Thread: more HP
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Alan L Alan L is offline
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Join Date: Apr 2006
Location: New Zealand
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OK, here is what we have so far;
1)SC cams (with a 'slight" )performance gain (Fred)
2)964 cams
3)Open ports
4)Leave ports

Somehow I need to make a decision on these. I have been dealing with Chris (Turbokraft) on some other stuff. Hopefully he won't mind. Copied below his comments;

Assuming you have Sport headers and a straight-through 3” muffler already, here’s what to do while the top end is apart, without falling down the slippery slope:
1. SC camshafts = $1100/pr new
964 is better, but technically straying outside the letter of the law
remanufacturing your rockers (magnaflux, re-grind, re-bush)
2. ARP head studs – safety against a head lifting under boost
3. upgraded valve springs & retainers – mechanical insurance against floating the vales in case of a missed shift (safe at 8,000rpm)
4. port & polish – 40mm intake / 38mm exhaust
• 40mm intake -- this is as far as practical with CIS injection, the limit of the stock intake gasket, the typical porting limit of the cast intake manifold
• TK billet CIS injector blocks @ 40mm
• 38mm exhaust – port-matched to common 1-5/8” sport headers
5. ARP rod bolts – yes, you can easily pull the rods w/o splitting the case (especially after the head studs are removed – easier to work)
A really nice improvement in durability is solid dry film coatings to the following:
• rod bearings
• piston skirts

Now, if you’re straying outside the spirit of the law – okay, blatantly cheating – is bumping it all +1 more:
* porting to 41.3mm / 41.3mm – exhaust is now matched to 1-3/4” tube headers
* big 1-3/4” headers, divided twin-scroll turbine flange
* custom K27-based turbo:
twin-scroll turbine housing – these divided K27 flanges are getting very hard to find
upgraded compressor wheel in stock K27 housing
* 964 camshafts, or
TK EFI-T camshafts + machine valve pockets into piston domes (extra clearance)

I have some leeway in terms of cams (internal mods are OK) and can probably go to K27-7006 and stay within the terms of the rules - since it seems the 930S came with 7006. At the end of the day they are letting cars outside the rules run - to keep the fields large (20-25 cars). The front two in the video do not comply - the white Escort has an $80k Cosworth engine, and the RX2 has an aftermarket 13B. Mine is the quickest compliant car, by a long way (and set a new lap record for the group in that race - which cost me all my points (break out time)).
But I do like to stay within the rules (and still win).
So assuming a 7006 turbo, do I port the heads, do I go SC or 964? Does the 964 fit straight in like the SC?
83 SC, 82 930 (track) - Stock except for RarlyL8 race headers, RarlyL8 Zork, K27-7006, 22/28 T bars, 007 Fuel head, short 3&4 gears, NGK AFR, Greddy EBC (on the slippery slope), Wevo engine mounts, ERP rear camber adjust and mono balls, Tarret front monoball camber adjust, Elgin cams, 38mm ported heads, 964 IC. 380rwhp @ 0.8bar Apart from above, bone stock:-)
Old 06-10-2014, 12:31 PM
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