G/day people, New members here. My house mate and I were given a '73 1200 coupe and where making it into a drag car. We got the motor to run and it has a average of 110psi to 130psi compression in the cylinders.

Now this has cost us only $60 bucks for the turbo and everything else was given to us, were doing it on a budget of as little as possible.

What we have also is a CT20 turbo of a diesel hilux (30'000klm old) and a 40mm side draught weber of a 2L escort and a 1200 manifold to suit the weber. Where having it as a draw through set up so no intercooler and I'm making the manifold for the turbo exhaust side etc.

The motor will be left stock except for a bigger radiator and a couple of other things.

What sort of boost level do you think would could go? We are not sure whether to run it on utilimate, avgas or meth.....

I've had 2 1200 utes and a 120y coupe, and my house mate had a 120y sedan all in n/a form and they all have done me well. I know that they can run in redline no worries at all but how they run under boost with a 9.0 to 1 compression ratio I don't.

Any thoughts... let us know....

I am no expert in A-series turbocharging. However, looking at turbo kits for the Nissan L-series, I would say no more than 5psi for this motor, as it is "draw through" and not "blow through".

There are several problems with the draw through turbo systems, they include:

1. A situation called "flame back" where, under certain circumstances, the air/fuel mix in the turbo/induction system can ignite inside the them and literally shoot out of the front of the turbo. This can cause SERIOUS damage and toast the car. do not put the air filter too close to the turbo in this system; put it very far away.

2. During, particularly off-throttle moments, the air/fuel mix can settle out inside the turbo compressor housing.

3. No blow-off valve can be used in the draw-thru type since it would vent air and fuel into the atmosphere, VERY BAD! Since you would not have a blow-off valve, you would have a bad case of compressor surge during off throttle periods. This is bad for the turbo and its seals, etc.

4. No intercooler, very limited boost!

Just so you know!

as per comments...

I want to go blow through but unsure the weber sealing ability, plus i would have to get a high pressure fuel pump and reg to equal the boost.....so I've been told.

1. never heard of flame back so thanks for the info.

2. flat changes mostly..... but see what happens.

3.Where using a plumb back so it's all good.

Thanks bloke.

Im just about to put a blow thru supercharger setup on my a12, and my mate has turboed a12. He has a 32/36 webber with upsized jets, he runs a low pressure electric carter pump as the problem we were having was the fuel bowl was emptying as the normal engine pump couldnt fill it fast enough!! He is running a fj20 turbo. At first we didnt have it intercooled and it ran at 7-8 pounds no worries. Next we put the intercooler on and run it at 10psi for about 2 months then he got bored so turned it up to 14psi and after a while did a ring land. The next motor we put in he thopught it would be fun to weld the wastegate shut and it ran on 20psi but lasted a night but all that happened was the rocker arms snapped mainly due to too much rpm. SO yeah they are pretty strong for their age!!!

Don't write off drawthrough just yet!!!!
You don't need a blowoff valve, when you shut the throttle butterfly, the engine uses all the air/fuel in the system, leaving only vaccuum. Then when the turbo starts to spool again, the compreesor wheel is not trying to turn against a mass of compressed air, so no lag problems.
You can buy a decomp shim off the self. I think it's made by permaseal.

Quote:

huh?

you don't need a BOV in a draw thru setup at all.

the butterfly is IN FRONT of the compressor, not after it. so shutting the throttle off isn't going to cause any problems with flow reversion, or "compressor surge" as you put it.

having a BOV in a draw thru setup would have fuel spewing all over a hot engine bay on every gear change. it's okay if you like fireworks i guess...

and like A14Force said, get a decomp shim and run 1bar thru it til it breaks, then rebuild it so it doesn't. why piss around with 5psi?

A series engines are stronger than most people give them credit for. and if you do break one, a whole engine rebuilt can be had for under $500.

have fun

For the price of a little A 12 I would get the turbo and all hooked up and boost the hell out of it !!! with good fuel should see at least 15psi I would go 18-20+psi whats the worst that can happen pop a head geasket??
Give it a go and let us know how it handles it all.
If in Doubt run even more boost

Quote:Well, i guess i see it from a diferent angle.
All i see is a perfectly good engine, in a bloody good car being screwed on the cheap for a few laughs.
With boost figures of 15lbs being mentioned, yet not a single sentence on detonation control, all being done by people who don't really know what thy're doing, i see an engine being reduced to scrap in short order. Once the engine's gone, & the novelty wears off, i wonder what will be the fate of the car, as it seems to have received scant attention here.
Along with cheap mega performance, there seems to be no interest in upgrading the chassis to handle it. The focus just seems to be on cheap thrills at what i suspect will be the cost of another of our beloved Datsuns in the end.

Please prove me wrong.

Quote:

it prob hasn't even been rebuilt yet. so if it doesn't die by the end of the week, it will once turbo'd or cammed / carbed up.

who cares if it blows? these engines are so cheap to rebuild that even if you did smash a piston a whole set of HE's only costs $AU175 and that will handle 1bar no sweat with an A14 head etc etc.

don't sweat the petty things dude