apexi safc

[danval]

Hey u guys.. anybody using the apexi super air flow converter with their turbo setup? Need some feedback. Thanks

[Q5Quint]

If this is it... then we would have a hard time using it as we don't have knock sensors stock.

I am also unsure if our ancient bmw air flapper has a frequency signal it puts out, which is what the apexi unit uses to trick your ecu into dumping more fuel.

http://www.apexi-usa.com/manuals/electronics/safc2_wiring.pdf

For nearly the same price you can build yourself a megasquirt, and actually tune your spark timing which is slightly important when you are in boost. This apexi unit, or even a chip, will have no way to know if you are actually boosting or not, because the stock sensor only sense air flow and not pressure like a MAP sensor does.

After reading this it seems that this unit was designed for ECU's that have a built in fuel cut based on stock injector size. By tricking the ecu with bigger injectors and this unit to make the ecu think there is less air flow than reality, you can get your bigger injectors to run properly under partial throttle, and under WOT you will have some extra badly tuned extra fueling for boost. I say badly tuned because the computer doesn't actually know if the boost is 0 or 30psi, it only knows the maf is open to 100% flow.

http://www.roadraceengineering.com/newafc.htm

Fuel Cut

It's a nice cool night out and your Eclipse was running better than ever. You were boosting a little higher than you normally do and BAM, the motor shuts off hard and there is a backfire. You ease back into the throttle thinking you just blew up something big. The car seems to run fine. Welcome to Fuel Cut.
You were just flowing more air through the MAS than the ECU was programmed to deal with.

There are several possible solutions to fuel cut. The dime store FCD works fairly well but is potentially dangerous and doesn't net consistent results. It doesn't really solve the problem but is a partial workaround. The next solution is to get the Fuel Cut removed from the ECU altogether via someone like Keydiver. This definitely does the trick but still doesn't really solve the underlying problem of running lean. Ideally you should install larger injectors and a fuel computer of some kind, like the AFC.

Fuel cut is caused by the ECU seeing a large airflow value from the MAF which works out to roughly 100% duty cycle on the stock injectors. If you install 550cc injectors which are 18% bigger than the stock injectors, then adjust the AFC to compensate for the larger injectors, you won't hit fuel cut until you
make up that 18% airflow buffer. Ideally you should get the injectors, AFC and the Technomotive ECU mods. This gives you safe, consistent fuel and allows you to run ridiculous boost levels without running too low on fuel or hitting fuel cut.

Also an EGT is generally a good idea once you start running high boost levels or hitting fuel cut. The ECU thinks you are getting close to maxing out your fuel system, and the EGT can tell you for sure. It is an expensive item, but cheaper than an engine. Just get the GReddy electronic gauge and mount it in the #1 or #2 exhaust runner. You will also need it to tune the car properly with a fuel computer.

It seems like a neat idea for certain vehicle ecus..... but for our ancient bmws there are better solutions.

We also dont have the fuel cut problem. We just adjust our stock afm for #24lb injectors, use a rising rate fpr... and tada! Now you have extra fuel under boost, with no fancy rice burning computer needed. Add a chip with a turbo tune (retarded timing at higher rpms) and horay, maybe your engine wont explode! And you didn't even have to actually tune anything!

Of course all that costs about as much as a megasquirt, so there is that too.

Apexi thing- $200 used and like $450 new. What the fack?

RRFPR (Fuel): $150
Turbo Chip (Spark/timing): $150

Megasquirt: $150 (used old version) up to $700 (plug and play/drive off)

Dude.... don't be tricked by these fools. You will have to actually do some work but for about the same $$ you can get a real timing and fuel table tuning computer.

I found this site but it said if you go over 4.7 volts on the maf.... so I dont think the safc could even read/intercept the signal if it is voltage instead of frequency based. Which means no, you cant use the safc at all, unless you do a maf conversion like some do. example: http://www.track-tv.co.za/forum/viewtopic.php?f=10&t=26

[danval]

If this is it... then we would have a hard time using it as we don't have knock sensors stock.

I am also unsure if our ancient bmw air flapper has a frequency signal it puts out, which is what the apexi unit uses to trick your ecu into dumping more fuel.

http://www.apexi-usa.com/manuals/electronics/safc2_wiring.pdf

For nearly the same price you can build yourself a megasquirt, and actually tune your spark timing which is slightly important when you are in boost. This apexi unit, or even a chip, will have no way to know if you are actually boosting or not, because the stock sensor only sense air flow and not pressure like a MAP sensor does.

