rb25turbo on rb20 q

[inissane]

so u can have boost control problems with boost controller/actuator design? is this why people are finding it hard to tune jaycar IEBC with some actuators?

which actuator should be used for RB25 turbo on RB20 with a jaycar IEBC?? (which uses the solenoid to regulate the amount of air pressure the actuator comes in contact with)

[TTT]

all turbo cars need to have an actuator.

this is base boost level.

it has nothing to do with the EBC.

if you are using the Jaycar doobie, read the thread Sydneykid has started in the stagea section.

that kit needs you to have a SOLENOID much like the one in the R33's.

that kit controls how much the solenoid opens and so forth.

if you are using an RB20 actuator, you will always have a base boost level of MINIMUM 10psi.

[Cubes]

Ronin, Looks like your stock injectors max out and go lean roughly where mine does.

Mine begins going lean over 175-176rwkw @ 9psi on the stock rb20det turbo, yours is around 180rwkw.

GTST, the base boost level with the rb20det actuator depends on the exhaust and how much air the engine is consuming.

With the RB20DET & its actuator the most boost I could hold was 12.5psi on the stock actuator. This was to a maximum of 7500rpm, I hadn't taken it over that.

On the RB30DET the stock rb20det turbo actually has a bit of a problem supplying anything over 9psi. As it comes on boost it spikes up to 12psi then quickly tapers off by 4400rpm where it makes its peak power of 175-176rwkw, by 4950rpm boost is starting to nudge 8psi.

My dump pipe is pretty bodgy at the moment as I bodged it when I dropped the rb30det in, basically I needed an extra 30-40mm height so I cut the straight part of the dump/front pipe and welded in a small extension that was slightly larger than the 3" pipe, So air flows down the pipe and causes a bit of turbulance when it hits the lip of the pipe. Hope that makes sense.

I think my issue is more so the stock rb20det turbo cannot supply any more air and is running deep in to choke. Chopping the air rather than pushing it.

[jazza08]

Why the hell wud u run an rb20 turbo on an rb30det? lol

Obviously ull be on boost all the time, but u shud be getting something alot larger for that baby

[inissane]

so both actuators are dodgy if u want to hold boost to higher than 12-13psi?

any reasonably priced actuators to replace with?

but I guess with the rb25 turbo the safe boost level and the level that can be held by the RB20 actuator are similar so not worth it? Am I on the right track

[Cubes]

jazza08

I wanted to see what it could do.

The tune only set me back $100.

Inissane,

Have another read of my post.

The RB20DET turbo has reached its limits, the back pressure in the exhaust housing is blowing the wastegate flap open, if I were to fit an RB25 actuator I might only get 6psi. So to answer your question.. The RB20DET actuator on a Rb20DET or RB25DET will be fine for holding 11-12psi, obviously the final boost level depends on how well your exhaust flows.

Just as a note the RB20DET turbo with the wastegate wired fully open still makes 6psi from 4000rpm. Obviously there is a lot of back pressure in that little housing.

[jazza08]

An elc boost controller will happily hold above 12psi dude!

However without one the actuator will never get above that no matter what mods have been done.

[Cubes]

Jazza08,

Ive had a little bit of experience with the small rb20t turbo on the rb20det running up to 16psi.

I found with bleeders and ebc's that run in a 'manual' mode (i.e set a duty cycle %) will drop boost over 5500rpm down to 12.5psi.

The cheaper EBC's you pick up will have this issue. i.e cheap HKS & Blitz SBC ebc's.

I quized my tuner at the time who was Tim Possingham the origional owner of RPM.

He said to get a good ebc that learns the boost curve, pulses the actuator and adjusts the duty cycle to force it to hold the higher boost in the higher rpms.

After a bit of research there was a couple of EBC's that 'learned' the boost curve and set boost automatically to the boost you wanted. Simply dial in 15psi and drive the car. At the beginning you start off with stock boost, progressively it increases boost to what you want.

The few EBC's that do this 'learning' or auto boost are, Blitz SBC-iD, AVCR, Greedy Profec E01.

But.. you wouldn't have the problem if you ran a decent sized turbo.

I do think part of my problem was my dump pipe. The auto EBC was a bandaid.

Mind you going from 12.5psi at 7000rpm to 15psi at 7000rpm only picked up 10rwkw. Pumping hot air is not too good for power.

[inissane]

yeh thats what Im getting at, I completely understand their jobs in isolation, but the interaction of the boost controller, solenoid and actuator on a certain turbo/engine is important me reckons

so with the jaycar IEBC as long as the boost gauge is accurate and the tune/settings good and smooth the boost curve should theoretically be perfect to say 12-13psi with the rb20 actuator on the rb25 turbo?

[neo32]

does anyone know the difference between the rb20 turbo and 25 ime trying to idenitify the one on my neo6 ime thinking its a rb 20 one tho it has the wastgate line out from the housing the other 34 turbos ive seen have it on the outlet pipe any help thanks

[TTT]

dude.

buy rb20 turbo

use rb20 actuator

buy boost controller of some sort to get the other 2 or 3 psi you want over 10 psi.

