anyone want to talk air flow and AFMs for FI

[davegt27]

Background:
OK working on a little project its supposed to be a fun little project to put quad Toyota 20V TB's on my MR2

if it works i want to adapt the same setup for the Opel

the Goal is to replace the stock FI intake manifold with a quad TB setup, but run it with the stock type ECU (AFM L-Jetronic)

The reason I like the Toyota 20 TBs is one cost (around $200 to $250). Two these little babies are independent meaning each TB has its own spring so you could space them out and get them directly over the intake port.

here are some adapted to a MR2 91 to 95 3SG (2.0) motor.

http://opelgt.com/photos/data/500/1140713sgtbset.jpg

[davegt27]

OK that is some what of a backround

oh a little more back round these Toyota TB's in there stock form are used with a L-jet FI system and have a factory airbox to inclose the inlets of the TB's

pretty neat for a factory setup. anyway on to the problem

I am just finishing up on the first Air box I have a choice of different AFMs I can use.

what i am pounding my head against the wall about is the air intake opening to the air box. i am wondering what effect it will have on the flapper of the AFM

Its an assumption that the TB's will make the intake port velocity go down so there wont be as big a draw on the air flow meter flapper?

But if I put a smaller say 2" inlet on the Air box (call it an orifice plate if you like) maybe the AFM will have a greater movement of the flapper?

any thoughts
thanks

disclaimer
this is a fun project kinda like getting your car to pass emissions without a CAT (i spent more money getting it to pass then the cost of a CAT)

Davegt27

[namba209]

Dave, if you were to emulate the air inlet to the air box the same size as the AFM you want to use, the air flow on the flapper plate should be the same as in the stock configuration, if the engine size is fairly close. Another option is to have the TB throttle plate(s) give the opening degree signal to the ECU vice the flapper plate. That is put the potentiometer from the flapper plate on the TB throttle shaft. My V-6 has that type of input to the computer. Just a couple of suggestions.

[davegt27]

thanks namba209 that might be an idea do you know if your V6 also has a MAP sensor




Davegt27

[Travis]

Attaching a TPS sensor to the AFM input isn't going to work properly as the two sensors indicate completely different things, and the computer has no way of knowing this.

Dave, why are you not just installing a megasquirt?

-Travis

[davegt27]

i have a megasquirt all built up and i might end up using it

its pretty application specific by the way and needs certain mods to the mother board for the opel (something to do with points if i remember right not a big deal)

but this is more fun

i am thinking of going with smaller injectors but use a higher fuel pressure. the reason i am thinking this is a quad TB setup has a lot less port velocity flow at initial throttle opening but the wot flow tons more

i learn alot more doing stuff like this

davegt27

[namba209]

Dave there are I think 48 inputs to the engine computer on the V-6 and MAP is one of them. Because I'm not too swooft on the L-Jetronic system, I don't know if it has a TPS or not. Using the flapper plate on the intake, I am guessing would be similar to a MAF sensor, but again, I'm not sure.

[baz]

dave the flapper box is a horror for airflow can you not change it to a hotwire one and enjoy the power the tbs will free up
autospeed an australian mag did a load of this kind of stuff but its now pay to view last year you could read the archive for free

[RallyBob]

Dave, you should definitely get rid of the AFM and go with stand-alone ECU. You'll have those beautiful individual TB's on there and no way to control fueling accurately at higher rpms with L-Jetronic.

[Hiro]

Originally Posted by davegt27 Background: OK working on a little project its supposed to be a fun little project to put quad Toyota 20V TB's on my MR2 if it works i want to adapt the same setup for the Opel the Goal is to replace the stock FI intake manifold with a quad TB setup, but run it with the stock type ECU (AFM L-Jetronic) The reason I like the Toyota 20 TBs is one cost (around $200 to $250). Two these little babies are independent meaning each TB has its own spring so you could space them out and get them directly over the intake port. here are some adapted to a MR2 91 to 95 3SG (2.0) motor. http://opelgt.com/photos/data/500/1140713sgtbset.jpg

Very nice TB!
What is the ID?
Hiro

[davegt27]

sent this answer to a Friend last week

there are two different size AE101 TB's
the one in my hand 47.35 input 43.0 (out) at the manifold
the other AE101s are slightly smaller

the AE111 TB's are 2 mm larger then the bigger silvertop (AE101) so 45mm out


What are the bore of the 101 vs. the 111 TBs?


Dasvegt27

[Hiro]

Originally Posted by davegt27 sent this answer to a Friend last week there are two different size AE101 TB's the one in my hand 47.35 input 43.0 (out) at the manifold the other AE101s are slightly smaller the AE111 TB's are 2 mm larger then the bigger silvertop (AE101) so 45mm out What are the bore of the 101 vs. the 111 TBs? Dasvegt27

Thanks for the details Dave,
It's worth trying for my 2.5CIH
Hiro