UnitedMotorsport 55 Posted March 29, 2010 Report Share Posted March 29, 2010 Only reason to ever bore a block is to get a clean bore for new rings to cut in.If you have a perfect 81mm bore block with no wear or lip then use it (a million in one chance)Only ever bore an 81mm block to 82mm and consequently a 82mm block to 83mm. Link to post Share on other sites
matty.vrt 120 Posted March 29, 2010 Report Share Posted March 29, 2010 Also if you after 700bhp c2 motorsports now do a pro maf setup so why go to the expence of standalone. i use there 630cc set up with 4" maf and it works brillient. it runs totaly like stock till you hit 3 grand then boost comes then at 4 grand then all hell brakes lose and thats just at 24 psi Link to post Share on other sites
FishWick 21 Posted March 29, 2010 Report Share Posted March 29, 2010 Only ever bore an 81mm block to 82mm and consequently a 82mm block to 83mm.If you want to keep the same block for 200,000+ miles, then fair enough, but there is no technical reason why you shouldn't go from 81mm to 83mm. I did that almost 50K miles ago and it's been perfect. Link to post Share on other sites
matty.vrt 120 Posted March 29, 2010 Report Share Posted March 29, 2010 I dont think i could afford to do 200.00 vr turbo miles lol. dont wossner do 83.5mm pistons Link to post Share on other sites
FishWick 21 Posted March 29, 2010 Report Share Posted March 29, 2010 Yeah I think they do. JE do aswell.Schimmel put 800whp through an 83.5mm 12V block :-) The 12V is a tank. Link to post Share on other sites
matty.vrt 120 Posted March 29, 2010 Report Share Posted March 29, 2010 So its proven then overboring a vr6 has no adverse effects on the capability to hold power. Link to post Share on other sites
FishWick 21 Posted March 29, 2010 Report Share Posted March 29, 2010 Yep, but for how long though is a different matter :-)I've read that some high boost R32 turbos have needed girdled blocks as they can't handle it. Doesn't surprise me looking at the block casting closely. It's not as 'chunky' as the 12V's. Link to post Share on other sites
matty.vrt 120 Posted March 29, 2010 Report Share Posted March 29, 2010 They use 84mm pistons standard dont they. so if they have overbored when theyve gone forged its starting to get close. Link to post Share on other sites
FishWick 21 Posted March 29, 2010 Report Share Posted March 29, 2010 Yeah 84mm, with longer stroke too. Link to post Share on other sites
Scaley 0 Posted March 29, 2010 Author Report Share Posted March 29, 2010 So judging by the info, its best to stick with the smallest bore you can for reliability issues seeing as its going to be a track car!Would it be best off using the AUE engine so you have good wall strength from the block but the benefits of the flow from 24 valves, are the head internals the same on the AUE and R32? Link to post Share on other sites
FishWick 21 Posted March 29, 2010 Report Share Posted March 29, 2010 R32 head has bigger valves and ports, but smaller diameter head bolts.Personally I would just go with a complete 2.8 24V and not worry about the R32 head yet. That's something you can do later down the line. Link to post Share on other sites
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