3.8l + Motec - spark plug suggestions?

roadsleeper · 08-21-2010, 09:50 PM

Hi all,

I am currently running a set of the OEM spec spark plugs in my 964, which has a custom 3.8l engine in it running off a Motec. We pulled one of the plugs out of the engine yesterday due to some rough running and found it to be fouled quite badly. The car has about 5,000 miles on it since the rebuild, but a lot of that mileage was built up whilst fine tuning the Motec.

I am guessing that perhaps the plugs are in the wrong temperature range for the type of engine they are in (too low?). Is anyone else running a similar set-up, who can advise on what plugs they are using?

A search I did yielded few results, but one was that the 965 can only use the Bosch single electrode platinum plugs (WR6 DP0), because these are in the proper heat range. Any relevance?

Thanks in advance.

group911@aol.co · 08-22-2010, 04:36 PM

I have a factory 3.8 with Motec. I'll pull a plug and get the number

roadsleeper · 08-23-2010, 12:21 AM

Quote:

Originally Posted by group911@aol.co

I have a factory 3.8 with Motec. I'll pull a plug and get the number

Thanks very much in advance, really appreciate it!

group911@aol.co · 08-23-2010, 05:49 AM

The Bosch number is FR5DTC stamped on the metal and R6 962 on the porcelain.
Engine is a Motorsports built RSR in sprint confuguration.

roadsleeper · 08-23-2010, 08:10 PM

Quote:

Originally Posted by group911@aol.co

The Bosch number is FR5DTC stamped on the metal and R6 962 on the porcelain.
Engine is a Motorsports built RSR in sprint confuguration.

Dangit, I'm running a set of FR5DTCs already... Are you driving the car exclusively on the track, or are you clocking any street mileage? If yes to the latter, what are your replacement intervals?

group911@aol.co · 08-23-2010, 09:18 PM

Actually, this engine is on the shelf and has been since Porsche built it and set it up on the dyno. Plugs looked pretty normal. The sprint engines were only supposed to be 80 hour engines at 8500 rpm.
At least you know you are in the ballpark on plugs.

roadsleeper · 08-24-2010, 08:09 PM

Quote:

Originally Posted by group911@aol.co

At least you know you are in the ballpark on plugs.

Yes, thanks much for the eyeball on the sparkplugs!