JasonAndreas

What is it about twin-plugging that makes it more difficult to program than a regular turbocharged engine? In terms of specifying ignition points is it not similar to programming a regular twin-plugged normally aspirated motor?

Jean

Hi Jason

I would not be able to tell you the specifics, but it took me about 6 months to find someone who had experience doing it on Motronic, and that included some of the best around the world. RS Tuning was one of them but any civilized contact with them was impossible and I had no patience to deal with them.

I ended up going with Protomotive and I am extremely pleased with the result, however it is a hybrid fixed boost controller/Motronic setup.

I know Andial does a 3.8 Twin Plug engine as well but now that they moved to Motronic from aftermarket ECUs, they had the ECU programmed in Germany By FVD. I know that getting the timing right in an optimum manner is very tricky. The N/A motor is based on pressure sensing, unlike the TT engine, which reads air density. I had mine converted to a N/A ECU.

I can try to get more information about this topic, as I have never researched it deeper than this. Maybe someone with experience can chime in.

Jean

Geoffrey

The method used to determine optimum timing is the same for single plug as it is for dual plug. I think the difficulty is in finding someone who has access to the Motronic tools who can program the ECU in real time which is one of the dependancies for finding optimum timing on a dyno, unless high speed in cylinder pressure monitoring/data logging equipment is used.

Red9

Who is capable of tuning Motronic for this type of hybrid?. It would certainly be easier to go to Motec or Autronic so why would you stay with Motronic? Why was the different Motronic ECU used/more suitable in your application Jean?

Kevin

It has been done already. There are select few people that can tune projects like this. You usually have to fly them in, or ship your car..

Jean

Red9
I considered Motec as an alternative and I would not mind at all using it, but in my case there are no good Motec tuners around here. The Motronic is an excellent ECU that has the knock control feature. By swapping to a manifold pressure sensing setup instead of a MAF setup, higher levels of performance were achieved on my engine, and it has become very similar to an aftermarket EFI setup, only keeping your Motronic.
I know that a key factor is that you need to tune the Motronic on the engine dyno initially (it takes about 3-7 days), and then, as Kevin said, for 100% success, you need to do the final calibration on the road with a laptop, therefore fly-in your tuner or send him you car.
Not a walk in the park for sure, and having been through it, I cannot recommend Juha to do it.

Red9

That knock cotrol feature is something other ECU's cannot do.I am happy to be corrected but that feature is enough to encourage me to Motronic. The irony is I have as easy as there could possibly be access to Motec and Autronic. I believe Autronic is better in this area than Motec- comments? How many and who are capable of setting Motronic up like this. In my case I would have to send engine and I am interested in what options there are. Is the technology transportable in the sense that I could fly it/them to me and what would be required. I am looking for serious numbers.

Jean

Yes knock sensing is the main advantage. Unlike what I have read in another thread on this same board, my car uses a 1995 993N/A ECU (not 964) and I do have the knock sensors fully operational.

It all depends what sort of engine you want to build and what is its main usage objective. If you are in the US, there are a couple of builders that I know of (already mentioned in the other threads), Ultimatemotorwerks' Kevin is also building (or ready to) a high hp package as well, with Gunther's programming. I am sure that package will beat 90% of anything any other tuner will give you, as it will use some very top notch turbosystems improvements. Keep in mind that above a sustained real 520-550hp, you will be better off opening the case for strengthening rod bolts etc.. TB993tt had experienced bent rods with his (true) 540hp engine.

Geoffrey

The MoTeC ECU is a much more flexible ECU than the Autronic, it is more powerful, has more features, more input/outputs, has dual built in Wide band lambda support, has 1mb of data logging AND it can do knock control if you feel you really need it. There is also a higher number of better qualified tuners out there to help support the ECU once in the car, so you do have a choice.

For a street driven 993TT, I would encourage anyone to look at the available Motronic tuned chip, turbo, packages which will keep the car OBDII compliant and is something that is becomming increasingly more important as more and more states are requiring OBDII connection at time of inspection.

JJayB

I have a bit of experience with the 3.8 twin plug conversion. Currently I'm running an FVD ecu which is very driveable compared to my race ecu by Thielert especially on the street. I was one of the first and paid 7500 for the privilege. They may have come down in the last two years. Some tunners may be cheaper and if your on a budget you have to decide.
If you considering a 3.8 with higher compression JE pistons, I'd strongly find someone who's done this mod before because its never cheap to be the first one. Several on the board have expressed reservations as to this course of modification. Go have fun and if it doesn't work out you learned a valuable lesson. Hey, I've gone through 5 sets of suspension set ups. But I learned what did work.

