Low Hp: Bad Gas or...

[FRed-S]

@350matt
I just wish I understood this stuff better lol. I mean, I understand what everyone is posting, for the most part, more than anything else I trying to get my head around why my car started out at only 105hp on the tune and I am hoping I don't have a compression problem. I'm grateful to everyone, especially @steve99 for giving me some hope that it was just the way the car has been driven (by necessity) back and forth to work and it'll get better lol.

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[sw20kosh]

Originally Posted by steve99

On the stock tune IAM initial parameter is set to 0.7, so when you reset the ecu on a stock tune iam will go to 0.7 not 1. After the reset on a stock tune you would need to drive for a period with the ecu seeing little or no knock for the iam to move up to one, light throttle runs 2000-6000 will generally achive this quickly if no\minimal knock detected.

If you on crap fuel the iam may actually go down to 0.5 or less,especially driving in lower rpm range and applying quick throttle applications.

The difference between runs at iam 0.5- 0.7 to 1 could be arround 8hp

Most tuners will set iam initial to 1 in thier tunes so after a reset ecu runs full timing. ie reset the ecu on a tuned car and iam will start at 1 not 0.7 like stock tune

Its a trick\trap that can make tunes look better\worse than they are

You missed the part in my post where I said reset brings the aim to .7 .

The fact that it made no diff in power means my aim before the reset was around .7

[FRed-S]

@sw20kosh, didn't miss lol. Just learning new things. My last car was a 67 Chevelle SS and we didn't tune those lol

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[HachiEnam]

It's probably the dyno. I know our cars get ~120whp manual with a maha dyno. Can you find out what kind of dyno it is?

[Tcoat]

Originally Posted by FRed-S

@sw20kosh, didn't miss lol. Just learning new things. My last car was a 67 Chevelle SS and we didn't tune those lol

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Sure we did. Loosen distributor. Turn 'till sounds right. Tighten distributer.
Fiddle with carb adjust screw until sounds right and exhaust is the right colour/odour.
All done.

[FRed-S]

Yes, we did that lol. There just wasn't any of this computer crap to contend with

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[nelsmar]

I can chime in here.

I tuned fred's car. And another local with an automatic that day. The other car had far more miles on it and I did a baseline on both cars the way they came in. The first car was obviously slightly lower ambient temps due to time of the day but very minor... The other car had non factory wheels & tires (i didn't check the spec's). I recalibrate RPM pickup between the cars and verified the RPM was within a respectable error margin.

With that out of the way the other car baseline was 123WHP with no tuning at peak. After tuning ~135WHP. Both cars were automatics.

Fred's car however ran 104WHP on the first run. I thought for sure I had something configured incorrectly so I checked the settings on the dyno and ran another pull after the car idled for a bit. If you do a pull right after starting a car the ECU actually changes the target timing during some init sequences so its always best to do a few pulls... The second pull? 105WHP... I however was not logging the OEM setup as I was being lazy and as the car is already loaded it I may as well tune it and see where it lands. First flash the car made 128WHP iirc. (if i recall there was a -2* timing event @ 7000RPM)

I had the car making around 130WHP for 2 pulls in a row with a minor ignition correction fine during one pull... Then I had done some partial throttle testing and one more full throttle pull and the car started pulling timing quite aggressively.

The car would consistently land in the low to mid 130's and then randomly timing would drop. It looks like there really was inconsistent fuel quality throughout the time I had the car up on the dyno. I took the map that was making 130's and put that on map #2 and then made another map with reduced timing globally to make sure the car was nice and light on timing to burn up the remaining fuel.

I don't have that laptop on me right now but ill try and get the logs later...

I don't remember what the actual total timing was at WOT compared to the first car but i remember pulling ~2* or so from basically 5200+ with almost identical AFR to the car before. Yet the car still managed to make almost the same power as the previous car.

As for the dyno its self yes it is a Maha LPS 3000. Automatics run typically 120-125WHP stock and manuals hover in the low 130's range. I recently had a friends car on the rollers with full bolt ons, and flex fuel and it made 180WHP. A car with the same mods on a mustang dyno with almost identical timing in colder weather made 220WHP even. So this specific dyno does come in reading on the very low side of the fence =D

Full bolt on 91 octane tends to run ~160-165WHP depending on the modifications. The C38 KW car that was on before fred had a catless exhaust and managed to tap 250WHP after spraying down the intercooler with some water.

[FRed-S]

Thanks for chiming in @nelsmar. I appreciate you input as always. I'm doing my best to burn that crap gas lol. As I told you earlier, I went out and did 4 3rd gear pulls and wasted a bit more fuel. Going to Vegas soon and it'll all be gone very soon. YAY!!!

[humfrz]

Originally Posted by Tcoat

Sure we did. Loosen distributor. Turn 'till sounds right. Tighten distributer.
Fiddle with carb adjust screw until sounds right and exhaust is the right colour/odour.
All done.

Ahhhh ....... yes, one could do a tune up with a 1/2" wrench, a screwdriver, a thin coin and a calibrated ear .......

But, did you not first gap the points with a thin dime (or a thin Canadian coin) .... ??


humfrz

[FRed-S]

I always used a large screwdriver. Blade to the motor, handle against the ear. High Tech all the way lol.

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[Tcoat]

Originally Posted by humfrz

Ahhhh ....... yes, one could do a tune up with a 1/2" wrench, a screwdriver, a thin coin and a calibrated ear .......

But, did you not first gap the points with a thin dime (or a thin Canadian coin) .... ??


humfrz

Oh of course. After I scrapped the green/white/burnt, fuzzies (tech term) off them with a jackknife of course.