Tuning 650s and maft

[2GSpeed]

Ok so ive been running my FIC 650cc injectors for a while and when I set my maft to the correct setting my car runs lean, I am gauging by my innovative wideband o2 so im not just guessing. when I zero all of my maft knobs out the car runs the way it should off of boost and not to rich or not to lean. I have been problems tuning the car on boost so I decided to throw my stock mass air back in and tune that way. I put the stock mass air in zeroed out my safc 2 and with the 650s the car started up perfect. Shouldnt the car idle really rough and die out from being to large of injectors? I bought the injectors from slowboy racing so I assume that they are the 650s. I am tuning with both the SAFC 2 and MAFT and cant seem to get it to run right on boost, what should i start with for base settings on the two

 

[1SloColt]

Never ever touch the MAFT except to plug it into the 3" MAF and to set it to stock settings which is whatever MAF you are using, most likely a 3" MAF and for 450s. Aux 4, Base 2 if you run version 2.02 with a 2g connector. Use your SAFC to do all the tuning cause the MAFT sucks for any type of air/fuel control, just too inaccurate. I have 660s and 3" GM MAF with version 2.02 translator set to 450s and my lo settings on the safc look something like this: 1k -10, 2k -8, 3k -8, 4k -6, and i just slightly richened it up to 7K. I really don't do any low throttle high RPM driving so I don't worry much over 4k rpm. But my lo fuel trims are leaned out according to my logger, which is good for gas mileage.

 

[xcelr8n]

Set the maf-t base to somewhere around 550cc injectors... maf-t wont work properly if you actually set it to 650cc injectors, my experience and many others experiences say set it to ~550cc injectors and the safc to 0 for the base.
After that for idle mid and wot leave the maft zeroed and tune with the safc!

 

[1993eclipseGS]

Do you understand the maft is basically the same concept as the safc but without the blue blinky lights everywhere? Why tell him not to touch it? There are alot of people that have had nothing but luck with the maft, Including myself.

 

[Newlogics]

Do you understand the maft is basically the same concept as the safc but without the blue blinky lights everywhere? Why tell him not to touch it? There are alot of people that have had nothing but luck with the maft, Including myself.

Because if you already have MAFT AND SAFC, SAFC provides more refined control and most importantly, can be adjusted on the fly. (not many people install MAFT inside the car). On the other hand, injector 'presets' in MAFT do seem to be really far off. (Somehow, I don't think that would be the case if MAFT was used as 'draw-through'). So there. Yes, it can be done with MAFT, but if SAFC is already there, why not take advantage?

 

[dsm-onster]

Because if you already have MAFT AND SAFC, SAFC provides more refined control and most importantly, can be adjusted on the fly. (not many people install MAFT inside the car). On the other hand, injector 'presets' in MAFT do seem to be really far off. (Somehow, I don't think that would be the case if MAFT was used as 'draw-through'). So there. Yes, it can be done with MAFT, but if SAFC is already there, why not take advantage?

Maft in blow through does read a little off. But not that much in my case. Almost dead on. I have to compensate up top a bit on dsmlink to calibrate my blowthru MAFt. MY MAFt in blow through read .27 grams/rev airflow at idle with my stock engine (stock cams, stock idle, etc). This is right where a stock engine reads with the stock maf.

To the original poster... You're saying that when you set your SAFC to 450s that you're getting the 650s to idle correctly, right? I had a problem similar to yours and it had nothing to do with the MAFt settings being off. It was a dead time issue. I had over 500+ microseconds more deadtime with my PTE 650s than my stockers. Which would make them run REALLY REALLY REALLY lean at at low dutycycles like idling. I know this because i used DSMLink to set global and deadtimes and this is how i figured it out.

I suggest doing what 1SloColt recommends first. But if you still can't get a good tune (and I suspect you won't), then to retain blowthru and a MAF you'll never outgrow, keep the MAFt and sell the SAFC to add to an eprom and chip combo. You'll find that you can tune really well with a MAFt when it's backed by a chip. I did a little experimenting with my dsmlink where i zeroed everything out but the deadtime and global and the maft tuned me just as well as dsmlink... this would be very similar to getting a chip for your injectors and using MAFt to tune. With a little math, this would allow you to upgrade to 950 cc injectors later even though you have a piggy back because the compensation is not nearly as drastic when the ECU is set for 650s.

 

[DevilSperm]

I had my aux at 1 and base at 5 with my FIC 650's. Though I went off spark plug color and knock since I dont have a wideband but it seemed to be about the best setting I could find.

 

[Newlogics]

Well yeah. I was taking dead time into account for being off on 'presets' Since not everyone has EPROM ECU and DSMlink, and can't compensate dead-time differences for injectors. But nevertheless, an excellent point to bring up.
Speaking of dead-time, DENSO 650s have dead-time closest to stock (about 180ms more I believe) compared to other 650s, so it's a bit easier to work with them. Still, without an ability to set injector dead time, tuning is a pain.

Maft in blow through does read a little off. But not that much in my case. Almost dead on. I have to compensate up top a bit on dsmlink to calibrate my blowthru MAFt. MY MAFt in blow through read .27 grams/rev airflow at idle with my stock engine (stock cams, stock idle, etc). This is right where a stock engine reads with the stock maf.

To the original poster... You're saying that when you set your SAFC to 450s that you're getting the 650s to idle correctly, right? I had a problem similar to yours and it had nothing to do with the MAFt settings being off. It was a dead time issue. I had over 500+ microseconds more deadtime with my PTE 650s than my stockers. Which would make them run REALLY REALLY REALLY lean at at low dutycycles like idling. I know this because i used DSMLink to set global and deadtimes and this is how i figured it out.

I suggest doing what 1SloColt recommends first. But if you still can't get a good tune (and I suspect you won't), then to retain blowthru and a MAF you'll never outgrow, keep the MAFt and sell the SAFC to add to an eprom and chip combo. You'll find that you can tune really well with a MAFt when it's backed by a chip. I did a little experimenting with my dsmlink where i zeroed everything out but the deadtime and global and the maft tuned me just as well as dsmlink... this would be very similar to getting a chip for your injectors and using MAFt to tune. With a little math, this would allow you to upgrade to 950 cc injectors later even though you have a piggy back because the compensation is not nearly as drastic when the ECU is set for 650s.

 

[dsm-onster]

Well yeah. I was taking dead time into account for being off on 'presets' Since not everyone has EPROM ECU and DSMlink, and can't compensate dead-time differences for injectors. But nevertheless, an excellent point to bring up.
Speaking of dead-time, DENSO 650s have dead-time closest to stock (about 180ms more I believe) compared to other 650s, so it's a bit easier to work with them. Still, without an ability to set injector dead time, tuning is a pain.

Absolutely. If you get a less expensive tuning device spend the money and get the more expensive injectors... This whole issue of deadtime and idle issues prompted me to get DSMLink. I already had high deadtime injectors and I needed something to control them better. Denso seems to be most effective injector when coupled to a piggyback. You know, from my experience deadtime has little to no effect on WOT tuning. A piggyback is a really affordable choice for a dedicated track car.

So to the original poster: since you've encountered this problem and, IMHO, it most likely is because of huge injector deadtimes, do the best you can and either put up with a lousy idle and light throttle tune issues for the best WOT tune; or make a choice: new, more expensive injectors or the costs of chipping (with this weigh the benefits of DSMLink; also getting just a keydiver, dsmchips, etc. setup will be more affordable).