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boring the vg30 block


uummm
12-03-2007, 12:44 PM
i have an 85 300zx turbo and blew my motor about a year and a half ago and i wanna rebuild it to make some serious power, the block wasnt hurt none but i was thinkin about boring it out anyhow cause i know more displacement=more power... but i dont know how far i can safely and reliabily bore it out. i was thinkin to a 3.3 since from factory they came like that (vg30 overbored) but i wanna replace my whole rotating assembly and i dont know where to go to start, i want new pistons and rods, and i would like a stronger crank, i know the rods and crank shouldnt give me to many problems, but i wanna make more power than what they can probably take.. also whats probably the biggest turbo you can fit on this car and still spool, i was thinkin of upping the compression ratio from 7.8:1 to something closer to 8.5:1 and using z32 pistons (not factory, but aftermarket, i wanna make use of the floating wrist pins.) any help would be greatly appreciated thanks.

Tach_it
12-06-2007, 09:40 PM
What are your power goals? You to bee more specific with what you are trying to gain, and if you are planning on getting high po rods, crank, and pistons you better have several thousand dollars. On that bore situation the stock bore is 87mm, most individuals rebuilding usually go with 20 or 40 over which 87.5mm and 88mm. Which would put you at 182 and 184 cubic inches which is 2991 CCs and 3026 CCs. Considering the VG30DE(TT) is 2958 CCs stock form it would be impossible to attain 3.3 liters and you could attempt to get some custom pistons made for the big bucks. Your other option would be a stroker application. Check with some crank and piston manufacturers. Hope that helps.

DeleriousZ
12-10-2007, 10:00 PM
fyi you CAN NOT bore a vg30 out to a vg33... CAAAAANNN NOOOOOOT

unless you're making more than 600rwhp (not bloody likely) then you don't need to worry about the crank... hell the electromotive z made over 1000rwhp on a stock balanced crank for a good long while before breaking it.

your power goals are VERY achieveable on the stock vg30, no matter what you think they are.

as for turbo's, people like SATAN and Stevez31 from z31performance.com are running gt42's, for an idea of what is useable. for something streetable, the gt3582 will do just fine. for better spool a .63a/r hotside would be best, if your goals are more top end then go for the .82 housing.

what are your other supporting mods so far?

k3smostwanted
12-11-2007, 05:26 AM
fyi you CAN NOT bore a vg30 out to a vg33... CAAAAANNN NOOOOOOT

unless you're making more than 600rwhp (not bloody likely) then you don't need to worry about the crank... hell the electromotive z made over 1000rwhp on a stock balanced crank for a good long while before breaking it.

your power goals are VERY achieveable on the stock vg30, no matter what you think they are.

as for turbo's, people like SATAN and Stevez31 from z31performance.com are running gt42's, for an idea of what is useable. for something streetable, the gt3582 will do just fine. for better spool a .63a/r hotside would be best, if your goals are more top end then go for the .82 housing.

what are your other supporting mods so far?

bah...tell that to Escort.

DeleriousZ
12-11-2007, 09:58 AM
escort uses a vg33 block for their vg34 engine

uummm
12-13-2007, 12:37 AM
actually they do not use a vg33 block, otherwise there would be no core for the motor when you get one, and i have heard that the vg33 is nothing but the vg30 bored out some, also ive looked for strokers, cost too much and not worth it really, you lose rpm on redline with a stroker, but i am lookin at tryin to get more than 600hp in my car, i wanna have a bad fast car and i have a spare motor for my car so time isnt really a big deal

DeleriousZ
12-13-2007, 01:03 AM
there is a TON of conflicting opinions out there on the actual bore subject, but let me tell you it can't be done... the physical wall thickness would be the same, but there are water passage differences that will not allow this to happen.

don't believe me? take a look at the short block next time its apart.

and you do NOT need anything more than the vg30 to achieve your power goals, the vg30 is a VERY capable engine of making power.

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