safc 2 max injector size?

[95DsmTsiauto]

i bought a 14 b turbo for $150 that i was just going to put on and keep the stock 450's. However i found a really good deal on a sleeper 20g that i just cant pass up. $350. I was just going to buy some 650's and use them but now someone told me that safc2 is only good for 550's and lower.. Is there any Truth to that? Also can i keep my exhaust manifold i bought from xspower or do i have to get a different one.

 

[crunchymilk]

I'm sure others will disagree with me, but I believe that 550s are the most you can use. The SAFC can definitely correct for injectors way past that, but then the ECU sees so little airflow so it tries to add timing. Too much timing and you have problems. IMO, don't go higher than 550 in a safc.

Regarding your exhaust manifold I would just port the one you have now. It flows plenty for a 20g.

 

[1993eclipseGS]

Easy, Just get an eprom and get a keydiver chip for injector compensation. You'll have a much easier time with tuning.

 

[MarkDML]

I'm sure others will disagree with me, but I believe that 550s are the most you can use. The SAFC can definitely correct for injectors way past that, but then the ECU sees so little airflow so it tries to add timing. Too much timing and you have problems. IMO, don't go higher than 550 in a safc.
Regarding your exhaust manifold I would just port the one you have now. It flows plenty for a 20g.

I agree with the 550 cc injectors using safc2 as your fuel management unit. I also know that with the use of the GM MAFT, you can use as 880 cc injectors.

I had 780 cc injectors using gm maft, safc2 and stock ecu. i was able to tune my car up to 25 psi max with the obvious fuel cutting problem and got out 488.7 whp.

that is my experience with the safc2

 

[92awddsm]

The max injector size that an afc can control is 50%larger than stock. That being said, with a 5 spd ecu, you can control up to 675cc injectors and with an auto ecu, the largest you can go is 585cc injectors. Even though the afc has capabilities of controlling injectors that large, you tend to get into too much timing advance and might have problems with knock. You can try the 650cc's but make sure you keep an eye on timing advance.

 

[spyderturbo007]

The max injector size that an afc can control is 50%larger than stock. That being said, with a 5 spd ecu, you can control up to 675cc injectors and with an auto ecu, the largest you can go is 585cc injectors. Even though the afc has capabilities of controlling injectors that large, you tend to get into too much timing advance and might have problems with knock. You can try the 650cc's but make sure you keep an eye on timing advance.

I think your math might be a little off. Running 585cc injectors only puts you at a baseline correction -23% and 720cc injectors puts you at a baseline correction of -37.5%.


Disclaimer: I do not recommend running 720cc injectors.

On the other hand, I have no problems at all tuning with 650cc injectors.

 

[92awddsm]

I think your math might be a little off. Running 585cc injectors only puts you at a baseline correction -23% and 720cc injectors puts you at a baseline correction of -37.5%.


Disclaimer: I do not recommend running 720cc injectors.

On the other hand, I have no problems at all tuning with 650cc injectors.

5 spd ecu is factory programmed for 450cc injectors. 50% larger(which is 225cc larger) equals 675cc. No math issues there. 1g Automatic ecu is programmed for 390cc injectors stock. 50% larger(which is 195cc larger) equals 585cc's. No math issues there either. So where is my math off?

 

[donmagicjuan]

5 spd ecu is factory programmed for 450cc injectors. 50% larger(which is 225cc larger) equals 675cc. No math issues there. 1g Automatic ecu is programmed for 390cc injectors stock. 50% larger(which is 195cc larger) equals 585cc's. No math issues there either. So where is my math off?

It comes from whether you apply the correction factor to the old injector size or the new one. To get accurate results, you should calculate how much smaller the 450s are than the injectors you're putting on, not how much bigger the new ones are than the 450s.

For example, to get 650cc injectors to inject the same amount of fuel as 450s, one needs to subtract 30.8%
(650 - 0.308*650 = 450).

This number should be able to be confirmed by anyone running 650s on an S-AFC 2.

 

[92awddsm]

It comes from whether you apply the correction factor to the old injector size or the new one. To get accurate results, you should calculate how much smaller the 450s are than the injectors you're putting on, not how much bigger the new ones are than the 450s.

