Thread: WHP gains by boring out block

Guys, I was just wondering. I have a VE which needs to be re-bored (switching from old pistons to new, and need a clean cilinder wall).

At first I thought about just boring it to 86,5 and call it a day. But I started wondering, what are the gains when boring out the cilinders? Is it significant?

I'm not looking to get a 2.2L motor though, I'm gonna turbo it later. But I was just wondering what a 87mm bored engine would do.

Not much at all, tbh. 87 vs 86 is only around 25cc's more displacement IIRC. Unless you go higher CR, you're not going to make more power. Maybe 2-3whp peak.

Thanks mate, then I'll stick to my original plan

86 = 1998cc
87 = 2053cc

My brother in law has an 87mm built DE and the extra torque is evident everywhere.

186whp with 15% altitude losses.

There should be no cost difference going 87mm over 86.5 so I'd just go 87mm if I were you. It still safe once you go turbo and I can't think of any drawbacks.

I have found on a DE motor and VE motor there seems to be a 13-15 WHP gain for every .1 in displacement, which is 2mm or 7 WHP for every 1mm over.


Cory VE made 217 WHP with 2L and 260 WHP with 2.3L


My DE made 175 WHP at 2L and 200 WHP @2.2L

i thought corys was a 2.2, just a 90mm bore with stock crank?

why would you think it is 2.2 when in every post about his car he say 2.3. his motor is 92mm bore x 86 mm stroke which is 2.3L

i dont really come on much and i dont read every post on his car, shows what you get for speed reading

Something to remember aswell though is that my whp gains were not from bore alone. The cc was opened up to macth the cylinder bore and deshroud the valves. This helps out the heads flow a lot.

sounds good. Who did the cc for you?

Is there like a build thread of your car?