Hi gang, heres my situation...

94 Cobra, Pro-M 77mm MAF housing, with a STOCK (unmodified) sampling unit.

Car runs like shit (surprise, surprise)

I have an EEC tuner, so what I really need is the correct transfer function for this combination. I called Pro-M, and they don't want to flow test it and give me the function. Called C&L (they are local to me), and they didn't want to flow it either....

However, Lee at C&L told me their 76mm unit uses a stock, unmodified sampling unit, so it seems to me as long as I replicate their MAF orientation, their 76mm function should be *almost* just right for my 77mm housing and stock sampling unit. Perhaps it will need a tweak, but it should be much better than it is now...

What do you guys think?

Also, does anyone HAVE the C&L 76mm transfer function?

 

The C+L's i have seen use the stock electronics sensor part, and they use different size tube's the sensor fits in, and thats how they change calibration the lil tube the sensor is in is bigger or smaller.
I'd be surprised if pro-m would not flow it, but they charge 100$

I'd think some1 on the eec tuner sites would know what the stock function is, but i dont think it will work without haveing the meter cal'd for the proper injectors, since the stock function only has so much range, and i'd think you'd need more with a turbo etc.

I am not really sure beause some chip guys say they can make any meter work and others say they can make any meter as long as the injectors are not larger than the meter's cal,
ie they can use a 42lb cal and 24lb inj but not 42lb cal and 50lb inj

 

What injectors the MAF is "calibrated" to is inconsequential in this case.

I have an eec tuner, and I can dial up whatever injectors I want. What I NEED is the transfer function for the MAF, plain and simple. If you punch in the correct function, and then punch in the correct injector size, the EEC has all the info it needs to properly go about its business.

This is not a turbo car, so again, I'm not concerned with turbo-compatible. Not to mention, you can tune around a pegged MAF if you want with WOT fuel multipliers.

The only part that C&L makes, is the actual housing. They do not make sample tubes or pitot tubes, so any 76mm ID "housing" will work.

 

looks like the C+L use's sample tubes to me

http://www.mustangwarehouse.com/mustang_1.mvc?c=CL

 

I'll be damned... I stand corrected!

Alrighty... Now I'm curious if someone can measure their C&L 76mm MAF sample tube and give me a diameter and length, and how far back the sampler is inserted... Its not going to matter what injector calibration you have, because I can work it using the injector slopes.

That way, I'll be able to get *damn close* on the transfer function, and 99% of my tuning will be done.

Anyone able to help me?

 

Why not try using a data flow sheet from a 75mm Pro-M? It may get it close and you can tune the remainder of the curve, with the Excel Program by Paul Booth..

http://www.allfordmustangs.com/techarticles/Decoding_the_Pro-M_calibration_sheet.doc

http://www.superstang.com/maf.htm

 

Because, I'm pretty sure that Pro-M alters the sampling unit itself to get the output response they want. So, their function only applies to their altered samplers... Unless I'm wrong about that. Lee Bender at C&L told me this.

 

If thats true, who is gonna have the info for your particular setup?

Like twinturbostrkr said i would get it close then alter from there, that is what the eec tuner is for from my understanding, i dont know any1 who has just entered the pro m transfer function points and just left it alone

 

Actually it's C&L that alters the sample via a calibration tube.

Yes Pro-M tailors the electronics by measuring the aggregate air flow over a given amount of time, although you have the ability to alter that curve with your EEC-Tuner, all 30 points of it, which is exactly what Pro-M does, but they only use 11 flow points and extrapolate the rest.

 

Yes, we're on the same page. When I wrote that last post, I was saying that Pro-M actually changes the electronics portion of the sampling unit. Sorry if I wasn't clear.

Anyway, I guess what I'm trying to do is simply skip the paying of the $170 for a new MAF. Seems to me that I can make myself a 76mm aluminum housing with a bell mouth entrance, a sample tube the correct diameter, and use a C&L function... Seems like it would work perfect, and cost less than $170.

 

You certainly can do this, provided a few things are taken into account. I did not see mention of what injectors you are running, the sampling tube should match the injectors otherwise you need to scale your displacement and injector size after installing the transfer function of the meter with the tube you are running. This brings about the next issue because C&L does not offer the transfer function for the meter and all of the sampling tube options. The easiest way for you to go about this is to call Lee back and ask him for a copy of the transfer functions he does have for the 76mm unit and matching sampling tubes then go from there. Getting the specs of the sampling tube at that point should not be much of an issue.
For what its worth however, you can usually pick up a 76 used with sampling tube for around 100 bucks, consider if your time is worth that to make one.

Paul

 

You bring up some good points...

Yes, the injector size the sample tube is intended for isn't much of an issue....as long as I *know* which they are. I can, as you mentioned, scale my injector size with my tuner to accomodate.

Also, for $100, it would hardly be worth machining my own...However, I'm curious if someone selling one used would have the TF for it... Most people aren't into that side of things.

I'll look into it though!

 

Buy a univer and be done with it. I tried tuning a 75mm bullet cal'd for 42's for 2 years and couldn't get any driveability or idle out of it so I just bought a univer. With no changes whatsoever, I bolted it on with a rock steady 14-15 AFR idle. Driveability rocks with it too not to mention WOT.

 

Most people will not have the transfer function for the C&L, however I do know Lee Bender will supply you with any transfer function he has on file, one of which is for a 76mm with red tube. If you are interested in a used 80mm with tube and transfer function, drop me a line.

Paul
562-307-5959

 

Can't you write your own xfer function?
I am not too famaliar with your tuning software but the stuff we use allows us to completely write our own. Any meter/Any injector
Using a wideband and a scan tool should tell you how far off your fuel is.

 

Here's a list of Pro-M's flow numbers for various injector sizes.

What injectors is your meter calibrated for and what injectors are you trying to run?

I'd highly recommend matching the two before tuning, or you're sure to run into headaches. I also hate having to rely on the eec-tuner like that, as it can take a shit at anytime and leave you stranded. Unless you want to carry your laptop with you everywhere.

Also, don't try and run bigger injectors than the MAF is calibrated for, you'll max out the voltage and run lean on the top end.

 

C&L's are made to work as a ratio to stock. So a transfer curve for a 36 # can be had by dividing 36/19 and multiply by each value by this. Then tweek the injector slopes and you are done.

Through some very complex division you can even get a 30# tube meter work with 42 # injectors! Wow

What's the big deal?

 

You wouldn't want to do that though. The 30# meter will max out too soon.

 

Yep, I know. All that ends up happening is that if you tune the WOT curves to work with the smaller maxed meter, the part throttle high load region between where the meter gets maxed and "actual" WOT is too rich....

 

I don't follow.
There isn't a WOT fuel curve, at least not in an A9L. It's a multiplier. There's not much you can do about maxing out a meter short of using an FMU.