you respect the gearbox.

Since the car will be apart anyways, I will reaplce both diffs. 2 way rear and 1.5 way front?

Clutch is already a twin plate will get it checked over while it lies on the floor waiting for a motor.