Jump to content
SAU Community

Recommended Posts

Hi all..

My 32 has a similar setup to many many other 32's in that i've got a series 1 r33 rb25 turbo on my rb20. I'm running 14psi and i'm pretty happy with the power it's producing, however it seems quite laggy for such a small upgrade in turbo.

I hit full boost around 4500rpm which is still usable, but i have seen dyno sheets from other cars (Bubba's springs to mind) with the same setup but reaching full boost closer to 3500rpm.

The only difference i can see is that i'm running a manual boost controller as opposed to an EBC.. could this delay in full boost be caused by wastegate creep which would be eliminated by an EBC or is it something else?

* i should clarify what i define as "wastegate creep" since i have heard other people define it differently: as the wastegate is a mechanical device, it begins to open slightly as the car comes onto boost. eg: rb20 actuator is 10psi for fully open, however when you're at 5psi the wastegate would be slightly open due to the pressure.. not enough to open fully but a little.

EBC's try to eliminate this by not letting any pressure reach the actuator till the boost is close to the desired target, thus keeping the wastegate fully closed for as long as possible

the manual boost controller i'm using is one of these: http://www.skylinesaustralia.com/forums/go...ntr-t73375.html

other mods i have are:

apexi pod filter

silicone induction pipe

greddy fmic

3" full zorst

nistune ECU

etc etc

So yeah.. just wondering if it's worth me picking up an EBC or not... will i see the boost come on any earlier?

th_24thOctBoost.jpg

Link to comment
https://www.sau.com.au/forums/topic/279128-rb25-turbo-on-rb20det/
Share on other sites

* i should clarify what i define as "wastegate creep" since i have heard other people define it differently: as the wastegate is a mechanical device, it begins to open slightly as the car comes onto boost. eg: rb20 actuator is 10psi for fully open, however when you're at 5psi the wastegate would be slightly open due to the pressure.. not enough to open fully but a little.

They're called "wastegate actuators". You can set the trim for the actuators, so you can have the car come on boost gradually or all of a sudden. EBC might be a good idea because you can set the trim on these to open the wastegate when you want it to, and usually don't open the gate until full pressure has been reached.

Edited by stormtrooper

yeah the actuator controls the wastegate.. but the actuator on the rb20 is completely mechanical (no solenoid or anything) so i can't set the trim since i don't have an EBC (yet)

manual controllers try and reduce this creep by using a restriction on the hose to the actuator.. it does work in theory, but i'm wondering how effectively (if at all) my particular boost controller reduces this creep.

I'm mainly looking for other people running rb25 turbos on their rb20 to see at what rpm they reach full boost using which boost controller.

thanks!

I was running a profecBII when I had my Rb20 w/25 turbo.. they have a fature that holds the gate shut until the boost level you choose, this helps bring boost on much faster.

I was also running a quality split dump pipe, 3" front pipe and 2.75" catback.

i'm just using a just-jap 3" dump / front pipe.. not great, but should still be good enough for my low-end horsepower ambitions..

I'm actually fitting an extractor style manifold soon as my current one is leaking and it was about the same price to buy a new one than to get this one fixed... maybe that will help slightly, but probably not enough.

I've also heard there are dodgey things you can do to reduce wastegate creep like using a long hose from the intake to the actuator.. but i don't think i'll be doing that

Have you tried another actuator? I know the ebc will help bring on boost faster but there's still 1000rpm difference between when mine came on and what yours is doing.. that seems like a huge difference..

P.S. love the avatar dude, we have wooden floorboards and 5 cats.. mucho amusement :blink:

Have you tried another actuator? I know the ebc will help bring on boost faster but there's still 1000rpm difference between when mine came on and what yours is doing.. that seems like a huge difference..

P.S. love the avatar dude, we have wooden floorboards and 5 cats.. mucho amusement :blink:

no i haven't.. that's probably a good idea.

I have tried 2 different turbos and 2 different dump pipes in my tuning adventures, but both turbos and both dump pipes gave identical results.

One thing i was considering trying was next time i get it on the dyno, disconnecting the actuator all together and giving it a run (obviously stopping as soon as the boost gets to 15psi) and seeing when it comes on boost completely un-wastegated .. should be a good indication of how much better it *could* be

i had this problem when i first put an r34 turbo on my rb20, but i found out that it was due to the actuator, the wastgate actuator had a sort of power band, would mid boost then full boost, i was full boosting around 4500, all i did was swap over my rb20 actuator over and then that cut the rpm by about 1k

worrth a shot, altho be warned it may change ur boost setting, mine went up to standard boost 13psi

no i haven't.. that's probably a good idea.

I have tried 2 different turbos and 2 different dump pipes in my tuning adventures, but both turbos and both dump pipes gave identical results.

