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twin-turbo TPI Zcar


Guest twinturboZcar

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Guest twinturboZcar

Has it been done?

 

I am looking for someone who might give me some pointers, as I am about to get the ball rolling on one for myself.

 

 

I have scored a rear-ended 5-speed Z28 camaro for 500 bucks, with a strong motor/trans... and I have Also procured a "partial" sponsorship on the turbos, intercoolers, and fab work from a speed shop....

 

honestly, I am going to be able to do it on a "budget" to a degree... i predict about $4k tops to have it running and driving, but that is without cosmetics and interior...

 

now, the question i have is this.

 

I have an R200 diff, that i am going to have to convert over to, and I know i am looking at custom driveshaft, and exhaust expenses...

 

is there any special concern when it comes to the clutch assy., shifter location, etc. in this configuration? I will be keeping the T5 out of the camaro...

 

this thing is only going to see VERY limited street use, and will have a Sheetmetal interior, and a cage...

 

also, i have access to a 240, 260, and 280z (of unknown years , currently)

as the recipient for this beast, and I am wondering which would be prefered.

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Welcome to the board.

 

You may want to rethink your idea of using the T5. They are only rated to 300 ft/lbs of torque for a World Class version. If you have to use it then look at having it built by G-Force. If thats out of the question then you should consider converting to a T56 or using a 700R4 automatic.

 

Automatics are better for drag racing anyway, faster shift times.

 

The R200 should be OK. The u-joints in the half-shafts will be a problem so you should consider converting to 300ZX turbo axles with CV joints or doing a full conversion to an R230.

 

I know of only 1 Z with a twin turbo V8. It's owned by a member here who goes by TurboMeister. His is a blow-through carb setup but he could probably help with the project some.

 

I would start with the 280Z. They are structurally stronger so would require less reinforcement than a 240 or 260.

 

Wheelman

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Guest twinturboZcar

Well, my choice of transmissions was mostly going to be dictated by which trans the Z originally came with...

 

I hate the idea of the automatic trans, and having to rip out the clutch assy's and such from the Z.

 

I have ready access to a non-computer controlled 700r-4, and I had considered it, but I am not familiar with autos, to be honest.... The V8 guys I associate with typically run the TH350 or Powerglides...

 

How much abuse can a 700R-4 tolerate?

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T5 will not handle a turbo charged V8. I run one in my V8 Z and have broke it several times. FYI, slow shifts will extend the life of a T5 but it will also slow down et's.

 

Another thing, you would also need to run a very heavy clutch to hold that much torque which is a pain. I had to build a firewall support because the firewall would flex when I pushed in the clutch which reduced the pressure plate travel.

 

Over the winter months, I'm planning on converting my V8 Z to a straight axle and automatic car. I feel I have hit the point were I have too much power for the stock rear end and GMT5. I break parts, eat clutches, and don't ran as consistant as I would like. I have a 400+ hp 362 cid then a 175 shot of n20 on top of that. The car runs 11.7's at 120 on the motor and 10.7's at 135 on n20. I think mid 11's are about as much as a T5 and a R200 can handle. Sure, I ran 10's with my setup but not for very long. If you want a safe and durable track car that runs better than mid 11's then go with a 3 speed auto and straight diff.

 

I had very bad results with 700r's. I don't want to even think about how much time and money I wasted trying to get a 700r to handle decent power. Use a 350 trans prepped for drag racing (manual valve body and trans brake)

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Guest twinturboZcar
If you want a safe and durable track car that runs better than mid 11's then go with a 3 speed auto and straight diff
.

 

ok, Point well taken.

 

now, that having been said, it would seem to be a pain in the butt to swap an independent rear to a solid axle....

 

are there any housings that are narrow enough to use? or should i count on having to get one narrowed....?

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now, that having been said, it would seem to be a pain in the butt to swap an independent rear to a solid axle....

 

So do you think putting a twin turbo V8 in a Z car is going to be easy? Yeah there's plenty of room for a V8 but with all that extra piping for the turbos, its going to get real crowded real fast.

 

If you going to a straight axle go with one of the common ones. Not one that is going to fit the easiest. Like the Ford 9" or GM 12 bolt. Parts are much cheaper for these than any other straight axle. A member of this site is also in the process of swapping in a Ford 8.8" , he goes by the name "Stony".

 

 

Guy

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I have converted my 72 Z to 383 Twin Turbo Configuration with TH 400 transmission and 9" Ford rear.

It would be great if you can do a similar conversion, especially since you are using a fuel injection system. But I don't think you are aware how much torque a properly set-up TT can develop. I have only run the 1/8th mile drags since I've been making 15 psi boost. The Z runs 6.3 seconds and 116 mph and never hooks up in the first 60 feet. And that's with a pair of outdated 14 year old Rajay turbos.

You will consume your entire budget on a strong enough Manual Trans and beefed Corvette Independent rear Suspension or Straight Axle Rear.

If you place the turbos in front of the engine, like I did, you don't have to cut into any sheetmetal under the hood.

But remember, turbos are not cheap and you also need wastegates, blow-off valves, bigger injectors, high volume high pressure fuel pump, &etc.

Good luck, I'll be watching for progress reports.

Hanns

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Guest twinturboZcar

to clarify, here is the setup I plan on using.

 

stock TPI 350 with stock rods/pistons swapped for forged units.

 

(2) .60 trim T3 turbos, internally wastegated, for now.

(2) T3/T4 turbos, externally gated if the motor holds up from the first stage.

 

the intercooler will use a 3.5" core 20x8" flowing top to bottom.

with a 2.25" inlet on each end of the bottom tank, and one 3" outlet from the top tank.

 

by setting it up that way, i will be able to minimize the distance the hot charge pipes will have to run. it will look like this:

ic1.bmp

 

By pointing the outlet down, I will be able to build the "intercooler-to-throttle body" piping to travel down, then turn to run parallel to the Pass. Side turbo discharge line and back into the engine bay the same way the charge line exits.

 

all of the fabrication of the tanks, charge piping and ehaust manifolds will be done for the cost of materials only.

 

I would like to run a "v8" rearend, but i will be swapping for an R200 for the time being.

 

my plan is to only run about 5-6 pounds of boost, temporarily, and the engine will be controlled by a TEC II system by electromotive, with crank-trigger ignition.

 

the way I have figured it is this:

 

the TPI 350 is rated at 245 HP. by changing to a lower compression ratio piston, i will effectively be lowering that to (just for an estimate) around 200 hp. now, I have heard, perhaps incorrectly, that you can almost figure 15-16 HP per intercooled pound of boost. if that is correct, at 5psi with the lower compression motor I will still only be making around 280hp, with the potential for a LOT more.

 

that having been said, and considering the ready availability of the 700R-4 and the R200 rear end, I will probably use those pieces for a little while untilI am sure the motor is going to hold up. I also realize that the eventual swap to a turbo TH350 or TH400 will probably necessitate driveshaft changes...

 

That is why I said I could get it "running and driving" for a lower amount. I didn't mean that that was all I would eventually have in it, as I would really like to do a solid rear, and more capable trans.

 

so, does any of this make sense? I am hoping to REALLy tuck the motor up against the firewall, since I won't have a Distributor blocking me.

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