n/a 1380 c/r help and advice
Turbo Mini Forums

Doing some maths for a mates 1380 and just want some help, it's a stage 5 head and a swiftune 310 cam. So we believe that we need a c/r of 12.5;1

So far I've worked out around 9.2
Heres the cc with some stock measurements form turbo-mini.

Dish 11
Head 23
Gasket 3.8
Ring land 0.8

And the deck hight is 27 thou down the bore.

Thanks in advance for for any help

13.95 1/4 mile on a 2.95 fd. Carnt be that hard to beat!

A stage 5 head is likely to have chambers of 20cc or less on an off the shelf head from one if the usual suspects. Also if using aftermarket pistons you need to consider the dish. Lots of variables. You need to look at some off the shelf part values and take it from there

Id deck the block so the pistons are only 10 thou down and go from there, also check all 4 pistons are the same height

I seriously doubt it!

Headgasket wise I believe an Af470 has a compressed volume of 2.8cc if that helps matters.

ususaly on a build with a cam like this you'd use 6cc or less dishes,

with the 11's your gonna have a hard time getting it up high enough unless you can skim the head a lot, in which case watch out for valve to piston contact.

Il get him to check the spec on the head.

Will do that Paul thanks

And its a bk450 we use

Was thinking the 11cc pistons would be too much

Edited by eden7842 on 30th Dec, 2013.

13.95 1/4 mile on a 2.95 fd. Carnt be that hard to beat!

With the figures you've given there 9.2-1 is correct. You're not going to be able to get 12.5-1 with those pistons though. Decking the block to leave no volume & skimming the head to 20cc will still only give you 10.8-1.
You need flat tops.
Phil.

WWW.TURBO-MINI.COM

Thanks Phil, Ive just done some maths with flat tops and that'll get it straight up there

13.95 1/4 mile on a 2.95 fd. Carnt be that hard to beat!

What affect would the low c/r of had on this engine when running with this cam?

13.95 1/4 mile on a 2.95 fd. Carnt be that hard to beat!

much less torque off cam , cam coming on later , worse mpg ,less power all the way up .

I would run 12.5 to 13:1 on the rd with v max fuel with that cam .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Before it came out it never ran right, almost like a misfire?

13.95 1/4 mile on a 2.95 fd. Carnt be that hard to beat!

wrong plugs?

Drives
-Ford S-max Mk2 Ecoboost
-Rover 100 VVC #2 - track project

Searching is all you need on TurboMinis

I believe he had bpr7es that's right with megajolt?

13.95 1/4 mile on a 2.95 fd. Carnt be that hard to beat!

Looks like we're going flat tops and deck it to 10thou

13.95 1/4 mile on a 2.95 fd. Carnt be that hard to beat!

Use Omega 6cc offset pistons

I seriously doubt it!

I can only seem to find 7cc Paul?

13.95 1/4 mile on a 2.95 fd. Carnt be that hard to beat!

Thats it - 7 not 6. Thats what I use

I seriously doubt it!

Ah that's kool, what cc is your head if you don't mind me asking Paul? And also out of interest, why not flat tops?

Not major clued up on high power n/a tbh

13.95 1/4 mile on a 2.95 fd. Carnt be that hard to beat!

Ive no idea what cc my head is tbh. It was years ago.
Its all to do with chamber shape

I seriously doubt it!