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1984 Single Turbo by JoBy continues

Old 07-14-2007, 08:24 PM
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Default 1984 Single Turbo by JoBy continues

As the original thread is locked from old age I have to start a nre one.

http://forums.corvetteforum.com/show....php?t=1250660

I ran the Corvette without turbo the last summer and I had one problem after another. I had some fuel problems and rewired to semi-sequencial injection. (The injectors fires i pairs) I lost spark and installed a MSD 6AL and converted to crank trigger. When I finally was ready to install the turbo the tranny started acting up with black oil.

I went to the dyno anyway to get a pre turbo run and that killed the tranny for good. I only managed to get one good run on the dyno with 230 rwhp.



After that I parked the Corvette for the winter.

It was the converter that had a major failure. The oil cooler and transmission was full of aluminum shavings.

I bought a new 9.5" Vigilante converter with a 3-disc lock-up.

I finished the turbo installation and started the Corvette one week ago.







I am running 10 psi boost now but the plan was to run 15 psi boost.
On the street I have to go faster than 60 mph to be able to step on it without traction problems. My tires might not be the best but they are not that bad.

I went to a local racetrack on the 11th.
This is a picture from the 'pacecar' lap before we could have some full speed runs around the track.



This is a short movie. I am having some traction problems coming out onto the straight.

Last edited by JoBy; 07-14-2007 at 08:29 PM.
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Old 07-16-2007, 12:22 PM
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looking real good joe, how much power you think you making now?
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Old 07-17-2007, 01:12 PM
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I've enjoyed your previous posts. Keep them coming, and the more technically detailed, the better!
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Old 07-17-2007, 02:03 PM
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Originally Posted by 69427 View Post
I've enjoyed your previous posts. Keep them coming, and the more technically detailed, the better!
Thanks for the update - it looked like an animal coming out of that corner
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Old 07-23-2007, 02:13 AM
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Very nice, are you still using the 84 hood? Can you post some pictures of the manifolds and how you ran them. I would love to install a turbo on my 84.
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Old 07-23-2007, 04:59 AM
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This is probably a stupid question, but I'm new to turbos so here goes...
I'm guessing it allows flow through the exhaust at a specific time?
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Old 07-23-2007, 07:09 AM
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if i'm not mistaking that would be called a wastgate or... a blow off valve

Last edited by GT40_GearHead; 07-23-2007 at 07:14 AM.
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Old 07-23-2007, 09:53 AM
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Yes, that is the wastegate. It is used to regulate the air flowing through the turbo. The more air flowing through the turbo, the faster it spins and the more boost it produces.
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Old 07-23-2007, 12:07 PM
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Originally Posted by GT40_GearHead View Post
if i'm not mistaking that would be called a wastgate or... a blow off valve
Definitely a wastegate. A wastegate sits in the exhaust stream and diverts exhaust gases from the turbine side of the turbo to prevent it from spinning too fast and making too much boost.

A BOV sits in the intake stream and bleeds excess boost before the throttle plates (after excess boost has already been made).
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Old 07-23-2007, 05:20 PM
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Originally Posted by 89onlyZ51 View Post
Definitely a wastegate. A wastegate sits in the exhaust stream and diverts exhaust gases from the turbine side of the turbo to prevent it from spinning too fast and making too much boost.

A BOV sits in the intake stream and bleeds excess boost before the throttle plates (after excess boost has already been made).
so basically you should use both, right ?

what would happen if the extra boost would make it in the engine, would it cause detonation ?
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Old 07-23-2007, 06:43 PM
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Originally Posted by GT40_GearHead View Post
so basically you should use both, right ?

what would happen if the extra boost would make it in the engine, would it cause detonation ?
You should use both on a turbo setup. The wastegate keeps the turbo from spinning too fast (and getting out of it's range of efficiency). The BOV is there to keep boost from spiking way up between shifts which causes two bad things to happen - 1) places an extradordinary load on the compressor and seals 2) slows the turbine down dramatically since it's pushing air against a closed throttle plate resulting in the need to spool up again after each shift.
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Old 07-25-2007, 08:03 PM
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Yes it is a wastegate in the picture.

