Reignman

I just had the Comptech supercharger installed yesterday and also hooked up the v-afc with a harness. Well when I went to have the v-afc tuned the guy was having problem because he would adjust the fuel settings and then run the car on the dyno and the horsepower would increase until about 6000rpm and then it would drop very quickly then it would pickup again. We found the only way to not have that happen was to zero out all the settings on the v-afc. Does anyone know why it would do this?

Yellow Streak

Did you move your VTEC engagement point? How much power did it drop? It would be helpful if you posted your V-AFC settings along with a dyno chart.

-YS

joe_s2k

You do know that zeroing out the settings is like not having a VAFC connected.

I would recommend that you PM Wesmaster. He took got his VAFC/SuperCharger dyno tuned with positive results. Either something is not connected correctly, or the shop you took it to doesn't know how to tune a VAFC.

Reignman

I dont have the v-afc settings because we cleared out the numbers before I left. Also he only printed out the dyno run after we reset the v-afc. He tried the VTEC engagement at both 5800 and 5600 and found that 5800 was the best setting. For the power, it dropped about 40hp at 6000rpm and started gaining again after that. I also wanted to ask you guys with the Comptech SC what spark plugs do you use and also do you think the plugs could effect the engine in this way?

Yellow Streak

I am running NGK R5671A-10 (5820) plugs. I seriously doubt that the plugs are the problem, but you should be running something colder than stock.

Two possibilities come to mind:

1. The V-AFC has to be wired between the Comptech ESM and the ECU. Where do you have the Comptech ESM spliced in?

2. Do you recall if your tuner had any of the V-AFC settings in the plus range?

-YS

Reignman

I bought the SC used and it didnt have an ESM and I was wondering about this also. I had it installed by the same mechanic that installed it the first time and he said that there was no ESM when he got the kit and nothing in the instructions mentioned it. I asked him how he blocked the engine from seeing the boost and he said that there is a MAP sensor by-pass. I guess the kit didnt have the ESM when it was first released. So I have the v-afc straight into the ECU with a harness.

RT

[QUOTE]Originally posted by joe_s2k
[B]

You do know that zeroing out the settings is like not having a VAFC connected.

RT

Oh sorry, you already answered some of the questions while I was snoozing (guess I should have hit refresh)
The lack of the ESM (or equiv) is your problem, I'm 99% sure.
What is this MAP "by-pass" you speak of? Check valve deal?

Yellow Streak

If an ESM isn't involved, the important question becomes whether or not any of the V-AFC settings were positive (as in adding fuel).

-YS

Reignman

YS,

I didnt see all the settings while he was doing it but I remember that most of the settings were positive and not negitive. He also said that with the v-afc values all at zero that the A/F ratios were spiking around 6000rpm and it was running lean around there.