Club Race prep help

[DrS]

I need some help. Motor exploded in Club Race this season and I have a core motor from salvage to rebuild. I want to up-date this "G" car to "F" to play where the competition is. To do so, I believe I need to use Euro spec p's and c's (9.8:1 compression?) for the engine. I also think the gearing in the tranny may need to be changed to Euro spec for the SC series.

Looking for information on the 'core' engine and freshened transmission based on number and advice on how to proceed to meet the rules at reasonable upgrade cost.

The 'core' engine number is: 6400447
Newly freshened tranny number is 915/61 718 6200

Yes, 'reasonable cost' alternative is to take up knitting but I'm limited in my reasoning ability....

Thanks for any help

[jester911]

DrS, you may get some help here with your question but there is another site that has many club racers in both classes you refer to. http://forums.rennlist.com/ Go to the Performance & Competition Discussion Areas and then to Racing & Drivers Education Forum.

There are tons of racers there and they can help you with most any question you have about club racing.

[DrS]

Thanks Jester911!

Hope to see you on the track someday!

[jester911]

Your welcome. Good luck getting your car back on the track.

[odog]

DrS,

Do you have the engine apart yet? The engine/trans numbers tell you what Porsche put in them...other hands may have changed some things around thereafter. Learning the "born on date" of the heads will help you determine if you should have big/small ports-measuring them will help determine if someone has altered them.. Progressing a G to F car makes for a very competitive car. With PCA Club Race scrutineers being more and more "watchful" over full and "correct" progressions ( MQ for instance), it is wise to document the differences and your respective changes-it may save you some time in impound! If you need help in outlining these- give me a ring!
Orrin

[DrS]

Thanks odog. I'm pretty sure the heads are small ports, 'born on' 5/79 (2) 7/79 (4). Wonder if they can be ported or perhaps better to just replace with big port heads? They certainly need to be rebuilt in any case.

Also, from Bruce Anderson's book the compression, port sizes, etc. for the 1980 USA and RoW engines are all the same but RoW makes 265 torque vs 245 for USA. The only difference in the Anderson table appears to be in distributor advance range. Is it possible that a distributor difference is responsible for the extra HP and torque? If so, can my 1978 distributor be re-mapped to the RoW specs?

Finally, I spoke with PHII and they checked the Porsche catalogs regarding the 915/61 transmission I have. From 1978 to 1982 the gearing in USA vs RoW is exactly the same according to PHII. This differs from the Pueblo experience in which some "F" cars were told they had different gearing in their "Euro" cars corresponding to USA specs rather than RoW (disqualifying them from "F" class). What's the real story?

[chrisp]

To take a USA SC into F you can go one of two routes. Run it as a Euro SC or run it as a prepared SC.

The Euro route requires that you make the car Euro in every way which is mostly if not all in the engine. The engine will need to be Euro spec. You can't mix and match Euro engine parts with USA parts. Some guys swear by running Euro SC's if F.

Running it as prepared requires you keep it as a stock SC but make allowed changes per PCA rules. This is suspension and brake type stuff. You could also make it a widebody I believe which would be an interesting idea. All told, the motor needs to stay USA SC.

So if you want to change the motor and can get all of the Euro parts that might be best. If you prefer to keep the motor SC based but still run in F then build the rest of the car to the letter of the prepared rules.

[odog]

DrS,

oh yeah- BTW...glad you are getting the car ready for next season-we missed having you out there!
Proper headwork will effect your power as much as anything-blueprinting your engine to perfection will net you the last half of what is on the table.
The SC heads from 78-79 world wide are large port heads originally- I39mmE35mm. From '80 forward worldwide the heads are small port I34E35. For building a progressed F Euro SC, you will need some small port heads. (Your other heads should be ok??)

Something to think about- look closely at the rules between a progressed car and a prepared car. Prepared can have short R&P, no AC,bump steer kit, suspension slotting,2" wider wheels, steel flares etc. etc.- large benefits. (some of these are proposed '08 rule changes-check first)

Small port heads are nice for lower end tq....There may be someone who would want to trade? I may have some-I'll look if you need..

The differences you are noting for the '80 engines specifically I think may be a typo here?
265 tq would be awesome!even if it was 265nm! (195ft lb)

The RoW '80 made (claimed) 8hp more than the US or JP even with a lower compression ratio! The '81-'83 RoW engines (note compression ratio diff) claim a 204hp/189tq.
Cam timing can rock the powerband around, distributor function & accuracy is critical to extract everything you can. Mapping distributors is almost a daily thing-it is unreal how many out there are way out of whack! One this week was down 11 degrees of advance...no wonder it was anemic.

PHII is incorrect. Partially. 915/61 trans are a worldwide trans ('78-'79)

in '80 the 915/62(ROW) had a 28/22 5th gear

but the '80 US/JP had the 915/63 with 28/23 5th gear and 18/32 2nd gear change as well....

your '78 transaxle should be a worldwide transaxle for '78. Do you know what 5th gear is in your box for sure? It is an easy one to change....box out, it should be less time than an average Rockies inning!

Best,
Orrin

[DrS]

Thanks Orrin. This is great info. I'll call you to discuss a build plan.

Looking forward to next season!

Dave