The wastegate is a pressure regulator, and it works in a similar way as a fuel pressure regulator.

It is a valve that can 'waste' a part of the exhaust flow so that is does not drive the turbine. A spring in the wastegate keeps the exhaust valve closed. Boost pressure works on a diaphragm to open the valve. When the boost force on the diaphragm is greater than the spring force the valve opens and reduces the exhaus flow thru the turbine.

If you increase the spring pressure in the wastegate then you will get more boost. It has the same effect as changing the pulley size on a supercharger.
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Old 07-29-2007, 03:15 PM
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JoBy-

You are my hero! I have been lurking for awhile , and am amazed at your skills (stealth ram mods, header/turbo system fab, etc). It is one of the reasons I just built a nice big garage to start my own project in.

Congrats on getting it going. Looks like you need a lot more tire for that beast!

Dave
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Old 07-31-2007, 04:24 AM
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Originally Posted by Tomsred84vette View Post
Very nice, are you still using the 84 hood? Can you post some pictures of the manifolds and how you ran them. I would love to install a turbo on my 84.
Yes, I am still using the stock 84 hood.
You can see a lot of pictures in the original thread. ( see first post )
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Old 07-31-2007, 04:36 AM
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Originally Posted by black85 View Post
JoBy-

You are my hero! I have been lurking for awhile , and am amazed at your skills (stealth ram mods, header/turbo system fab, etc). It is one of the reasons I just built a nice big garage to start my own project in.

Congrats on getting it going. Looks like you need a lot more tire for that beast!

Dave
Thanks!

Yes, I need more tires.

I went to a test and tune day on a airstrip and ran three times with similar results.

On one of the runs I lined up against a Chevelle with a cage, real big tires and a 720+ hp 572 cui crate engine.

The chevelle ran a 11.508 sec ET @ 121 mph with a 60' of 2.163 sec.

My best was 13.459 sec ET @ 118 mph with a 60' of 2.561 sec making tiresmoke forever.
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Old 08-05-2007, 11:05 AM
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My best was 13.459 sec ET @ 118 mph with a 60' of 2.561 sec making tiresmoke forever.
HA HA!! Sounds a few seconds slow. That must have been a big cloud of tire smoke!

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Old 08-06-2007, 03:14 AM
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Regardless of ET, that is an impressive MPH. Good work man, keep it up.

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Old 08-07-2007, 10:45 AM
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Originally Posted by JoBy View Post

My best was 13.459 sec ET @ 118 mph with a 60' of 2.561 sec making tiresmoke forever.

Joby, Just as a reference I ran a 12.5 @ 118 mph with a 2.1 60' with my old 350 and 6-8 psi.

My 350 was totally stock Buick Roadmaster LT1 except for a 230/236 cam. Iron headed and stock stamped 1.5 rockers. Pre-turbo best was ~13.5 @ 109 mph with a 6 speed.

That quick spool turbo has got to be great on the street, but is killing you at the drag strip. With an auto and some decent street tires you should be pulling some 1.7x 60' times.
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Old 08-07-2007, 01:00 PM
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Originally Posted by mn_vette View Post
Joby, Just as a reference I ran a 12.5 @ 118 mph with a 2.1 60' with my old 350 and 6-8 psi.

My 350 was totally stock Buick Roadmaster LT1 except for a 230/236 cam. Iron headed and stock stamped 1.5 rockers. Pre-turbo best was ~13.5 @ 109 mph with a 6 speed.

That quick spool turbo has got to be great on the street, but is killing you at the drag strip. With an auto and some decent street tires you should be pulling some 1.7x 60' times.
It was very bad traction at the temporary track. It was just regular tarmac without any preparation.

I had worn out street tires.

I am not running out of boost at higher RPM, the tranny (4L80E) is programmed to shift at 5300 rpm. The engine would rev a lot higher but with the stock 1984 crank, rods and pistons I want to stay a bit on the safe sife.

With better traction I think I have power to get into mid 11 ET with a trap speed of 125 mph.

I don't know when I will be able to try the quarter mile the next time.

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Old 08-13-2007, 10:23 AM
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