re dishing std pistons
Turbo Mini Forums

Hi has any 1 re dished std turbo pistons to lower the comp instead of spending fortunes on omegas etc? Thanks scott

do a search - I think Sprocket did a few years back

there are plenty of people on here running standard turbo pistons and worked the head chambers instead

I use dished metro turbo pistons. extra 12cc or something like that

That would make them 21cc Alex? Are you sure that they haven't just been dished out to 12cc from the standard 9cc?

If something is worth doing, it's worth doing half of.

I thought std turbo pistons were 12cc anyway not 9? Or am I wrong I've had turbo phil mod me head already I think its 26cc what boost would yous recommend running with std turbo pistons & that head also have a front mount fitted its not the biggest but is an intercooler in good air flow

Ignore me. I think I am wrong. 12cc rings a bell for std turbo piston dish.

If something is worth doing, it's worth doing half of.

here you go,

its pretty easy to find the 2-3 cc that you will need, I managed to find 7cc in a set of Powermax's, but that's pushing it a bit.


http://www.turbominis.co.uk/forums/index.php?p=vt&tid=246578

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=364472

Who done them for you sprocket? Are thay still available? Would you run std chamber head with them or still a mod chamber head iam not sure what the ideal compression ratio is I have a good head ported etc but std chambers come from a car with 18cc pistons & I have a turbo phil head with 26cc chambers & iam just trying to get some ideas for a good build iam planning next year just don't wana spend 400 on pistons so thought re dish std pistons & the 26cc head should see some good boost = good power

Pistons were sold, sorry.

Head Shop UK did those for me, to my 'specification'. Basically cut the dish 5mm deep with a 6mm radious cutter leaving 5mm from the outer edge at the squish band. that resulted in the most even crown thickness and gaining another 4cc over an unmodified piston.

Note though that the pistons were removed from the rods, and that is the difficult bit.

I know do u think its worth the effort or just try getting a hold of some 18cc je or omegas what head would be best?

I just whacked about 6mm off the top 16 years ago when I did mine. ( creating an almost flat top piston....except sitting down the bore a bit lol

May not be pretty or great, but it was basically free, and it worked.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

what is your power target ?

power target => boost => CR => chamber / piston volume

I believe I read somewhere on here the 12G940 can be modded up to 29cc, this seems cheaper / easier than some piston modding

Rusty by nature

Iam after around 130-150 for now just wanting the cheapest way to go but safe enough that iam not rebuilding every other month lol

for that power std turbo pistons or any decent cast piston will be ok,

if you cant enlarge the dish yourself on a lathe, then you can get it done for about 40 quid, force racing above can do it.

What boost will be ok with std pistons & 26cc in the head? I was thinking 10 safe 12 max am I right in thinking this? I appreciate all the help

We have standard metro turbo pistons with new total seal rings in our van. we have 28cc in the head and a CR of around 8.2:1. WE have at times ran more than 20psi of boost and it hasn't gone bang... yet

Weather the pistons have survived will only be know when the head comes of for a winter rebuild.

10-12psi will be fine, at that boost you wont need to take anything out of the pistons, you'll have about 8.6:1 if you flush the pistons with the deck, or around 8.2 if you leave them down the bore as std.

There going to be down the bores as standard I've got new rings from mini spares that I've had for about a year & a half & going to get green & white to do the short motor build just got to get a cam & vernier set next would yous run an intercooler at that boost or not? I've got a set up on the car now just thought it would be a safe option

Intercooler= good. Same boost more power.

"So wat we gonna do tonight Brain?"
"Same thing we do evernight Pinky!"
"Try to take over the world!"

For the price you can get a cooler I wouldnt not run one.

I just leave it on then just didn't know at that boost if it would make any difference does any one know of a vernier & cam for sale? Also would a std gear box survive or would it need a straight cut?

we're putting 150bhp through a standard gearbox with s/c drops. used for road and drag strip. I think it's days are numbered though so it's getting s/c box over the winter

At that boost you can bank on the turbo charger adding about 75 degree's C to the inlet charge, with even a small intercooler you can loose most of that extra heat, moving you further away from det, and adding a few more hp,

IMO a std box will be ok at that power unless you abuse it with lots of wheel spins, you will need to change to a 4 pin diff though.

Phase 2 cams are cheap at avonbar at the mo, about 80 quid, (rather than the 200 odd that they were...)

Are champion ill get on to avonbar & I've already got a 4pin diff it not get a lot of abuse really to be honest. would yous get a cam kit with new followers etc or not?