My 4k is getting some work

[ollieboy]

Finally I finished exams so I have time to do it.

I am wondering how much I can get planed off the head before it gets dangerous, I'm wanting to run Av Gas, what sort of compression is the MAX I can run with that? I know people running 200 psi fine on Av Gas.

What do I ask for when I'm getting my Cam Ground for a good spread of power?

And Finally what size pipe should I use for my exhaust? I already have extractors on there.

Any other suggestions for a bit of power? Apart from, "$&#$% 4age it au!"

I forgot to say, I already have a webber carb to go on and the flux capacitors been sent out .

Cheers
Ollie

[Dell'Orto]

With avgas 11:1 will be alright, probably could just get away with 12:1. How much you can plane off depends on what sort of head, what pistons, etc etc. Your engine builder will be able to do this for you.
You ask for exactly that, a cam grind that gives a good powerband. When you go to your cam grinder, they'll ask you lots of questions to figure out what you need.
Exhaust, go with 1 3/4" unless you're building a top endy screamer, then 2" will do the job.
For more power, arsehole the Weber carb (assuming its downdraft) and get a pair of Weber/Dellorto 40mm side drafts. Will be the best thing you could do.

[ollieboy]

Awesome, thanks for clearing that up.

[ke25sr]

I was running 230 psi @ crankin speed in my 4k with a F12 cam & double valve springs to suit.
It could rev round to 9000rpm but made power to about 8000.


I highly suggest balancing everything that turns, get som +60 pistons, 40mm sidedrafts take 120 thou off the head (if its got dished pistons).
F12 cam and Springs. Deck the block, Chrome rings. ( I found the standard rings dont like high compression).
A good Port n polish but not to big 35 mm seemed to be good for mine
go nut on the Exhaust side though.
good Extractors and a 1"3/4 pipe through it.

I can send some videos of 1 in a wee starlet this set up.
Kept up with a JZA80 supra 2JZGE manual off the line. Mind you Supras are heavy.

[TOYROTA]

hey ollie i have a twin carb inlet manifold if you are looking for one, i was gunna use it but decided on 4age