I think this is what Mardigrasmax initially did, but I want to be sure.

If this is true, then I can install 370 cc/min injectors, adjust fuel pressure at idle downward with an adjustable fpr, and dyno-tune to get the S-AFC settings needed at WOT.

At partial throttle operation, the stock ECU can handle the increased injector flow capacity by reducing pulse width.

Am I right, or am I full of it? I really don't want to spend $600 having the ECU programmed at this point.

 

True but matt also used a 3:1 fmu with the adjustable fpr.

 

Good point. Matt is using the 3:1 with a 2.62" pulley. I would keep my 3.25" pulley for now, and go to a smaller pulley later. Or, I am thinking of going to higher boost by raising the rev limit instead (or a combination of the two), which is attractive because I would be taking advantage of high rpm power produced by the MEVI.

So I'm wondering if the S-AFC will handle the tuning under these scenarios, and which one is preferable:

• 3.25" pulley, 370 cc/min injectors, no fmu. S-AFC would be used to enrich mixture when boosting.
  
• 3.25" pulley, 370 cc/min injectors, 3:1 fmu. S-AFC would be used to lean out mixture when boosting.

Probably the second scenario is safer since it results in a rich mixture if the S-AFC craps out.

 

I say the with an Adjustable FPR, it can be done and was done. But the S-AFC won't do much for this situation because it only FINE tunes the Air/Fuel band, it doesn't actually change the fuel pressure that needs adjusted......

 

I think you should go with the 2nd scenario. The s-afc's ability to modify the maf voltage is directly limited to the maf total output and what that ecu is designed to recieve and given the cfm with the supercharger the maf is already maxing its operating range. Fuel would need to be boost referenced (3:1 w/bleeder if need be) and use the s-afc to lower the voltage the ecu sees from the maf sensor effectively shortening pulse width. When Matt does something to his car there is usually good reasoning behind it. Don't second guess the man.

 

You're right, it doesn't adjust the fuel pressure, rather it affects injector pulse width. I'm not sure what the adjustability potential is with the S-AFC. My understanding is that it is capable of more than just fine tuning, but I don't have much experience to base that on.

I guess the safest plan is to start with a 3:1 fmu (along with an adjustable fpr), which will provide way more than enough fuel for the 9 psi I get with the 3.25" pulley (based on Matt using a 3:1 fmu for 13.5 psi) and play with the S-AFC to see if I can get reasonable performance. If the S-AFC is not capable of leaning out the mixture enough, then I can go with a boost bleeder valve to reduce the fp/boost curve.

 

Don't forget that Matt's tuning is based on a 2.62" pulley, which I am not ready to go to yet (not sure I'll ever go that small). So what works great for Matt will be way rich for my (relatively) huge 3.25" pulley. Which is why I'm researching the subject as much as I can.

I'd like to go smaller than 3.25", but the next size is 3.125" which seems like an insignificant jump compared to the work involved. The 2.87" pulley is the next smaller size, and that makes me a little nervous. I'd like to go with a 3.0" pulley, but that has to be custom made, right?

Wish I'd bought that ECU from you along with the injectors, AllGo.

 

QUOTE]Originally posted by Stephen Max


Don't forget that Matt's tuning is based on a 2.62" pulley, which I am not ready to go to yet (not sure I'll ever go that small). So what works great for Matt will be way rich for my (relatively) huge 3.25" pulley. Which is why I'm researching the subject as much as I can.

I'd like to go smaller than 3.25", but the next size is 3.125" which seems like an insignificant jump compared to the work involved. The 2.87" pulley is the next smaller size, and that makes me a little nervous. I'd like to go with a 3.0" pulley, but that has to be custom made, right?

Wish I'd bought that ECU from you along with the injectors, AllGo. [/QUOTE]

Yeah I wish I would have kept the ecu and had it modified for a z32maf and the 370cc for a great turbo setup. With a 2.87 and the stock ecu you should consider either awic or the j&s to keep detonation down.

 

Go look for Cheston's G-force ecu deal. that might be another option

 

3.00 is custom made by ASP IIRC. Kevin has one in his garage.

 

For sale? Which Kevin?

 

y2Kevse....drop him a PM. I saw it sitting around in his garage and Jane is now using the 2.87.

 

Thanks, maxi!