2nd Attempt: RB30 + 750cc inj + z32 AFM

vn_luke · Post by **vn_luke** » Sun Aug 03, 2008 11:14 pm

Hey guys,

Just hoping to get some feedback + tips from people with a bit more experience + knowledge than myself

- hopefully some rb30 gurus floating around somewhere!

Specs on the car are:

- RB30 SOHC (9.0:1 comp) - $150 wrecker special experiment motor with "acl monotorque" head gasket.
- xf falcon throttle body
- auto trans
- tight 4000ish rpm stall converter
- 750cc simmens 3145's @ stock rail pressure (3 bar?)
- gt35 with .82 rear @ 14psi
- custom intake + exhaust manifolds
- intercooled
- z32 AFM - a reproduction one, not genuine bosh

, mounted pre-turbo
- plumb back bov
- running (and always will be running) 98 octane fuel.

I've fiddled for a while and have a tune that seems to work nicely. (attached with log)

my concerns/queries are: (and they're numbered! - 2 gold stars for effort)

1) spark timing - Is this too much? how much have other people managed to run with similar setups? - I can't hear any pinging (with "ping-ear" knock detection (tm)) - but I've retarded the timing by 3 degrees on the last load points to play it safe for the time being. From what I understand there should be a 'dip' in the timing map around where the engine is most efficient? does anyone have a timing map I could refer to?

1.4) spark timing on boost transition - what is the theory there? what gives best results?

2) AFR's: I've aimed for 11:1 at full boost. The wideband doesn't quite read the same as what the fuel map says - but it's almost close. What have people found to be safe and best power producing AFRs on boost? If you look @ the 'boost transition' afrs, they end up being about 9-10:1. I figured I'd dump the fuel in there on the transition so that it doesn't go lean - is this costing me spool time?

3) wanting to stall - every now and then when you back off after a full throttle run, it will want to stall for the next 30 seconds or so. Is there anything obvious in the log that would explain why?

4) cruising afr's - how come they're so fat? is my K value/pulsewidth combo wrong?

5) accel enrichment - I can't find anything about this in the address file. is it automagic?

6) random AFM reading spikes - I'll double check the wiring I guess

unless anyone has another theory as to why it'd be spiking?

7) fuel cut and recover tabels what do these do? why? [/b]

tp spikes How come they're there? should I extend my tables to cover the spikes?

9) general Should I smoothen the maps? is there anything generally wrong/bad about the tune?

RB30-POWER · Post by **RB30-POWER** » Tue Aug 05, 2008 8:34 pm

have you got the standard narrow band oxygen sensor plugged in, it shows 0 volts on that channel in the software, most likely the reason the cruise mixtures are mid 13's instead of approx 14.7:1, unless you unplugged it for the log?

accel enrich is handled by the standard airflow meter overshoot, rather basic, not maps for this function like the latter nissan ecu have that rely on a throttle postion sensor, which the rb30 does not have anyway.

fuel cut tables are so the fuel is shutoff on overrun/closed throttle when rpm is higher then set rpm, needs to be a higher rpm when cold to keep it smooth.

rb30 manual fuel cut values are way to high, copy the z31 maps over for these to save fuel.

bosch states maximum power is developed at 12.5:1 afr, rb30 seems to respond ok to this at lower power levels and holds true, but above 250rwkw or when backpressure is high from small a/r turbines maybe aim for 11.5:1-12.0:1 for added safety margin at expensive of slight power gain, combustion chamber is not as good as the twin cammers so flame front propogation is not as ideal as it could be.

timing figures look a little high to me, but maybe the gt35 is not really making all that much power at that boost level?

didn't look that hard, but are you sure your throttle position switch is set correctly and working, could not see decel fuel cut in effect in the logs, which uses the tps idle switch, could be part of your other problems.

other guys will know more.

Matt · Post by **Matt** » Wed Aug 06, 2008 12:17 am

the TPS_IDLE switch seems to be on a lot so check TPS switch out firstly. It could have reason to do with stalling issues maybe? It is used to determine when decelerate has finishes and restarted

Also with the AFM spikes. Normally I see this if there is a problem with the HD46510 chip on the ECU because of too much voltage entering it. Sometimes its 0.0 volts and othertimes 5.1 volts in the spikes. ECU may have a problem and need another chip. Do you have a zener diode fitted to this when you did the AFM conversion? Dont know about the TPS spikes though

vn_luke · Post by **vn_luke** » Wed Aug 06, 2008 1:38 am

Thanks for taking the time to look over this guys! I really appreciate it.

Since posting I've tinkered a bit more with the tune and have increased boost to 16ps, changed the K value slightly, along with latency which has repaired the 'cruise' mixture a bit. I will take your suggestions on board and do another log in the next day or so to show how it all went!

have you got the standard narrow band oxygen sensor plugged in

I do not at the moment. I intend on programming one of the analog Innovate LC-1 outputs to replicate the original "narrow-band"signal, and plug it into the ECU.

rb30 manual fuel cut values are way to high, copy the z31 maps over for these to save fuel.

all done - stay tuned for results in the log! thanks!

timing figures look a little high to me, but maybe the gt35 is not really making all that much power at that boost level?