One thing i was considering trying was next time i get it on the dyno, disconnecting the actuator all together and giving it a run (obviously stopping as soon as the boost gets to 15psi) and seeing when it comes on boost completely un-wastegated .. should be a good indication of how much better it *could* be

I was going to suggest that and try it on the road.

just run it and watch the guage, but its not too safe :P

im thinking actuator is the culprit

ive got a s2 r33 turbo on my 32 (rb20)

and i also have the boost tee and very similar mods to yours, minus nistune and plus splitfires,

my boost guage is unpluged atm (dont ask) so ill get that in this weekend and give it a smash :mellow:

however im pretty sure it comes on before 4500 bro

ill keep ya posted

Are you going off just your dyno graph or out on the street? I was looking at your previous dyno sheets and it looks like it ramps up quicker when you had lower power. Id say it's just a slower ramp rate on the dyno.

hey mate just came back form a chill wiht some of the sau boys, and i took my car for a little burn wen on the freeway,

and anyway, althought my guage isnt plugged in atm - i rkn i hit full boost (12psi) at around 3,200-3,400

:banana:

Had a bit of test on the weekend and mine is making 10 pound by 4k and creeps to 12 pound a few hundred RPM afterward maybe 4.2k or thereabouts.

I'm using one of those GFB bleed valves. Sounds like i may have to find a stock RB20 actuator and swap it over?

i put my old S2 rb25 turbo on my mates r32 not long ago. hits full boost (15psi) at 3200rpm in 4th starting at 2000rpm and flooring it. i would say take ur wastegate actuator off and test it with a compressor with a valve on it and gradually increase the pressure untill it opens the actuator. i think the spring inside urs if screwed and opening way too easily causing ur boost to come on slow. or ur wastegate isnt properly closed.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Seat of the pants assessment of the new intake: The car is way less "doughy" when hitting the loud pedal, especially off idle when stopped or in traffic, I did use a cheapo lazer thermal thingo to measure the temp around where the pod filter got its air, it was between 55 - 60°C, in saying this the car was shut off and not moving, so the OEM intake pipe was not supplying any fresh air to where the pod was when the car was at least moving A weird bonus was induction noise on the throttle in the cabin increased a bit,  I was worried that I was actually going to lose some of that induction noise I love so much, outside though, when I got the daughter to do a WOT drive by pass for me, the induction noise has increased alot when on the throttle, not quite ITB doort, but well up there I'm extremely happy with the results and have been exploring the country roads in the region  As for house mods: 1.New front fence is up and is awesome, it really upgraded how the joint looks from the street, and the added security is nice 2. Electricians have replace some interior lights, and with more lighting in the garage, a few new motion detecting lights out the front above the garage, front room, and at the front door, which I have already found heaps helpful coming and going, also now has fancy pants CCTV all round the house The only hold point for power though is the solar and batteries due to supply issues, although this will happen over the next few weeks 3. I have done a heap of landscaping out the front and I'm almost ready to do a new small retaining wall with some nice blocks to replace the brick and cemented in rocks around the raised garden beds cemented in river stone "was the fashion at the time" the house was built. I currently have a pallet of retaining wall blocks and 2 bulka bags of 20mm blue metal to replace the wood chip that is in the raised garden beds around the house 4. I now have 3 big raised garden beds for out the back to grow some vegetables, about 70cm high, 200cm long and 100cm wide 5. My 2 compost bins are already pretty full with brown, green and kitchen waste from the landscaping I'vedone so far, but they will probably take a few months to break down, so anything else that gets chopped, trimmed, and kitchen waste will just start filling the base of the raised garden beds to about 30cm before I start throwing 40cm of good compost, and stuff, for the vegetables to grow in, I'll need a few ton of compost and soil, but the local supplier can sent me bulka bags of the stuff Basically the logs, wood chips and a few strategically placed rocks for drainage, will give the beds some good organic materials down low to break down over time, and they will hold moisture during the warmer months to save the water in my big arse water tank if we don't get alot of rain So, all in all, the car and house mods are going well, and I'm really enjoying being retired, I sleep in too 0700 and slowly plod around inside until I feel like actually doing anything, and only work in the yard for as long as want, which has actually been alot over the last few weeks,  although when you look at it, it seems that not a huge amount of work has been done,  until I look at the before I started the work pics Happy days and good times indeed 
    • hahaha yeah. Plan is to get side skirts and probably just rear pods. But going to do them one-by-one. I've got a set that I really like from RHDJapen, but that one isn't shipped to AU. So need to find someone who can get it for me
    • Here's an idea, answer the questions I asked you as they are trying to work out WHY the LSD will be binding up in a straight line.
    • You haven't driven many modern cars then have you? Most of them have sfa steering feel with their stupid electric bullshit steering systems.
×
×
  • Create New...