For example, to get 650cc injectors to inject the same amount of fuel as 450s, one needs to subtract 30.8%
(650 - 0.308*650 = 450).

This number should be able to be confirmed by anyone running 650s on an S-AFC 2.

Thanks, that clears that up. That is funny because I have 2 friend using safc, one with 650's, the other with 680's and both are around -42 or so in order to get a/f in the 11.6 range. I personally dont use an afc so I was going off of what others have told me.

 

[donmagicjuan]

Thanks, that clears that up. That is funny because I have 2 friend using safc, one with 650's, the other with 680's and both are around -42 or so in order to get a/f in the 11.6 range. I personally dont use an afc so I was going off of what others have told me.

That sounds about right, the additional offset being necessary to get from 9.5-->11.6:1.

 

[kraka]

Jeez, your friends tuning for 11.6 at WOT? Jeez, a little lean, eh?

 

[95DsmTsiauto]

For example, to get 650cc injectors to inject the same amount of fuel as 450s, one needs to subtract 30.8%
(650 - 0.308*650 = 450).

This number should be able to be confirmed by anyone running 650s on an S-AFC 2.

so if i get 650's i can run them ok with safc2? or should i just get a eprom with keydiver chip for 650's? I have eprom but i guess i have to buy a new one already chipped and sell mine or what?

 

[kraka]

so if i get 650's i can run them ok with safc2? or should i just get a eprom with keydiver chip for 650's? I have eprom but i guess i have to buy a new one already chipped and sell mine or what?

Wait, what?...You dont need to get a new chipped ecu, just get your eprom socketed...Its like $50, and a chip wouldnt cost too bad...It would compensate for the injectors, and you would only to lean it out a tad more than that...

650's on their own is not too bad tho as far as tuning with an safc....A few friends of mine tune with 680's on an SAFC...Its about the limit, but it can be done

When your using 650's, just watch out for excessive timing advance

 

[exiletalon]

a keydiver ship is recommended to use SAFC with it, it will work without, but to get the most out of it, you need one- with a chip, you can run whatever with SAFC/chip combo.
however- you have a EPROM, SAFC2 ( $300), socket ECU ( $50), stage 3 keydiver ( $125), datalogger ( $175)-thats $650!!! when you can get the ultimate tuning tool- DSMLink for $600 BRAND NEW!!!! and never worry about anything tuning wise again. the only limit will be your injectors/engine/experiance/etc.. but not the tuning tool!
then you can really push that 20g, but I would recomend at least 720cc for 20g to use its potential- 750cc would be excellent

 

[blcknspo0ln]

Wait, what?...You dont need to get a new chipped ecu, just get your eprom socketed...Its like $50, and a chip wouldnt cost too bad...It would compensate for the injectors, and you would only to lean it out a tad more than that...

650's on their own is not too bad tho as far as tuning with an safc....A few friends of mine tune with 680's on an SAFC...Its about the limit, but it can be done

When your using 650's, just watch out for excessive timing advance

Ah, finally someone who pointed out the main reason why you would want to go with a chipped ECU. I've had my car at 10.1:1 AFR using -45% taken out across the board on HI settings. This was using 660 injectors with a PTE BB5031. There was definitely a lot more tuning to be done with that, but the point is that I was hitting 24* peak timing @ 6700 rpms

Compensating that much air signal with an SAFC will only lead to aggressive timing maps that hinder performance. With a chipped ECU and injector compensation, you are now only leaning out the SAFC a tad bit to fine tune your car. This gives you a health 18-20* peak timing and in theory optimizing your power.

 

[95DsmTsiauto]

ok my buddy has an safc2 he will give me for 180 because he is broke as a joke. So i have that.. Ill get my eprom socketed somewhere.. Ill have to see if hybrid dynamics will do it or maybe ill just drive to slowboy and see if they do.. But you are saying 650's arent enough for a bastard 20g.. I only want to run 18-20 lbs of boost on stock internals right? i was hoping they would be enough because i can get them for 150 used..

