What did you use for a TPS? I have a late model Chevy one here but it turns the oposite direction is it possible to use the stock S4 or S5 TPS, I have both.

 

the stock S5 wide-range tps is what we're using, and that works fine.

 

Thanks, did you use both pots or just one?

 

We used the wide-range one...

 

So I guess that would be the one closer to thye TB that rides on the cam?

 

yeah, it should be the one that stays in contact with that lobe from 0 throttle to full throttle.

I'm pretty sure the narrow-range one loses contact pretty quick.

 

narrow range loses contact at half throttle I believe.

 

Actually, its like 20-25%.

Is there any reason with Megasquirt to actually use the full-range TPS? I mean, its only used for acceleration enrichment and flood-clear, correct?

 

You can use it for idle advance and several other things... for example you can set up your injector staging to be based on tps instead of rpm. Fuel cut uses it too.

Some of those features don't require a full range though.

Oh, and another function that the TPS can be used for... you can use it to decide when to go open loop (if you're running closed loop, but want to run open loop above a certain throttle position for example).

So it's not REQUIRED that you have a full range I guess... but it's useful.

 

Well, the reason for the question is that I've got 2 RX7's withen the next few months that I want to switch over to Megasquirt...and I just used my only full-range setup. I'd rather just use the crappy stock TPS as opposed to adapting something.

 

Well, idle advance and fuel cut could probably be done with the narrow-range tps, as they are both done when the throttle is just about shut (usually 1-2 raw ADC points above the tps closed raw adc point).

Things like turning off closed loop are usually done with the throttle almost all the way open, but I think those can also be done using MAP instead of TPS.

 

Yes, you can deactivate closed loop based on MAP. I've been running without a TPS at all for quite some time very happily. MAPdot handles AE well and I can flood clear by turning off injector and FP power (though I've never had to).

-Mike