Offroad-Express

do you hook the water cooling up when doing a turbo conversion on a 3L? or leave it to stop the strain on cooling system?

Also do you put a thicker head gasket in (head is off) to lower the compression?

specs are
hi-flowed ct-20, water/meth inj, water/air barrel cooler, slight head and cam work

yes hook the water up. it doesn't add bugger all heat to the cooling system. its only a problem if the cooling system is rooted.
water cooling helps extend the life of the turbo. either use factory setup or if you make it fit get the pipes in the right places, otherwise it won't work right when the engine is off.

the stock oil system feeds oil from BEFORE the oil cooler to the turbo. ie turbo gets fed hot oil not cold oil. if you don't use the water hook up i would change the oil feed to the other oil feed points that are after the oil cooler.

don't worry about head gasket. with a ct20 you will never ever get boost high enough to warrant using a thicker head gasket.
if its a rebuilt engine it may already be running the thickest head gasket anyway. its a dirty engine building trick which tends to make them run poor offboost and when cold.
so measure piston protrusion and get the right gasket.

i'm keen to hear about the head and cam work tho.

tweake wrote:...i'm keen to hear about the head and cam work tho.

Me too

Talked to a head place in christchurch who are going to do the head up abit, they said in there exp porting and polish is not worth the time and effort and are just going to put some more tension on the valve springs, and also going to grind a cam for me, they are talkin about modifing a 5L cam to suite with a grind on it

The head isnt off yet so while im re-ringing/ bearing the eng i thought i might aswell change the comp abit while im in there if it will net me any gains, i will see what my head gasket is and maybe just go to the thickest toyota does

the turbo is hi-flowed with a larger comp wheel and polished internal housing and the bench set them to 12-14psi, they run these no problems on the 3Ls/2Ls they have done them for

don't bother lowing the compression, it just makes it run worse.
you need the compression to make the heat to ignite the fuel.
to drop the compression you need to be able to keep the heat in. IDI loose a lot of heat hence the high compression. i have heard of thermal coatings been used but use it on the wrong place cause ignition problems.

no real need to increase valve spring pressure. your not doing high rpm like a petrol. but a bit more won't hurt.

cam and cam timing will yield gains. there a few posts on that topic on the aussie surf forum.

but all that won't do much if the piping/intercooling isn't up to scratch.

tweake wrote:don't bother lowing the compression, it just makes it run worse.
you need the compression to make the heat to ignite the fuel.
to drop the compression you need to be able to keep the heat in. IDI loose a lot of heat hence the high compression. i have heard of thermal coatings been used but use it on the wrong place cause ignition problems.

no real need to increase valve spring pressure. your not doing high rpm like a petrol. but a bit more won't hurt.

cam and cam timing will yield gains. there a few posts on that topic on the aussie surf forum.

but all that won't do much if the piping/intercooling isn't up to scratch.

at the end of the day theres no real point in doing most mods, but what we are after here is gains where we can get them,

as for intercooling, the water/air cooler will sit on top of rocker box so will be a very short trip from the from the turbo to the intake