Turbo mods - need help

[Guest Anonymous]

Hey Guys - Am new to turbo mods and not well versed in all the different turbo options so please bear with my ignorance here. I have an 83 ZXT with a JWT modified ECU, HKS intercooler and Greddy ProfecB EBC, and some exhaust mods (only the ECU and IC are installed at this point and still running stock boost - havent had time for the EBC install yet). I was going to have my stock t-3 rebuilt and possibly just get the turbine and compressor wheels lightened for a little better performance. Is there another semi-economical performance option that I should consider when I am having my stock T-3 rebuilt? I have seen some T-3/T04E and t-3/t-4 Hybrid turbos for sale though. Would this be a much better option and can I do this without re-plumbing my HKS IC?? Also if I went that direction will I need an injector upgrade or am I okay? I am figuring on running 14 lbs of boost or so. This is my daily driver and I am not looking to do much more to it - or blow it up. (I am saving most of my cash for the 240zt swap that is my next project)Also where can I get a high quality downpipe for this thing? Any advice welcome - Thanks in advance-

 

Glenn

[SleeperZ]

if you are only targeting 14psi boost, you are setup for it right now. Install the ProfecB and turn it up.

 

[Len]

Sleeper is right, your nearly there already.If your going 14lbs. boost with stock injectors, I would really watch your Air/fuel gauge to make sure it won't run lean. If it does you can put on a carteck RRFPR to push more fuel out of stock injectors or just go with some SVO/Mercur 370cc. injectors (stock are 260cc.). Just a precaution be sure and retork your heads, may keep from blowing a head gasket. ScottieGNZ at one time offered really nice Downpipes for 280zxturbo engine install into the 240Z. They are not compatable for the stock 280ZXT. Further Scottie is really having problems with the guy he uses to manufactor the DP flanges. I believe he doesn't sell them anymore just because of the PITA he is having with his manufacturer.Ask Scottie he can tell you first hand.

Len

[Lockjaw]

Ok, you say you have a JWT modified Ecu. Which one? My understanding was that his set up came with larger injectors and a Mustang Cobra MAF. IS that the set-up you have?

 

That is what I have in mine. I have an 83 ZXT with 89 ecu modded by JWT, larger injectors and a cobra MAF. I also have an HKS intercooler kit.

 

Where did you get the set-up? Did you buy it from JWT or a private party? Sounds to me like you may be missing some of the stuff needed. Let me know and I will see if I can help

[Guest Anonymous]

Lockjaw - Now I am even more confused. I got my ECU direct from JWT but did not get any larger injectors or Cobra MAF and at the time(maybe 3 years ago) I dont recall them even mentioning any of that. JWT told me this was all I would need with my IC and they suggested the Greddy ProfecB which I have not yet installed (as a matter of fact the car is down for paint at the moment but should be on the road again soon I hope). JWT also said that 14lbs with this setup would be fine. Ironically enough I have been trying to sell a 85 300ZXT ECU that is also a JWT and the guy that I have been talking to about it has also asked me if it had a Cobra MAF (it doesnt either)- I had no idea that this was being offered by them. I guess maybe yours is a more current mod by JWT? How does yours perform and which injectors are you using ? Thanks for the help

[Lockjaw]

I have had my set up for about 3 years. When I talked with JWT, what they told me was to send them a 84 to 85 300ZXT ecu and they would mod that. My impression was they could not mod the 83 box. They ended up deciding the 88 thru 89 NA 300 box was a better choice, so they just swapped me out even.

 

They used to use the MAF off the 300, but the cost to replace one is expensive, and they did not like the way Nissan set up the hot wire in there. I guess every time you shut the car off, the ecu would send a nice voltage spike thru the wire to clean it.

 

I was the second person to use the cobra MAF set-up. They were in development stage with it when I talked with Clark. The car they were doing was an auto with a big stall, so I was the first 5 speed person.

 

I went thru about 6 chip revisions with Clark since I was esentially R&D'ing the set up for them. At first my car was slower than with the factory set-up. What I noticed was the car would not really rev over about 5k, so we started adding some timing. Every chip I got with more timing made an improvement.

 

The chip I have now rocks. The Ecu is set up with a 7k rev limiter, I have 420 cc injectors, an HKS intercooler, big fuel pump, and a hybrid turbo.

