2g maf 550cc inj no afc

[Fastazzevo]

Can I run a 2g maf with 550cc inj on my 1g without a afc?

 

[blkwidow]

No. You need some sort of tuning device for injectors larger then stock.

 

[kenamond]

No. You need some sort of tuning device for injectors larger then stock.

Apparently, if you use a 2g MAS on a 1g, the Hz signal from the 2g MAS is different (lower than) that of a 1g MAF. So the 1g ECU will "think" it's getting less air than the 1g MAF would have provided, and this offset is just about equivalent to the difference in fuel between the 450 and 550 injectors.

But to the OP, I don't know how close it is. It might be "close enough" or it might be that you'll run a bit rich or lean and that you *should* still have an AFC to fine-tune the difference.

Hopefully someone who knows more about this will respond to the OP's original question (and intent).

 

[Pursuit]

Can I run a 2g maf with 550cc inj on my 1g without a afc?

I already try to put RC 550cc on stock 2G maf with out any tuing it's run but very badly.
If you wanna put big injectors you shoud to take some afc.

 

[snowborder714]

I already try to put RC 550cc on stock 2G maf with out any tuing it's run but very badly.
If you wanna put big injectors you shoud to take some afc.

But you did that in a 2g. The OP wants to do this in a 1g which means the ECU is looking for something different compared to a 2g ECU.

I have also heard about it being iffy when swapping in the 2g MAF (as kenamond stated). The best way to get the answer is to try it and hook up either a wideband O2 or a logger and see how it runs. Worst thing that could happen is it runs rich and you have to swap the injectors again.

 

[Pursuit]

But you did that in a 2g. The OP wants to do this in a 1g which means the ECU is looking for something different compared to a 2g ECU.

I have also heard about it being iffy when swapping in the 2g MAF (as kenamond stated). The best way to get the answer is to try it and hook up either a wideband O2 or a logger and see how it runs. Worst thing that could happen is it runs rich and you have to swap the injectors again.

You are right but the 550cc it's alot bigger from the stock 450cc.
I know he can run with maf-t and 550cc with out safc becouse u use only one knob on my maf-t with rc550cc.
I know it's not perfect tuning but the my car run good and better than stock maf.

 

[xdxoxuxgx]

I've seen that people have run a 2g maf with 550's on a 1g and it should run ok without an afc, though I wouldn't recommend it because you're going to eventually need to tune your car so you might as well get the afc awhile.

 

[kenamond]

You are right but the 550cc it's alot bigger from the stock 450cc.
I know he can run with maf-t and 550cc with out safc becouse u use only one knob on my maf-t with rc550cc.
I know it's not perfect tuning but the my car run good and better than stock maf.

But you do realize that the original poster (OP) has a ***1g*** not a 2g. And the 1g MAF is ***completely different*** than the 2g MAS, right? The airflow signal from the 2g is lower than the 1g. Therefore, the 1g ECU is receiving airflow numbers that indicate that there is less airflow than there actually is. Therefore, it will pulse the injectors for a shorter period of time to get the desired AFR. If you just swapped the MAS, you'd run way lean. But with 550 injectors, they deliver more fuel in the same pulse width than 450 injectors. So if you replace the 1g MAF (on a 1g) with a 2g MAS **and** put 550 injectors in, the lower airflow reading from the 2g MAS causes the ECU to fire the injectors for a shorter period of time, but the larger injectors end up flowing ***nearly*** the correct amount of fuel, so the two errors cancel out, and you get bigger injectors without needing to compensate with AFC or some other piggyback unit. But what the OP was asking was ***if*** the two cancel out "good enough" or if he should still get an AFC to fine tune things so that it *is* good enough.

And to repeat. I don't know if it's "close enough", so don't misinterpret my post to mean that it will or won't be close enough. I was just correcting the folks who misunderstand that he's doing this on a 1g and are telling him he'll run pig rich.

 

[kenamond]

To the OP: Another thing to keep in mind is that the ECU uses the airflow to compute timing advance in addition to fuel. The 2g MAS is telling a lie to the ECU much the same as SAFC does, and this has the side-effect of causing the ECU to reference the wrong load on the timing map, which usually gives you more timing advance. This may cause more knock. Ideally, you'd increase your injector size and then have the ECU just pulse the injectors a smaller percentage of time than the stock injectors, but leave the timing alone. Just an FYI.

 

[Fastazzevo]

thanks for all the help......

I will just try to put the maf in and log and see how it runs.

I got the 550cc in now and it runs, but i can tell in the upper rpm band its just dieing from to much fuel.

 

[dsmsucks]

thanks for all the help......

I will just try to put the maf in and log and see how it runs.

