please can someone help identify my engine
Turbo Mini Forums

Hello, first off I apolagise if this has been covered before but I have searched everywhere and cant seem to find what im looking for. Im converting a 1275 n/a into a low boost turbo engine which I would like to run 10psi to a maximum of 15psi, the engine number has been removed so unfortunatley I dont have anything to go by for my standard compression ration. I have removed the head and the piston crowns have the following numbers stamped: 21268 g7 L33 can any body tell me what dish size these pistons have and what compression ratio they give using a standard head? Because there not out the engine I think il have a job using a pepet and perspex to measure them. Also are these pistons ok to use with the boost pressures I have mentioned. Please help! Many thanks, rob

The answer is simple measure the CR and dont go off the numbers...

Have a search for how to measure the piston and head volume.

You can then enter the data into an online calc and it will work out your CR

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

Low boost and "10 to 15psi" don't really go together....

That's what I was thinking. 5 to 8 would be low, 8 to 12 mid, above 12 high, above 18 getting there, over 20 excellent - Any more expensive!

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Ok my fault il stay away from the term low boost then, I know its best to measure the cc of each part and work out the compression ratio but I thinkk thats going to be a pain to do with the pistons still in the bores, if I could just find out the dish size of the pistons and even if there going to be ok to use in a turbo engine then im more thst happy to measure everything else and work out the compression ratio :) hope someone one can help :) thanks guys

I would say I found out the hard way with running an engine with the wrong cr for the boost that I wanted, and it cost me lots of fucking around! Just pull them and do it right from the start!

Simon.

I have started posting on Instagram also my name on there is turbomk1golf

Nothing is impossible it just costs more and takes longer.

Thanks for the advice simon. It will be annoying if I di have to pull the pistons out as ive only just put tge motor in after changing gearbox and cam. Really should have thought more at the time :(

If you're unsure on the pistons don't use them, it'll only end up in tears, have a look around and see what others use for a similar spec of engine, there's no real cheap way of having a reliable engine, spend the money where it counts, having a quality piston is definitely one of those areas.

Ok carlzilla. Just didnt know if anyone else had any experience with these pistons, cant find much on them :( thanks for the advice :)

Right ive had abit of a think and decided im going to try these pistons out. It doesnt seem anyone else really has so I thought iI should give it ago and see how I get on. Im still learning alot so I think some trial and error is good :) I think like you guys have said 15psi is fairly high so planning to run 10psi with a maximum of 12psi. Can anybody please tell me a way to work out the piston dish size without pulling the pistons out the bore?.. thats even if there is a way :L thanks

Da-Daaaaaa

Estimating piston volume:
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=711

Cheers turbodave16! Thats exacrtly what I was hoping for! I will borrow some more precise measuring gear tomorrow from work but after a quick measure with a straight edge across the piston crown and a spike painted in fresh tipex in the middle of the piston crown. I then gentley rubbed the straight edge against the spike leaving a wear mark in the tipex. I measured from the bott I m of the wear mark to the bottim of the spike and it showed 8mm :) like I said I will use more accurate equipment tomorrow to confirm but hopefully ive found my answer