[nedb]

I'm fairly sure you want to run a 12:1 AFR

14:1 was before I changed the fuel pump and now the AFR is about 11.3 on stock boost.

[Z00MxRACING]

ok ok ..

just got my FMIC and AVCR fitted ... but dunno really how to tune the AVCR .. ive noticed that with the AVCR switched off mode - the car runs smooth but sort of lost power .. but once i have the AVCR setting to B (high boost setting) with 1.1bar & 60% duty the car actually only hits 1.09bar ,with 98% throttle, 6589rpm and 78klms ..is dat a good / fair enuf tuning for a 1.1bar of boost?? would it cause damage to my engine? i dont feel power loss in the top end but sometimes it back fires ...could dat be the GFB BOV not being tuned correctly?

modz are:

GFB Stealth plumb back BOV

AVCR

RUF FMIC

hks Pod,

hks exhaust setup as: 3inch dump / front pipe --> 3.5inch high flow cat -> 3.5inch resonator --> then finally 4inch piping all the way to the hks supper dragger!

wot kind of a exhaust setup is dat?? i was told by some mob that its a HKS GTR exhaust setup. and dont bother changing .. (so i didnt)

but do u think i could be having back pressure issues??

who could i go to get my AVCR & GFB BOV tuned??

wot power figures could i be expecting once all tuned??

[jazza08]

1.1bar wud be alil much for an rb20 or rb25 turbo.. unless its been rebuild/hi-flowed of course! If its an rb20 wit an rb25 turbo and those mods.. probably around 240-250rwhp on 1.1bar once tuned. You cant tune a BOV, but they can play wit ur boost controller abit better and check out ur car. You dont have anything to tune the car wit (ie SAFC or Rom etc) so they wont be able to change air/fuel ratios etc for more power and to make it run better until u get one of these dude!

[Cool Hand Luke]

I think that 1.1bar is the maximum for an rb25 turbo on an rb20, and a bit too much for the rb20 turbo.. I ran upto 17psi for a while with no problems with a S2 RB25 turbo, but that doesnt mean there wouldnt've been eventually.. but it was a good few months of driving every day.

1.1bar wud be alil much for an rb20 or rb25 turbo.. unless its been rebuild/hi-flowed of course! If its an rb20 wit an rb25 turbo and those mods.. probably around 240-250rwhp on 1.1bar once tuned. You cant tune a BOV, but they can play wit ur boost controller abit better and check out ur car. You dont have anything to tune the car wit (ie SAFC or Rom etc) so they wont be able to change air/fuel ratios etc for more power and to make it run better until u get one of these dude!

[TTT]

I think the backfire you are talking about is actually a MISS FIRE.

since you are now running so much more boost than standard, you're probably blowing out the spark.

change your spark plugs with some copper NGK items.

Either buy them with a 0.8mm gap or Gap them yourself to 0.8 or even 0.7

this should fix the MISS FIRE high in the rev range.

and I'd say that holding 1.09 Bar is pretty good when set to 1.1 and probably on a cold night, it will hit the 1.1Bar..

I'd also liek to know what turbo you are using.

[Z00MxRACING]

I think the backfire you are talking about is actually a MISS FIRE.

since you are now running so much more boost than standard, you're probably blowing out the spark.

change your spark plugs with some copper NGK items.

Either buy them with a 0.8mm gap or Gap them yourself to 0.8 or even 0.7

this should fix the MISS FIRE high in the rev range.

and I'd say that holding 1.09 Bar is pretty good when set to 1.1 and probably on a cold night, it will hit the 1.1Bar..

I'd also liek to know what turbo you are using.

yeh i got the sparkies changed to a ngk r copper items ... pre gap to 0.8 .. but the original ones that was in there was HKS irridiums ..and they actually still looks ok might actually put them back on after cleaning ..

yeh i was amazed how it held 1.09 bar ...and the turbo i was still using was the stock r32 turbo .... i wonder if it will still hold the boost levels when i wack the r33 turbo with thr r32 actuator ...

well see how that puppy goes ..

about SAFC / power fc .. im thinking of getting one ...but the cash is out of the question at the moment ..until i sell my 7in pioneer indash dvd touchscreen wit tv tuner and spare 7inch sceen......

if yah know anyone who is looking to buy one ... tell them to check me out

http://forums.fastfours.com.au/viewtopic.php?t=93481

[sr20detnz]

I installed a RB20DET actuator RB25DET on R33, i only got 108rwkw. When the standard RB25DET actuator back on i got 140rwkw. The rest of the car is factory standard.

[Cubes]

lol... Thats what happens witht he lovely rich/retard/powerdip R33 ecu.

Obviously it wasn't able to handle more boost.

[sr20detnz]

I also installed 3 inch exhaust from the dump pipe ( 2 resonators only, no cat ) and K&N pannel filter. With the RB20DET actuatoer i was hopeing to lock boost at 10psi but the boost goes up to 11.2psi and i have huge power loss.

But with RB25DET actuatoer it holds 7psi through out the power curve and give good power.

Explain the power dip, as u mention some thing about the computer?