I got the 550cc in now and it runs, but i can tell in the upper rpm band its just dieing from to much fuel.

Two rich isnt good. The car needs to be tuned

 

[c4uldr0n]

If you are trying to make a fast/reliable car, doing this with no tuning *WILL* damage your car. I've been waiting for Defiant or Oldman to come in here and chew you all out! 550cc w/ 2g mas in 1g car will make you run lean w/o tuning.

P.S. A logger or SAFC would help you look @ your o2 voltage to get a better idea.

 

[dsmsucks]

If you are trying to make a fast/reliable car, doing this with no tuning *WILL* damage your car. I've been waiting for Defiant or Oldman to come in here and chew you all out! 550cc w/ 2g mas in 1g car will make you run lean w/o tuning.

P.S. A logger or SAFC would help you look @ your o2 voltage to get a better idea.

Im pretty sure their tired of saying the same thing over and over and over and over and over and over and over and over and over and over and over and over and over......................... o yeah, AND OVER

 

[c4uldr0n]

Im pretty sure their tired of saying the same thing over and over and over and over and over and over and over and over and over and over and over and over and over......................... o yeah, AND OVER

HAHAHA yeah, indeed... you can only say "you need to tune" so many times

Don't try to finish a project without having the proper tools. Sure you can pound nails in with a plumbers wrench but it will look very ugly in the end!

-c4

 

[rrussell]

I have been down this road and it would idle but that's about it. (550cc/min injectors,2g maf on a 93 talon).

It would hit a wall around 4000rpm. Can't remember if it went lean or rich trying to find my logs from then.

I will keep digging, but anyways you will need a SAFC or some type of fuel controller.

[EDIT] Found the log it went big time rich.
2800rpm-11.8 a/f
3400rpm-11.2 a/f
4000rpm-10.7 a/f
4600rpm-10.0 a/f mis fire
5200rpm-9.8 a/f mis fire
5800rpm-9.4 a/f mis fire
6400rpm-9.4 a/f mis fire
7000rpm gave up and let off

This was on a mix of C16 and pump 50/50 mix for saftey reasons. Also the boost was 18psi

 

[eclispestar]

Ya I think you need a SAFC with 550cc injectors and I want to know does anyone know where I could get some 550cc injectors for a good deal.

 

[snowborder714]

does anyone know where I could get some 550cc injectors for a good deal.

http://www.dsmtuners.com/forums/ven...nuary-special-injectors-regulators-pumps.html

 

[Fastazzevo]

If you are trying to make a fast/reliable car, doing this with no tuning *WILL* damage your car. I've been waiting for Defiant or Oldman to come in here and chew you all out! 550cc w/ 2g mas in 1g car will make you run lean w/o tuning.

P.S. A logger or SAFC would help you look @ your o2 voltage to get a better idea.

lean or rich?

if rich, i can put the boost up to lean it out some.

 

[kenamond]

lean or rich?

if rich, i can put the boost up to lean it out some.

From rrussell's log, he was running rich, but your car may be different. And turning up the boost isn't going to help your AFR unless you turn it up so high that you max out those 550s (don't do that!). The MAS will know that you're flowing more air and the ECU will add more fuel, but since the injectors, 2g MAS, and 1g ECU apparently aren't "the perfect cheap injector upgrade mod" that you were hoping, you'll still probably run rich at higher rpm.

Time for SAFC and a logger.

 

[kenamond]

If you are trying to make a fast/reliable car, doing this with no tuning *WILL* damage your car. I've been waiting for Defiant or Oldman to come in here and chew you all out! 550cc w/ 2g mas in 1g car will make you run lean w/o tuning.

P.S. A logger or SAFC would help you look @ your o2 voltage to get a better idea.

The whole point of this thread was that the OP was asking whether or not he could/should do this. The sooner someone would have posted their experiences, the sooner he would've got his answer. I was just here to straighten out those folks who thought he was doing this to a 2g or didn't realize *why* he was even considering this (I like to blab the theory stuff) - I didn't know the answer but wanted to make sure folks knew the question.

 

[steve]

Im pretty sure their tired of saying the same thing over and over and over and over and over and over and over and over and over and over and over and over and over......................... o yeah, AND OVER

Ya, it gets really old.

http://www.dsmtuners.com/forums/tuning-engine-management/241084-2g-maf-1g.html

lean or rich?

if rich, i can put the boost up to lean it out some.

That just shows you don't grasp how the EFI works. Turning up the boost should cause the ECU to see more air and provide more fuel until you run out of fuel from your injectors or fuel pump. Leaning out is then a sign that you have reached the limits and need to turn things down. You can make some adjustment by turning down the fuel pressure but better tuning devices are available.