Rb25/30De + T Conversion Help

[walky01]

hey guys, im at the stage where i want to turn my N/A 30de to turbo. because of the high comp. im guessing 11:1 im thinking of running standard RB25 turbo on around 6-7 psi, at the moment im making 155rwkw and 250nm so im wondering if anyone has done something similar and what power they got. it will also be custom tuned but exhaust mani will be std turbo std and dump std with a straight through exhaust.

[walky01]

Also should add ive found a turbo and mani for $350 which i will probably get, along with the dump while im there and im thinking of using a FG intercooler as it comes with all piping and extras i could probably use.

[Dose Pipe Sutututu]

I would put a bigger turbo than that on the motor, the stock turbo will choke that motor..

I recall you said it was built from the ground up, so why not spend a tiny bit more and go for a massive turbo and feed it some E85

[walky01]

running rb25de pistons, thats whats holding it back, i plan to only run around 6psi at this stage to give it more torque, im happy with power just after more torque...its what happens after driving an F6 as a daily

[Ben C34]

That's big compression. I don't think you will find anyone with experience running a turbo rb2530 wit that sort of comp.

I remember reading you were going to sell the car?

[walky01]

Yeah ive got one guy interested in the motor, if that falls through ill probably run a cheap turbo setup DIY but get a tune lower rev limit. its built to rev to 7500 easily but power drops off at 6600 so with a turbo wouldnt need it to go that far anyway.

[Simon-S14]

Nothing wrong with the pistons.

E85 ams large rear housing on a decent turbo is the only way you can do it safely

[Dose Pipe Sutututu]

Yeah ive got one guy interested in the motor, if that falls through ill probably run a cheap turbo setup DIY but get a tune lower rev limit. its built to rev to 7500 easily but power drops off at 6600 so with a turbo wouldnt need it to go that far anyway.

Not sure what you mean it's built to rev up to 7500rpm easily.. a stock motor does that?

I reckon get a Hypergear SS2 or even SS3 or even a G3 and feed it E85.. hello 300kW+

[GTSBoy]

Or, for a cheapish 2nd hand turbo option use an XR6 turbo. I agree you need a big turbo rather than a tiny one (like the RB25 turbo really is).

[walky01]

Im new to the whole turbo thing....if i used rb25 manifolds what turbo will bolt up to it? they wont all bolt up im guessing they are different.

[Dose Pipe Sutututu]

Stock RB25DET manifold, Hypergear SS3 OR G3 and all you need a custom dump/downpipe

then go bake tyres

[discopotato03]

What about an RB25 Neo head and RB30 NA pistons , smaller chamber should bring the CR up to a reasonable figure .

A .

[Dose Pipe Sutututu]

What about an RB25 Neo head and RB30 NA pistons , smaller chamber should bring the CR up to a reasonable figure .

A .

Adrian, I hope you've read the very first post.. he's already running an estimated 11:1 static CR

[GTSBoy]

Maybe "reasonable figure" is something like 13:1 for A?

[KiwiRS4T]

What makes you think you have 11:1 compression? What does a compression test come up at?

If you want more torque get a bigger turbo than stock and run it at whatever boost makes the most power. Hypergear as above should do nicely.

[Ben C34]

He said he has to 25 De pistons in the 30 block. Calculating the comp is way better than a compression test.

[Blackkers]

with non turbo engine internals you want a bigger turbo as choking the engine's hotside with a small turbo will increase internal cylinder pressure per pound of boost.

the other thing is that high compression makes it want to ping its head off. E85 will help keep temps down and detonation at bay. Also a big turbo + less boost will help increase the lifespan of your dirty mix up of skyline/VL parts.

I'd suggest something bigger than the stock turbo, and E85. perhaps go for around 10-12 pounds on a hypergear SS2? That would make for a fast car with HEAPS more torque than you are aiming for currently

[discopotato03]

Didn't realise he'd already built it with NA RB25 pistons , why is another story . You'd think the original pistons with the Neo 25s more compact chambers is easiest as long as valves and pistons don't meet .

There are workarounds but I think fitting the right pistons is the answer .

Longer cams with more overlap would reduce effective compression to a degree .

Water injection reduces combustion temperature and pressure .

Absolute minimum exhaust restriction so it can reject the heat in its exhaust gasses most effectively .

All these things cost money and only the individual can know their financial vs convenience priorities . I'm guessing the cheapest option may be to grab another RB30E short block , hunt around for a Neo 25T head and start again . Cheap cheerfull rings and bearing rebuild whilst driving the current setup .

A .

[walky01]

I was never going to turbo it..... but now im looking for more power.

[KiwiRS4T]

He said he has to 25 De pistons in the 30 block. Calculating the comp is way better than a compression test.

Calculating alone won't do it - you have to measure and then calculate - easier said than done.

An 11:1 compression will soon show up as a very high number c200psi on a compression test.