hgray14

I just purchased an '82 turbo donor and a '72 receipant….both Z cars. Now I have some questions. I am already getting a bunch of books on Turbos and Boost and Horsepower and etc plus the factory and aftermarket manuals for both cars. I am also feverishly going through these archives but have some specific question that maybe you can help me with.

1. Pistons…do I want them dished or flat-top. What does that mean?
2. I plan on rebuilding the engine before I drop it in the new car…what should I do? I have been told to really beef it up so that I won’t have to rebuild it if I want to start modifying it. I was told to get forged pistons, etc – hardened internals. What parts should be modified and about how much will this cost for my stock engine?
3. I have also read about thermal coating the internals of the engine. How much difference does this make and what does it cost? When I call my local shop are they going to know what I am talking about when I ask about thermal coating?
4. I keep reading about people pulling their 2.8s and replacing them with 3.1s What is a 3.1? Is it just a bored out 2.8? Are 3.1s turbo? If they are not turbo how does a 3.1 compare to a 2.8 turbo? How much more power do you get out of a 3.1? I hear they are expensive; is this true?
5. Tranny. What kind do I want to use? I like 5 speeds for their top end.
6. Turbo. Are turbos expensive? Am I better off boring out my stock turbo or picking up a new/used larger one? What should they cost?
7. Intercooler. I have read about the Isuzu NPR and it seems pretty nice. I have also looked at a Ford Powerstroke and it looks like it might work too. I assume there is such thing as a intercooler that is too small…does this hold true for too big concerning performance?
8. Is anybody running nitrous with their 2.8 turbo? What are the pluses and minuses?
9. low boost/high boost? I was reading about someone getting tons of HP with low boost on a 3.1 and other times I read about 2.8s with high boost. What is up? Do you normally run a 3.1 with low boost or was that persons just showing that at low boost they were getting lots of power and so if they up’d the boost they would get even more? I am sure that one is answering in one of the books on its way to me…but I am impatient.
10. What is hot tanking?
11. Where do I get a decently priced t4 turbo? What kind of car do they come in?
12. What is a t3/t4 hybrid? How much should they cost used? How do you they compare in price and performance to the t4? Are there any other turbos that are good for a 2.8l turbo engine?
13. What are the largest wheels I can fit on my ’72 without fender flares? I hear that I can fit 17”ers if I bend the inner fender lips up and away from the tire. Any advice?
14. Last question…and this going to probably make you scratch your head. I want to take the 2.4 engine and put it into the ’82. I do some work out in a harsh desert and would love to have a beater car that I can push over a cliff if I have to. Since I have the body of an ’82 and the engine of a ’72 that will go to waste otherwise I want to put them together. Is this going to be fairly easy or am I in for some surprises? I assume it will be under powered but that is ok since I need it to do patrols at between 5 and 40 mph…plus I like the idea of T-tops for my patrols. Stop laughing…just tell me if you see any problems. LOL


Thanks for any help you can give me. I am totally stoked to be starting this project and want to do it right. I have the time and space to not have to rush this and want to do it right the first time.

AlansZ

I can only answer some of your questions:

1. Flat top and dished pistons mean just that- one is flat, and one has a dished surface to lower compression ratio for turbos.

4. The 3.1 motor is bored and stroked 2.8 motor. 3.1's can be trubo if you want them to. You need the L28 diesel crank, i've heard it's exspensive. Ask Ben, i think he's building a 3.1TT.

6. I'm not sure if turbos are exspensive, but whether you buy a bigger turbo or high flow the exsiting one depends on how much boost you run. Doing this changes where the turbo is more efficient, as you want it to be most efficient at the boost you are running.

9. Incresing the boost does increase the power

13. I have 225/60/15 tires on my 71 Zed and the front right tire scrapes on the guard at full lock, and the tires also scrape on the guards when i go fast over a bump, so i don't think 17's would fit, but i have pretty beefy tires, so with low profile tires it could be possible.

14. Go for it- there's no ponit in wasting the cars, also you might want to return the '72 back to stock after a while, so you would want to keep the motor

Alan, Australia

240z

I can answer some of your questions too.

1. Dished Pistons are lower compression than flat top and are found in the turbo L28's.

2. If you want a 500hp monster I recommend doing everything in one hit. That's what I plan on doing but it will take me a while to get the money together.

3. Thermal coating won't give your engine more power to my knowledge but it will make your engine last longer by providing protection.

4. 3.1 or I've even heard of 3.3l in some extreme cases are an L28 block bored and stroked, stroked using a L28 diesel crank shaft and bored out the usuall way, however I believe boring can be quite expensive.

5. I've heard that the gearbox's out of a NIssan Skyline GTS-T will be a good swap from the RB25 series. However the stock gearbox on a 280zx turbo would be good till you reach higher HP numbers.

6. Turbo's like anything are expensive the bigger the more expensive. What I would like to do is have a twin turbo L28. As I've been told 2 is better than one when it comes to turbo's.

7. I'm not sure if the Isuzu intercoolers are from trucks are not but if they are I've read that you should keep away from a truck intercooler because trucks generally rev to around 3500rpm to 4000rpm and at 5000rpm - 6000rpm they might not be so good.

8. I've seen many Z's that are bottle fed with Nitros but here in Aus it's illegal for a street car to have it so I know nothing about nitros.

9. Higher the boost the more power but if you can get more power than someone else on less boost it's probably because u have a better flowing exhaust manifold a better engine head etc... there's alot of variables as to why some L28's would have more HP than others with higher boost.

10. Hot tank - no idea sorry.

11. Not sure what a T4 turbo comes in your best bet is to call a local turbo expert and get some prices on a rebuilt one.

12. T3/T4 hybrid is just that two turbo's combined together by using I think the smaller exhaust wheel off a T3 the turbo will spool up earlier and boost will kick in quicker. It's a cheap and effective way of getting more power but I wouldn't recommend it if you were going for high HP figures.

13. You can fit 18" wheels if you want but it's all to do with your suspension setup. If you want huge wheels you need coil overs I'm told. 18's are perfect size for a Z I think fits the guards perfect and there's no fender flares involved.

14. Well it's your call as to what do to with the left overs but It's alot of stuffing around especially if your changing one from carbs to fuel injection and the other from fuel injection to carbs again. If you know your electrics well go for it but I know nothing about wiring looms and hence it all seems best left to experts and they are expensive. Your call you know how good condition each car is in and if it's worth while.

Ok that's it. If I'm wrong with anything here please let me know as I'm still learning about turbo's and L28 and anything I'm wrong on I wanna know about.
thanks guys,



Gavin,
Melbourne
Australia
73' Datsun 240z

AlansZ

Its easy going from FI to carbs- there are no electrics to worry about. About truck intercoolers, I thought that they were used often in turbo applications, especially Volvo intercoolers as they are so large. I don't see how the revs would affect the intercooler, as the air only flows through them. Is nitrous really illegal here?!? I've seen cars with nitrous in Aus

Alan, Australia