Jump to content
SAU Community

Recommended Posts

Hi All,

I have been doing research here and there, and it seems Mitsubishis incorporate lean spool by factory. Their ECUs are so powerful in comparison to ours, dual maps (lo & hi octane), lean spool features, etc.. ra ra ra...

BUT I own a Nissan and I love them, enough of the crap ;)

I have been re-tuning my car here and there and I would like to see how others have their A/F set vs Spool.

Currently, I've played with my PowerFC and when the car comes onto boost it's quiet lean, on full boost A/F is around 11.7~12 which is safe and timing is at 13 degrees @ 18PSI, for some reason when I dial in even 1 extra degree I get retarted knock on a 30degree day, but at 13 degrees its fine, knock no more than 30.

So, could everyone post up their Boost vs A/F graphs? that would be great.

R31Nismoid, YES I have looked in the RB25 Dyno results. Mainly its all Power Graphs which I'm not interested in. :banana:

Sorry, I'm trying to establish what you are trying to determine - you mention spool but it sounds more like you are trying to work out why you are knock limited when trying to add timing at 18psi of boost?

I assume you are road tuning? Bare in mind not all things are equal with different cars, an obvious which would apply to your example would be turbo choice. If your car is experiencing high exhaust manifold pressure then you will be able to run far less timing than if you have no major restriction on the hot side. Same would good for good intake charge quality (good intercooling, not maxed out compressor, WMI etc...).

I have no AFR graphs for my car printed, but am targetting similar afrs - ranging from Stoich at very light load to around 11.6 at full (17ish psi on an RB25 running a GT3076R) boost.

Edited by Lithium

I agree, since i started playing with late model evo's, my thoyughts on spool a/f have changed. I no linger have any dramas tuning my cars to run 14.5 at 2psi, and 13.5 at 5 psi, this is dependent on the car and mods though obviously.

Hi All,

I have been doing research here and there, and it seems Mitsubishis incorporate lean spool by factory. Their ECUs are so powerful in comparison to ours, dual maps (lo & hi octane), lean spool features, etc.. ra ra ra...

BUT I own a Nissan and I love them, enough of the crap :)

I have been re-tuning my car here and there and I would like to see how others have their A/F set vs Spool.

Currently, I've played with my PowerFC and when the car comes onto boost it's quiet lean, on full boost A/F is around 11.7~12 which is safe and timing is at 13 degrees @ 18PSI, for some reason when I dial in even 1 extra degree I get retarted knock on a 30degree day, but at 13 degrees its fine, knock no more than 30.

So, could everyone post up their Boost vs A/F graphs? that would be great.

R31Nismoid, YES I have looked in the RB25 Dyno results. Mainly its all Power Graphs which I'm not interested in. :blush:

um nissan has had all that for decades also...

agreed, mitsu is factory tunable. evo 7 and up needs no modification PERIOD to be tuned. plug in and go. earlier models require a 7+ ecu and a minor re-pin, even the earlier models with the different motor. no less than excellent.

Yet I wonder, what would happen if you dropped the AFR to something a little richer and then tried to add the timing. Considered this?

um nissan has had all that for decades also...

Sorry trent, would have to disagree on this one, mitsu ecu's are far more powerful than the nissan rb ecu's.

SInce when does nissan have lean spool, which is an rpm/time/load dependant feature, active(knock monitered) ignition mapping on individual load points, and a total knock count ingition map trim?And mivec of course

what do you think is causing the knock?

do you think its the AFR's?

do you think its the intake temp?

do you think its the ign timing?

why do you need to run 18psi?

is your compressor efficient at that level

turbochargers once out of the efficiency island give diminshing results, that is, for every psi extra you dial in, you dial in assloads of hot air

the more hot air you dial in, the more the engine detonates

so - reasses - is 18psi efficient and giving you good gains, ie from 17 to 18psi do you gain 10kw or do you gain 1kw?

omg, I just read what I wrote, didn't make sense! trying to multitask at work, failed!

Forget about what I wrote about full load, I'm quite happy with the result I got, I'm just working on getting the boost to come on earlier.

anyways, what I am actually after is the A/F everyone runs when coming onto boost. I know the leaner the harder it will spool due to exhaust gases.

Paulr33, FYI I'm running HKS2535 and supporting mods, so chillax I'm not running a stock turbo like you!

No need to lecture me about turbo efficiency ra ra ra, yes HKS2535 is rated most optimum at 1bar but many have run them at 1.3bar and get quite outstanding results, such as Robo, and a few other people

So what I am after mainly are dyno graphs which have the boost vs a/f ratio pre full load

Sorry trent, would have to disagree on this one, mitsu ecu's are far more powerful than the nissan rb ecu's.

