Boost control using OEM ECU for S14/S14a SR20

[PL]

Hey guys,

Just been doing some testing on this. Results are same as for S15. It works but for some reason it doesn't respond to load - only RPM. Which is exactly the same as S15. Weird - cos they look like 3D maps to me! I tested both S14 (74F00) and S14a (83F00) ECU's.

Anyway, what you need to know is that you must set the same values for all load points for your particular RPM. During testing I set all cells for 3000rpm to "0", 3200 rpm to "20", 3600 rpm to "50" and so on up to 4800 rpm where I used "100". See image below.

Then when rpm was swept across 3000 - 4800rpm I watched the signal going to the control solenoid and it went from being pretty close to off at 3000 to about 90% at 4800.

So you can control the duty cycle between 0 and about 90% at any RPM point you want. Works great. And after nearly an hour of continuous testing the WG solenoid was only vaguely warm. So it's up to continuous duty. I was using the OEM solenoid as found on S14/S15 SR20DET.

So there you go. Hook that up with suitable jets to get the boost levels where you want and you have fully programmable boost control.

I had to use the "knock" boost control maps but I suspect that's just because my dodgy bench test setup is missing half the inputs...

PL

s14 boost map.jpg

S14 boost control map - test

(50.56 KiB) Downloaded 5897 times

[PL]

Update : It is proper 3D except the X axis isn't load - it's TPS voltage!

I'm such a tool. I should have worked that out myself. Matt was around and he suggested TPS straight away. Ran it up on the bench and away it went!

So far left is TPS closed, far right is TPS wide open (around 4.1V).

This means that all S14/15 owners effectively have fully mapped boost against both RPM and throttle position. Awesome! This is a big thing for S14/15 owners.

There'll be a NIStune update out soon with proper TPS voltage values across X axis for boost maps.

PL

[Matt]

Updated code tonight for this fix

[chris2712au]

ahh thats more like it.. the copying all the values across the values made it work but was so lazy compared to my ID3 blitz ebc..

atleast now you should be able to run agressive values on the lighter throttle votages and less agressive on the wide open throttle..

Cause from my tuning guide i was struggling to find that balance..

[HermaN]

Nice one! I know a few folk who will be happy to hear this.

[IceManPL]

how should i connect the stock solenoid, like mbc ?

[PL]

Connect exactly as stock. You'll just need to change jet sizes if you wish to change your turbo and/or run boost much higher than stock.

I can't remember how high we were able to get the boost before we started changing jet sizes. It'll be different for every different turbo and obviously depends on strength of WG actuator spring, WG preload etc.

PL

[Fordy]

Sweet this will help me loads when i try to run the mac valve instead of the stock valve

Just need to get some warmer weather so i can fenture outside

[Matt]

Could come over here... is 40degC hot enough!! Glad my outside work area has air cond

[HermaN]

40*C Matt?! I wish I could be in that kind of climate! We get a MAX of 16 - 17*C in summer up here, and even then it never stops raining, during the winter we get as low as -16/-17*C!! Instead of raining like it does in summer it snows!! Can't wait to leave to somewhere with a warmer climate. :p

Also first post of the forums 2011!

[Fordy]

first day of the year and its raining typical british weather. Altho no more work till the 4th so i can get cracking

[PL]

Wow - some nasty extremes going on with the weather! We had 43 degrees on 31st Dec. Made for a toasty New Year's Eve! And the night before that it was 33 degrees at 1 in the morning! Not ideal sleeping weather.

Can't complain just too much though - we've had an unusually mild start to summer. And today we're back to a rather nice 25 degree max. Best I go get some yard work done before we get hit with 43 again...

PL

[Matt]

latest version up with the TPS changes. let me know how it goes

[HermaN]

Cheers Matt, just grabbed it and installed, will try to get round to having a play ASAP.

[immy21]

I have a strange result, first of all my setup.

Thin pipe under throttle body too T-Piece, Actuator-T-Piece, Side/top solanoid to T-Piece, Front of solanoid to intake trunk. No restrictors.
Forge adjustable actuator with 1 bar spring, set roughly 13-14psi. Stock T28 trying to run 17 psi, S14a.

Wierdly, with the stock boost map I got my target of 17psi, but I had to play with it so set boost and knock map to 0 and got actuator pressure, fine.

The part that I don't get is the only part of the map being accessed is the last 240 colum, making changes here made no difference until I copied over to knock map too. Replaying log shows both boost and knock are green (green is definatly a good idea ), how can they both be used? It's not knocking, my KS4 isn't picking up anything anyway and normal fuel and timing maps seem to be used too.

I got 17 psi by doing this, I know I don't have to bleed high rpm but didn't see anypoint in refining the map as wierd things are happening.

Stock:


What I ended up with, as said only the last colum (240) seems to be used regardless of throttle position


Any idea why only 240 is being used?
Also why does both boost and knock boost maps seem to be used?