firstly thanks to danielblues, bent-axle-bob and other senior members for letting me in!
i am an owner of 1980 Datsun 120Y(square lights B310) it has A12 engine in it. i am going to install a turbo in it, most probably a Daihatsu 1000 cc diesel turbo unit. i need a lot of help from u guys. go_the_datto installed same unit in his A12 but 2 instead of one. now i have never actually seen it, but i know i can get it easily,
go_the_datto u should know answer to most of these questions
Firstly i want to know does it have wastegate(internal/external etc..) and blowoff valve or not.
And i dont want to box the whole carb, so how much PSI should b safe for carbs seals?
can i expect 50% gain in HP from this setup?
I dont have any intercooler for it. can i use any Aluminium water radiator instead of intercooler, is it better then nothing?
is Daihatsu turbo too small for A12 to work optimally? or 200CC difference is ignorable?

BTW i am from Pakistan, and hopefully the first guy here who is going to modify any Datto ever
so guys help me as i want to kick some Honda 1.5 litre butts
barpk

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No turbo comes with a blow-off valve, it's a seperate device.
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Only one way to find out. Quote:Not with that tiny turbo you won't. Quote:Remember that diesels have drastically lower RPM limits and loads. You can't compare CC size of a diesel turbo that only sees 4000rpm, to CC's of a gas engine that will turn 7000rpm+. If you only want to run one turbo, I personally think you need something bigger than that one.

Welcome to the club!
As for the smaller turbo being the optimum size, probably not. But it will spool up faster than a bigger one. You might not make as much top end power but it will still be a hoot to drive. I'd say go for it and get a bigger one if this one doesn't make you happy.
I think I follow what you are thinking with regards to the aluminum radiator. You want to blow the air through where the water is supposed to go? If so, I would say the pressure losses and restrictions would outweigh any cooling benefits. Intercoolers generally have huge internal passages for a reason. I could be wrong though, it might work just fine.
Best of luck to you, and welcome again.

daihatsu RPM limit is 5500, i dont know about the A12 limit? anyone.....
i know that BOV is seperate unit! i just wanted to know if it is in the cars bonnett or not? so does the W/G?
i want to run air through the water channels in the radiator, its not more restricted then intercooleri i suppose.
what about getting a Pajero diesel turbo? have any one of u know anything about it?
barpk

Regarding the Turbo size I would go for a turbo off an engine the same size or one that is a bit bigger!
And I agree that the smaller turbo will spool up quicker but this will reduce top end power because you are putting out more exhaust gas flow than the turbo can handle!
This will lead to excess heat from the turbo and eventually turbo failure!

Regarding how much pressure to safely run in a standard carbie with out modifications to the seals! I have found that anymore than 10 psi causes the top seal on the carbie to loose boost! ( Anyone who has ever rebuilt a datsun 1200 carbie will know that the top of the main body warps and has to be filed flat! This is because of the flimsy design around the srew points!)
Because of this when boost is applied the main body flexes around the float bowl and cause boost to be lost! this is right neartheneddle and seat the vacumn effect of the boost blowing out causes the incoming fuel to be sucked out and the float bowl to go empty! This causing the engine to lean out and problems start to arise!

One major thing to remember when turbo charging is to make sure that at any given time you have more fuel pressure than boost pressure! (other wise boost is blowing the fuel back down the fuel lines!)
So if you are running 10 psi boost you need over this in fuel pressure say around 15 psi fuel pressure!
But with a carbie the needle and seat can't hold15psi fuel pressure unless it is getting used up straight away! So you need to run a malpassi rising rate ( carbie not efi ) fuel pressure regulator!

( One other thing is if your carbie has vacumn secondaries you can't boost it as the carbie won't work properly! )

my Datto is the last model with A12 engine (1980) i have replaced its full carb kit 3 times in past 10 years, and i never had to file its any carb part. i hope it doesnt blow under 10 PSI(its seals r made of cork sheet, r they ok for 10 PSI?). as i aint gonna go above this for a month atleast.
can i use ANY 2000-2500 diesel turbo for A12?, as their CC is more, shoudnt higher RPM compensate the compressor buildup or not? e.g diesel RPM is 5500, A12 is 6500 which means 19% RPM difference, but engine capacity is 80% - 100% more, doesnt that mean the turbo made for larger engine wont buildup any considerable PSI for A12??? or, as the diesel turbos spool up in lower RPM ranges due to its OEM requirment, the 6500 RPM should give it enough boost???
can this big turbo stall if i put it in A12??
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what r these vacuum secondries? how do i know if they r present or not, BTW my float is solid plastic. and my A12 is the latest modified A12 from japan.
phunkdoktaspok; u also wrote in reply to "turbo A 15 being built" that friend of yours fittedT3 turbos in A12! now these turbos r used in 2.3 Mustang and 3 litre nissans and many other above 2 litre engines! does that mean a larger diesel turbo will also work fine in my A12!!! clearify plz.....

what suggestion do u guys have of fabricating IC out of radiator?
barpk

I think the turbo will be too large, but it may work.

Even though others are talking of using T3's on an A12-A15, this is a very large turbo, and probably wouldn't be well suited to an A-series engine. With a small engine, getting more torque down low, by using a reasonable sized turbo, will give you better results. I doubt that any A-series carby will be able to deliver enough atomised fuel for a T3 turbo's airflow..This would be only ok if you ran a proportionally sized throttle body and fuel injection.

