Amber Wells

**first time poster**
**Newbie Boxster owner**
I drive a 97 Porsche Boxster tiptronic. I was lucky enough to salvage a few parts off a 98' manual Porsche Boxster before it hit the scrap pile...
In my collection of salvages I have a Bosch montronic cartronic ECU with the numbers 996.618.601.04. on it.

I have done a little research trying to figure out what exactly it is... And haven't had much luck.
What I am wondering is; can I put this unit into my 97' tiptronic Boxster seeing as it came out of a manual 98' Boxster??
Reason being I am curious to see if it would make any improvements in the fuel mileage and or performance. I imagine there could only be improvements in the unit itself as it is a year newer...
I appreciate any info, thoughts and comments you may have to share !!

Thank you

Starter986

Yes. Install it today and report back tomorrow.

paulofto

First off, welcome to the forum. Always great to see another Canadian here. Secondly, don't let Starter986 make you wonder if coming here was a bad idea. He pulls everyone's chains to get a reaction. Thirdly, I don't know if the 98 unit will work with a 97 but I'm sure someone wilh experience will chime in. People like Macster who has years of 986 experience will, I'm sure, steer you right. Fourthly (is that a word?) you may want to join 986forum.com in addition to this one. There are a ton of experienced members there, some of whom are also here, and technical discussions are very active and informative.

Lastly, how about some pictures of your car? Have fun.

Macster

Was a bit reluctant to respond as I'm not an ECU expert.

But let me offer this:

Best to leave the ECU alone unless it absolutely needs attention. There is the risk of static discharge, bending/breaking a pin, socket/mounting damage, etc.

Can offer no guarantee but even if the '98 ECU has the same pin out as the '97 the '98 ECU is not just a drop in replacement and even if it is will probably *not* work in the '97. (I used to have hard copy early and to I think 2002 Boxster wiring diagrams but no longer.) I would certainly not attempt this unless I had 100% confidence it would fit and work. A Porsche parts department may be able to look up the part number of the part you have and confirm if it will work or not.

It is very important you know what you are doing before you do it. By installing an incompatible ECU one could damage the car's sensor population or the instrument cluster or who knows what and then even with the right ECU installed the car may not work right. It is possible the good ECU could be damaged.

Even if the ECU worked I doubt you'd realize any benefit. There will almost certainly be no gain/improvement gas mileage or performance. Each ECU has a program that is designed from the ground up to efficiently fuel the engine to maximize the engine's output. (Word is Porsche runs the engine at very near detonation which allows it to keep the timing advanced which maximizes the output of the engine.)

Any MY to MY gains in HP or mileage have come with hardware changes: More sophisticated valve timing control, variable valve lift, different cam profiles, increase in displacement, and other changes that often require a change in the engine controller program to make full use of. But without these changes present in/on the engine the program would probably not work right and the result would be less than the sum of its parts.

For the 2.5l models, there was one change to the ECU flash that I"m aware of. This was to accommodate a different/newer MAF that was incompatible with the older cars' ECU programming.

With an older Boxster -- and this is my experience with my 2002 -- you would be better served by ensuring the engine is in good "tune" This means the engine air filter is fresh. The plugs are at least not at their replace by date or mileage and the plugs are the correct plug and properly gapped. With a used car one never knows what was done or not done. The plugs may be spot on perfect or they maybe out of the previous owner's farm tractor.

Along with the plugs that the coils are in good condition. Ditto the O2 sensors.

While coils and O2 sensors may appear ok -- at least there is no CEL and not code/codes pointing a coil or sensor problem -- I can tell you when I had the O2 sensors replaced in my 2002 Boxster at around 305K miles -- the sensors probably had way over 100K miles on them -- engine perked up some. While I never got around to replacing the coils in the Boxster -- at 317K miles they were original -- when at around 140K miles I had the coils and plugs changed in my Turbo the engine perked up some. The plugs were about 10K miles shy of being due to be replaced and previous plug services did not have the engine react one way or the other. The new coils were the difference. And I might add there were no codes which prompted the coil change. I just had this done on a whim.

Also, with the Turbo prior to the coil/plug service at 132K miles to address an O2 sensor error -- but the engine was not manifesting any untoward behavior -- I had the O2 sensors replaced in the Turbo. To my surprise the engine perked up.

My point is that even if the coils appear to be "fine" the O2 sensors appear to be "fine" replacing these can have a positive effect on engine performance.

Last but not least the Boxster engine perked up some when I switched from Shell V-Power (91) to Chevron Supreme (also 91). Even before a full tank of Supreme had been consumed the engine perked up. The Techron removed fuel system (probably injector tip) deposits and the engine reacted positively to this.

What I am trying to impress upon you just seeing to the engine and its vital sensors, filters, replacing them -- with suitable replacements: I shied away from OEM preferring to use, have the Porsche techs use, OE hardware; could deliver noticeable performance gains without the risk associated with swapping ECUs.

The things above are way less risky to do and can deliver based on my experience rather impressive improvements.

Amber Wells

Your replies are very much appreciated!

Macster, thank you for your consideration. I have a new engine compartment air filter waiting for me in the mail. I changed the spark plugs back in March. I did notice some minor cracks in the coils but am putting that purchase off until it absolutely should be done!

I also have some new header gaskets on the way(and some bolts) for bigger, shinier aftermarket headers. Im hoping bigger headers can make my Boxster sound better!




Now, I know a valve service should be done. I want to do it. I just need to learn how. If anyone knows of some quality DIY material for servicing the valve timing and what-not please do share!

In conclusion; I will put the 98' ECU back into the bubble wrap and box I had it in. Thanks again !

Macster

If the coils show cracks they should be replaced.

Not sure what valve service you are talking about. There is no valve service for the Boxster. (The intake/exhaust valves are hydraulic and do not require lash adjustment. There is no need to bother "timing" the valves (cams) under normal circumstances. (If the engine is torn down some if the cams are removed as might be the case to replace bad lifters or in the case of my car to replace a bad VarioCam solenoid and actuator then the cam timing needs to be set/checkedd to ensure it is correct.)

Oh, perhaps you are referring to replacing the IMSB? There are write ups on this, videos on this. Use Google to find them. Pelican Parts web site has a write up on this. Here's a link:

https://www.pelicanparts.com/techart...ft_Bearing.htm

Darkblue

@Amberwells I think I have your car. If you want to talk about it pm me.

Amber Wells

You do have my car. I sent you my phone number on renntech. Please give me a call.