There was audible detonation once I put any more weight in the car other than just myself - and once a bit of heat soak set in - seems it was just too much timing. The new tune follows the stock timing midrange rpm 'dip' and is a fair bit more conservative. I think I'll wait till I get some dyno time before pushing this further, but I might get greedy with my $150 wrecker special motor.

Well spotted! the TPS switch does seem to be on until about 10% throttle. Will fix this before next log.

Also with the AFM spikes. Normally I see this if there is a problem with the HD46510 chip on the ECU because of too much voltage entering it. Sometimes its 0.0 volts and othertimes 5.1 volts in the spikes. ECU may have a problem and need another chip. Do you have a zener diode fitted to this when you did the AFM conversion? Dont know about the TPS spikes though

This is an interesting one - I was sure to install the diode as per the installation manual before installing the AFM. (two thumbs up for that guide, by the way! easy to follow etc.)

Seems that when i have the power inverter on in the car (which is wired to the same cable that runs to the efi/eccs power feed) then I get AFM spikes. When power inverter is off, I get no spikes! - I'll have to look into this a bit more.

I'll get the log + tune up in the next day or so! Thanks again for your help guys.

blownvp · Post by **blownvp** » Sun Aug 30, 2009 1:34 pm

could be the aftermarket z32 afm.did the mods for a vlt ecu for z32afm.used aftermarket z32afm voltage was spiking to 5 volts and then dropping to zero.set up afm and ecu on test bench.blew through afm and monitored voltage tested ok.then i set up ignition coil about 50cm away from afm to simulate the spark you would get between rotor and distributor cap.when the coil was sparking at lower spark rate the afm voltage would go from zero to 5 volts and keep alternating between the two voltage levels.even tried it with ecu disconnected and the afm by itself would do the same.i think the cheaper aftermarket z32 afm may not have enough filtering to reject voltage spikes.will be trying another afm soon.boost afr try about 11.5 should be safe and transition afr about 12.if its got na compression ratio i would reduce the timing more when its on boost.ive tuned a few rb30na with a turbo and i used the na timing map and reduced timing on boost to stop it detonating.mods rb30na front mount cooler standard rb30 turbo 440cc injectors.standard afm.

Matt · Post by **Matt** » Sun Aug 30, 2009 9:20 pm

this is very interesting. i have a similar setup and pete has recently redone my RB30 loom because of problems during previous dyno runs

I am noticing the same spikes about 2:22 after our rewiring job shows the problem with jumps to 5.12 volts and to 0 volts

Wiggling wires around the Z32 AFM plug etc make no difference. I'm running the laptop from battery only. Interesting theory on coil affecting things.

Would be worthwhile me monitoring the AFM voltage on the DLP converter to see if its the ECU or actually from the AFM. I think its the ECU still but not sure how. Looking into it

Main prob I'm having is my cold start mixtures are really lean after doing the Z32 AFM mod. Once its warm things are fine. I see why michael was wanting information on those tables. Ideally an injection pulsewidth for R31/VLT/Z31 would be good so looking into going through the code again this week for these ECUs to find something ...

Matt · Post by **Matt** » Sun Aug 30, 2009 9:25 pm

actually i remember luke sending his ECU this way (re the spikes) and after resoldering the diode and using new wire then putting tape over it, he reported no more spikes. connectivity/insulation issue? i have to check my own setup now...

blownvp · Post by **blownvp** » Mon Aug 31, 2009 4:23 am

the brand new aftermarket z32 afm was faulty.the varying voltage out of it was enough to make the car buck when you go to accelerate +5 then 0 then +5 etc..hooked up a second hand rb20 afm.runs good now just have to put the wideband on to dial in afr.still notice you get +5 and 0 spikes every so often on screen but doesnt seem to alter the running of the engine.cheers darren.

Matt · Post by **Matt** » Mon Aug 31, 2009 10:08 am

i've had the car buck only a few times with this one. its rare but does happen and i think its when it gets a longer spike than normal where it affects tp quite a bit

Matt · Post by **Matt** » Tue Sep 01, 2009 2:08 pm

rb30 manual fuel cut values are way to high, copy the z31 maps over for these to save fuel.

- agreed this works very well. tried it this morning

STATUS · Post by **STATUS** » Thu Oct 15, 2009 10:29 pm

Matt wrote:i've had the car buck only a few times with this one. its rare but does happen and i think its when it gets a longer spike than normal where it affects tp quite a bit

wish i had seen earlier, i had this issue on a vlt a few months back and could not sort it (spikes)

keep up the good work.

ps lukes car is quite the weapon now, twin charged and all

Matt · Post by **Matt** » Fri Oct 16, 2009 6:24 am

see this also
viewtopic.php?t=1216

procedure for doing the Z32 AFM mod has changed to prevent spikes