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what boost do you run in your RB20?

bbenny

By bbenny,
in Engines & Forced Induction

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bbenny Mentor

bbenny

Posted
Posted

Hey guys, i know its the age old question "how much boost do you run?" or how much can you safely run.

But i am interested to see what kind of boost you run on your RB20 and what internal changes you have made in order to do so. eg metal headgasket, forgies as well as turbo set up etc.

I ran a max of 1.2 bar (18psi) on my internally stock RB20 last week on the dyno with no problems. using a HKS 2530

what do you think is the max i could/should run with this turbo set up, assuming i have plenty of fuel to flow and good cooling?

cheers!

Ben.

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Roy Grand Master

Roy

Posted
Posted

My theory, which will be put to the test when i FINALLY get my car tuned and running 100%, is that revs hurt engines more then boost. So if i can get my think perculating with around 1.0 bar by approx 4,000rpm then im going to limit my revs 6,800rpm.

So with my revs limited to 6,800rpm , im going to wind all the boost i can into it. See what power it makes at 1.2 bar, then 1.3 bar, then 1.4bar, if its making substantially more power at 1.4 bar then 1.2 bar, then for drag racing ill use 1.4 bar in 3rd and 4th gear. (if i can get traction in 2nd with 1.4bar , then hell ill give it a go :) )

For the circuit though ill leave boost at 1.2 bar. My gut feeling is at 1bar the thing has more then enough power for me, so im sure ill be happy with 1.2 bar for most occasions. Though ill have the scramble button on my AVCR set for 1.4bar (if its worth it.... for the straights when im getting humbled by cars with more power :Oops: )

If i cant get meaningful boost by 4,000rpm and the thing doesnt really hit until say 4,600rpm, then im going to limit boost to 1.1bar and use 8,000rpm.

What revs do you plan on running?

Get the thing dynod at 1.4-1.5 bar and see if it really makes any more power, and has safe A/Fs. Then with your gearing in mind, overlay the plots to see if you limit your rev limit to say 6,400rpm with 1.4 bar, do you make more average power then you do with say 1.1bar and 7,800rpm (allowing for changes in gear and drops in rev range....how are your spreadsheet skills :D

jnr32r Proficient

jnr32r

Posted
Posted

im with you there Roy, high revs in an internally std motor will hurt more than high boost.

driving to work i rarely go past 0.9bar.

I have taken it to 1.5bar in a couple of occasions to see how it felt. Not much different than 1.4 bar. But i have it set to a max of ~1.4, but most times i set it to 1.2bar when i feel like a squirt.

my rev cut is set at 7000rpm to keep things on the safe side...

bbenny Mentor

bbenny

Posted
  • Author
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well as you can see on my print-out im making max power around 6000rpm or earlier.

but i think i will have to give it a bit at least just on the dyno to see what happens, however driving it with that much boost might be a bit risky.

neil_se Experienced

neil_se

Posted
Posted

I'm running 1bar on my rb20det with hks2530. Its just a bleed for the moment, i'm waiting to get clutch then install my profec a when i get a tune. I plan on running 1.2bar as well, the only thing holding me back from running 1.4 is i don't think the stock injectors will hold up that far.

Fast31 Collaborator

Fast31

Posted
Posted

mate its all in the tuning. I have run 20psi through mine for a long time with no problems,

However, we have pulled a few degrees of timing out and also have it running reasonably rich. Make sure all your support systems are up to scratch tho. One slight lean out at 20psi and its all over.

bbenny Mentor

bbenny

Posted
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yeah i have all the support systems needed, however i still have stock injectors.

but when playing on the dyno last week, higher fuel pressure saw the a/f drop below 10

Fast31 are you running 20psi on the road all the time, or only when you race/dyno etc?

also did you pull the timing out of base timing or are you talking about the ignition timing on your remaped ecu/or other management?

i dont mind giving it a quick power run at 1.4bar but doubt i will run the car on the road or track at this boost level.

Sydneykid Grand Master

Sydneykid

Posted
Posted

Simple question bbenny, complex answer..........

We ran 1.5 bar for a while at 195 rwkw. Then I fitted the GTR cams, adj pulleys and a hi flow cat (real hi flow) and it now makes 225 rwkw at 1.3 bar. Since boost is a measure of resistance, and by fitting longer duration, higher lift cams I have reduced the restriction, this is not surprising. :rant:

bbenny Mentor

bbenny

Posted
  • Author
Posted

interesting sydneykid.

If only i got the GTR cams to work :rant:

but all my support systems are great, i havent skimped anywhere apart from engine management...

considering i have good a/f ratios at higher boost, would you consider it necessary to install a thicker metal headgasket?

Sydneykid Grand Master

Sydneykid

Posted
Posted
interesting sydneykid.

If only i got the GTR cams to work :rofl:

but all my support systems are great, i havent skimped anywhere apart from engine management...

considering i have good a/f ratios at higher boost, would you consider it necessary to install a thicker metal headgasket?

Nope RB20's are low enough. :rant:

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