Originally Posted by IcemanG17

This is GREAT NEWS........one more piece of the puzzle for adding HP (dumping restrictive stock intake)....

Originally Posted by Tony

So the air intake temp sensor on a twinscrew application would have to be mounted just prior to the intake valve..ie..after the air has been heated via compression and then cooled via intercooler so you are getting a true intake temp reading?

Originally Posted by jcorenman

Malcom, to follow up on your questions, and for Andy and others also: As John said, the install was straightforward. The hardest part was fitting the precision throttle sensor, that required unbolting the intake and lifting the left side 2 or 3" to remove the TPS switch and get the new sensor and mounting plate installed. A voltmeter is used to set the mechanical zero (slotted holes on the sensor) and then everything is bolted back together.

The new throttle sensor connects to one pigtail on the Alpha box, another connects to the original TPS connector, another followss the left side fuel rail harness to the Temp2 sensor, and the last pigtail plugs into the MAF connector. I mounted the intake-air sensor to a small plastic block glued to the side of the lower airbox, along with a fitting for a small tube to the pressure-sensor.

There are no changes to the LH or EZK boxes, just a different bin-file for the LH, and then tuning.

It is important to note that we don't expect any real changes for a relatively stock car-- the goal here was to see if we could make it run as well as a MAF on a stock intake. If we could duplicate the performance of a MAF then that would be a pretty good test. And it was also what we had available

As for conclusions and impressions: It runs fine. That sounds silly, but this is a fundamentally different way of managing the fuel injection, so that actually says a lot. The engine starts readily, idles fine, and runs just like always, without any odd hesitations or stumbles.

My impression is that the throttle response is better, and looking at the plots I think the fueling is more accurate at higher loads, where the MAF shows some scatter. There is no expectation of more horsepower, this car was well-tuned with a MAF (JDS rebuilt).

The real value of this system is the flexibility it offers for intake design. Does it make sense to fit it to a standard intake? I think the only reason would be to eliminate the issues with MAF's: aging and calibration. A rebuilt MAF is cheaper,and careful Sharktuning will account for differences of calibration.

And, as always, before changing anything first make sure that the engine is running 100% the way the factory intended. If you've got a bad sensor then that won't go away with an Alpha conversion. (Of course a badly-calibrated MAF will go away )

So my suggestion, if this all seems interesting, is to start with the Sharktuner, learn how to use it and make sure everything is working 100%, and do some fine-tuning with the MAF that you've got. Then decide whether to make changes or enjoy what you've got.

As for what to replace the MAF with: A badly-calibrated MAF is a good option, don't use a good one because it will continue to get dirty but won't be getting burned-off. But a better option would be to get our favorite in-house plastics guy to mold a replacement lower air-box, with a nice bell-mouth that extends down to the throttle boot. (Jerry, are you copying this??)

Originally Posted by justaguy

OK so if I'm understanding this correctly we can now use the stock ECU to manage an engine with ITB induction. If so I'll take one and a set of ITB's when can I have it?

Originally Posted by Lizard931

If you find it let me know. It is 3.75" OD and I have searched high and low for this. I normally end up taking a piece of 3" OD pipe cut it down the side and add a little material.

Originally Posted by jcorenman

Yes, it needs to be the actual intake air temperature for best results, there is a lot of heating/cooling going on with an intercooled T/S engine. The Bosch sensor (shown above) could probably be mounted in the side of the lower plenum-manifold thingie, anywhere that gets airflow at the same temperature/pressure as the valves.

I mounted the air-temp sensor in the corner of the lower airbox, but it would respond to changes faster if it was in the real airflow.

Originally Posted by FUSE69

John,

Absolutely fantastic work as usual!!

I'll be making an order as soon as you are ready... will you be able to supply the sensors along with the box? Or would you prefer that I source them elsewhere?

Originally Posted by John Speake

Thanks ! I'm building a first production unit this week. I expect to be selling within the next two weeks. You can place an order now for delivery before the end of this month.

The ST-Aplha includes the air pressure sensor (built into the box) and the Airtemp sensor is also provided. You need to purchase the throttle posisition pot. I can supply the recommended Penny & Giles pot at cost with a small additional cost for the adaptor lead.

Originally Posted by AO

Haven't read the entire thread, but from my discussions with Jim at SITM, it was pretty clear that this unit may not be well suited for boost applications. The reason is that there could situations where you are at 3/4 throttle and one time you're in boost, and another time you're not. But this is a great way for the ITB guys to get a great tune.

I understand that further developments may be in the works to incorporate a MAP sensor which is exactly what us boosted guys would need. Any comment on that John?

Originally Posted by John Speake

The announcement in bold type in post #1 says we are developing a MAP (speed-density) version From what we know we believe this should follow quite quickly.

Your twin screw s/c should match even a ST-ALpha system pretty well as the vlume displacement is well defined relative to rpm. There would be a problem if there was suddenly significant belt slip, and of course if the belt broke...

For the belt broken case, it would be possible to construct a "no boost" map get you home map and store that in the unused (non cat in your case) slot and select it with a simple switch on the code plug.