Making the intercooler out of an old radiator is not a great idea. Just use a cross over pipe in the short term. You will have enough carby headaches to fix first. Get an intercooler out of something else. Even a small one will make a difference, do this after you get the engine running.

I read recently hre, thatthe old copper bulb can be squashed under boost, so the solid plastic float sounds like it will help you. The cork gaskets in the carby may not work, but it's worth a try.

So I think your priorities should be:
1. Get the concept to work.
2. Put an intercooler in.
3. Get a larger turbo / carby.

There's a lot of variables, and you don't want to spend loads of money to find your carby explodes into pieces everytime you put your foot down.

Remember with carbies you are more likely to burn out pistons etc. due to bad mixtures. The tuning of the carby to suit the turbo boost curve will be a huge job.
It's much easier with fuel injection because the fuel delivery under the different load conditions is variable. With carbies you are limited to:

1. idle jets
2. Accellerator pump jets
3. main jets

During tuning you will need to make/borrow an air/fuel mixture meter, to ensure that your ratio is good to stop lean-out.

It's not as easy as just making a manifold and pushing compressed air in the carby.

You may have good luck and it will be easy.

Good luck, I'm always happy to discuss my opinions. I've not done a turbo'ed A-series project, mainly due to R&D costs and unknown results.

Chris.

First congadulations on never having a warped carbie! ( I would like to see it! even smaller than 1 mm is a lot of warpage on a carbie!)

Regarding cork gasket- I have never seen them used ( maybee they will last but probably they won't! )

Personally i wouldn't bother putting the carbie back together with standard gaskets, as even you said it - 10 psi only for the first month!
Trust me if you drive a boosted car you wont be able to stop yourself increasing the boost, even if you have strong will power!

Regarding diesel turbos - From what I know diesels and petrol engines have a big differents in exhaust gas flow! So unless you know turbos I would stick to petrol turbos for petrol cars!

Vacuum secondaries - Being yours is an 80 model chances are it has vacuum secondaries! ( not sure! )
If you have a vacuum line running to a solenoid to open the secondary throtle valve ( you have vaccum secondaries!)
If you have mechanical linkages to the secondary throtle valve! ( you have mechanical secondaries! )
( I dont know how else to explain them! )
Mechanical secondaries are required as if you apply boost to vacuum secondaries they will not open up and this will cause the engine to lean out!

Regarding the Turbo - I said a T3 off of a Nissan VG20 engine ( not sure which car this came in! )
This T3 has to wastegates! One works as normal and the other is an anti-lag wastegate! It works by causeing the exhaust gases ( at low boost ) to travel in a narrower path! this making higher velocity causing the turbine to spool up better at low RPM! then is opens up at a certain boost pressure to slow the turbo down at a higher RPM This making the car keep the same boost level!
( On the 1200's we left off this anti-lag wastegate so that the turbo would spool up more and increase boost!)
This is basically the same as modifiying a turbo to have a large compressor wheel and a smaller turbine wheel!

If you get a turbo off a bigger engine it means you will have to rev the car more to get enough gas flow from the exhaust to spool up the turbo! But at the same time this will mean the car will have a higher top end power as the Turbine housing will not be causing as much back prssure!

Regarding Radiator Intercooler- Like the other blokes have said the radiator is not designed to flow like an intercooler! ( it is designed to cool water and to cool it it would be better if the coolant was slowed down! This telling me that it couldnt flow air as good as an intercooler!)
Just look at the drag cars if a radiator was a good intercooler I am sure all these cars would use them!

Just to add to what Dattodude has said I agree there is no use spending big dollars on an engine if you haven't had experiance with the setup you are going to use!

If you do plan to do this setup do it on a stock engine and work out all the little bugs on this engine before you spend the money!



Also all the drag cars you see don't think that their engines are their first attempts!
I always think it is morelikely that they have a new engine each time as they are always trying to go better and are experiancing engine failures!

In regards to the radiator for the intercooler I dont think it would would work because in an intercooler there is little fins on the inside of the tubes (just like on the out side) to cool the air passing through, and a radiator doesnt have them on the inside.

I have set up two turbo a12's now and through experience I would recomend......

- running some sort of intercooler, even a small one is a help

- To box in the carby, I have seen some other set up's where the carby's havent been boxed in and they have given trouble. With the carby boxed in you dont have to worry about gaskets or seals leaking.Just make sure the carby is running well in the first place. Oh and I found that running 110's for the primary jets and 200's for the secondary's worked the best for me.

- the single diahtsu turbo I found worked well, it was very torquy around town.
The twin set up had more up top.
I would recomend a turbo from a jap wrecker of about the same size as a T2 off a pulsar. Maby in our cases when I guess money is an object it is a bit of a case of suck it and see.( for want of a better phrase)

- I used an electric fuel pump with a regulator and discarded the mechanical fuel pump. Then had a pressure switch on the manifold so as when boost reached a set pressure the regulator would get bypassed and the fuel pressure jumped to 14 psi this worked very well

- also for starters I recon a standard engine would be good. I would hate to see you blow an expencive engine up, and as was said before it is very hard not to screw up the boost