my 20B porsche project
01-27-09, 03:51 PM
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my 20B porsche project
It's taking a long time. But I think I'll post a couple of pics as proof.
The car is a 1974 911 tub, with all the good stuff on it already: cage, 25G fuel cell, dual bosch fuel pumps, big turbo breaks, coil overs, turbo torque arms, g50 tranny with Guards LSD and 8/32 ring and pinion, etc.. And it's smog exempt.
The car is a 1974 911 tub, with all the good stuff on it already: cage, 25G fuel cell, dual bosch fuel pumps, big turbo breaks, coil overs, turbo torque arms, g50 tranny with Guards LSD and 8/32 ring and pinion, etc.. And it's smog exempt.
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01-28-09, 01:19 PM
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Awesome project man. Couple questions
Is the Rad/Intercooler/oil cooler going to be front-mounted?
Do you expect to have problems with keeping that big thing cool in the trunk?
Is the Rad/Intercooler/oil cooler going to be front-mounted?
Do you expect to have problems with keeping that big thing cool in the trunk?
01-28-09, 02:22 PM
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My goals are not lofty, considering the 3.8 twin turbo porsche motor that I took out of the car was putting out 630whp at 1 bar, and 800+ whp at 1.5 bar.
I think I can get to 500whp on low boost, and 650whp at 1 bar with water/meth injection. The good thing will be that I'll be running a 4.0 rear end vs. 3.33 with the porsche motor.
The turbo is a BW475 with 1.10 a/r and 83 trim exhaust.
Will have more info later, hoping that it can be at least started in a few weeks...
With 335 tires in the rear, and all the weight in the back with a decent suspension, this car can really put that power down. The car weights 2700 lbs with the old set up, should be a little lighter with the 20B.
attached is the dyno of the old engine.
I think I can get to 500whp on low boost, and 650whp at 1 bar with water/meth injection. The good thing will be that I'll be running a 4.0 rear end vs. 3.33 with the porsche motor.
The turbo is a BW475 with 1.10 a/r and 83 trim exhaust.
Will have more info later, hoping that it can be at least started in a few weeks...
With 335 tires in the rear, and all the weight in the back with a decent suspension, this car can really put that power down. The car weights 2700 lbs with the old set up, should be a little lighter with the 20B.
attached is the dyno of the old engine.
01-28-09, 07:22 PM
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Have 3 coolers in front for water, have one Setrab oil cooler in the rear quarter panels for now. The cooling is pretty much the big unknown, we'll have to see how it goes once she's running.
Good thing you have a much bigger rpm range with the rotary and running those lower gears to compensate for the torque difference you will see.
01-28-09, 11:36 PM
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Seems like air to water would really help with your airflow management, not sure what class you're running or the rules.
01-29-09, 01:38 AM
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The 5 speed G50's were made from 1987 to early 1990's. They are much better than the 915's before them, but it requires quite a bit of modification to fit into the car. The 6-speed ones from mid 1990's on are too long.
I'm using one from 1987, with stock gears, but race r&p. I don't know much about dogboxes at all... But I don't know if you can get one in there, remember that these trannies are Transaxles, tranny & diff all in one.
01-29-09, 11:27 AM
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There are straight cut gearsets ("dogboxes") for G50's. Be prepared to spend some SERIOUS coin.
http://www.californiamotorsports.net/
http://www.californiamotorsports.net/
01-30-09, 03:19 PM
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You are my hero haha. I had one guy tell me to go rotary on my judge. Never really cared for porsche til now, but a earlier model i dont like the exhaust pipe on the newer ones.
01-30-09, 04:27 PM
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If you run Methanol injection, you can run a small air/air intercooler. You don't need to run air/water IC. Sweet setup though. I have my 914 sitting in the weeds waiting for a PP 20B build. 
Make sure you get a really good Meth kit.
http://www.alkycontrol.com/ makes excellent kits with SS braided lines.
Make sure you get a really good Meth kit.
http://www.alkycontrol.com/ makes excellent kits with SS braided lines.
