ideola

Installing an intercooler in the 931 is non-trivial. The objective for this car was not a max output motor. I have two other projects (the Club Sport and the Ultra Wide Body) which will be intercooled, not to mention my 937.

A little history on this car...the #2 intake valve developed a problem where the valve guide was floating in the bore, causing the valve stem seal to get mashed, which in turn dumped oil into the combustion chamber, fouling out the plug, causing it to run like crap and smell even worse. It's very difficult to just pull the head on the 931 due to the turbo and exhaust arrangement, so I made the decision to build a motor out of my "extras" lying around without disabling the car. The idea was to do an engine swap as quickly as possible. Since the body work and paint is still fresh and hardly even broken in, there was no way I was going to cut the hood for a TMIC or mangle the front nose section for a FMIC. There is just no easy way to get one in on the 931.

All that said, if I find that I'm wanting more power from this motor, my backup plan is to install a methanol injection setup rather than an intercooler. I will have three intercooled 931 variants, so I want this one to be different.

ideola

Well, got her fired up on Saturday...but encountered a couple of minor issues with the turbo...the first issue was I discovered that the turbo rebuilder used the wrong seals in the integral bypass valve (lesson learned: don't trust any one else's work!!!). Also, I somehow managed to damage the round metal crush seal that goes between the down pipe and the turbine housing, such that the turbo was not spooling. D'oh. Spent the afternoon yesterday getting those two issues sorted out, and now she runs great. Starting to work on break-in.

FRporscheman

Dude... that work of art is what you build with your spares? I can't wait to see your club sport.

I swear, one day I will own a 924. It's calling me... I'd love a 924S with shaved reflectors and trim strips, slammed on some 18s that resemble the 924 tarantulas (perhaps some cayenne wheels), a 968 engine, a dark tobacco interior, and something like azure or ossi blue paint. A 931 set up this way would be my runner up.

ideola

Heh, yeah, I'm swimming in 931 parts over here The biggest expense on this motor was the custom rods since I got the pistons for a ridiculous price because they were basically headed for the scrap heap due to Diamond's mistake. I acquired the head for a song on eBay...it was already completely rebuilt and setup. The bundle I saved by not having to do head work was redirected into porting and port matching of the head and intake by a friend of mine who is a top end specialist at Roush Racing here in Livonia MI. The crank scraper was pretty cheap, so a worthwhile indulgence. The hydrographics on the intake components I got at cost in exchange for promotional considerations from another friend in the business. Otherwise, everything else on the motor was pulled from my spares bin.

It's getting close. It should be together and into break-in mode by the end of August if all goes well.

That would be a fun project! After I finish the 941 and the Club Sport this year, the Ultra Wide Body will come back onto the front burner. Some day, I would love to own a hopped-up 924 NA with D Production body stylings. Someday.

DSMblue

[/QUOTE]That would be a fun project! After I finish the 941 and the Club Sport this year, the Ultra Wide Body will come back onto the front burner. Some day, I would love to own a hopped-up 924 NA with D Production body stylings. Someday.[/QUOTE]

With CIS dumped for side-draft webers? IIRC, many moons ago, Precision Porsche in CA had a project for 924NA's where they used a 931 head, shaved things to bump CR up to around 10:1 and used side draft carbs and different cam to have around 175-200hp. At the time when I had my 924, it always looked like a fun project. The engine looked so much cleaner and meaner with the carb setup.

ideola

Yeah, I think what I would do is rather than trying to duplicate the D-Prod engine is to do something that would be "in the spirit of" with modern components. I'm thinking 931 head with custom high compression pistons (11:1???), convert to modern EFI configuration with independent throttle bodies. Big valve head. Bursch tuned header. Something like that. The Dellorto and Weber carbs are getting harder to find rebuild parts for, so not much better than CIS from the standpoint of cost and repairability. An ITB+EFI setup would be in complete keeping with what they might have done from the factory had the technology been available to them at the time.

sca037

GREAT progress Dan!

Brian

ideola

You should look for me roaring around the back roads in Salem & Superior Townships later this week!!!