Show full size 924Board.org
Discussion Forum of 924.org
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
 Technical FAQ924 FAQ (Technical)   Technical924 Technical Section   Jump to 924.org924.org   Jump to PCA 924 Registry924 Registry

S1 931 (1980) Piston Options?

 
Post new topic   Reply to topic    924Board.org Forum Index -> 931 Discussion
View previous topic :: View next topic  
Author Message
Harhmless  



Joined: 09 Sep 2015
Posts: 14
Location: Buffalo, NY

PostPosted: Sun Feb 14, 2016 7:32 am    Post subject: S1 931 (1980) Piston Options? Reply with quote

Hey guys,

I know I've found some information on here about pistons before, but I'm to the point where I'm going to need to make a call. I'm setting up the car as a track ready street car with the end goal of about 350 hp in mind.

What options do I have for pistons at the stock bore, and maybe a size up? I have to have the block checked over but my guess is I'm going to have to bore it a bit to make it work, as I have a little bit of damage to one cylinder wall.

Cheers,
Hayden
_________________
1980 931 (US) - Elise
Back to top
View user's profile Send private message
ideola  



Joined: 01 Oct 2004
Posts: 15548
Location: Spring Lake MI

PostPosted: Sun Feb 14, 2016 9:41 am    Post subject: Reply with quote

Best bang for the buck (in my opinion) is a full set of Diamond pistons. For the money, it includes custom slugs in any bore and dish desired, includes fresh wrist pins, spirolox retainers, and TotalSeal rings. There are a few off-the-shelf options out there (flat tops), but they will end up costing the same amount of money by the time you include rings and wrist pins, and will not have ideal compression height, dish geometry, or quench characteristics as the Diamond slugs designed specifically for the 931.


You will be hard-pressed to find oversized OEM slugs, and OEM 931 rings are not available, at least not at anything resembling a reasonable price. However, we do have TotalSeal rings available for OEM pistons, and can have these custom made in any bore desired. These are of a superior material than the OEM rings and far less expensive.

Pistons alone will not get you to your desired power output. To achieve 350BHP, you are going to need some serious thermal management (intercooling + modified coolant circuit) in order to handle the boost required to hit those numbers. Strongly recommend a revised K26/7 hybrid turbocharger to achieve greater efficiency at high boost.

You will also almost certainly need to address the biggest constraint on this motor: the head. Consider the big valve kit, plus a high lift cam.
_________________
erstwhile owner of just about every 924 variant ever made
Back to top
View user's profile Send private message
Carrera RSR  



Joined: 08 Jan 2010
Posts: 2309
Location: Somerset, UK

PostPosted: Sun Feb 14, 2016 6:23 pm    Post subject: Reply with quote

Or talk to Mittelmotor who have a package of off the shelf GTS spec parts, including Pistons rods turbos IC's etc. etc, which have been proven to all work together and achieve 350-400bhp in their FIA Historique race cars
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    924Board.org Forum Index -> 931 Discussion All times are GMT + 10 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group