New Zealand Datsun Club

85_Z31 wrote:

2 doors wrote:Have just been reading up on Kitch,s compression ratio chart, and it recommends between 7and 8 to1 for turbo motors, so I may be well off on my 8.5/1 .
To be fair it was a number I got off a build thread on 1200.com,

lower thasn 8.5 to 1 is unnecessarily low with decent fuel and the massive improvements with turbo's and inter cooling.

a lot of factory turbo cars started out in life around 7.5 to 1 or 7.8 to 1, and after a few years of production were moved up to 8.5 to 1.

sure you can run more boost but having the extra compression there will let it be more drivable, better fuel eco ( off boost ) and will actually help it get onto boost nice and pronto.

Are you going to be running Carbs or EFI ?

good to know my recent pouring over the net hasn't been in vain, looks like its back to 8.5 to 1 with a mild 8psi of boost.

2 doors wrote:good to know my recent pouring over the net hasn't been in vain, looks like its back to 8.5 to 1 with a mild 18psi of boost.

FIXED!

Bartman wrote:

2 doors wrote:good to know my recent pouring over the net hasn't been in vain, looks like its back to 8.5 to 1 with a mild 18psi of boost.

FIXED!

lol that's gold

18lb may be pushing things on cast pistons but 12.5 if everything else is in order should be okay.
Phil Stanley at Turbo Tech. always told me that 12.5 was about the limit on cast pistons but obviously things have changed alot in terms of engine management over the years and even if you are going fuel only with the computer as long as you are using good fuel ( and enough of if ) and conservative spark all should be well.
Are you going to use ARP head studs? They probably are well worth considering.
Cheers
Dave

b110sss wrote:18lb may be pushing things on cast pistons but 12.5 if everything else is in order should be okay.
Phil Stanley at Turbo Tech. always told me that 12.5 was about the limit on cast pistons but obviously things have changed alot in terms of engine management over the years and even if you are going fuel only with the computer as long as you are using good fuel ( and enough of if ) and conservative spark all should be well.
Are you going to use ARP head studs? They probably are well worth considering.
Cheers
Dave

yes thanks Dave, after our pms back and forth, ARP will definitely be in order for both head and rods.
pretty sure 8psi should be all I need for now. looking forward to seeing how it all works out.

Even though im not at this stage yet, Im curious as to how people run in their engines when they are boosted?

hey folks, well another week down and a few steps further along, My water jetted flanges finally got done today,
so very stoked with how they turned out, have bought some injectors off Brendan, I didn't realise they were side feed at the time, but I think they will work out really well,
I have sweated the injector bosses off the injector rails and will obtain some pipe this week to cut to size and re weld onto the inlet pipes, but that's a week or so away.
I have mocked up the turbo where I think it will work well, and have started on the flange that bolts to the turbo .

well its been a busy weekend, Daughter turned 13 yesterday so garage was out of bounds, and took the family out to Disney on ice today, BUT managed to squeeze a couple of hours in this afternoon and got some pipes tacked up into place,
BIG THANKS to nick m for the discussion on Friday night regarding header pipes and exhaust design, also big thanks to james for posting pics of his rb turbo manifold, as it gave me some inspiration as to how to bring the pipes together at the flange.

Was about to post and ask on progress....great stuff, very impressive....will be watching this.

if you guys can tack these manifolds up that quick im buying an FJ Flange !!!!

Love ya work, keen to come over one night and check this out