Sam Lin

The thing with choosing the MAF is that you cannot choose based on dia. You need to choose based on the MAF's calibrated flow curve, so your usage gives a signal with good resolution.

It may be easier to explain with an example - if you put on a diesel MAF calibrated to go from 100-800cfm, and our engine works in the 50-450cfm range, you'll never pull the MAF to full voltage and will never get a very accurate signal at low RPM.

Sam

Pauerman

The folks at Split Second told me that tuning software for the PSC1 will calibrate the signal according to the size of the MAF sensor.

Vic

Sam Lin

MAF signal massagers can indeed scale MAF output voltage so a mismatched signal output from 0-2.5v for example is scaled to 0-5v for use with engine management. However, that does not solve the MAF's internal resolution issues. If it takes a 5cfm change to change the MAF's output by .01v and the signal massager needs to see that change before it will change its own scaled output, you'll never get 2.5cfm resolution with that MAF. For the best performance you need to pick a decently matched MAF sensor for the application and not rely too heavily on signal massaging.

Sam

John.

I can lend LOTS of advice to this subject. I just finished the tuning on my twin turbo 928 and used a PSC1-009 with a Pro-M MAF. Sam is correct, you want a MAF that is sized basically for the amount of air you want to flow, which is directly proportional to the power you want to make. You want to use as much of the sensor as is possible....in my case I used a Pro-M 75 mm Bullet...after all was said and done I am using it out to about 5 volts....got lucky there for sure!

The PSC1 works quite well, but plan on spending a lot of time tuning. My advice would be to send the AFM to Pro-M and have it bench flowed on their stand and get a calibration curve for it....i.e. volts vs. lbs/hour. Then have them select a meter for the car in question....and flow that. If you have the crude calibration charts, you can then have a good idea of where to start with signal conditioning. The AFM and MAF curves are different in shape....but not totally unlike each other.

The 944 should be an easy one to tune because it is a 5 volt system...my old 928 was more difficult since it is an 8 volt L-Jet. The guy you need to get in touch with at SS is Mark, he can tell you all you need to know. For the money these little things work exceptionally well. I am running a bone stock L-Jet brain with cranked up fuel pressure. The MAF with PSC1 made the car run soooo much better than with the old AFM with a cranked up spring. It dynoed at 366 RWHP and nearly 390 ft-lbs. RW torque on 11-12 lbs of boost.

If you beg and plead Pro-M might be able to make a fully calibrated meter for the 944 turbo without the need for a massager....not sure the curves may be way off to allow this but it might be possible. Pro-M was sure their MAF would not work with the L-Jet because the L-Jet AFM has a reference wire....Mark at Split Second solved my issues totally with a custom PSC1-009....it has a +2.5 volt offset to get the 0-5 volt of the MAF to look like the 0-8 Volt the L-Jet needs. To the best of my knowledge, the Motronic uses a 0-5 volt signal....this is why I think Pro-M can massage the electronics inside the meter to do a direct calibration for the Motronic....it is done on Ford Mustangs all the time.

My car's throttle response is crisp and right on the line like it should be. Not only do you gain the ability to tune the voltage right in, but the MAF is about 10X faster than the AFM is....that is where the instant response comes into play....it isn't about just making more power, but rather about the transient response while getting to that power point. It was money well spent on my 928 project.

Best bet is to have Pro-M get you calibration curves.....then mount the IAT from the AFM into your new MAF sensor. This way you have the same air temp sensor doing the job with the Motronic...no guess work, plus it is cheaper and looks better.

Sam Lin

Great info John, and for the rest of you, it really IS that easy.

Sam

toddk911

John, it osunds like this way is, of course more wprok, but still in the end more money than pre made MAF kits.

Would you be willing to give ball park on what you spent, or give rough idea, what it would cost to go this route for a 951??

Basically, if I am looking at more than a grand to do it all my self, I would rather just get a pre laid out kit for a few hundred dollars more or a nice used kit for less than $1K on ebay.

Sam Lin

Todd, to give you a price idea, I'm estimating materials to cost less than $600 for my project. That does not include tuning time - I have my own wideband so tuning is free for me.

Sam

cas951

This is out of subject a little but I have to ask.

Is there a tuner out there that will make a MAP/MAF kit that will pass the SMOG test as well as the Visual inspection? I live in California and have heard and read too many times that these kits will pass the SMOg test but will not pass the Visual. I thought GURU racing was coming out with one but nothing so far.

Sam Lin

The problem with CA emissions is getting the CARB EO number - besides having a clean-running product (which is pretty easy), you need to pay thousands of dollars in certification fees - that's what keeps a lot of manufacturers from doing it. With demand as low as it is for 944/951 parts, I seriously doubt anyone'd make back their certification money, so don't expect it.

Sam

951carter

The flow of the mustang is on par with the 951. The sensors will work fine. Look at the sensors that come from the tuners........they have the ford emblem sanded off and they slap a sticker over it. Of course you would not want to use one off of a diesel or a 1.8 litre. A blown 2.5 is close to a NA 5.0 in flow, all things being relative.

I get parts at reseller's price so I had about $400 in the first kit I built.

I bought a mandrel bent aluminum intake kit from Pep Boys for a civic and adapted the pipe to work on the 951 on my first kit. I think I had to add 1 connection for the BOV but the rest were already on it. That's about a $1200 savings.

You tune it the same as you would any tuneable MAF kit ( it is the same sensor). The trouble is figuring out which wires to hook up, Ford has crap for literature. I used trial and error the first time.

Pauerman

951 Carter, excellent info man!! Thanks for the input.

jchaley

The Autothority MAF kits have a CARB exemption. I built my MAF kit for the following. New autothority MAF (MAF only) ebay $150.00. Split second PSC1-003 $235.00. Mandrel bent 3" pipe $15.00. K&N cone filter $40.00. The electrical connector (ford) to the MAF came from the junk yard as well as the temperature sensor. You can find performance ford MAFs on ebay for less than $200.00 all the time. I was going to buy a used C&L MAF as they have different sample tube sizes for different HP/Flow levels. There site is here http://www.cnlperformance.com/index.shtml check out the calibration chart. The tuning is going to be the same for any tunable MAF system.

john

johne

On a similar not have any of you checked out the Megasquirt?
http://www.bgsoflex.com/megasquirt.html
It is a $150 build it yourself standalone MAP based EFI controller. I've been thinking about it for a while and am still undecided.

EDIT: Hmm maybe I should start a seperate post and not hijack this thread.

John

toddk911

"EDIT: Hmm maybe I should start a seperate post and not hijack this thread."

No problem at all John. That was my main intent or hope of this thread is there are always many ways to skin a cat. If you have ideas or ways we can get "tuner" performance with out "tuner" prices, great!!!

Of course, no offense to the tuner guys, but in the big picture, the more people pushing the envelope, the farther the cars will go as a whole. Or something someone brings up in here might spark an idea to one of the tuners and push the envelope even farther.

And I am all for someone making a buck off me, just not 2 bucks

Sam Lin

Megasquirt would be a fun one to mess around with it seems - I've heard of it before but this is the first time I finally got some info on it.

For me, I'm down to SMT6, PSC-004, Pro-M custom calibration, SAFC and still doing a lot of research. I may build a Megasquirt for the hell of it and try running my VW Scirocco junk car off it if I have time next summer.

Sam