Boost And Rpm On Stock Rb30 Bottom End

[leeroy_25]

Just running in my stock RB26/30 combo at the mo and starting to get some plans and things together ready for the full map and dyno run.

Can people who have built and/or are running an RB25/30 or RB26/30 using the stock RB30 bottom end internals let me know what boost you are running and what rpm you set your limit to to have a safe, lasting engine? It will be road use 95% probably if that makes any difference. I have read a few opinions just would like some hard facts. Maybe let me know how long you have had your engine running for as well.

Cheers

Lee

[JonnoHR31]

just getting myne going atm, planning to rev it to 7-7.5 depending on where it stops making power and gonna be running 20+psi boost. but if you wanna be real safe keep it to 7k rpm and 17-18psi

[GT32]

Well during my run-in tune we only had to rev it to 5800rpm on 17.5psi and that already netted us 297rwkw on the RB30/25 combo (balanced and treated stock bottom end/forged low-comp pistons) with a GT3582BB. Speaking to my engine builder he recommended that my tuner should stick to a mild 6400/6500rpm redline when we re-tune it due to the RB30 crank and rods still being stock items. Plus it's a street car, I don't think that you'd really need to rev it that hard anyway if you're after longevity. I've well and truly ran the motor in now (completed around 8000kms) so it's actually due to go back to my tuners in a few weeks time for more boost and more rpm .

[TiTAN]

6000-6500 on a completely stock bottom end (no extra balancing etc).

run what ever boost it takes to make the power you want (keep the power sensible). its the massive increase in power/revs over stock that kill these engines not lifted heads etc from too much boost.

[leeroy_25]

Thanks for the advise guys. I was thinking 6750rpm and 1.2bar boost so I was not a million miles out! I would be interested to push the treated rods but not just yet!!

Cheers

Lee

[waxracing]

Thats about the same as I am after leroy

I have rebuilt the bottom end with a bore and new pistons.

Its very easily inside the performance limits of this engine to make 400hp and to rev to 7000.

Im going to go for 18psi or 400hp what ever comes first

[sherman89]

Yeah i dont see why you wouldnt rev it to 7ish. As you would know, its all in the tune!!

[leeroy_25]

waxracing... Are you talking 400rwhp? Gross power that would be easy. A stock RB26 an make that on 1bar. I want to top 500 flywheel and really over 550 if possible but I guess I will just have to wait and see. I want to use as little boost as required.

[waxracing]

rwhp I dont have access to an engine dyno to calculate engine power

[KiwiRS4T]

waxracing... Are you talking 400rwhp? Gross power that would be easy. A stock RB26 an make that on 1bar. I want to top 500 flywheel and really over 550 if possible but I guess I will just have to wait and see. I want to use as little boost as required.

I think that's a little ambitious. Some say not but if you read the RB30 thread of dyno results you will see very few big hp that are not at least rebored and balanced if not fully forged. I am using the stock (as in original) crank, pistons and rods with a/m rings, bearings and rod bolts and will be limiting revs to 6, 800 and probably using less. I would like to make 500hp but will be happy if I hit 300awkw and anything else will be a bonus. I can't afford to blow my engine so won't be asking tuner to push the limits. BTW I think stock rods are fine - I expect the pistons to be the weak point.

[waxracing]

300 kw is more than 400hp

[GT32]

500hp at the motor is roughly 320-330kw at the rear wheels on a manual FR (dependant on drivetrain power loss--normally I go by 15% loss for 6cyl/FR/manual, 20% for 6cyl/FR/auto etc.). I found that formula on some automotive site years ago and been using it as a personal guide ever since. It is not truly accurate by any means but it does gives you an indication of power at the motor.

[rb2?]

its all in the tune alrite, i was running a garret 35/40 .82 rear with 560cc injectors (evo's i think) with haltech and 500hp walbro external pump.. it made just over 300kw and was at 17psi.. and lasted 3000kms before detonating and breaking 3 pistons. its bcuz it ran a bit lean after 6000rpm because the fuel pump couldnt handle the jandle. so i suggest u make sure it has a good air and fuel ratio mixture , upgrade anything that needs upgrading for it to run good. that was my mistake :<

my 2c's anyway

Now its forgie time for me baby!

[waxracing]

guys talk in hp or kw

500hp is 373kw.

Trying to guess loss in the drive train is really not worth it. Just talk in rwhp and your fine.

Unless of course your trying to put your engine on an engine dyno.

The fact that you had deto and blew up shows lack of a decent tune. No engine tuner should have let that car go out with a lack of fuel delivery.

The forged pistons will not stop deto but they will handle it for a bit longer before putting you back in the same situation.

[rb2?]

The fact that you had deto and blew up shows lack of a decent tune. No engine tuner should have let that car go out with a lack of fuel delivery.

The forged pistons will not stop deto but they will handle it for a bit longer before putting you back in the same situation.

i agree 100% with you and the fact that my engine was left on lean was cuz of limited coin and was a slapper. this next build will be a smarter approach. I HOPE

[JonnoHR31]

300 kw is more than 400hp

402.3070hp if you wanna get real technical. essentially 300kw is 400hp

[KiwiRS4T]

300 kw is more than 400hp

I was referring to the "over 550hp " which is over 400kw