About To Start Tuning My Car Need A Few Hints

[Crans]

Guys I am ready to start having a play with my tune. RB25det stock injectors(740cc coming soon) stock afm(Z32 on the way soon). Bosh 040 being installed as well. Running a Nistuned rb20 ECU with nearly complete home made VCT controller. I would like to log boost aswell where can i buy a map sensor that has a known configuration table? i was thinking a bosch 3bar?

Also any tips on getting better boost response? I have a Hpyergear atr28g4 installed and it is very laggy and has a large pause on gear shift bfore it starts making boost again. I am not running a BOV atm but the stock item will be reinstalled soon.

Any tips will be helpful

[paulr33]

what configuration do you need? a map sensor reads pressure from it's vac line and then returns it in voltage, there's nothing to configure? you need its ramp table values, ie what voltage = what pressure, but thats it. be sure to note map sensors are rated in sweeping pressure not boost, so a 3 bar map sensor is actually 1 bar below vacuum and 2 bar positive pressure or "boost". so a 3 bar map sensor will cap out at 2 bar boost.

you mention a homemade vct controller, your tune and engine will run like ass if you dont have this spot on.

to eliminate endless fault finding you should get your VCT controller work spot on on the dyno before doing anything else. a homemade device could be the cause of endless hours of fault finding and debuggin why, so be sure to nail this before even cotemplating tuning anything else.

the gearchange boost response will because you have removed the stock bov, reconnect it with the factory setup to re-use the dumped airflow/pressure from gearchange, this will improve gearchange response.

for the most response ensure a good cold air intake, lots of ignition timing, a good stable tune with good AFR's

make sure your boost contorller is setup correctly to, to test this run unlimited boost (blocked actuator) on the dyno and ramp it to about 1bar and then back off (be careufl, its unlimited boost) and note the RPM it wakes up at. this is the best possible "on boost" RPM and your boost controller should match that. ie if it winds up 10psi by 3400rpm when you fit and setup your boost controller, it should still make 10psi by 3400rpm as it did in unlimited boost and then you set it to run whatever. an often mistake is mangled or guessed ramp / duty which may add extra lag to the boost build stage

[KiwiRS4T]

When you say "have a play with your tune" do you have anything with which to measure what you are doing i.e wide band meter to measure afrs, some kind of knock detector and an exhaust temp meter? Otherwise you could end up destroying your motor.

[StealthX]

lots of ignition timing,

+1. For decent response, put in heaps of timing (still safely though), just as you're coming onto boost i.e. just as your coming out of vacuum, and the first few pounds of boost. Maybe make it a little on the rich side around those parts, to be ultra safe. Also put your stock BOV in for better between gear boost. And as Paul said, make sure you have a decent cold air intake and that your cooler piping is nice and short/unrestrictive.

Do you have a wideband to check your airfuel ratios?

[Crans]

I should have mentioned before I have some experience mapping with Nistune on my old mildly modified R32 as well as mapping the Wolf ECU on my old S14.

I have a techedge Wideband unit permanent wired in to the car.

When i said configuration i meant exactly what you said Paul. I also realize with the 3 bar that 1 bar is vacuum and 2 bar for boost.

I thought the lack of BOV might be causing the lack of boost response on gear changes.

The internal gate has a lot of preload on it and is currently holding 0.7bar perfectly through to redline. I wont wire it shut for testing until i get it on the dyno i am quite careful with my car.

So basically to loose the lag(or make is as good as it will get) i need to give it more timing before and during ramp up. Tune fuel to 13.5? in this area richening up as boost comes on to 12 - 12.5 depending on how nce and safe i want to be.

So more details on the vct controller:

Using an Amtel chip. Reading in the rpm signal from the ECU through a resistor, diode then an optio isolator, ensuring a nice clean signal.

Software has been written to count the RPM, just working out the bugs now on the output that will ground the VCT wire on the loom.

Also plan to use this board for data logging and maybe experiment with boost control, as i dont like my current unit too much.

Thanks for the tips guys

[Dose Pipe Sutututu]

ideally if you want quick spool up, less timing = hotter exhaust gases, but the car will feel like a nugget or you can run her leaner

I have mine like on 13 A/F coming onto boost and when it hits around 3700rpm it's flat on 12.0 all the way to redline.

[Crans]

Hopefully some of this info helps. Currently i'm just getting 3psi by 3000rpm not hitting full boost(tad over 9psi) until 4400

[JonnoHR31]

as said heaps of timing everywhere off boost, makes a huge difference to the way it drives. as for afr's, simple rule is to aim for 13-13.5 at 0psi then ramp evenly to around 11.5 at peak boost then back to 12 to redline. for safety i tend to richen and retard the cells just on/after limiter a bit.