Finally Ready to Bore Need Some Input

[Quiz 0]

After two years, a nasty divorce (worth it), and a custody fight (also worth it) i am finally ready to buy my pistons. I am looking to buy JE rods and pistons with a 83mm bore. My dilema is what compression to run. I am going to turbo charge so i know that 8.5 is recommended. The setup is SUPPOSED to handle 1000hp. I am sure the crank wont though and a dont want to replace it. I would like to run 9.0 or 9.5 but im not sure how this will affect things. I could deffinetly use some input cause ill be ordering in 2 weeks. Thanks guys for the help.

[junkie 0]

What engine you boring?

[VR6 0]

I'm guessing:

 

http://www.the-corrado.net/.archive/forum/viewto ... =1&t=61191

[Kevin Bacon 5]

I would use 83mm Wossner pistons, or JEs supplied by Schimmel. Both are forged to take into account the later head gasket (thinner). In other words, you need an 8:1 piston to get a final static CR of 8.5:1

 

I would run 8.5:1 personally. The part throttle differences between 9 and 8.5:1 on the road are negligable, but with 8.5:1 you can run more boost with more timing.

 

If you're going for the big power, I'd use Crower rods. Stock rods are OK up to 450-500 crank power. The crank will handle what ever you throw at it.

And of course strap the whole lot together with ARP or Raceware bolts.

 

Worth considering a good s/hand 2.8 24V lump too which is a far better turbo engine because of the superior head flow. You can get a good one for £500-£600, spacer plate it, stick a GT35 on the back and you're looking at well over 450 crank power @ 1 bar. The pistons and rods alone for your 12V will be well over £1500 + machine work.

 

But good luck in which ever route you take :D

[Quiz 0]

I have a 2.8 with a distributor. No electronic ignition. I believe this motor is the first year vw ever built the vr6. And if it matters its an obd1. Also with all the tuning i will probably need the ecu reprogrammed. Whats the best course of action to take with this? Oh and the rods are a part of the deal as well. Its a packeage deal with je rods and pistons in a matched set with arp rod bolts. Im going to build it right from the ground up replacing or upgrading about everything. Its just real crittical in the early stages not to make mistakes, thats why ive turned to you guys for input and exsperience. VW's are notorious for running hot and in this southern heat i don't want problems.

[VEEDUBBED 0]

If you get the chance Flex-hone the block,i've done 3 engine blocks using the Flex-hone and it makes a huge difference

to oil consumption,especially when using forged pistons.

I used JE-pistons in my turboed 'raddo,Toyota mr2 turbo,8v turbo golf etc,oil consumption so far on all the engines is

0.

[Quiz 0]

The motor is going to a machine shop to get bored. But that is something i have never heard of so enlightnen me what exactly is flex honing and what does it do for the engine? I know what it means to hone the cylinder walls but ive never heard of flex honing. The only warning ive been given with forged pistons is some piston slap until the motor gets warm.

[VEEDUBBED 0]

Sorry for the late reply!,i'm on so many dam forums that i lose track...

Anyway,seeing as your going to get the job done at the machine shop you may

aswell as them if they can do it for you,they will know what the tecnique is.

The Fex-hone is a sort of brush that you attach to an electric drill and after you've

done the boring you pass it up and down the bores to finish hone the cylinders.

I did it my self whilst rebuilding my 'raddos engine.

Yes you may suffer with some piston slap,i have a bit but nothing bad as many people make it out to be.

1 other thing,lots of people have had issues regarding heavy oil consumption

when using forged slugs,especially JE-pistons,after doing at least 3 engines with

both JE-pistons and Italian CPS forged jobbies and using the Brush techniques supplied Flex-hone all three engines consumed no oil.i wonder why...