Right. Strictly speaking, what the OP is asking about can't be done. In addition to the software side of things, there are a whole host of physical changes between 2.7 and 5.2 cars. Not the least of which is there are 2 separate ECUs on the 2.7 car... But - maybe there are other tuning options for a 5.2 car that would yield some of the gains that I would assume prompted the question? I don't think you can flash tune most versions of Bosch Motronic through the OBDII port, but you can certainly "bench" tune the ECU once it's removed. Our cars are old enough, and esoteric enough that I doubt anyone is still offering ECU tunes on a commercial basis, but I could be wrong. Anyone have experience with this?
Todd at Protomotive has a 355 file on hand. 355 ECU is the same Bosch Motronic as many other cars used in that era. I believe the 5.2 uses the cc460 chip and to flash it, it has to be removed from the ECU. They are soldered on and so the real way to proceed if you want to flash it is to have a socket installed in the ECU circuit board so that you can R&R the chip easily.
Thanks for the information. I had the cams turned 4 degrees and my intent is to align the more aggressive ECU settings from 95 with the mod. Ive seen the cams done before on the 95 and really screams. Also I’ve seen it on a 360 as well. As of now, The idle is a little rough but midrange and above pulls noticeably harder. it is my understanding the 95 settings are less emissions restrictive and a stronger setup.
I would look at getting an ECU like Vems -- it's really hard to tune the 5.2 at this point. Very old tech, very few people have the equipment or knowledge to work on it. I've been there done that on my 993, which uses the same ECU. Just get something new and livemap it easily on a dyno and be done with it.
The intake system is different (5.2 is more longer and restrictive than 2.7) The exhaust system is different (5.2 y-pipe is smaller in diameter) So, you do not want the 2.7 tune on a 5.2 car--that is not to say you could not tune the car to get 2.7 performance figures but the map would be different.
I assume you mean they advanced the cam timing - was this on the intake only, or both intake and exhaust?
I would have to as my mechanic on than one to be sure. I don’t recall from when he described the modification. Why do you ask?
I literally was just popping a CC460 back into a chip holder. Just snapped this picture. The chip needs to be de soldered, a chip holder installed then the chip programmed. Chances of breaking this old stuff? Pretty good. Sorry I don't do any customer work at all The post above about is the guy to talk to is a good start. Remember a chip tune is only as good as the dyno time efforts. Not many folks know much about the 5.2 in the 355. They are very easy to blow up. You best bet would be a standalone ECU with a new harness, remember the computer you had back in 1996? LOL Image Unavailable, Please Login
This guy makes plug-and-play ECU's for 90's Porsches. They use the stock DME harness and 55- or 88-pin connector. Very nice guy and quite skilled. I bet he'd make something for a 355. I've been around the block on ECU stuff with my 993 (very non-stock) and if I was going to play around with the 355 engine, step one would be ditching the ancient ECU in favor of something modern. https://www.facebook.com/vemsporsche/
Not sure if it would be much help in your position, but I am working with someone on making a plug and play piggy back tuner for the 2.7/5.2s that allow modifying of fuel (not timing). I am pursuing this because my bottom end is lean post intake/exhaust work, and I'm looking to richen it up. More to come
Oops. If I swap one 5.2 ECU for another 5.2 ECU will I need to swap the immobilization ECUs as well and possibly the remotes?
Yes, but why are you swapping the ECUs? If you are fitting another car’s ECU to your car and you want to keep your Immobiliser set (fobs and Immo ECUs), there are gentlemen on F-Chat who can erase the pairing information from the Motronic ECU.
Do the Challenge cars actually have a different ECU tune? I can’t find much info about that. Sent from my iPhone using FerrariChat.com mobile app
This guy may be able to handle the immobilizer issue, assuming it's the same tech as the 993 (the 993/355 OBD2 ECU's are the same -- both Motronic 5.2, so maybe the immobilizer setup is the same as well). https://www.ezimmoblock.com/
More info on that? I'm interested in adding to my car or going to a standalone, but my concern with a standalone is getting a decent base map to start with along with all of the proper sensor settings.
The problem with standalone is that you need more than the ECU -- you need an entirely new, custom-built, engine wiring harness. In the Porsche world, that's around $8-$10k. What I like about the Vems ECU is the guy sends you the ECU already wired into a 55-pin or 88-pin harness connector, so you don't need a new wiring harness and the ECU uses the sensors in place on your engine. It plugs into the wiring harness like the stock ECU. I asked him about doing this for a 355, and it sounds like if there were a few interested people, he'd do it.
I definitely am - but there's the wrinkle of 2.7 vs. 5.2 as well, each would need a different connector setup.
I had Unichip on my 95 for years. You do not need a new harness, it spices into existing harness. Willrace has my car now. Made a huge difference