SInce when does nissan have lean spool, which is an rpm/time/load dependant feature, active(knock monitered) ignition mapping on individual load points, and a total knock count ingition map trim?And mivec of course

remmeber compare apples to apples ie year model to year model, the early evo stuff is pretty clunky also. Most of what you post is tweakable with aftermarket mapping gear.

lean spool = R32 gtr ecu feature

active(knock monitered) ignition mapping on individual load points= r32 gtr std ecu feature

total knock count ingition map trim= r32 gtr std ecu feature

mivec= nissan fail :) not till much later

the mitsy stuff of the same era (1990) was no better but if your comparing evo 6 onwards than yes they are a better beast.

to be honest the best stuff around is the holden (ls) and ford (fg) gear there is more features than nissan and mitsy combined (current r35 excluded)

somethings going on with that power curve .

knock knock whos there?!

and isnt 10psi and 15:1AFR at 3250rpm bad mmkay? thats just asking for EGT issues IMO...

knock knock whos there?!

and isnt 10psi and 15:1AFR at 3250rpm bad mmkay? thats just asking for EGT issues IMO...

nah the ramp afr's are pretty much ok, remmeber there is a lag between engine and tail pipe and a cat, so i reckon its closer to 13:1 and 5-6psi.

Trent from your experience, what A/F ramps are safe? do you have a graph I can look at?

Also, I notice I mainly get knock off lift off, why's that? there's no explanation on the web! I tried to alleviate the problem by dialling in more fuel and pulling back timing, it just results in FLAMES on the overrun LOL

i get random knock spikes at the exact point i lift off too, havent worried about it too much. use it as an excuse to keep going through to limiter :)

last worshop tune i got was on the very safe side and started at 14:1 at 2psi then linearly down to 11.5 at peak torque at 17psi, then back to 12:1 for the rest of the way. was 13:1 at around 6-7psi

Edited by JonnoHR31

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

    • Hi, is the HKS  Tower Bar still available ? negotiable ? 🤔
    • From there, it is really just test and assemble. Plug the adapter cables from the unit into the back of the screen, then the other side to the car harness. Don't forget all the other plugs too! Run the cables behind the unit and screw it back into place (4 screws) and you should now have 3 cables to run from the top screen to the android unit. I ran them along the DS of the other AV units in the gap between their backets and the console, and used some corrugated tubing on the sharp edges of the bracket so the wires were safe. Plug the centre console and lower screen in temporarily and turn the car to ACC, the AV should fire up as normal. Hold the back button for 3 sec and Android should appear on the top screen. You need to set the input to Aux for audio (more on that later). I put the unit under the AC duct in the centre console, with the wifi antenna on top of the AC duct near the shifter, the bluetooth antenna on the AC duct under the centre console The GPS unit on top of the DS to AC duct; they all seem to work OK there are are out of the way. Neat cable routing is a pain. For the drive recorder I mounted it near the rear view mirror and run the cable in the headlining, across the a pillar and then down the inside of the a pillar seal to the DS lower dash. From there it goes across and to one USB input for the unit. The second USB input is attached to the ECUtec OBD dongle and the 3rd goes to the USB bulkhead connected I added in the centre console. This is how the centre console looks "tidied" up Note I didn't install the provided speaker, didn't use the 2.5mm IPod in line or the piggyback loom for the Ipod or change any DIP switches; they seem to only be required if you need to use the Ipod input rather than the AUX input. That's it, install done, I'll follow up with a separate post on how the unit works, but in summary it retains all factory functions and inputs (so I still use my phone to the car for calls), reverse still works like factory etc.
    • Place the new daughterboard in the case and mount it using the 3 small black rivets provided, and reconnect the 3 factory ribbon cables to the new board Then, use the 3 piggyback cables from the daughterboard into the factory board on top (there are stand offs in the case to keep them apart. and remember to reconnect the antenna and rear cover fan wires. 1 screw to hold the motherboard in place. Before closing the case, make a hole in the sticker covering a hole in the case and run the cable for the android unit into the plug there. The video forgot this step, so did I, so will you probably. Then redo the 4 screws on back, 2 each top and bottom, 3 each side and put the 2 brackets back on.....all ready to go and not that tricky really.      
    • Onto the android unit. You need to remove the top screen because there is a daughterboard to put inside the case. Each side vent pops out from clips; start at the bottom and carefully remove upwards (use a trim remover tool to avoid breaking anything). Then the lower screen and controls come out, 4 screws, a couple of clips (including 3 flimsy ones at the top) and 3 plugs on the rear. Then the upper screen, 4 screws and a bunch of plugs and she is out. From there, remove the mounting brackets (2 screws each), 4 screws on the rear, 2 screws top and bottom and 3 screws holding in the small plates on each side. When you remove the back cover (tight fit), watch out for the power cable for the fan, I removed it so I could put the back aside. The mainboard is held in by 1 screw in the middle, 1 aerial at the top and 3 ribbon cables. If you've ever done any laptop stuff the ribbon cables are OK to work with, just pop up the retainer and they slide out. If you are not familiar just grab a 12 year old from an iphone factory, they will know how it works The case should now look like this:
    • Switching the console was tricky. First there were 6 screws to remove, and also the little adapter loom and its screws had to come out. Also don't forget to remove the 2 screws holding the central locking receiver. Then there are 4 clips on either side....these were very tight in this case and needed careful persuading with a long flat screw driver....some force required but not enough to break them...this was probably the fiddliest part of the whole job. In my case I needed both the wiring loom and the central locking receiver module to swap across to the new one. That was it for the console, so "assembly is the reverse of disassembly"
×
×
  • Create New...