BC

The early L-jet throttle bodies pose a challenge. The Spring area where the cable goes is full of stuff. No real place to put a TPS with full motion. The other side is capped off. I propose that I will take it apart (duh!)... And then while I am getting a larger plate put in, I will also put a LONGER shaft in, and have it go out the other side, to attach the end to a TPS sensor.

On the pulley - that large rounded off area between the 2 V's colin, - is very thick. I had a machinist machine that area flat for an 1/8 inch wheel. It seemed the best place without sacrificing AC. I need it here.

plastex

The good thing with MS is that you don't have to use a TPS. when I did my 76' 911 that had the CIS it just used the MAP as the signal because the car didn't have the TPS.

Oscar

BC

Isn't that called "Alpha N"? And its not so exact?

Lizard928

Another reason why on the early 16V (read non LH) to convert to a throttle body off the rear of the center plenum.

And Brendan is correct, it requires more work to get it to run 100% and it isnt nearly as precise.

plastex

Here is link to my old 911 that I am talking about.

http://www.bitzracing.com/gallery/Os...ith_turbo.html

Oscar

plastex

Yeah, it's not too exact but you can't tell when you are driving it. The Map changes almost as fast as the TPS would. It might not be the "best" way to do it, but it works.

Oscar

BC

Do you think that the rear throttle body would make it different in the air delivery? I was thinking of doing that, - I think an LS motor Throttle body would work on the back side. How would one weld such old aluminum and have it work?

I was thinking the regular throttle body, enlarged and with a longer butterfly shaft would be the best bet.

Lizard928

Brendan, there was pics of a 928 that had that done to his and it worked fine.
As to the welding to the old metal, I have never had an issue. Just use alot of heat, and if you are really having issues then you could always put it in the over around 400 for awhile to outgas it. But I doubt you would have that much of an issue.
The initial contact would have abit of contamination but the heat would burn it clean for the rest and you simply go over that area again.

BC

Do you think its worth it over the 70mm throttle body for a 4.5L

On Topic for Megasquirt: People can use Chevy Corvette/Truck/whatever LS2 coils for each cylinder and wire it 4x2 - 4 logic-level (not a full 12 signal - cleaner, safer, better for interference) outputs running two coils each. They coils are 20 bucks (8x20 - 160) and the pigtails are about 75:

Coil

Pigtail

Lizard928

On a 4.5L the 70mm throttle body may be enough, but alittle larger wont hurt, it may just make the bottom end more sensitive to throttle and you may not see any gains past 90% throttle (which is how I would like it anyway.

hacker-pschorr

There is nothing wrong with using a new TB welded to the plenum. For simplicity sake, why not use an 84/85 euro or 85/86 TB with the TPS already installed?

BC

Extra cost. I can get the TB enlarged pretty cheaply. Trying to save budget for other things.

Lizard928

Simplicity and cost never seem to coincide with each other.

All TPS on the 928s (LH cars) are simply switches, not true TPS with varying resistance with the moving of the butterfly.

toofast928

Great job Colin! best thread read in a long time.

What about the cold start injector? Just make it stand alone or is MS able to start the engine without it?

Any benifit to using MAF? Or does the MAF logic of Megasquirt follow the same fuel map as a MAP sensor.

Thanks for your efforts.

Tony

Lizard928

Tony, I have tried to call you a few times this morning

With MS there is no need for a cold start injector as that is all controlled electronically.