Danno

"I know Paul tested a bunch of chips and settings. No real power gains anywhere. "

Which dyno-test are you referring to? On the last one, we got a chip that was worth +5hp, or over twice the gains of the others he had. He also gained +2.5hp from removing the balance-shaft belts, but had to put them back on per the rules.

"How does adjusting spring tension impact fuel mixture. Can I get more than 3.1% reduction if needed?"

You can tighten the spring-tension to have the flapper door open less for any given air-flow. However, this is not a linear function due to the angle of the door and voltage-to-door-angle response curve. The results tend to have more fuel removed from low-flow conditions like idle & partial-throttle and less fuel, if any removed under full-throttle high-flow conditions. Best air-fuel ratio on NA seems to be around 13.0-13.5:1 or so to make maximum power.

M758

Danno...
RE..chip testing
I never saw Paul's dyno testing, but all were in the few hp range. After all this testing he said he made some 132 rwhp and when with that. I think that may have been with your chip. Not really sure. But as a comparison my motor without a chip made 131 rwhp on the same dyno. Lots of close running with him showed our cars were comparable on the track so that is why I figured no significant gains were made. I still expect 2-3 hp from nearly all chips. If you get 5 hp them great, but there were no earth shattering amazing gains. Yep 2.5 hp from no balance shafts, but the vibes might kill the motor. Not worth it even if it was legal.



RE... Spring Tension
I am using a LATE DME and from the FR wilk AFM info he shows output voltage to be liner vs flapper position in the late DME's. So it may not be as bad as you think. Either way which is the tension adjustment screw and which way does what.

I have been having some PM's with dgz924s and think my rich condition may have been cause by running 10.2 pistons with DME set for 9.5:1 units. Now that I will be back to the 9.5:1 Units my mixture may perfect, but I still want to know how to adjust the spring tension just incase.

Ok so I should be shooting for 13 to 13:5 to 1 A/F Ratio for peak power. Well see what I get.

Jim Clark

I was given the advice to unplug the 02 sensor and turn the FQS switch off or counter clockwise tilll stop. I'm having the same issues with runnig rich and looking for direction as well.

Jim Clark

I've got a bit of interest on this subject as well. I'm having the same issues at WOT with my track car. I was advises by the 944 wrench at Zotz in Orlando to unplug the O2 sensor and turn the FQS switch full off counter clockwise.

Danno

Unplugging the O2-sensor won't affect full-throttle fuel-mixtures in any way as the O2-sensor is ignored. At partial-throttle driving, your mixture will most likely be even richer, because the USA maps have +5 to +15% more fuel than needed. The O2-sensor feedback is then used to lean out the mixture to around stoich. The ROW/Euro maps for cars without O2 sensor is leaner and the fuel-values match actual airflow a little better.

"RE... Spring Tension
I am using a LATE DME and from the FR wilk AFM info he shows output voltage to be liner vs flapper position in the late DME's. So it may not be as bad as you think. Either way which is the tension adjustment screw and which way does what."

Yup, the angular-position of the flapper-door and resultant voltage curve is linear. However, airflow volume to flapper-door position isn't linear. So a 20-degree change in the flapper in the middle corresponds to X change in air-flow. However 20-degree change near the max-opening end represents 5X change in air-flow.

Probably best way would be to do dyno-testing with various changes in the spring-preload on the AFM. Send me the dyno-charts and I can customize a chip for you. The NA cars actually responds more to ignition-timing than air-fuel changes, so once we get air-fuel ratios around 13.0-13.5:1, we then advance the ignition to the values giving most effective power (with appropriate fuel-octane).

M758

Danno,
I ran on the dyno saturday. It was not dyno jet, but one with two 8.5" rollers and had AWD capability. It used eddy currents to load. Owners said 8% lower than typical dyno jet. (Edit) It is a Dyno Dynamics unit.

Anyway. I am working on the charts, but peak was 134.2 rwhp between 5500 and 5800 RPM Curve was pretty flat. A/F Started 13.0:1 at 2500 RPM and at 4000 dropped to about 12.2 at 5500 then dropped to 11.9: then stabiized back to 12.2:1 at 5800 RPM to 6500 RPM.

I decided not adjust the curve since this was close to the A/F ratio I had from a dyno run a couple years ago when Chris Cervelli tweaked it.

Also of the 3 pulls they were all with in 1 hp of each other and the 3rd was richest and more powerfull. I run 91 oct pump gas and like to keep it that way and was using the 9.5:1 pistons.

I am not certaint leaning the mixture will gain me any hp. That is why I did not mess with it.