 

The car runs high 12's with drag ta's on the back, and I have run a high 12 once with street tires and using pump gas. Since I don't drive the car everyday anymore, I usually always have some racing fuel in the tank, mixed with super unleaded.

 

My best pass so far is a 12.77 at 113.75. I have run an 8.39 1/8th at 89.25. I have a fully loaded 83 280ZXT, and when I had it on a dyno last fall it made 307 hp to the rear wheels. It is very responsive and the drivability is way better than I could have ever gotten with the stock set-up.

 

If your car is being painted right now, I would snatch the ecu out and send it to Clark at JWT. Have him check it out for you. I only deal with Clark out there. I think Jim is a jerk and he doesn't like to talk to people unless they are a technician. Clark usually only takes calls in the morning, and he does programming in the afternoon, so you won't be able to talk to him after lunch. If there is something funky going on, Clark will take care of you. He's a nice guy, and truth be told, he is probably the brainchild for the operation.

 

Does it have a sticker on it? Mine has a sticker on it from JWT saying what it is. You should see about getting them to upgrade you to the cobra maf set-up. Much better way to go. The MAF is only about 200 bucks, the nissan one is well over 400.

 

It sounds to me like you may have a Motorsports modified ecu. Could that be possible? They are the only people I know of that were ever modding the stock 280zxt box. It should have a sticker on it if from Motorsports too.

 

Check it out and let me know. I will check the board periodically to see what you found out. Good luck.

[Guest Anonymous]

Lockjaw - 307RWHP?? Awesome. I will check the part #s on my 83 JWT ecu and look @ the sticker for the description. I did in fact send my stock ECU direct to JWT and I believe I got the same one back but not sure if they just used mine for a core- will get back to you- Thanks,

[Lockjaw]

Yes 307hp to the wheels. The engine is basically stock with the exception of forged pistons and I used 240 rods instead of 280 ones just to be different. Actually I used the 240 rod since it is slightly longer in an attempt to improve the rod to stroke ratio and lessen detonation potential. Don't know if it helped or not.

 

I have no porting, stock cam, head etc. I had it all balanced, used ARP rod bolts, and did a lot of rod work like polishing and shotpeening and having the two oil holes drilled in the small end like in the Hotrodding a nissan engine book. The rods should be good for a lot more HP.

 

My number is pretty good, but there are plenty of guys out there making more. I am hoping to get up close to 400. I think that would be brutal.

 

My next engine will be much more modified. I will likely bore it out a little, I have a friend who has a diesel crank he said I could have, I just have to pull the engine out of the car, so I may do that. I want to port the head mildly, and use a little larger cam. I will likely use some of those coatings, and want to get some stuff extrude honed as well.

 

It would be easy to stick 5k in an engine. Machine work is really expensive if the people are good. I guess I should start ordering stuff someday. I could probably put one together over the course of a year or two that would be pretty wicked. With my luck, I would have to take it back down for an oil control ring, which I had to do on this engine. Sucked. Ran great for about a hundred miles and then started doing the oil puking thing. Number 6 cylinder. I was really careful too.

 

Let me know what you come up with, I would really be interested.

[Lockjaw]

Oh I forgot to add. You can have your stock turbo upgraded. If you change to a hybrid, you will have to do some wastegate actuator modification, which is kind of a pain. I ended up sending my turbo (hybrid) out to Top End to let them fab up a bracket after I clocked the turbo properly.

 

When John Meyers was alive, he would mod the stock turbo by having both housings machined so he could fit larger compressor and turbine wheels in them. They worked pretty well, particularily if you used the GN wheels. The plus to that is the turbo is physically the same size, but it just makes more power due to the larger wheels.

 

I would think any of the shops could mod your stock turbo. I would get the super 60 compressor wheel, and go to a stage II or Stage III turbine wheel. That is if you stay with the stock turbo.

 

If you go to the hybrid, you have to make some modifications. I had to change how my oil drain line ran, and the inlet of T4 housing is bigger than a T3, so you have to get that plumbed. I used 3" pipe, and went to a truck shop and got some different 3" nitrile connections and plumbed mine that way. I had a slight bend put in one but if I had to make any bends more than 30 degree's, I would get some mandel bent elbows and cut and splice them and have a muffler shop weld them together. Then just prime and paint them. You will also have to get a down pipe made if you use a hybrid, and I would have a 3" one made.

 

There is a lot to consider. And it gets more expensive as you go.