rocketrider2

Just wondering what the cost is to twin plug an 87 930?
What all is involved and who would you recommend to do it?
Thanks guys

Brent 930

I figure around $2500 for parts and labor...LOL

Brent 930

I figure around $2500 for parts and labor...LOL

PorschePhD

Brent is close with ignition and wires. This price wouldn't include the labor to tear down the motor. Also I know who can do them

Brent 930

O'yeah I forgot, Stephen is Mr. Twin Plug...no pun

justkickenit

Ok this is probably a stupid question but I'm a computer guy - not a motorhead: what is a twin plug and what benefits does it give you?

Steve Weiner-Rennsport Systems

Lookee here,....http://www.rennsportsystems.com/2a.html

This should help answer your question.

PorschePhD

That's right, how else could I give the warranties I do on the motors without all the safety checks in place. I have pulled so many motors apart that I could tell you if a car was twin plugged or not based on the burn pattern on the piston. If you saw the pattern of one then the stock pattern you would be very clear what the benefits are. Not a cheap route by any means, but then again neither is rebuilding a new motor

Brent 930

No doubt that twin plug is good stuff, as you know I didn't stray from the original P's and C's stock spec. and there haven't been any reports of any real design issues if you stay single plug so I didn't twin plug. You do alot of 3.4 motors even though you still twin plug 3.3's.

PorschePhD

Boost is boost and pressure is still pressure. The efficiency of the chamber is not changed regardless of 3.4 or 3.3. The valve pockets and the placement of the plug will never provide a proper burn in the chamber. It isn't so much an issue of 3.3 to 3.4. It is an issue of pushing the car harder. Anytime you add HP and timing, boost etc you only increase the heat and burn deficiency in the chamber.

Signed "Mr TwinPlug" LOL

Brent 930

So why didn't Porsche twin plug the 930's???

LMAO at your new signature

Brent 930

So are you saying once you upgrade the power you need twin plug? Or is there a hp limit to where your still good running single plug?

Thanks

Bruce M.

I'm sure Porsche didn't twinplug for the same reason they otherwise inexplicably stayed with CIS on the 930 from 1975-1994, over which time the whole rest of the world went to far more sophisticated and precise fuel systems--cost.

This business I often hear about "if it's so great, why didn't Porsche do it originally" completely misses the unavoidable fact that Porsche, for all its technical skills, was subject to the same market forces and pressures as any other company, and chose on occasion NOT to do what was best, but instead what was cheaper. CIS, especially from the mid-80's on, is a classic example of this phenomenon. And so is twin-plugging.

PorschePhD

Exactly Bruce. Why would Porsche do it Brent? They turned the boost down and placed a shroud on the InterC and called it a day. Fat AFRs, made good power and hit emissions. The day was done. When they needed it they did it. I do feel that any car that heads down a path of modifications in the internal sense can benefit and should have twin plugs

Mr. Twin plug

jhunt@huntinter

The 934 was CIS and single plug (probably a requirement) and the 935 was MFI and dual plug. The 935 engine produced about 300 more hp (not all because of the dual plug of course).

The decision to dual plug or not (or any mod) really comes down to what the goals are for your car, where and how are you going to drive it. Do you expect your spouse to ever ride along. yada yada yada.

It always gives you bragging rights at the club DE's