Datsun 720 sd22

[Jr's sd22]

Wanna ask some questions take advice and learn I'm 22 and am about to buy a sd22 720 wth 83,000 miles on it wanna what can and cannot be done with it I wanna turbo and build as much hp as possible and still be cheap as I am young but also be able to down tires A little 

[datzenmike]

Loose the run on sentence with proper punctuation and it will be easier for us to understand future questions. Less time will be spent back tracking to clarify.

 

wayno's the turbo SD member here. I think he has more than one SD in his collection. 83K is barely broken in.... how did you ever find this gem? Post a picture of her.

[wayno]

OK, I will try to make this reply as short as possible, I have 2 SD25 series turbodiesel engines, all the SD25 engines came with turbo pistons and have 5 main bearings, I believe the only turbo pistons that will fit your block came in the SD33 turbodiesel, that engine came in the Scout.

That said I have talked with a guy that turbocharged his SD22 3 main bearing engine way back, it did not work out for him for a long time as he had issues, but like me he figured it out and put a lot of miles on his engine, at least that is what he told me, I only found out about him because he was trying to sell his turbodiesel engine on Craigslist, he is the guy that said something to me while on the phone that gave me an idea on how to pipe my turbo associated lines the way I had mine piped(draw thru), it worked out for me but gave me another idea that even worked better(blow thru).

The guy I am talking about had a thread about turbocharging his engine in the Nissan diesel forums, but that thread was never updated with a happy ending, I never seen a thread with a happy ending except mine, I have no issues, and anyone could drive my truck and not smoke it/blow it up if driven normally.

After driving mine for a while now I believe that an SD22 could be turbocharged with the stock pistons, as my EGTs(exhaust gas temps) are under 900 degrees 90 percent of the time, but when I am going up a long freeway upgrade like over a pass my EGTs can get up to 1400 degrees, but I am trying to keep my speed up above 70mph, if I back off and go under 60mph the EGTs do not climb that high, I would not take an SD22 with stock pistons over 1100/1200 degrees for long, but keep in mind that if you floor your SD22 for over a minute going up a long grade/hill it will get to 1400 degrees without a turbocharger as I put an EGT gauge in my non turbocharged vehicle to see how hot they run without a turbocharger, I was very surprised at how hot they run when floored for only a minute.

OK, first you need to decide what turbo you want/can get, bigger is not better, I am using a Subie 1800cc turbocharger out of an AWD vehicle on my 2500cc engine it works great, I have seen as high as 20psi a couple times, but I have it adjusted for around 12psi now, I am not racing it so I don't see a point in pumping 20psi into the engine, normally going down the freeway at 75mph I am at around 6psi with an EGT of 600/700 degrees, the EGTs will go up to 800/900 degrees on a hill that is not really steep.

I would suggest finding a 1600cc turbocharger for a SD22, I would not go above an 1800cc turbocharger, all the threads I have read that a larger turbocharger was used had unhappy results, most could only build up 2/3psi, after that the threads all died as they likely gave up.

Next you need to figure out how you are going to mount the turbo, the easy way is to make a "U" pipe coming off the stock exhaust manifold, have it end beside the alternator just low enough for the turbo oil line on top of the turbo to clear the hood when shut, I have one that way but mine id mounted too high and I had to cut a hole in the hood, my 521 turbodiesel has the turbo mounted directly to the side of the exhaust manifold where a hole is cut in it and a mounting flange was welded in it, this is a lot harder to do as the exhaust manifold is cast, and when welded on it tends to crack when it cools, I like the turbo mounted this way the best.

Once you get this far the rest is fairly easy, I don't need an intercooler although my 720 has one, it does not run any cooler than my 521 turbodiesel that does not have an intercooler, but my dually 720 turbodiesel is different, the injection pump has been turned up, and the intake vane on the turbo was machined out to except a larger vane, this truck doesn't like the freeway the way I drive(fast), but it has a shitload of torque, I have towed complete 720 diesel behind this truck that has 3.3 gears in the rear and I could hardly tell I was towing anything except when it came to stopping.

Here are a couple of my threads on the NissanDiesel forums, read them both and you will see all the ways I have tried to turbocharge these engines and how I figured it out in the end.

http://nissandiesel.dyndns.org/viewtopic.php?f=5&t=3380

http://nissandiesel.dyndns.org/viewtopic.php?f=5&t=3474

In one or both of these threads I made a diagram on how to pipe all the lines between the turbo and the injection pump.

[Fetch]

Damn wayno, you are good!  I don't have a diesel but, I got really excited reading your narrative.

Thanks.