| AFM To Air Flow Sensor |
| Jon 86 745 MS | Has anyone thought about a conversion to a MAS. Jens and I have discussed it several times. I wish there was a EE out there that might help resolve the problem. I would guess that we could pick up at least a 10% HP gain in removing the restrictive AFM.
Comments?
Jon Jacobs
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| Jens | Hey I told u I'm working on it :)
Also did u get me E-mails?
Jens
Sincerely Jens |
| Jon 86 745 MS | Yes I got them. I'm to tired to talk tonight I will talk to you tomorrow. If I don't email you call me at your lunch hour :).
Jon
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| Bob745_Dallas | A couple of years ago I spoke with Split Second about their conversion kits. They said then that they were looking for a 745 to use as a test vehicle (in California). They have a conversion for the 735 but not the 745. Last year, John Stein told me that he had a Split Second unit that did not work so well when he tried it on the 745, but was planning on trying it again in the near future.
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| scottie | I think we could manage this conversion ourselves by using a Porsche unit. We need a "box" that will convert the signal from the P unit into a voltage that the Motronic will understand. This should be easy, but we will need a volumetric sensor to calibrate the test. Sucks too because I had an aftermarket MAF for a Porsche 3 liter turbo motor that I sold last year. This still sounds like a very doable project.
Scottie Sharpe
Sysop
84 745i
85 535i |
| Afshin-Switzerland | Nothing to worry about with my 1982 L-Jet system I guess ?
Soory guys, but I don't underestand your -too high tech to me- discussion....!!!
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| scottie | Afshin,
Like the "flap door" AFM BMW uses, the MAF measures the amount (volume) of air entering the engine. Except that the MAF does this by using a heated wire that changes resistance as it is cooled by the passing air. Because the wire is has less resistance than a spring-loaded door, it is more efficient and lets more air pass by, thus more power.
Scottie Sharpe
Sysop
84 745i
85 535i |
| Jon 86 745 MS | I talked to some of the guys on the Porsche board awhile back. There is a company that makes a conversion to a MAS for the 944 Turbo. None of these guys seem to know that much about their cars. I know the 944 Turbo uses the same Motronic setup we do on the 745. Flap door AFM and all. I also can tell you that a guy named Wilkerson is doing a conversion on the 4 chip Motronic to a single chip. I have no Idea if it would work on our setup. I myself would volunteer to try it on my car but need help doing the electronics (Where are you Jens?).
I hope someone out there will help on this endeavor. We could realize a fair amount of HP gain to get rid of the flap. Not to mention the mechanical failure aspect of the unit.
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| scottie | This is really not a very difficult project, but we will need some items:
1. an MAF sensor
2. Some way to produce and measure a varied air volume in a constant, calibrated way. I would imagine we could produce this with a compressed air system and a regulator, but I don't know if could approach the maximum flow of the CFM. What is the max flow we need to measure 400-500 cubic feet / minute?
3. An electronic means to convert the signal from the MAF to match the output of the AFM at the calibrated flow rate.
Scottie Sharpe
Sysop
84 745i
85 535i |
| Jens | "Guy's"
Listen we r jumping up a tree here ok,
here is what I'm currently doing,
I'm measuring the ins and out at load no
load and so on, from our AFM so that way we have
all the specs in all aspects, then you go and do
a research on an Mass Flow meter, and find one sim,
and then maybe build an electronic conversion box,
to send same info to the motronic.
Does that make sense?
So maybe some of us can get going on understanding the
measuring issues on this, then climb the tree.
Sincerely Jens
Sincerely Jens |
| Jens | Ps.
Scottie that box would be simple to build.
Sincerely Jens |
| Jens | "Guy's"
Listen we r jumping up a tree here ok,
here is what I'm currently doing,
I'm measuring the ins and out at load no
load and so on, from our AFM so that way we have
all the specs in all aspects, then you go and do
a research on an Mass Flow meter, and find one sim,
and then maybe build an electronic conversion box,
to send same info to the motronic.
Does that make sense?
So maybe some of us can get going on understanding the
measuring issues on this, then climb the tree.
Sincerely Jens
Sincerely Jens |
| Afshin-Switzerland | Thanks Scottie, now I can follow.....
Regards,Afshin.
quote:
Afshin,
Like the "flap door" AFM BMW uses, the MAF measures the amount (volume) of air entering the engine. Except that the MAF does this by using a heated wire that changes resistance as it is cooled by the passing air. Because the wire is has less resistance than a spring-loaded door, it is more efficient and lets more air pass by, thus more power.
Scottie Sharpe
Sysop
84 745i
85 535i
|
| Jon 86 745 MS | It would need to be tunable. Meaning some kind if mixture control at idle, midrange, etc. Once Jens measures all of the outputs we can head for the junk yard and find what we need. Like he says we are proably barking up a tree untill we know what we need.
Jon Jacobs
86 745i (Das Rocket)
16 psi+ Boost with
Team WWW.745i.com Performance Parts |