boost control using nistune experiences anyone ?

chris2712au · Post by **chris2712au** » Tue Nov 18, 2008 8:50 pm

just after some feedback on people that are playing around with the standard boost control function in the ECU..

I started out finding a boost level that was optimum.. I filled the whole maps including the knock maps with 50... I fitted a 1.2mm restrictor replacing the 1.4mm one in the boost line and removing the other restrictor out of the suction line..

I also have a 0.8 bar spring inthe actuator... what resulted in way too much boost... so then I went to 40 still too much boost.... then to 30... and got 13.8 psi... then went slowly up to 39... where i got 15psi.... I then coppied 39 across the whole map and copied it to the knock map... Next I started to take out waste gate creep by cracking the solenoid early result is alot more mid throttle response... however if you take the creep out you get boost spike... which I am currently experiencing so I am currently setting the maps to 39's back to the 3000rpm marker... the only problem is there seems to be a tonne of difference between 39 and 40...

anyone else with trial and error testing ?

Fusion Ed · Post by **Fusion Ed** » Sat Nov 22, 2008 10:44 pm

Any idea what the PWM freq is? Also have you thought about trying a more modern solenoid rather than the OEM one?

chris2712au · Post by **chris2712au** » Tue Nov 25, 2008 9:46 pm

the thought had crossed my mind of trying an after market one.. More on the story is that I have gone back to the 1.4mm (standard) jet size... Reason is that the 1.2mm one that I had put in did let me adjust ridiculous amounts of boost however if you found a flat boost map of say 39 was a good wind up of third gear... when you smashed first and second you got a spike that was off the charts... 18psi + what could be contributing is my 0.8 bar actuator... and also the pre load that I have on the wastegate... I am continuing to trial it out... will keep you the thread up to date..

PL · Post by PL » Thu Nov 27, 2008 2:18 pm

Hey Chris,

I reckon it might be your 0.8 bar actuator. We were using the same setup on Graeme's S15 and boost was totally controllable. But he has the standard actuator that comes with the 2871 - which I'm assuming is around 0.5 bar.

PL

chris2712au · Post by **chris2712au** » Thu Nov 27, 2008 7:13 pm

well I got it soughted.. well for the moment...

I ended up settleing for the standard restrictor... seems like running a stronger spring needs more air to open the wastegate and that the restrictor just was not putting out enough air and giving me a spike...
connecting the restrictor to the actuator directly with no bleed gave a rather interesting spike.. but was great for not much wastegate creep..
now it is just a matter of finding the sweet spot again...
I am getting 14 psi at 50 PWM... I want to hold at 15 and dont mind if it spikes to 16... I event tried the standard maps...they got me to 16psi standard with the stronger actuator but I didnt like the lag... they let the boost come on really slow... however they start off at 100% on the Jdm image.. thats the one I was using...

chris2712au · Post by **chris2712au** » Mon Dec 01, 2008 7:42 pm

well found the sweet spot.
its about 60 - 65 pwm... 60 is like 15psi and 65 is like 15.8 ish...
now I will just play around with some other bottom and top end stuff..

chris2712au · Post by **chris2712au** » Tue Dec 02, 2008 8:59 pm

started to tune in the top end slowly approaching 100 pwm... boost is dropping off a little... so might have to tweak the actuator a bit..

as for the few lead up points I have bled the air off in the lower RPM and it is making a hell of a difference... I will get some maps up here soon with the results if anyone is interested..

Pete... it is weird my 1.4mm (stock) restrictor and my actuator on 65 is giving me 15psi like graemes with the 2871

chris

PL · Post by PL » Tue Dec 02, 2008 9:24 pm

Hey Chris,

That makes sense. A stronger spring will need more pressure to open it, so a bigger jet would be correct.

When I did my bench testing I found that the solenoid was fully open by the time I got to "90" in the tables. So anything over that would make no difference. You'd need to decrease jet size to get more.

Or fit a weaker WG actuator.