Red9

In my case I am contemplating converting 993 RS CS 3.8 to twin turbo.Already has excellent valve gear, heads etc. I have rods ,cams(proven spec) ,TWM throttle bodies ,donor K16's.This engine is for track only car so will be looking for big numbers.I can collect data thru Motec dash.So any system I go with will need unique? programming. The choice of ECU is important part of the decision process. Does the 95 993 N/A ECU have the same features as Turbo ECU? Why use it? Sorry to hijack thread but I also am curious about compression ratio's. I am told that the Motronic is quite superior ECU to Motec.

Geoffrey

Which TWM throttle bodies do you have, the 3006 or 3003s? I have found that high butterfly individual throttle bodies (especially the 3006s) do not work very well in turbocharged environments. In order to use individual throttle bodies, you will need an ECU that can use TPS as the main load factor, a secondary fuel table based on manifold pressure and engine RPM, and a third table for general MAP. I will say that the MoTeC ECU will do a much better job with the setup you are describing than a Motronic ECU due to its ability to program each of the tables I described above. Any Motronic ECU will be either an air flow meter or MAF for load, unless it has been converted by someone to MAP with an integrated MAP sensor. This by iteself will not be sufficient for an individual throttle body turbocharged engine.

Further, the MoTeC ECU will communicate to with your Dash over CAN bus, and with the new Version 3 software, you can send channels from the Dash back to the ECU. I do this in my setup for wheel speeds where the Dash receives 4 wheel speeds, generates a ground speed and drive speed channel which gets sent back to the MoTeC ECU so it can do traction control.

Red9

They are TWM 3006 that I have. I previously had them on an earlier 3.6 single tubo Motec enginethat made quite good real numbers. Why are they unsuitable and what would be preferred to them?Can the Motronic be mapped in the same way?Or at least to give the same end result?

Geoffrey

One of the major benefits to individual throttle bodies is that they provide for better throttle response, primarily because of better velocity and the isolation from reversion that occurs in the other intake runners in a common plenum environment. There are advantages in throttle body placement, injector placement, air horn size, etc. I have found that on a N/A engine, a low throttle body by itself is not ideal, however, when combined with a manifold (3.8 RSR for example), you can build torque. In a N/A environment the high butterfly injection has better response due to the higher velocity and better atomization of the air fuel charge. In a turbocharged invornment, the engine design is much different. The engines suffer from poor VE% in the N/A range due to the low static and dynamic compression ratio as well as having to "suck" the air through an air filter, through a turbocharger, through an intercooler. Velocity is very slow. When the turbocharger begins to build boost, the engine becomes much more efficient. It is in this range where I have found the high butterfly injection to be inadequate and the fuel requirements can change drastically in a very narrow load or narrow RPM range. While I agree that you can get a turbocharged engine with high butterflys to produce good power while on boost, the throttle response off boost is terrible and very inconsistent to the point that I don't see any benefit to them over even a common plenum manifold. While you can develop a common vacuum chamber and get stable MAP readings, they change so rapidly and inconsistently that MAP no longer becomes a good input for fuel in the ranges we are talking about. MAP is required because it is used for ignition timing and for fuel delivery calculations. I have not had the same issues with the low butterfly injection and have been able to use straight MAP as the load calculation without any TPS input for main fuel and ignition tables. It is that much better. I have mapped engines with injection from the 3.8l RSR, TWM 3003, 3006, Jenvey, and Bob Holcombe, but there are probably a dozen others out there to try.

For turbocharged application, I like the Bob Holcombe setup the best. For N/A price/performance, I like the TWM 3003 setup. For N/A torque, I like the factory 3.8RSR setup, and for best high RPM performance, I like the Jenvey setup. I do not like the 3006s because the linkage is overly complicated, the throttle plate of #2 and #5 vibrate due to the linkate, the seals leak over time, the linkage is hard to adjust because there is not enough space for a wrench, and I've seen several of them send screws through the engine.

Just my opinion...

Jussi

in summary there is no difference for programming Motronic if you have single or twin plug system. Idea is to adjust right timing and pay attention to knock sensors and also other parameters. Am I right?

This Motronic adjustment is not a problem for me. My friend here (Finland) is the best of best with these Motronic, really genius. He can optimize Motronic for any combination in real time on dyno. Has done that 20 years already.
I have been using his service for years to my earlier projects, not p-cars..
Only problem seems to be getting these Twin Plug equipments..
(Another problems is my limited budjet )

So that's way I ask my question again :
Can I first take "stage 1" version with 3.8ltr 8.5:1 compression with moderate ECU tune and after step "stage 2" with twin plug system and rise boost/power to another level?
By going that way, I can make the most of first stage parts and only invest money to twin plug (and Motronic programming).

If I look Jean's and Edpurplett's 3.8TT dyno curves, Ed has lots of low and mid(<4500rpm) torque more. I know that 8.9:1 compression value is not only reason for that but it is at least one reason.
I prefer more good low and mid torque than maximum peak hp. My aim is about +520hp and 700Nm/4000rpm

-Juha