Big16g psi for dyno

[TalonBoy90TSI]

I have a 99 gsx mods are 255 walbro rewired, 850 injectors(yes i kno theyre overkill), fmic, mbc, 3" turboback, maft, safc 2, aeromotive apfr, big16g...stock internals, im running 20 psi now on no tune....wats the most psi i should run when i go to get my car dynoed?...### numbers should i be looking at? any suggestions would be appriciated, anything but the injectors.....thanks

 

[TSIMonsteR]

I don't think you'll be able to dial in a good tune on the safc on those injectors without a chip(even with maft too). You may want to pick up a set of 560's or something of the nature. I think with that setup, assuming you can get it tuned.... Maybe 260whp or so... it's really hard to say

Also, the point in going to a dyno is to get it tuned, you really won't know what boost you can run until you log it/tune it

 

[staticbrainwash]

Unless you're using maft for injector compensation ^^ is right. There's no way you can compensate for injectors that large with just an safc.

 

[Ultimatedsm]

I noticed 650cc are max for the SAFC before it has major issues. If you have an eprom, just get a DSMLINK.

 

[daren_p]

Like others have said unless you have something to compensate for those injectors you are going to have trouble tuning. You'll either end up knocking from too much timing advance while trying to compensate for those injectors or you will be running pig rich. If you are only running the safc with those injectors I would expect your numbers won't be very impressive...

 

[mitsuclipsegsx]

720 are the max on a afc

 

[CanadianTSi]

I would go for around 22psi depending on the Octane used. You should be able to break 300whp quite easily.

 

[JayRolla]

Damn 20psi without a tune. I see some engine damage going on there. Yes everyone above is right. You need a burned chip(eprom) or dsm link for those large injectors. If you are not getting a tune soon I would turn down the boost to between 10-14psi. Im guessing your motor is knocking like crazy.

 

[larsrya8]

Unless you're using maft for injector compensation ^^ is right. There's no way you can compensate for injectors that large with just an safc.

The MAF-T and S-AFC do the same thing to compensate... they both alter the airflow signal. Using either one will yield poor results on injectors larger than 650cc. I don't think the car will want to do much of anything with the 850's... your timing will be insanely advanced. That's almost twice as much fuel as stock you know...

You'll need to get your hands on a 1995 EPROM ECU and get it chipped, or you could skip the chip and go straight to DSMLink. Keep the S-AFC but sell the MAF-T if you go with the chip, and sell both if you go with DSMLink.

 

[staticbrainwash]

You need to retain the maft if your running a gm mas, especially with dsmlink. The maft sync's with dsm link to run the gm mas properly.

But i agree with you, i wasn't saying a maft could compensate for 850's but more trying to say that either way an safc couldn't do 850's.

The best way to go with what it sounds like he wants to do with the car (and those giant injectors) would be to get the Link.

 

[larsrya8]

I meant to say that he should reinstall the stock MAS. A 16G isn't going to overrun the stock sensor, and if he uses the stock MAS he won't have to go through the bother of trying to calibrate the the GM sensor. The GM MAF is frustratingly inaccurate when used in blow-through mode, which makes it very difficult to create a solid tune. If used in draw-through mode the sensor seems to work perfectly.

I was thinking that selling both the S-AFC and the GM MAF/MAF-T would help raise money to help pay for the EPROM ECU and DSMLink, since neither would be necessary for his setup.

Those are my suggestions.

 

[TalonBoy90TSI]

yes...i am using the maft to compensate for the injectors....the car runs without a problem..ive been driving around for about 3 weeks with these injectors and maft setup...im not going to use dsmlink because of the lack of funds....i ordered an safc 2, should be getting it tomorrow....i dont plan on doing anything too crazy with the car since i will be going to school soon....i know i shouldnt be running these but i got them from a friend for $50 bux....i know someone thats willing to trade me 660's for my 850's...the car ran a 13.2 at 98 last week with the current setup....i kno im a dumbass for doing so but peer pressure does it ....if i do get the 660's ill be using the maft to compensate as well....thanks guys for your input......

 

[larsrya8]

How much timing and knock are you getting with this setup?

 

[TalonBoy90TSI]

i have no clue...car hasnt blown up yet, but finally came across some money to get my car done...so im doing it the right way, which is ### i should have done at first

 

[staticbrainwash]

660's would be MUCH MUCH easier to tune out correctly with safc and maft combo'd. Do what you can to get those.

Honestly, the car might feel fine, but i can't imagine your battling knock very well. Because too much fuel can be just as bad as not enough fuel. You just can't compensate like you should safely with just piggyback tuning.

If you got a eprom, all would be taken care of. But i would pick up those 660's if i were you, that way you know everything will be running well when you hit the dyno. Not to mention they will be able to tune you far easier with smaller injectors.

 

[TalonBoy90TSI]

once again guys..i want to clear things up.....id rather have dsmlink but i have no money at this moment.....i am using the maft and safc2 to tune my car..central florida turbo will be tuning my car btw.....

 

[staticbrainwash]

Thats great man, but what we're saying is. . . You can't tune injectors that large with piggybake devices. Either get smaller injectors or a chipped eprom. Not only will it help your car, but it will also make tuning the car period easier for the shop.