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dangers of not using the turbo motor


Guest 280ZX_Classic

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Guest 280ZX_Classic

I finally broke down and bought a '79 280ZX a little while back. While it was in the shop for extensive body work, (pics of that coming soon) the guy said his brother owns an engine shop and would be happy to rebuild the motor. I got him to do a full rebuild with new rings, pistons, cam, and crank, and got him to clean and prep the block and heads. Pretty much everything on this motor is new in terms of the actual block. I live in Auburn, AL, so the Z junkyard Ira owns is only like ten minutes away. I guess i just hate the idea of losing the money I put into the motor rebuild, but I still want more power. If I get the turbo equipment and put it on the '79 engine, will it hold? Everyone has told me to use the turbo engine, and that's what it says in all of the searched posts, but I don't see why a new engine couldn't handle a few pounds of boost. I am not looking for serious horsepower here, just a nice little advantage when I'm running against some local mustangs. Any advice would be appreciated...

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280ZX_Classic,

 

Welcome aboard. I'm new to the forum myself, but it's a good site to get a wealth of information and advice from. I'm in the process of purchasing a complete turbo motor only because it's convenient. You get all the pieces together in one package. There's a book, a lot of forum members make reference to; "Maximum Boost" by Corky Bell. My copy has been ordered already.

 

Setting up a custom turbo setup is very possible, but how much do you want to spend? I think you end up spending more money in the long run or land up waiting a long time to get all the parts together.

 

In a very generalized statement, every pound of boost is worth approximately 10 horsepower. If you only want to run 4 to 5 lbs of boost it's worth something like an extra 40 to 50 horsepower. Is this going to be worth the horsepower versus money spent to you? :shock:

 

Building a stroker engine with a bigger cam might be cheaper if you only want a few more horspower. If moneys no object build the current engine with 8.5:1 forged pistons and run direct port injection nitrous until you can get all the parts together :D .

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With a fresh rebuild I think the motor can handle stock boost levels. I would swith to a 2mm head gasket though. That will drop your compression ratio closer to 8:1. As long as you're good about resisting the urge to turn the boost up and you run an intercooler, it should hold up.

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I would give the NA engine a go, but I would take it easy, ive seen ringlands go from 5 degrees too much timing....

Ive seen the NA setups with turbo injectors and various other tweeks put down good power, and Ive heard of Ira too, he knows the deal.

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Guest bastaad525

Hmm... just read the first post here so pardon me if I ask or say anything that's already been said.

 

One important thing to know is which pistons and head you are running, and therefore what compression you're running? I've seen N/A combinations have CR's of about 8:1 all the way up to 11:1 +. If you're at the lower end that will be very helpful. However, with the right fuel setup and a good I/C people HAVE run boost on 10:1 + compression engines.

 

Things I would consider necessary to do turbo your rebuilt motor, assuming you are on the lower end of the compression.

 

1. The exhaust manifold and turbo from a 280zxt, and downpipe as well unless you plan on fabbing one

2. The distributor from a zxt

3. The entire ECCS system from a ZXT... important to try to get all components from the same year (also try to get a same year distributor). You will want the ECU, AFM, wiring harness, injectors

4. A good intercooler

5. A good blow off valve, which you should recirculate back into the intake

6. A good fuel pump to replace the stock one. While the stock one handled 200rwhp fine on my own setup, it is just good insurance to upgrade to a new one

7. An adjustable fuel pressure regulator to help supply some extra fuel for extra safety margin and add some tuneability.

 

Alternately, you MAY be able to take the route that lots of honda guys do when adding turbo's to their normally N/A cars, but wanting to keep their mostly stock EFI setups. While not as tuneable or flexible, you could conceivably keep your stock N/A EFI setup, and run a rising rate adjustable fuel pressure regulator (quite a mouthful eh?). The RRFPR will supply extra fuel pressure ONLY when boost is present. It is adjustable for how much extra fuel you want per psi of boost, and at what point you want it to start affecting the pressure (usually, at 0hg's of vacuum). You would probably still want to run the turbo injectors, at least, as well, but this way you wouldn't have to rewire the whole darn thing. There are a few guys out there running turboed motors on N/A ECU's. If you did decide to try that, you will also want something like the MSD unit that retards ignition timing under boost, as well.

 

I've seen or read about guys running lots of boost on even relatively high compression, normally N/A motors, with setups like this. As long as you can cool the intake charge enough, supply enough fuel, and pull enough timing... also the best octane fuel you can get helps. I could easily see you running enough boost to put 250hp or so to the wheels and still be safe.

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Guest 280ZX_Classic

Thanks for all of the input so far. I am going to Ira this week to see what he thinks about a turbo setup. Also I am looking at scrapping EFI altogether and just getting carbs off of one of his old Z's laying around. If I go the carb/na route, I was just wondering how much the Cook Racing supercharger was? I might consider buying a blower if I go with carbs.

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Guest bastaad525

but why? Those supercharger kits were never very popular for a good reason. While some others have fabricated custom supercharger setups that look awesome and probably run great, that's only for those with very deep pockets. Anyways, the only premade supercharger kit I've seen for the L6 motor ditches the carbs anyways, it comes with it's own carb/EFI setup, I believe holley pro-jection or something like that, but either way the SU's will be tossed.

 

The turbo motor is the easiest, cheapest, most effective way to get reliable forced induction performance from your L motor. Everyone always wants to do something different, but I say, why not just follow the proven path and stick to what's proven to work, and save yourself the headache.

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Guest bastaad525

Does Jim Cook Racing even still manufacture those supercharger kits? I was under the impression they'd be discontinued.

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Guest 280ZX_Classic

not really sure they still make them, I was just considering that an option. I just know that a stroker kit will cost me more than the rebuild did, and I figure there is no reason a brand new engine can't handle a little boost.

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Guest bastaad525

nope you're absolutely right... it would still be easier, and more cost effective to install factory turbo stuff over the supercharger... I think that kit goes for upwards of $2500. You could easily get a turbo unit, manifold, and all the other bits you would need for less than that, and even have plenty left over to dyno tune it and be sure you're running safe. You'd end up having more leeway for more power down the road as well, should you go with programmable fuel/spark managment and such, upping the boost is easy as cake, or just swapping to a bigger turbo.

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