2gMAF on 1g, SAFC?

[xhaust50]

Mods are in profile, but important ones are 550 Injectors, 2g MAF and Big 16g. I bought the car with all of the work done already, and it runs very strong and gets 24mpg mostly city so I know it is tuned pretty well. Anyway, the SAFC on low throttle is all up 11%, and on hi-throttle starts at +4% and gradually increases to +12% by 6000 rpms. It seems everyone on here is subtracting fuel, which makes sense. But the car seems to run very well, and I bought it from a moderator on a DSM forum.

I read on these forums that a 2GMAF flows about 20% more than a 1g, so that when used on the SAFC you should add +20 across the board. Is this correct? It seems to make sense, then my car would be at -12% if I had a 1gMAF.

Although the car has run very strong for the last 8 months I just got a logger for x-mas so I want to fully understand this before doing any readings and trying to alter anything. Thanks.

 

[timloomis]

The 2g mas and 550's are *supposed* to cancel eachother out.So adding a 2g mas and 550s to a 1g car can be done without an afc.You dont need to compensate for the 550s with that mas in your car.

 

[dsmsucks]

WRONG!!!!!!!!!!!!!!!

I have the same set up. U will need a safc and a logger to see whats Really going on with the engine!!!

 

[DJ23GSX]

I too have a 2g maf in my 1g with 560's and a small 16g and my safc settings are almost identical to yours. Mine was tuned for 20psi and 0 knock. Every car is different so you gotta keep an eye on the logger to make sure everything is in check.

 

[xhaust50]

Thanks for the replies. I'm not sure if the first two people read my entire thread, I have an SAFC already, and it has been on these settings since I have had the car, for about 9 months. I just wanted to make sure this seemed reasonable since I am just getting a datalogger to learn more about the engine. Car runs extremely strong as it is though. Merry Christmas.

 

[timloomis]

Yes I read your entire post and no I am not "WRONG!!".An afc is ideal to tune it perfectly,and people have been using 2g mas and 550s for years without an afc with success.Not saying its the right way to go,but it works.Just look at your datalogger and see what your car is telling you.Just like what was said,every car is different,all 550s dont flow the same,and all 2g mas' dont flow exactly 20% more.

 

[oldman]

Yes I read your entire post and no I am not "WRONG!!".An afc is ideal to tune it perfectly,and people have been using 2g mas and 550s for years without an afc with success.Not saying its the right way to go,but it works.Just look at your datalogger and see what your car is telling you.Just like what was said,every car is different,all 550s dont flow the same,and all 2g mas' dont flow exactly 20% more.

Not exactly, anyone who says a 2g mas and 550cc cancel each other out is probably not logging. A 2G mas flows up to about 33% more than a 1g maf where as 550s flows about 22% more than 450s, OP's settings are right in the ball park. Can you run them without tuning capacity? Sure, but how well is the question.

 

[xhaust50]

No need for arguments, my post didn't mean to be argumentative. It's just someone was saying I will need a SAFC and a datalogger when I already have them. I see what you are saying about nearly cancelling each other out, but the main thing I was concerned about was if the 2g MAS doesn't effect the SAFC my settings would seem way off. Just checking to make sure my tune sounded reasonable so I can go on from here. Thanks.

 

[oldman]

I don't understand the point of your post. You asked a questions and got two different answers, if we don't disagree, how would you know which is true?

timloomis is implying that your tune is off because the two components should cancel each other because he was under the impression that both the 2g mas and 550s flow 20% more than stock which is not true. Should we just not address it and let you and other readers in the future to take it as it's true?

 

[xhaust50]

I don't understand the point of your post. You asked a questions and got two different answers, if we don't disagree, how would you know which is true?

timloomis is implying that your tune is off because the two components should cancel each other because he was under the impression that both the 2g mas and 550s flow 20% more than stock which is not true. Should we just not address it and let you and other readers in the future to take it as it's true?

Well I think if you wanted to continue the argument between your 33% and his 20% to get a consensus feel free. However, I wanted to confirm that my settings on the SAFC, which seem in general 20-35% higher than people with the same combo but with the 1g MAS, are in the ballpark. I was initially concerned because my numbers were positive when those with the same combo with a 1g MAS were negative, but my numbers seem to be somewhat accurate with your arguments. Thanks for the info. Time to start datalogging for myself.

 

[oldman]

You're welcome. As for consensus, I wasn't looking for any, think of it as fact checking, I came to your thread in response to someone hitting the "report mis-information" button.

 

[JayRolla]

Just to add to the post, when I ran 550's and 2g maf no safc, I would see knock at any boost level. As soon as I hit 1-2psi. One log at 9psi netted 30+ counts of knock.

 

[xhaust50]

Just to add to the post, when I ran 550's and 2g maf no safc, I would see knock at any boost level. As soon as I hit 1-2psi. One log at 9psi netted 30+ counts of knock.

That seems to support Oldman's theory of the 2g MAS flowing more than the 550's (as does my SAFC settings). Maybe there is a consensus.

 

[bfdahl]

I have the same setup as you, I started with 550s and am now on 660s.

My settings have always fluctuated if I added or subtracted honeycombs in the mas or if i found a boost leak.

so when you get your logger and start to tune it your way, check out the fuel trims and see for yourself how accurate you current tune realy is.

it may be spot on or really out of whack, which is what you were thinking when you started the thread.