After reading this it seems that this unit was designed for ECU's that have a built in fuel cut based on stock injector size. By tricking the ecu with bigger injectors and this unit to make the ecu think there is less air flow than reality, you can get your bigger injectors to run properly under partial throttle, and under WOT you will have some extra badly tuned extra fueling for boost. I say badly tuned because the computer doesn't actually know if the boost is 0 or 30psi, it only knows the maf is open to 100% flow.

http://www.roadraceengineering.com/newafc.htmwow! Lots of great info! I modified my fuel rail already. Im going to run an aeromotive 1:1 boost reference ratio for fuel. Im going after the chip too. I already have the apexi just sitting there. Guess ill have to sell it! Lol thanks for your imput man! Lot of good info






It seems like a neat idea for certain vehicle ecus..... but for our ancient bmws there are better solutions.

We also dont have the fuel cut problem. We just adjust our stock afm for #24lb injectors, use a rising rate fpr... and tada! Now you have extra fuel under boost, with no fancy rice burning computer needed. Add a chip with a turbo tune (retarded timing at higher rpms) and horay, maybe your engine wont explode! And you didn't even have to actually tune anything!

Of course all that costs about as much as a megasquirt, so there is that too.

Apexi thing- $200 used and like $450 new. What the fack?

RRFPR (Fuel): $150
Turbo Chip (Spark/timing): $150

Megasquirt: $150 (used old version) up to $700 (plug and play/drive off)

Dude.... don't be tricked by these fools. You will have to actually do some work but for about the same $$ you can get a real timing and fuel table tuning computer.

I found this site but it said if you go over 4.7 volts on the maf.... so I dont think the safc could even read/intercept the signal if it is voltage instead of frequency based. Which means no, you cant use the safc at all, unless you do a maf conversion like some do. example: http://www.track-tv.co.za/forum/viewtopic.php?f=10&t=26

[sayed ali]

^ +1

However, I've used one on my m20, and it was on a custom wiring harness, it was good enough! if you have m50 engine you can use it with the stock wiring.. but sure after a while you'll shift to a standalone like what i did and everybody do, so DO IT WELL or DON'T

[danval]

Thanks a lot gentlemen! Great info!

[Q5Quint]

I have a rrfpr I could sell you- I am so tangled up in megasquirt love that I dont think I could do even a low boost rrfpr/chip setup.

If you are planning for over 10psi... ie maxing out injector size on the stock ecu setup.... you will want to go for megasquirt.

If you want to keep the stock clutch, max 10psi around 250hp, the rrfpr + chip setup will work fine.

TCD is getting a solid 100hp increase over stock with 10psi, the rrfpr, and a chip. He has a stage 2 kit that supposedly goes to 170 which is amazing with the rrfpr.... but look at his video page. Almost every stage 2 kit uses megasquirt. The chip will be fine for wot and preventing exploding...but under partial loads off boost your timing will be way way retarded leading to poor off boost performance and higher egts.

Dyno: http://www.youtube.com/watch?v=jSRmGHiYeTo

And video link from TCD:

http://turbochargingdynamics.com/?page_id=77

Notice how almost all of them use megasquirt?

Decide if you want 100hp and limit yourself to the stock clutch... or 150+hp and a new clutch. the rrfpr and chip works for the lower boosted setups which are still lots of fun.... but anymore than that and you will want to go with the squirt. The squirt will get you more power and more safety/control off boost as well.

[danval]

I have a rrfpr I could sell you- I am so tangled up in megasquirt love that I dont think I could do even a low boost rrfpr/chip setup.

If you are planning for over 10psi... ie maxing out injector size on the stock ecu setup.... you will want to go for megasquirt.

If you want to keep the stock clutch, max 10psi around 250hp, the rrfpr + chip setup will work fine.

TCD is getting a solid 100hp increase over stock with 10psi, the rrfpr, and a chip. He has a stage 2 kit that supposedly goes to 170 which is amazing with the rrfpr.... but look at his video page. Almost every stage 2 kit uses megasquirt. The chip will be fine for wot and preventing exploding...but under partial loads off boost your timing will be way way retarded leading to poor off boost performance and higher egts.

Dyno: http://www.youtube.com/watch?v=jSRmGHiYeTo

And video link from TCD:

http://turbochargingdynamics.com/?page_id=77

Notice how almost all of them use megasquirt?

Decide if you want 100hp and limit yourself to the stock clutch... or 150+hp and a new clutch. the rrfpr and chip works for the lower boosted setups which are still lots of fun.... but anymore than that and you will want to go with the squirt. The squirt will get you more power and more safety/control off boost as well.

Thanks for the info and offer. I actually have an aeromotive boost sensitive fpr. And im going with 10 psi only. Its my daily driver. Perhaps ill leave the megasquirt to my 5.0 swap e30. This m20 is going on my daily e12