 

[2gGSX]

You can run however much boost you want as long as you tune for it. 650cc injectors maxed will flow about 4.35 lbs/min fuel at 100% IDC, or 3.92 lbs/min at 90%. In that case with an 11:1 AFR you could support 43 lbs/min airflow assuming pump gas and ideal conditions. A 20g compressor can definitely flow more than that, but there is no guarantee that your setup will. It would not be a bad idea to go larger, especially if you are getting your ECU chipped to compensate, but 650cc injectors would be enough for a while.

You should check to make sure you have an EPROM ECU first before going any further.

 

[eclipsegsx1736]

ok my buddy has an safc2 he will give me for 180 because he is broke as a joke. So i have that.. Ill get my eprom socketed somewhere.. Ill have to see if hybrid dynamics will do it or maybe ill just drive to slowboy and see if they do.. But you are saying 650's arent enough for a bastard 20g.. I only want to run 18-20 lbs of boost on stock internals right? i was hoping they would be enough because i can get them for 150 used..

650s are plenty for 20 psi on that snail, now you'll just have to worry about whether or not you have enough octane to run that kind of boost. 93 might work, but 91 probably won't, at least not without a fight. Now if you plan to max out your 20g, you should definitely go bigger than 650s.

 

[95DsmTsiauto]

i dont think i can go any more than 20 lbs on stock internals right? O and i always use 93 or 94 octane and im a 95 so i have an eprom.

 

[andymoraitis]

The amount of boost that you run isn't as big a factor as you would think on stock internals. The air/fuel and timing advance are what can eat stock parts from a poor tune. When I still had a stock 2.0, I ran 26psi on it daily with a Big 16G. My tune was smart and my chip had custom maps in it to cap timing and control the A/F ratio.

If you tune by looking for knock, you can easily find the safe limits of how much boost you can run and how aggressive you can get with the tune. Just be smart and be careful and you won't hurt anything.

Good luck,

Andy

 

[nightspeed87]

im thinking i want to go with 720s chipped with safc2 and not sure of what turbo i want yet, just something that doesnt lag too much and can get me out the hole, but yet still be big enough to support at least 23lbs of boots efficiently... Only thing that comes to my mind is like super 16g, any opinions.... And does putting a larger aftermarket fuel rail and bigger lines significantly help with injector flow?

 

[kraka]

The amount of boost that you run isn't as big a factor as you would think on stock internals. The air/fuel and timing advance are what can eat stock parts from a poor tune. When I still had a stock 2.0, I ran 26psi on it daily with a Big 16G. My tune was smart and my chip had custom maps in it to cap timing and control the A/F ratio.

If you tune by looking for knock, you can easily find the safe limits of how much boost you can run and how aggressive you can get with the tune. Just be smart and be careful and you won't hurt anything.

Good luck,

Andy

True that....I found that I start knocking badly after 11.0, which is not that lean...Every car is different, thats why it helps to tune and tune, test and tune....Trial and Error

Stock internals will take the boost, stock internals wont take a lean a/f...

Just remember, you will need more than an safcII to tune....If your just taking out % with the safc, your just tuning blind....You wanna make sure your using a logger/wideband or an eprom to help tune with confidence

 

[2gGSX]

im thinking i want to go with 720s chipped with safc2 and not sure of what turbo i want yet, just something that doesnt lag too much and can get me out the hole, but yet still be big enough to support at least 23lbs of boots efficiently... Only thing that comes to my mind is like super 16g, any opinions.... And does putting a larger aftermarket fuel rail and bigger lines significantly help with injector flow?

Our stock fuel rails are more than sufficient for the goals of about 99% of members on here. With the lines, if anything, you can reuse the stock return line in place of the feed line then add a bigger line for the return. This will not significantly help injector flow though, it would only help if your fuel pump were so huge that you were losing significant flow/pressure due to the stock lines.

 

[95DsmTsiauto]

ok guys thanks alot i decided to go with 720 injectors, safc 2, keydiver chip set for 720 , and ill snatch up a pocketlogger to help tune with.. Ill let you guys know how it goes.. I'll run 18 lbs of boost for a while until i pay someone to tune it because i lack tuning knowledge.. Ill just check for knock and if i have any i wont drive it until i get it tuned..

 

[spyderturbo007]

You did verify that you had an EPROM before you ordered everything, right????

Don't worry about the tuning problem, we will all help you for free. Or you can drive to my house, buy me a case of beer and I'll tune it for you.