new customer looking fo rtuning help

[Cosmik de Bris]

Hi All, I'm looking to learn a few things about tuning with HPTuners. The car is a 2000 C5 export model which is new to me, it has a K&N cold air intake but otherwise stock. It doesn't look like it has been tuned at all. I compared it with a stock tune and there don't seem to be any differences. I have done a little reading and have some basic questions.

I've attached the log for a run at the local strip, this was a 13.6@103 run with two people in the car. First I notice that the LTFTs are around 25 which from reading should be around -5 to +5 indicating that it may be running a little rich at WOT, the O2 seem to indicate this also. My main question is about timing, the tables indicate around 28 degrees at WOT but the log shows 22 - 23. At the top of 3rd gear there is 4 degrees of KR reducing the timing to 18 - 19 degrees, I think this is caused by the IAT being high but looking at the table I think it should only be pulling 1 or 2 degrees.

Why is the timing only 22 - 23, what is lowering it from 28? Any insights gratefully received.

[planethax]

Looks like it may be two things;
1, you are using an interpolation of high and low octane spark
2, and the IAT.

Copy High table over to low ATM and recheck.

[johnm545]

The LTFT of +25 mean the trims are compensating for a lean condition which needs fixing. Looks to be a bad MAF because the airflow numbers are low. It's maxing out at about 210 g/s MAF flow - should be 250-300 g/s on a stock LS1 at sea level depending on ambient temps. The MAF wires are probably crudded up with K&N oil, try cleaning them (alcohol and q-tips work, be very gentle). Or better just wack a new or known good used maf on.

You coolant temps are also higher than I like to see, check for crud on/in the radiator etc.

[Cosmik de Bris]

OK thanks for the advice.

[Cosmik de Bris]

Hi again, it turns out my car has a Granatelli MAF, could this be the reason the airflow numbers are low? I have read that their MAF is re-calibrated to compensate for a cold air intake. I don't read very good opinions of their MAF but no-one seems to say why.

I've logged the LTFTs and have got them all around the -1 to -2 region which I think is good. The O2s at WOT are still a bit rich but I think I can bring them down in the PE table. When I reconnect the MAF the LTFTs go high again (20 - 25). Any more thoughts?

[mowton]

Hi again, it turns out my car has a Granatelli MAF, could this be the reason the airflow numbers are low? I have read that their MAF is re-calibrated to compensate for a cold air intake. I don't read very good opinions of their MAF but no-one seems to say why.

I've logged the LTFTs and have got them all around the -1 to -2 region which I think is good. The O2s at WOT are still a bit rich but I think I can bring them down in the PE table. When I reconnect the MAF the LTFTs go high again (20 - 25). Any more thoughts?

Are you tuning with a wideband? if not, I would stay out of WOT for now. DO NOT TRY AND BRING THEM DOWN IN THE PE TABLE! You cannot tune WOT using the narrowband O2's. They are only accurate at Lambda 1 or what is referred to as "14.7 AFR". That is why they call them narrowband. The wideband will give you accurate readings across the AFR range so you can monitor the WOT requirement of .85 lambda or "12.8 AFR"

You can tune in the non-wot area's with the LTFT. How did you go about this.? Did you reset the trims before each logging session?

Ed M

[Cosmik de Bris]

I'm not using a wideband yet, I was going by the tutorials which suggest that 890 - 900 mV is where the narrow bands need to be. I followed the LSX tuning tutorial for tuning the LTFTs and yes I reset the trims before logging session.I do have a couple of wideband sensors but I don't have the extended IO thingy yet.

Cheers

[mowton]

I'm not using a wideband yet, I was going by the tutorials which suggest that 890 - 900 mV is where the narrow bands need to be. I followed the LSX tuning tutorial for tuning the LTFTs and yes I reset the trims before logging session.I do have a couple of wideband sensors but I don't have the extended IO thingy yet.

Cheers

Please don't listen to that. Narrow bands could hit 900 mv at 14 AFR....With E10 you are trying to get to an equivalent of 12.3 AFR for NA WOT. Are you willing to risk your motor for the sake of a wideband. That's why they are called narrowbands!

[Cosmik de Bris]

OK thanks, I haven't touched the PE table yet, I will install the wideband first :-) I'm running on the SD tune at the moment because the MAF seems to be upsetting the tune, I'll get an OEM one soon.

[johnm545]

OK thanks, I haven't touched the PE table yet, I will install the wideband first :-) I'm running on the SD tune at the moment because the MAF seems to be upsetting the tune, I'll get an OEM one soon.

1. Open trash can.
2. Place Granatelli MAF inside.
3. Crush down then close lid.
4. Fit a good stock MAF.

Or you can just leave it off and run SD, but the VE table will need some work, and heatsoak will throw things off a bit. I prefer to run a MAF on stock engines, it costs very little power and gives a more stable tune with less work.

[Cosmik de Bris]

I've bought an OEM MAF, it's an 85mm one because of my cold air intake, we'll see if I can get it tuned.

[johnm545]

I've bought an OEM MAF, it's an 85mm one because of my cold air intake, we'll see if I can get it tuned.

The 85mm ones work great - copy paste the table from an LS2 GTO, 2004 LS1 corvette, or any other car that comes with one and it should be very close.

[Cosmik de Bris]

OK thanks.