ALFAGTV6.COM

x-rad · Post by **x-rad** » Wed Dec 07, 2005 2:03 pm

Three QUESTIONS:

For a 3.0(non Verde, normal interal parts, headers, etc..):

1) Has anyone every found an air flow sensor ( the round tube with a heated wire in it) that puts out a resistance similar to the L-jet air mass sensor, and the associated electronics to make the conversion while keeping the L-jet?

2) I have also looked at BMW 30, 33, and 35 engine size Bosch flappers from the late 1980's. Looks like similar set up, plug and start, anyone used one?

3)I think this change think will make a difference in air flow at higher RPM's, but have any of you done this swap and noticed a change?

Post by **Zamani** » Wed Dec 07, 2005 2:12 pm

You need to build a lookup table if you intend to use a hot wire AFM so the voltage vs. air flow curve is properly understood by the ECU. I believe since the hot wire is resistance based the curve is linear. The flapper ones, probably non linear....

You can use UNICHIP. The problem is UNICHIP is not cheap...it should be called UN-CHEAP. May as well get a megasquirt to run the injectors.

DaveH · Post by **DaveH** » Thu Dec 08, 2005 6:48 am

I just did a bit of research into programmable analog amplifiers. To accomplish this task, you're looking at the best part of $400, on top of the cost of the hot-wire AFM. That's a lot of dough.

It could also be done with a PLC that has an analog card with 0-10 in and 0-10 out ($112 + $149). Although I'm not sure what the Vmax signal the AFM pot sends to the ECU is. As you mentioned Zamani, look up tables would be the way to program this. Check out this: http://web4.automationdirect.com/adc/Sh ... /D0-05DD-D

The $99 software is what you need to program the PLC. It uses ladder language, which is not so difficult; if you can understand a wiring diagram, you're 1/2 way there. Well, maybe 1/3.

A-D PLCs are small, but just a bit big for automotive apps. Still though, it could fit out of the way in a plastic box on the RH inner fender...

DaveH · Post by **DaveH** » Thu Dec 08, 2005 9:09 am

Good article: http://www.autoshop101.com/forms/h34.pdf

Note the part about the signal to keep the fuel pump running. On our Alfas, I beleive it goes to the combo relay. So it is not just a case of dropping in a programmable amplifier/converter; you need an aux output to replace the AFM switch.

Go Gotech, IMO.

x-rad · Post by **x-rad** » Fri Dec 09, 2005 4:42 am

Thanks for the suggestions! I looked into PLC's. Many different kinds, sizes, prices...etc. I could figure out the programming by the voltage tables (if I had them, I don't even know if the flapper pot shows increased or decreased voltage with increased air flow). Fuel pump switch could probably run off a "minimum voltage" type circuit if I could get an output from the PLC. Hard part would be compensating for ambient temperature changes.

Anybody use the bigger BMW flapper?

I think it would be easier just to get a new HALTECH unit.

Greg Gordon · Post by **Greg Gordon** » Fri Dec 09, 2005 6:28 am

I have looked into the hot wire sensor thing extensively. It's just not worth it. It's less expensive to go with Gotech, and a lot more effective.

DaveH · Post by **DaveH** » Fri Dec 09, 2005 6:32 am

No prob getting an aux o/p from the PLC for the FP.

Even ambient air could be compensated for with a thermocouple wired to an analog input.

Here's the prob I see: You can draw up your air flow curve based on sampling points on the flow/voltage curve the AFM outputs. Then you could program the exact curve into your MAP based system. So far so good. Then you go ahead and remove the AFM flap. The intake's flow/friction characteristics just drastically changed. So is your sampled curve any good now?

Perhaps the O2 sensor can make up for a small amount of error that may be inherent here.

Gotech sounds really, really good to me at this point. I have been involved with 1 GT installation, mostly from the sidelines. It really is a very cool system and not so difficult to implement.

x-rad · Post by **x-rad** » Fri Dec 09, 2005 4:30 pm

Checked out posts by 'ar4me' and Gotech(or Haltech) seems like the way to go. Just need to save some dough......
What do you guys use for a crank position sensor?

Post by **Zamani** » Fri Dec 09, 2005 9:42 pm

You don't have to go with GoTech. Megasquirt is a lot cheaper if you can DIY. At this point it seems that all you want to do is to get rid of the AFM, a basic Megasquirt unit is all you need. Shouldn't cost more than $350 or so.

ar4me · Post by **ar4me** » Sat Dec 10, 2005 6:35 am

x-rad,
For a "GoTech Standard" install on a 12v V6 you don't need a crank angle sensor. If you go with "GoTech Pro" and coil packs, then you will need the crank angle sensor. My 3 liter milano runs GoTech Standard. But yes, it will cost more than the cost quoted by Zamani above, but also give you a fully programmable system, fuel and ignition - not sure the $350 MS does that, maybe?
Jes

x-rad · Post by **x-rad** » Tue Dec 13, 2005 8:02 pm

Thanks Guys!
How does the GoTech standard determine engine speed? From tach output? Is that accurate enough? How does it know TDC? Also, waste spark required?

Do you know if it has 'true' sequential injection (each injector in turn...for a six pack?)

I looked over the GoTech website already....

ar4me · Post by **ar4me** » Tue Dec 13, 2005 8:34 pm

In order, to the best of my knowledge:
- Engine speed from Hall sensor on distributor (on milano) - think distrbutor on some GTV6s is different. Switching to Milano style may make life simpler.
- With GoTech Standard you still have your distributor, which you lock, but it contributes to timing. After that everything is set with GoTech.
- I believe GoTech Standard fires all injectors at once - not sequential. I imagine more advanced GoTech products feature sequential firing.

Hope that helps,
Jes

Post by **Zamani** » Wed Dec 14, 2005 12:40 am

Autronic has true sequential

That's why you need crank angle sensor and a cam angle sensor.

Anyway it's a nice novelty and good for emissions. Otherwise don't worry about sequential injection.

If you want a complete system, I would go GoTech. If you can DIY a little, go for Megasquirt which can do both ignition and fuel.

x-rad · Post by **x-rad** » Wed Dec 14, 2005 2:21 pm

I figured that at high rpm's, sequential does not matter that much anyway. I do have the hall effect dizzy. Sounds like a pretty straight install. Now, to save up some more dough........
Thanks for the info!

Marqui · Post by **Marqui** » Wed Jan 11, 2006 6:12 pm

Que pasa people!

Hey X-Rad, Hope I am not 2 late but here it goes. Check this site; www.splitsecond.com, they have a MAF sensor installed on a milano. It's kind of expensive, but it looks like a strait foward instalation without losing the L-Jetronics.

By the way, SDS by Racetech (www.sdsefi.com) has a fuel management system that uses a hand held programer that you can program without a lap-top.

Marqui

Air flow meter