Helix 860's and StreetTUNER

[bigmike25rs]

Can't get the car to run properly on these injectors. I tried a 20G map for PE 850's and it got me nowhere. The car idles, but when you give it throttle, it leans out and stalls. I need injector scaling, tip in enrichment, and latency values.

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[Christian.]

Mike from Gruppe-S may be a good source for this information.

[bigmike25rs]

Talked to Gruppe-s earlier today. They gave me the Helix website. I got this info from the site, but I'm not sure how to relate it to the StreetTUNER.
On Time: 0.85ms / 12.5v /2.5kg/mm

[bigmike25rs]

Anyone?

[R4ND0M_AX3]

You could start by taking that number (.85ms @ 12.5) and compare it to stock at the same voltage. Then adjust the stock numbers by the same percentage. It won't be perfect.

Wolfplayer posted up some info about his Nismo injectors. He had witchhunter do a latencey test. You might consider that same thing. It didn't cost too much.

[05redrex]

Did you try the scaling formula in street tuner? Hit F1 in that cell...

new val = (original size/new size) * existing val

[Quack]

yep, the injectors are scaled.

we'll have a go at it again tomorrow, he got the on-time info

[kccobra]

What is your complete setup?

[bigmike25rs]

Perrin GT30R .63a/r, Perrin UP and DP, HKS catback, Turbo XS FMIC, NGK +1 iridiums, Crucial thermostat, Helix 860's, Perrin 4" rotated intake, Big MAF, and COBB streetTUNER. I think that's it for power.

[Christian.]

bigmike25rs, the Big MAF your are using is going to cause serious issues IMO. My experiences have never been good using that piece of hardware. Here are some tips for tuning for different intakes:

If the injectors are modified WRX injectors, start with ???? for the scaler value (you can hit the F1 key to see the formula for changing the scaler value). You can always make small adjustments to that value to assist your closed-loop fuel trims. Although, since you have an aftermarket intake do not move the scaler value from the original ????. You can adjust the Intake Calibration table for the MAF voltages that are off from the aftermarket intake.

Start your vehicle, let it idle, and come to temperature...it may not idle perfect, but just deal with it until it comes to temperature, 180-190 F. Use the dashboard to pull up your A/F Trim Immed., A/F Trim Learned, MAF Voltage, and Coolant Temp. After the vehicle has come to temperature, re-set the ECU (you will be prompted to turn the vehicle off then back on). Start the car again, then watch your MAF voltage and A/F trims. You want the combination of your A/F trims (Immed. & Learned) to be as close to 0 as possible. EX = If your A/F Trim Immed. is +5% and A/F Trim Learned is 0, then simply look up the MAF voltage, which should be close to 1.2-1.28 volts at idle, on the Intake Calibration table and adjust the grams/sec value for that voltage up (+) until your total fuel trims are 0 or close to. I would shoot for a A/F Trim Learned value of +/- 5% max. You may have to re-set your ECU throughout this process. Make sense?

Do this along the Intake Calibration table up to 2.3 volts or so ON A DYNO at part-throttle. Then, datalog your actual A/F and dictated A/F in your Primary Fuel table @ WOT; you can make your adjustments from there. If your targeted A/F is 11.0 and you hit 12.0, then you will want to add (+) grams/sec for the MAF voltage that corresponds for that RPM and load point. If you have a properly designed intake system the Intake Calibrations should look very similar to your stock Intake Calibration graph under the table data.

Your trim values will always adjust back and forth (+/-), let them, that is what they are supposed to do. Do not beat yourself up trying to get them at exactly 0...it is impossible (temperature, weather, gasoline, etc. changes will not keep anything constant while you are tuning).

If you are seeing plateaus, spikes, dips, or flat spots in the graph for the Intake Calibration table then you know something is wrong...replace the intake system with a properly designed one.

Take care,
Christian.

[bigmike25rs]

I still have my old COBB SF intake from my previous setup. We also tried that and the weird part was that the car threw no codes. With the BigMAF I got a flashing cruise light and a CEL due to PCV blow by. (this is because the new inlet didn't have the plug for the sensor like the stocker.) Not sure what's going on here. I am not going to do the final tune, I just need to get it running enough to get to the dyno.

[Zumble]

I have nothing to add to this but I just want to say it's really cool that Christian is on the forums answering ST questions. It will only make more people want to switch to ST with confidence.

Originally Posted by Christian.

bigmike25rs, the Big MAF your are using is going to cause serious issues IMO. My experiences have never been good using that piece of hardware. Here are some tips for tuning for different intakes:

If the injectors are modified WRX injectors, start with ???? for the scaler value (you can hit the F1 key to see the formula for changing the scaler value). You can always make small adjustments to that value to assist your closed-loop fuel trims. Although, since you have an aftermarket intake do not move the scaler value from the original ????. You can adjust the Intake Calibration table for the MAF voltages that are off from the aftermarket intake.

Start your vehicle, let it idle, and come to temperature...it may not idle perfect, but just deal with it until it comes to temperature, 180-190 F. Use the dashboard to pull up your A/F Trim Immed., A/F Trim Learned, MAF Voltage, and Coolant Temp. After the vehicle has come to temperature, re-set the ECU (you will be prompted to turn the vehicle off then back on). Start the car again, then watch your MAF voltage and A/F trims. You want the combination of your A/F trims (Immed. & Learned) to be as close to 0 as possible. EX = If your A/F Trim Immed. is +5% and A/F Trim Learned is 0, then simply look up the MAF voltage, which should be close to 1.2-1.28 volts at idle, on the Intake Calibration table and adjust the grams/sec value for that voltage up (+) until your total fuel trims are 0 or close to. I would shoot for a A/F Trim Learned value of +/- 5% max. You may have to re-set your ECU throughout this process. Make sense?

Do this along the Intake Calibration table up to 2.3 volts or so ON A DYNO at part-throttle. Then, datalog your actual A/F and dictated A/F in your Primary Fuel table @ WOT; you can make your adjustments from there. If your targeted A/F is 11.0 and you hit 12.0, then you will want to add (+) grams/sec for the MAF voltage that corresponds for that RPM and load point. If you have a properly designed intake system the Intake Calibrations should look very similar to your stock Intake Calibration graph under the table data.

Your trim values will always adjust back and forth (+/-), let them, that is what they are supposed to do. Do not beat yourself up trying to get them at exactly 0...it is impossible (temperature, weather, gasoline, etc. changes will not keep anything constant while you are tuning).

If you are seeing plateaus, spikes, dips, or flat spots in the graph for the Intake Calibration table then you know something is wrong...replace the intake system with a properly designed one.

Take care,
Christian.

[R4ND0M_AX3]

Originally Posted by Christian.

...I would shoot for a A/F Trim Learned value of +/- 5% max. You may have to re-set your ECU throughout this process...

Christian,

While doing this it appears that the ECU has stored the values of A/F Learned for the various MAF voltages. As the engine sweeps through the MAF voltages you can see it knows where it should be based on past learning. Is there a table that can be exposed (similar to knock learned) so we can get a better idea what the ECU thinks is right?