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650cc injectors on Apexi SAFC

Number996

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Feb 12, 2012
Messages
143
Location
Gaithersburg, MD
As the title says gentleman, i want opinions on using 650cc injectors on an APEXI SAFC.

My homework leads me to believe the Apexi maxes out at 660cc so they should work. Was lined up to buy a set of 550cc RC's today but the guy sold them. Found some 650cc's and want to know for sure if they wil work before I buy.

Anyone gone this setup before? Speak up.

Thanks guys!
 

turbowop

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Apr 29, 2001
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11,971
Location
Yakima, WA
It's doable, and the correction will be less if using a 2gMaf with them. It would be more ideal to get a chip made for your mods and use the SAFC to fine tune it. SAFC's work by changing the airflow signal to the ECU, but that also creates issues. Using larger injectors requires you to subtract airflow signal to the ECU via the SAFC. This makes the ECU squirt less fuel, but can also put you into a different (higher) timing map and could create knock.

The farther away from stock injectors, the worse this gets. This is why an SAFC should really only be used to fine tune a custom chip.
 

Number996

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Feb 12, 2012
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143
Location
Gaithersburg, MD
Money is the problem. I'm running stock 450cc injectors now but my 2gMAF is causing problems. I originally hbought he car with vpc but dont want to use it, hence the 2gMAF.

Will 450cc/2gMAF/apexi safc work? Because then i wont buy the injectors. I was going 550cc to compensate for the 2gMAF but they were sold. My next option is 650cc's
 

James

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I've got a friend with a set of 550s for sale. 125shipped super clean
 
Last edited:

turbowop

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Quoting Number996:
Money is the problem. I'm running stock 450cc injectors now but my 2gMAF is causing problems. I originally hbought he car with vpc but dont want to use it, hence the 2gMAF.

Will 450cc/2gMAF/apexi safc work? Because then i wont buy the injectors. I was going 550cc to compensate for the 2gMAF but they were sold. My next option is 650cc's



At least you have a 2gMaf. That makes the correction on the SAFC much smaller. It's not ideal, but it will work fine. I would try to find a chip though. I'm sure somebody around here has a 2gMaf/650 chip kicking around. Post up a WTB ad to see.
 

turbowop

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Location
Yakima, WA
Yes, but since you have to add airflow to make up for the larger Maf, you will hit fuel cut much faster. IMO, the better setup between the two is the 2gMaf/650.
 
Last edited:

James

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Port richey Florida
If you can't swing the chip then 550s are the best bet... Since it requires very little SAFC changing.
 

ktmrider

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Sep 10, 2007
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3,128
Location
Tempe, AZ
Quoting turbowop:
The farther away from stock injectors, the worse this gets. This is why an SAFC should really only be used to fine tune a custom chip.

To be totally honest you NEED to go back to stock! You're compounding problem after problem and not addressing the root cause. Adding yet another potential problem is not gonna get you there.

There are tons of 1g MAF's floating around. You seem to have stock 450's already. Get one, have the car running well, THEN go after all the upgrades. Quit trying to band-aid a bullet wound, your car and pocketbook will thank you later.
 

James

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Port richey Florida
If you can't find a local 1g MAF I have one sitting here. Pay for shipping and I'll ship it. If it works and you want to keep it send me $10. If you don't want it ship it back to me.
 

James

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Apr 7, 2012
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Port richey Florida
For the record if you want my friends 550cc injectors he said he can ship out today if you get through the transaction quickly with him.
 

snohacking

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Mar 16, 2010
Messages
233
Location
Menomonee Falls, Wi
I think I still have a chip of 650cc/660cc injectors, it is also set up for a stock maf. Pm me if interested.
 
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