max boost for RB20DET (internals only)

[Doctor 30]

What is the max boost you can run on a standard RB20DET that DOES NOT have a ceramic turbo. Pretend you had the greatest IC,BOV Wastegate and turbo you could fit. How much boost could you run before the motor internals would shit itself.

Please do not mention the standard turbo I don't have one of those anymore and it is not an RB25 unit either. So please just focus on the internals as I could run easy 18psi but I don't want it to go bang.

[JH32]

I know of more than a couple of RB20s running 19psi through T04E turbos, with stock internals.

So far they haven't gone bang and they've been doing this for at least 6 months now

[Doctor 30]

Thats great, I'll definitely wind her up to 16+ psi then

[bbenny]

before you do that get it on the dyno as your standard ecu might start doing stupid things, mine did. i got it rechipped and dont have any probs now.

but dont wind it up without checking on a dyno. its too expensive not to be sure.

[Sydneykid]

What is the max boost you can run on a standard RB20DET that DOES NOT have a ceramic turbo.  Pretend you had the greatest IC,BOV Wastegate and turbo you could fit.  How much boost could you run before the motor internals would shit itself.

Please do not mention the standard turbo I don't have one of those anymore and it is not an RB25 unit either.  So please just focus on the internals as I could run easy 18psi but I don't want it to go bang.

Boost is really irrelevant, it's airflow that makes power. More power = more combustion pressure and that's what kills engines. Think about the airflow differences between a huge turbo at 16psi and a smaller turbo at 16 psi. Boost is not a very good ruler to measure by.

So I prefer to have a power limit on RB20 standard internals, not a boost limit. The current rule of thumb is 265 rwkw, over that and the pistons and rod bolts have problems. That said, the real limit is TUNING, a good tune at 265 rwkw is less likely to cause problems than a poor tune at 200 rwkw.

Hope that helps

[Roy]

My concern isnt so much boost, but revs. Was at Phillip Island the other day and because of rough house tune and the amount of wide open throttle and high rpm, i was happy i was only running 8psi with an 8,000rpm rev limit. (wound it back from 13psi as the engine was tuned in 45 minutes at 9pm the night before

Im hoping to run 18psi with a 7,000rev limit, it depends how much mid range i can get from the adjustable cam gears. If i can get a healthy increase then ill wind the revs back and creep in a bit more boost, 18-19psi.

If i cant make 1bar before 4,500rpm then i may stick with the 8,000rpm rev limit and only 15-16psi.

So id be looking at a balnce of things such as water temps, oil temps, revs and boost...my thinking is its a big soup bowl and all are important if your engine is going to stay healthy

[rb20-calais]

when on the dyno my car had problems with missfiring at anything over 17psi, now on the street it can spike to 18.* psi with no missfire, the tuners said the problem was the wolf had 4 ignition outputs and they had to work too hard doubled up (?),

What ignition do you use with a 20psi+ rb20?

I want to up the boost to 1.4bar.

Evan

[Doctor 30]

Sydney Kid-- I have a link ECU which is tunable to anything I like, I am running some turbo with double the airflow of a standard one (going by compressor outlet size) and a supra IC. My dyno tune registered 106rwkw in top without a fan at 16psi. I would expect more power and less pressure on the road as you get cool air actually running over the IC. I also have a 3" mandrel bent exhaust although I am skeptical of the cat size. I also have a BOV running at 16.5 psi post IC. So what I want to know is with these mods what is the max KW at a max safe pressure and what would that safe pressure be?

Thanks

BTW, I have read some of your previous posts so I think I can trust your opinion on this

[BBQ]

It all depends on the tunning, If you running stock ecu and bigger turbo, you will lean out your computer and your internals will go bang, (From experience) but if tunned correctly it should handle it, on say 18 PSI, But be sure to not go over about 20 as the head gasket won’t seal for very long on that much Psi. And you will more then likely kill the ring lands on the RB motor (which is common fault) or put a conrod though the side of your block. In due time.

[Doctor 30]

Great, then 16.5 should be no prob. Keep the advice coming

[DCIEVE]

rb20-calais, can you upgrade the wolf to have 6 ign drivers? if not then you may need to look for a some form of ignition amplifier (lotsa $$) other ecu's have the req'd no of drivers so i cant see why you wouldnt be able to upgrade yours tho.

[Sydneykid]

when on the dyno my car had problems with missfiring at anything over 17psi, now on the street it can spike to 18.* psi with no missfire, the tuners said the problem was the wolf had 4 ignition outputs and they had to work too hard doubled up (?),

What ignition do you use with a 20psi+ rb20?

I want to up the boost to 1.4bar.

Evan

Hi Evan, we don't use Wolfs, I suggest you have a chat to Steve-SST he uses them all the time. I can't say that I have heard of Wolfs having the problem that you describe.

[Doctor 30]

So all are agreed that 18psi is safe with my mods???

[Roy]

So all are agreed that 18psi is safe with my mods???

Nothing is safe. Fullstop. If it dies then dont be disappointed. All you can really do is take sensible precautions.

How long have you had your car? Do you know the history of it? Id say the condition of the engine, combined with the tune, and control of coolant and oil will mean the engine at least has a chance.

I could be wrong but i dont see too many RB20s throwing rods or with failing pistons. But they are getting on a bit and many have high kms so the general condition of rings/bearings valvertrane etc can vary widely.

If you owned an R34 ppl could be a little more confident in saying safe.

[Doctor 30]

engine has done around 70000 kms. 20000 has been on freeways. The head was off and got a clean up and no 3 piston had a little damage from turbo shrapnel that went through it but the bores were clean. It also hasn't revved past 6500. The tuning is slightly rich when floored to prevent pinging.

does that help? If so what is a estimated safe level for the mods on my car?

[BBQ]

I don’t think there is a safe level for any car, to tell you the truth.

You can tune a car at 1000hp or you can tune a car at 200hp, either way any one of the cars could die first eg, the 200hp one due to the fact that there are so many moving part and any thing could give way at any time.

We can only give you a guide, on how to setup your car. Not tell you a safe level to tune at, because we aren’t responsible for anything going wrong.

Take it to a Work shop that will guide you in the right direction.

[Doctor 30]

Alright then, I want to make 300fly wheel horse power, what boost (manifold post IC) do I need to run with the mods I have. Assume the turbo is the same size as and RB25 but has no ceramic bits.

[Sydneykid]

We have a ball bearing hi flowed RB25DET turbo on our RB20 DET and it makes 225 rwkw (~380 bhp) at 1.3 bar (19 psi). It makes 165 rwkw (~300 bhp) at 0.9 bar (13 psi).

Hope that helps

[Roy]

We have a ball bearing hi flowed RB25DET turbo on our RB20 DET and it makes 225 rwkw (~380 bhp) at 1.3 bar (19 psi).  It makes 165 rwkw (~300 bhp) at 0.9 bar (13 psi).

Hope that helps

LOL...get a TD06, makes 180something rwkws at 0.65bar. Only it needs 4500rpm to make that boost :Oops:

If you have owned your car for a while and its been pretty healthy then id say you wont have any problems with 300hp. Whats that 190-200rwkws...

[Ronin]

We have a ball bearing hi flowed RB25DET turbo on our RB20 DET and it makes 225 rwkw (~380 bhp) at 1.3 bar (19 psi). It makes 165 rwkw (~300 bhp) at 0.9 bar (13 psi).

Thats not too flash, i have a stock rb25 turbo on my r32 and make 185-190rwkw at 14psi.