720's with an AFC?

[boostngst]

I know I've heard people talk about it in the past but I cannot find anything about it now.

Who is running 720's with only an AFC to tune them down? I know they should be about at the limits of the AFC but will they surpas the limits?

 

[dsm-onster]

I know I've heard people talk about it in the past but I cannot find anything about it now.

Who is running 720's with only an AFC to tune them down? I know they should be about at the limits of the AFC but will they surpas the limits?

IMHO, you'll hate life and timing advance with injectors that large using a piggy back to tune... Piggybacks have their place. they work great in their place. If you're going to exploit the fuel flow of those 720s, you'll need more than a piggyback. If you never feel the urge to go that far then you should not have bought them . But, I think everyone gets bit by the boost bug.

 

[98spydert]

IMHO, you'll hate life and timing advance with injectors that large using a piggy back to tune... Piggybacks have their place. they work great in their place. If you're going to exploit the fuel flow of those 720s, you'll need more than a piggyback. If you never feel the urge to go that far then you should not have bought them . But, I think everyone gets bit by the boost bug.

+1

Not to mention the dead time difference will make you hate your car for DD.

 

[GVR4592]

My brother ran 750's with an SAFC for about a year, it idled fine, drove fine, timing advance was too high though with stock fuel pressure. We lowered the base pressure a bit and it was more controllable. I wouldn't reccomend it though, it's a pain in the ass to tune. If it's a 2g or a 1990 1g ecu it would be better because they don't have as much timing advance as the 91-94 cars.

 

[dsm-onster]

My brother ran 750's with an SAFC for about a year, it idled fine, drove fine, timing advance was too high though with stock fuel pressure. We lowered the base pressure a bit and it was more controllable.

It is possible to get a decent idle, i suppose. I got a good idle with my 650s and MAFt. You helped out the timing advance by effectively reducing the folw of the 720s to that of a smaller injector. Therefore, IMHO, there's no reason to get the injectors. EXCEPT if you were planning on going big later . Which your brother probably was. Then, you'd need the injector and be plagued with the timing advance with the piggyback .

If it's a 2g or a 1990 1g ecu it would be better because they don't have as much timing advance as the 91-94 cars.

My 1990 ecu advances timing as much as my 1992 ecu i swap into it (eprom). The 2gs do seam to be more conservative. But, doesn't the higher compression offset that and you're still left with a finicky tune? I may be wrong about that though. I don't know exactly how much the compression difference affects the timing curve yet.

 

[arash15]

i got 720 and im tuning with a safc2. no problems at all. my settings are in the mid-high 20's. timing is at 18 degrees. i still wonder is you get hairly palms from jacking off too much. dont believe everything you hear.

 

[dsm-onster]

i got 720 and im tuning with a safc2. no problems at all. my settings are in the mid-high 20's. timing is at 18 degrees. i still wonder is you get hairly palms from jacking off too much. dont believe everything you hear.

WTF 18 degrees timing is advanced more than stock for a 2g. So it is true. I hope you don't shake my hand. Hairy palms with crust . You get timing advance over stock. You can get things to run very well like that for the most part but the tuning proccess can be twitchy for alot of people.

 

[CanadianTSi]

i got 720 and im tuning with a safc2. no problems at all. my settings are in the mid-high 20's. timing is at 18 degrees. i still wonder is you get hairly palms from jacking off too much. dont believe everything you hear.

Your only taking out -20's with 720's???

I'm at -38 up top with 650's...

 

[arash15]

Your only taking out -20's with 720's???

I'm at -38 up top with 650's...

its a conservative tune, i didnt lean it out to the max. remember i only run 91 octane, plus theres never a cold winter in california, or a winter season period.

 

[CanadianTSi]

plus theres never a cold winter in california, or a winter season period.

Lucky bastard, my cars been parked for the last month and a half

 

[arash15]

my question is what is all this talk about 18 deg peak timing adance being too damn high. Its crazy how people believe to build a fast car with stock characteristics. I guess i have no clue what im doing and my car must be slow.

 

[dsm-onster]

my question is what is all this talk about 18 deg peak timing adance being too damn high. Its crazy how people believe to build a fast car with stock characteristics. I guess i have no clue what im doing and my car must be slow.

Hey, hey. I'm assuming that you were referring to my post. I'm not saying that your car doesn't run strong and is very "streetable". But, you said,

"i still wonder is you get hairly palms from jacking off too much. dont believe everything you hear"​

It came across to me that you were saying not to believe timing gets substancially advanced when compensating 720s with the precentage of their increased size. Afterall, your timing is advanced 2 degrees and you're compensating only 20%. Of course your timing wouldn't be crazy high . If you did not mean to say that timing does not get greatly advanced when you compensate 35% or more, then i am sorry.

This substancial timing advance that becomes apparent forces tuners to walk a very thin line, too thin for the skill level of many.

 

[CanadianTSi]

I hit about 20 degree's at the top of 3rd and 4th which IMO is perfect for pump gas.