Std Turbo Head ??
Turbo Mini Forums

Hi all what sort of power are you getting from a std turbo head as i've got a really good one and wouldn't mind using it when i've opened up the chambers and cleaned up the ports a little..

Karl.
P.s. is the TAM1361 Exhaust Valve the Sodium item..
:cool:

Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe.

OK chaps i went and CC'ed my Std Turbo Head and it came out at 22.4cc so with all the other bit's i've put together it's going to work out at 8.5:1 if i deck the block to the piston hight and around 7.9:1 if the pistons are 0.020" in the hole...

Karl.
P.s. I'm thinking 10-15psi should be ok, whats do you think ????

Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe.

What pistons are you running... that CR seems very low for that head volume!

alex

AlexF

Now heres where it gets interesting... I had a set of very think crown pistons fron Hepolite back in 1994 and after speaking with Stu from Vmax he gave me a recomendation to machine the crown out to form a dish of 14.7cc. this is how i can get the comp down and still run a 22.4cc head on a 1293cc engine.
By decking the block and moving the piston closer to the head i should be able to run good boost figures and keep away from the trapped gasses that form around the top of the rings and the gap between the piston and head this in turn should help to suppress detonation when running under boost.

Karl.
P.s. if you'd like the calc of my comp let me know.

Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe.

Nah I trust ya, was just wondering if you got the standard figures right... coz you won't get that with a 20813...

Are these the Hep's that come as flat tops..?

Alex

AlexF

Do you remember way back when Stu at VMax was running the black 1293GT ?. Well they're the same pistons he was using and with the machining that he recomended.
Their not the flat tops but did start out life with a very shallow dish and after machining you can still see the bottom of the original dish so you havn't made the crown any thinner you've just made the dish deeper towards the edge of the piston.
Now i'm not saying the top land of the piston is going to remain intact but there's no fun in not trying them out.

Karl.

Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe.

They sound like the pistons I am thinking of...

Yes I remember the black beasty :)

Definatly worth a try!!!

What's the rest of the engine spec?

Alex

AlexF

I'm not to sure just yet as i want it to be an everyday drive, i have 2 complete turbo engines to play with and a 1275 MG Metro engine with about 80,000 miles in it, oh and not fogetting the 998 with 40,000 on it.
I'm currently running a 1450 with JK 5speed S/C box and 40 DCOE which is a bit of a handfull for everyday use so if i can get a smooth runner with the option of boost on tap i'd be very happy.
My train of thought is to bore out to 1293, fit the turbo head after a little tickle with the grinder, Std T3 turbo and Std gearbox with the 4 pin diff, I'm hoping this should be a good starting point to get it on the road and get a feel for things.

Now if it's better that the 1450 who knows where things will end up, it could be a morph of the two cars in about six months.

Karl.

Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe.