alternative TPS options

[WankelsRevenge]

I was curious if there are any easily adaptable TPS setups for a S4 N/A motor out there. I'm looking for something to replace the stock system that's more accurate. I'm already running a stand alone ECU so tuning won't be an issue.

[Pete_89T2]

What exactly are you trying to achieve by replacing the stock TPS? Since you said S4, I'm going assume you have the stock S4 TPS & throttle body which lacks a "full range" TPS sensor (i.e., it doesn't measure throttle position from fully closed to WOT), and you need a "full range" TPS for your stand alone ECU?

IF that's the case, you can probably find a used S5 throttle body and S5 TPS sensor and swap in the necessary parts. In addition to having the same partial range TPS sensor as the S4, the S5 TPS adds a 2nd full range TPS sensor to the TPS assembly to support the electronic OMP. Just use that one to support your ECU.

As you probably know, all the FC's used a linear potentiometer (variable resistor) as its TPS. The 3rd gen (and just about everything else these days) use rotary potentiometers that rotate directly with the throttle shaft or thru some sort of geared arrangement. Adapting one of those to work with an FC throttle body would take some serious fabrication effort.

[WankelsRevenge]

Any idea if I can just mount the full range TPS off the S5 on the stock location of a S4 throttle body? Dont want to have to swap out throttle bodies if I dont really need to.

[TitaniumTT]

Throttle bodies are a bolt on affair, that's would I would do.... I've never tried it but knowing the difference between the S4 & S5 TPS, I'm gonna go ahead and say, no, you can't bolt the S5 TPS to an S4 body

[TitaniumTT]

Oh, and the Halltech TPS's total piece of shit..

[WankelsRevenge]

Im running a Megasquirt so no haltech stuffs for me. Looks like Im gonna be in the market for a S5 throttle body and TPS soon though.

[C. Ludwig]

The S5 throttle body and TPS is the only bolt on affair. You need the throttle body to get the full range cam. If you're handy, you can make a cam to take the place of the lever arm on the S4 and rework the S4 TPS mount to make it work well as a full range sensor. I've done this and it's worked great. Mentioned to FFE it would be a neat and easy product too. :) I've seen a lot of attempts to make it work with other sensors, and very rarely has the execution been worth a damn. That's why I tell everyone to swap the S5 throttle body and TPS.

The sensor Haltech sells now is actually a very nice piece of Bosch material. They're really proud of it too for what they ask for it. The problem everyone runs into trying to fit it, or most any other alternate sensors, if that those sensors typically work on an 8mm D shaped shaft. The RX-7 uses a 10mm shaft with two flats. So you need to turn down the shaft to fit. This invariably gets buggered up.