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| 85 GT with Miller Woods turbo (Page 1/2) |
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Raydar
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DEC 03, 07:04 PM
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Some of you may remember this car. It's an 85 GT that used to belong to Predator, on this forum.
Way back in the day, a friend of mine bought it from him. He drove it for a while, but it has been sitting for... ever.
It's currently sitting in my garage, waiting to be looked at. (As soon as I get the keys from him - long story - and replace the battery.)
The current owner said he thought it had a bad map sensor. But who knows?
So... The background. 85 GT. 4 speed. Miller Woods stage II setup. I think it has an intercooler, based upon Predator's and Travis's (remember him?) old posts, here.
It supposedly has the 85 ECM, with a "tuned" chip, and a knock sensor. It also supposedly has a piggyback tuner, called a "dyno-tuner", or some such. Trouble is, I seem to remember that it has a volatile memory, that obviously is now blank, due to the dead battery.
Obviously, technology has improved by quantum leaps, since the car was built.
What is the hot ticket for a "mildly turboed" 2.8. I don't want to compromise reliability for that last bit of power.
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pmbrunelle
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DEC 04, 08:05 AM
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If the car already has the Miller-Woods PROM, shouldn't it run as-is without the piggyback?
From memory, the Miller-Woods kit didn't require the use of larger fuel injectors; it just opened the stock Fiero ones to 100% duty when a lot of fuel was needed.
So, are you looking to have normal-sized injectors, and possibly a new computer to control everything?
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Raydar
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DEC 04, 10:52 AM
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| quote | Originally posted by pmbrunelle:
If the car already has the Miller-Woods PROM, shouldn't it run as-is without the piggyback?
From memory, the Miller-Woods kit didn't require the use of larger fuel injectors; it just opened the stock Fiero ones to 100% duty when a lot of fuel was needed.
So, are you looking to have normal-sized injectors, and possibly a new computer to control everything? |
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That's what I was wondering. But there were some problems. It's blown at least one set of head gaskets due to running lean. Apparently that lean condition was also observed during the dyno runs. (Maybe that's what the "piggyback" was about.)
(A search of "Predator" in the forum and archives was a real eye-opener.)
I'm not sure if that was due to a poor tune, or too small injectors, or just the injectors being clogged. I never read that they were replaced.
I'm thinking about replacing the injectors with something that won't have to run 100%. The car dynoed 190-something at the wheels. That's ~210-220 at the crank.
IMHO, 15s just aren't large enough. I had 19s in my 3.4, to accomplish what should have been about the same power.
I'm also not against swapping ECMs, if there's something more suitable. If there is a suitable tune already available for the original ECM, given a known set of parameters that I can meet, I don't have any problem with that, either.
I'm sure that there are more than a few people out there who have experience with this kit. Lots of "institutional knowledge" as it were. So...[This message has been edited by Raydar (edited 12-04-2023).]
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IMSA GT
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DEC 04, 11:29 AM
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BingB
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DEC 04, 01:31 PM
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| quote | Originally posted by pmbrunelle:
If the car already has the Miller-Woods PROM, shouldn't it run as-is without the piggyback? |
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The system includes an ecu. It is more than just a chip.
The systems are plumbed in different for auto and manual transmission. No intercooler on the basic kit (because no real high boost)
Don't know about the injectors, but if you don't upgrade them then you would probably have to upgrade to higher pressure fuel pump.[This message has been edited by BingB (edited 12-04-2023).]
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Raydar
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DEC 04, 01:57 PM
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Thanks guys. Much appreciated.
Can't do much of anything yet. Waiting for the keys to show up. (They rolled it onto the trailer in a hurry, and left the keys.)
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pmbrunelle
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DEC 04, 07:26 PM
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| quote | Originally posted by Raydar:
If there is a suitable tune already available for the original ECM, given a known set of parameters that I can meet,
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Probably the first logical step once you get the car running is to evaluate the mechanical state of the engine. Compression, valve opening, vacuum gauge readings, check spark plugs, etc.
If you're not sure of the engine's mechanical health, then you don't have a set of known parameters.[This message has been edited by pmbrunelle (edited 12-04-2023).]
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MarkS
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DEC 04, 07:50 PM
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I love threads like this. I remember the Miller Woods when I still had my original 85 GT. But there were life changes on going at the time. Go get 'em!
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Raydar
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DEC 04, 08:14 PM
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| quote | Originally posted by pmbrunelle:
Probably the first logical step once you get the car running is to evaluate the mechanical state of the engine. Compression, valve opening, vacuum gauge readings, check spark plugs, etc.
If you're not sure of the engine's mechanical health, then you don't have a set of known parameters.
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Thanks for that. That's good advice. In the absence of ticking or clattering, it's easy to assume that everything is good, when it may not be.
The owner was not be aware of anything major, but I'll check, anyway.
It probably hasn't run in almost ten years. I'm sure it will wake up "mad". 
Obviously the gas in the tank will be "shot". Probably the pump and injectors, too. At this point, I'll be happy if the tank isn't all rusted up.[This message has been edited by Raydar (edited 12-04-2023).]
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fierofool
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DEC 04, 10:57 PM
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For injectors, if you know what the crank HP is, injector size can be calculated by the number of cylinders and the duty cycle. Several injector sources I spoke with don't recommend more than an 85% duty cycle.
At 190 HP, 6 cylinders, Gasoline, Turbo, 80% duty cycle, you would need 24 Lb injectors or for 220 HP, would require 27 Lb injectors.[This message has been edited by fierofool (edited 12-04-2023).]
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