PL

chris2712au · Post by **chris2712au** » Wed Dec 03, 2008 7:49 am

Got the result I was after... 15 PSI solid with no fade in the boost on a 3rd gear pull.. Still working on the lower values to reduce the creep.. But I can say that I am more than happy with the results I am getting... I have not touched the WG actuator yet... Hopefully I dont have to but I can adjust the preload a little for a couple of PSI...

Going to do a little more playing around... I will adjust the lower values allthe way up untill I get a spike then back them off a little... I have not reached that yet...

Trying to get this done before the christmas break and double demerits.. Just incase..

chris2712au · Post by **chris2712au** » Sat Dec 06, 2008 8:27 pm

looks something like this...

flat on 15psi with an 0.8 actuator...

However I am still getting a little bit of fade... about 0.4psi in the top end so I am just going to tweak the actuator a little.. I am loving second gear...

However beware if you use this as my wastegate is a ittle bit larger than standard and the ar of the rear housing is a little different is has been opened up a little

chris2712au · Post by **chris2712au** » Tue Dec 09, 2008 8:36 pm

After crankingup the pressure on the actuator a little I found that the whole curve moved up and the fade stayed the same... so sad to say it isnt the wastegate being pushed open by the exhaust gasses from the oversized w/g...

Maybe a weaker actuator as suggested could be the go... with the smaller jet... I still have the standard one I could put it on and the jet in as I have the 1.1mm one...

or what I am going to do is to open up the standard solenoid a little as the solenoid is not 4mm it reduces down to 2mm however the seat is 6mm so might give it a tickle I have not measured it yet...

Still I am happy with the tune I just want to get it to the point where I can get boost to rise in the upper section of the maps... Under load it will hold 15... however on not so heavy loads it will fade...

the maps are good to go the waste gate creep could be adjusted even further however you will get a spike so you could put values in below the 65 to help suppress it... but then it will be noticeable on a third gear wind up..

chris2712au · Post by **chris2712au** » Wed Dec 10, 2008 5:14 pm

well drilled the solenoid out a little

It was 4mm in and then 3mm out... standard i think it was around 2.6mm...out and 3.5mm in

and yep a noticeable difference.... now back to square one... looking to find a peak value of around 50 ish so I can get more bleed in the top end..

will load a few different maps in and get another tune for the new solenoid..

then will post them up...

rain rain and more rain not good for tuning boost control setups.. but the mod definitely made a difference the creep on the wastegate was definitely improved but a hit on the accelerator and yep fuel cut and 17psi so a new map is in order...and then to find the right hill... to eliminate this spike..

chris2712au · Post by **chris2712au** » Sun Dec 14, 2008 2:29 pm

we have success... the solenoid mod is doing it perfectly... is what I was hoping for...

I moved the load scales a little and the rpm a bit...

Anti creep is awesome... even more bottom end... I am loving it.. will post the intermediate results tonight..

what I found was that the smaller restrictor gave me good boost adjustment however there was boost spike from how long it took to actually open the actuator from the volume of air available...

The larger restrictor gave be good boost adjustment (little spike) but had problems in the top end due to the solenoid could not flow enough air.. at 100% PWM..

So I left the standard restrictor in, and re flowed the solenoid... results were beautiful however still some spike..

So then i re-arranged the rpm scales to give better resolution on boost transition where it is needed.. and results were amazing... boost is hitting fast and strong mid range torque is unbelievable.. no spike however I will tune it a bit more to reduce the creep even further..

chris2712au · Post by **chris2712au** » Tue Dec 16, 2008 8:22 am

second and third gear testing was great...

Having a big problem controlling 1st gear spike... Hits 15psi and then fuel cut.. but in second gear all is good...

Anyone with any ideas ?

TBH.. I think the standard solenoid cant handle holding off the pressure off the fast spool up of ist gear..

PL · Post by PL » Tue Dec 16, 2008 9:07 am

Normally boost spikes in first are not a problem as the engine isn't loaded up enough to create much boost anyway. Good luck controlling it - if they do make any boost then the ramp rate is so fast that it's almost impossible to catch.

I just use a bit of driving technique - go easy on the throttle in first and as soon as you have a bit of road speed grab second and then feed it in.

Most turbo cars will just light the rear tyres if you boost them up in first gear anyway! And second. And third...

PL