Marty, both him and his wife joined me in Germany for a week to fine-tune the car and sort out the final details while driving it and with a laptop, as they had only the engine in the US. Pressure sensing on Motronic is a great modification and the key to numbers like these, but it needs considerable fine tuning to be perfect. Usually it is used on race cars where idle and drivablity at low RPMs is not an issue, in this case they had to make it right, and they did.

 

Jean, at the expense of showing off my ignorance, what is "pressure sensing" on the Motronic. I believe my car has the same Motronic and is this a feature that could be added?
Thanks

 

Jean has no MAF sensor on his engine. It is tuned with a MAP sensor. I am working on this same project on my next kit. It would require a entire retune of your Motronics at great expense.

 

LAT, this is not something everyone knows, I learnt more about it while the engine was being built so no question is a bad question. As Kevin said, I have no Mass Air Flow on my engine. The Motronic has been calibrated to read and program based on manifold pressure rather than the air coming through the MAF.
Sorry to link to a non sponsor, but it is too much to write about here and I think it is an interesting subject, please read: http://www.geocities.com/protomotive/psvsaf.htm for a summary of pros/cons
or go to the main page and under the drop down menu on the right and check "fuel management summary".

I would guess that the RUF that come converted from Germany or have to be sent out to Germany for the conversion are the ones that might have pressure sensing. I believe if you have a TT Motronic serial number then you don't have pressure sensing.

 

Jean, you are correct, I have a MAF sensor which I recently replaced and improved drivability with.
The explanation given on the web site you provide and further if you ckick on the top right of the page on "fuel injection summary" would lead one to think that any other system for a turbo is a compromise. I agree with their findings on coming off full boost to a vacumn and the engine going a little wonky trying to remap the fuel curve.

What would a conversion yield and what would it cost. If I could get RUF to do it an maintain the RUF integrity of the car it may be worth doing at overhaul time.

MAF vs pressure sensing may be worth starting a new thread over.

 

LAT , the only people who can tell you what it would cost is RUF themselves. The work involved is substantial, the tuning has to be done in their premises in Germany, unless they fly out the technician who knows how to do it. This is not something more than a handful of people can do "succesfully" on Motronic, even less on a twin plug setup, which is the reason it is not done more often. Also pressure sensing is one of the main reasons you see the gains that you see from going to a Motec-like setup as it combines pressure sensing and throttle position system.

For non extreme hp engines, MAF works just great. This is just my opinion, which can be somewhat mistaken so take it with a grain of salt.

 

There are other options like installing larger MAF units, and re-calibrating. You can install a Boxster MAF but a retune will have to be done. We are seeing 650-700 on the 996TT and they still retain the MAF.

 

Kevin, can you shed some light on the difference between the 993TT sensor and the Boxter unit,

 

Are we not also reaching the thermo dynamic limits of the air cooled engines with the stock MAF?
I thought the pressure sensor system would allow better mapping and a greater area under the curve, is this not the case?

 

Personally, I wouldn't do anything to your Ruf engine. If you need more performance yank the engine out and put it on a shelf, and start from scratch with another engine. What are your HP goals? 650-750? You'll need flame rings, camshafts, rods, custom headers, turbochargers to support the output. The list goes on.. Then custom programming that will allow a MAP based solution. We are reaching the limits of the MAF threshold, however, thermal dynamics limits are cured with tuning and oil coolers..

It's not possible to swap a MAP sensor for a MAF unit and gain 100 horses without changing boost, injectors, camshafts, its a waste in monies. Even swapping to a larger MAF, why if you don't have the mechanical support to do it. Now if you want to dial the boost up to 1.3bars and see how long things stay together, that would be and interesting project..

 

Kevin, I am not about to touch the RUF engine. I am just learning as much as I can about a hobby I enjoy. Until the recent posts I was not aware that MAP sensors even existed.

I will not be dialing the boost up to 1.3 anytime soon. My settings are 100% stock and will remain that way, but thanks for the suggestion.........

 

LAT that's great. I'd definately leave the Ruf engine "stock" We should start a thread.. "Dream 993TT engine build" Then we could explore all avenues from machine work, parts, and cost.

 

Jean,
Todd is one smart guy, and has been converting MAF to MAP for at least 10 years! With A/F ratios like yours, you are very safe, and thus your recorded power is conservative! Sounds like an absolute blast to drive. The power under the curve must be staggering.

Do you have a 0-180 mph time, via GPS? Or 0 - 150mph?

Marc

 

Jean,
Waiting for your videos mate...!!

 

My take on the MAP v MAF for our 993tt engines. The first GT2 race cars (450PS) came with a slightly bigger side to side intercooler with the exit lined up for pressure sensing induction . In 2002 I had the (what I thought was) bright idea, (having read the Protomotive web site amongst other things) to get RS Tuning fit one of these I/Cs with the MAP set up and gain some more hp. The thread is here:
https://rennlist.com/forums/993-turbo-forum/31267-engine-freshen-up-brings-usual-problems.html
If you can be bothered to read the thread, bottom line is that there were no tangible gains to just going pressure sensing over the existing set up, the limitations of the engine power was the intercooling and only the Secan unit could address this since the GT2 MAP intercooler even though bigger was no better than stock (I know change the record ).
I guess the proof in this for me is that RS did not want to take (a considerable amount) of money off me to change to MAP.
For our cars and over 540hp it is all about the intercooling.