PramTT

Does anyone know which Bosch/NGK spark plugs does the 993TT uses?

TIA
Pram

Anir

Pram,

The Porsche internal part # is 999.170.195.90 according to my service record. This Porsche part is manufactured by Beru, Type 14F 6 LDU according to Robin's website, but a previous post by Dick in TN seemed to indicate that his TT owner's manual called for Bosch FR6LDC.

If I remember correctly, Steve Weiner has warned against using Bosch Platinum plugs (except the older DPO series) because they do not idle/run well.

PramTT

Thanks Anir,

AFAIK the Bosch DPO series is the double platinum electrodes (side gaped). I uses the F5DPOR on my turbo Audi.

I was wondering if the Bosch FR6LDC is the double platinum electrode type?

Anir

Pram,

Interestingly, the Bosch website does not list a appropriate model under <a href="http://www.boschusa.com/AutoParts/PartFinder/PartFinder.asp" target="_blank">Bosch spark plug search engine</a> for either the NA or TT 993s. The factory supplied TT spark plug by Beru is a double electrode unit, compared to a 3-electrode Bosch or Beru unit for the NA engines.

Here is an intersting article on spark plugs, as it pertains to the previous generation Turbos, from <a href="http://www.pelicanparts.com/techarticles/rice_ramblings/rice_ramblings-4.htm" target="_blank">Pelican Parts</a>.

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Guest Technical Article:
Technical & Safety:
Spark Plugs by Lee Rice

I have been using three electrode Bosch plugs for years. They are specified on the 911 3.6 liter Carrera and 911 Turbo. What is really surprising, is the increase to a warmer heat range. The early 911S and all Turbos used a ridiculous cold and expensive W3DPO spark plug. This little plug costs about $16.00 each and I have never removed one that wasn?t dark and sooty (indicating too rich or too cold of a plug!) Tuners of these expensive Turbo and early 911S cars were, and are, reluctant to vary from the factory specifications. This is a problem. as Porsche can not respecify the older cars without recertifying the whole engine emission certification all over again. Porsche is not likely to do this.

What is interesting though, is what has happened to the 911 Turbos. The trend became to increase the power output while meeting tighter emission standards. The compression ratios were increased to 7.5:1 (from 7.0:1) and even without knock sensing using a much hotter spark plug, the FR6LDC. This is a copper core, double ground electrode mini spark plug. The fact that the Porsche factory specifies this very warm spark plug for the awesome 3.6 Turbo is not so difficult to understand. I have talked to Bosch, BERU, and NGK about their new applications for old W3DPO spark plugs, and have been told that those were really too cold ? even for a street Turbo. The factory originally specified them in the same way they specified spark plugs for the special 356 Carrera 4 Cam, 911 S, 2.7RS and other higher performance "street" Porsches. The factory expected these owner drivers to run the daylights out of their Porsches and they did not want the engines to "ping" and detonate from using non-German gasoline. So they specified cold spark plugs. It worked. The 911 Turbo came along at first as a batch of 500 only, to be sold originally for "Friends of the Factory." They got the same treatment as the earlier specials. Nothing changed until 1992.

The 3.6 Carrera has used Bosch FR6DTC triple electrode since 1989 and these run great. I started using these 3.6 spec spark plugs in just about all 911?s and have had excellent results with them, especially in my own hard run Turbo motor. I will keep my pile of old "W3DPO", but only for competition events.

In the near future, I?ve been told that we may not see the large inventory and range of spark plugs in our favorite auto parts store anymore, as the new generation of plugs will be reduced to only a mere dozen or so types. It seems these new plugs have such a wide range, that one spark plug will work perfectly in dozens of different engine types.

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Steve Weiner-Rennsport Systems

Gents:

The FR6DTC (triple electrode copper) and FR6LDC (extended electrode triple copper) are recommended for 993's and 993 TT's.

I'd use the "5"s on Turbos used for DE events or ones with engine upgrades.

You can't go wrong with either one,...

Anir

Thank you, Steve!

PramTT

Thanks Steve,

My 993TT has the Porsche 450hp kit. Does it mean that it is better for me to use the "5" plugs?

Pram

Steve Weiner-Rennsport Systems

[quote]Originally posted by PramTT:
<strong>Thanks Steve,

My 993TT has the Porsche 450hp kit. Does it mean that it is better for me to use the "5" plugs?

Pram</strong><hr></blockquote>

Hi Pram:

Yessir, that would be my recommendation.

PramTT

Mucho thanks Steve