Jump to content
SAU Community

Recommended Posts

cheers for the advice

just looking at the dyno plot, the torque curve drops off at 4100 rpm

where as the manifold pressure doesnt riset above boost pressure till 5000rpm

how do you explain the torque dropping off before the pressure (restriction) rises in the manifold.

Im not trying to discount anyones theories - i welcome them.

But i would like to be certain before spending anymore time and money on this bloody car.

cheers rob

  • Replies 50
  • Created
  • Last Reply

Top Posters In This Topic

the way im looking at it

everythings looking good up until 3750rpm.

at around 3750rpm your gate starts to open.

by 4000rpm its fully open and the interference with the ehaust turbine starts to cause turbulance in the housing. this contnues to build.

by 5000rpm the exhaust wheel has lost a tonne of speed as the gasses are trying to split between the gate exit and going out thru the wheel

due to the turbine slowing down the manifold pressure starts to rise higher and higher.

which only compounds the problem and hence why your torque dies in the ass.

not sure what a non gated rear housing is worth but i would assume not a lot.

and getting your manifold builder to install the gate into the manifold would be a simple procedure.

lowering your exhaust manifold pressure is a must and you have the dyno sheet proving its out of control.

so switching housings is the only way you will fix your issue.

  • 3 weeks later...
we now run the wastegate from the turbine housing where possible. I understand you feel its dodgy, I think the exact opposite, I'd PREFER to run it off the turbine, and do so on my own car, everyone of my friends cars, and any customer that will listen and let me do it. You have better boost control, more hp, faster spool,

6BOOST

Just a quick update, finally got the ecu back with the starting problem patched up (some interference/noise from the idle controller so the dealer just turned it off)

Anyway run it up on the dyno again checking the timing manually found it to be drifting around 10 deg or more under load. Called the dealer to check all settings ie sync falling edges etc. Could not get it stable.

Quickly tried a untuned motec - dead stable.

So ecu is back with dealer.

Has anyone had problems with these TF electronics plug in autronic ecus before ???

Cheers

rob

Imo, the 2nd manifold looks good + iv seen too many spastic 9sec street VL's running that style of gate take off to remember, to think its that. Many ppl swear by that style.

10deg variance under load? that surely could be your issue. Thats a fantastically huge fail from a piece of Autronic hardware. Many a car would go bang with an extra 10deg thrown in at redline and wot.

I blew a wad over your dump / exhuast setup btw man, looks fantastic, love the gentle flare off the back :P

  • 2 weeks later...

dude, that hole is the size of the waste gate on mine....lol

also noted your CAS is almost cranked right around to fully retarded....recheck your base timing.. .

and if that head is the R33 vvt head you might want to ensure the vvl is working aswell as the rb30 blocks dont cater for the

extra oil gallery..

Edited by nizmonut
  • 1 month later...
How recent is the Autronic? The earlier ones had big issues with the standard CAS and required a change in the internals to give clean trigger signals.

Cheers

Gary

Ahh, version 1.07 from memory, yes it required a change of the trigger disk. (recent versions do not)

Ive finally got a bit more power but its still not all there. :miner:

Ill run through when has happened since last post.

1. Dealer changed some settings and ignition modifiers to stabilise spark timing (on different car as we are not in the same city)

2. Spark timing on my car STILL changing with revs, so took car to dealer and after 3/4 of day found the problem to be the spline in the cam that drives the CAS was missaligned causing a nasty vibration. Aligned as best we could but still a 2 deg shift at 3000-3500rpm.

3. Fixed a few issues - seated injectors 4mm deeper, sealed a hairline crack in the inlet manifold that was causing crap idle, replaced dead alternator.

4. The big one, checked the cam timing again with degree wheel and found in and ex to be 7 deg out. Retuned (road) with correct cam timing and got another 15% duty cycle, now up to 65% on denso 720cc injectors at 21psi. Therefore approx power 280 - 300kw.

The exhaust manifold backpressure is still 2 to 1. ie over 40psi which i really need to sort out.

Next plan is to try another turbo wastegate setup - as soon as i can find a donor...

Unfortunately speedo drive has sheared off and gone through the gear box so ill have to sort that first. Choice.

Ill let u kno how i get on, any ideas on the backpressure would be great.

cheers

rob

Edited by roba
  • 8 months later...

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

    • Nope.    Grab a varex and turn it down as you get close to home, win win? 
    • So, I've had my V36 for about a month now and have already copped an "excessive exhaust noise" notification from QLD TMR, reported by someone in my local area. It's a twin as per the original, and can have a bit of a throaty note to it when idling cold 😄 and if I do get up it a bit, it can be noisy, but it did pass a roadworthy inspection before sale, so.... ... but in the interest of being a good neighbour, I do want to quieten it down a bit. Is anyone here running a quiet aftermarket cat-back on their V36 or 370Z? And the big, bold question: does an aftermarket cat-back really make much of a performance difference on these cars?
    • The wiring diagram for the R33 RB25 is freely available, and is essentially the same same as most other RBs (just with differences as to which pin # does which job). To get the ECU to power up, you just need to provide power to the ECCS relay, and have the other power feeds that come in from the top left of the wiring diagram (wrt the ECU) that give perma power to the fuel pump relay, the ECU itself, etc etc, all connected. When you put power on all these it will just come to life. It's pretty clear from the diagram what needs to happen. Just follow the lines from the 12V + supply stuff in the top left over towards the ECU. I've even posted snips of such diagrams (not for vanilla 25, I think for Neo and 26) to various threads here in the last few months, talking about what it takes to get the fuel pump and FPCM up and going. Search these up and they will help get you started on doing the same with the vanilla 25 diagram. Hell, for all I know, I've done the same with that one in years past and have forgotten.
    • Yep...so unless someone posts up the answer you will need to probe from the ECU connector to the dash plug with a multi meter in continuity mode to trace the wires.  Note the ECU has multiple - and + (and across different key settings - Battery, IGN and Start) and most likely the power is fed from the connector(s) that is normally near the left hand headlight.
    • Thanks Duncan, I am actually just trying to get the Rb turning and running with the RB25DET S2 original loom itself  I am just trying to get it going outside the body and not thinking about the S15 or trying to match anything to the S15 loom at all I am only trying to see if anyone has done this and what pin they found to be the ignition trigger and ECU+/- on the dash connector, that's about it. Thanks  
×
×
  • Create New...