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My 931 performance mods
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CÚdric  



Joined: 27 Aug 2004
Posts: 1732
Location: Sweden

PostPosted: Mon Sep 09, 2013 10:23 pm    Post subject: Reply with quote

DutchPug wrote:
Nice results George.

They probably gave you a print with power at the wheels and torque at the flywheel, that is why the torque and power numbers don't add up.

According to your torque figures you have around 256 hp at the engine. That is a substantial increase over stock power output.


Sounds reasonable, 260hp should fell pretty darn fast in a 924

If you want to compare your acceleration results I have a full load run made with race chrono on an air strip (more or less standard euro s2 engine and not lightened car), although a pretty careful start (don't like changing clutch ). Could be a nice performance comparison
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┤79 924
http://www.garaget.org/show.php?car=211
┤80 924 Turbo
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GeorgeV  



Joined: 14 Mar 2010
Posts: 301
Location: Brisbane, Australia

PostPosted: Mon Sep 09, 2013 11:50 pm    Post subject: Reply with quote

CÚdric wrote:

Sounds reasonable, 260hp should fell pretty darn fast in a 924


As I said before, the acceleration is instantaneous and brutal. I have no complaints with power levels. Also the sound of the turbo spinning fast in 3rd and 4th is heaven!
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1981 932 with mods:
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WEASEL149  



Joined: 19 Aug 2005
Posts: 592
Location: UK, Sheffield

PostPosted: Tue Sep 10, 2013 1:15 am    Post subject: Reply with quote

DutchPug wrote:
According to your torque figures you have around 256 hp at the engine. That is a substantial increase over stock power output.


Yes, this is what I estimated also, 255-260hp at flywheel.

Numbers mean nothing if the car feels slow, and to be honest rolling roads are a way to compare, not to accurately measure.
So going by a 50% increase and the butt dyno, I'd say that's a great result.

300hp is all good and well if you're confident of the engine's internals.

Your power level is sensible for an engine that hasn't been rebuilt and a stock clutch. You can enjoy a quick car without worrying if the engine is going to let go, and if it does, you can always rebuild the engine accordingly with a higher power in mind.

This build should be applauded rather than criticised. Not many people go this far and come out the other end with a running and reliable motor.

These cars are a hobby. When do we ever consider them 'finished'. The journey is a big part of the enjoyment as well as driving (for me at least).

What's wrong with 130hp per litre from a 30+yr old car? Plus ~280lb/ft torque is a sizeable increase


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morghen  



Joined: 21 Jan 2005
Posts: 7857
Location: Romania

PostPosted: Tue Sep 10, 2013 2:38 am    Post subject: Reply with quote

WEASEL149 wrote:
This build should be applauded rather than criticised. Not many people go this far and come out the other end with a running and reliable motor.


Agree.
Didnt mean to bring any critique...was just wondering about the numbers.
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WEASEL149  



Joined: 19 Aug 2005
Posts: 592
Location: UK, Sheffield

PostPosted: Tue Sep 10, 2013 2:56 am    Post subject: Reply with quote

morghen wrote:
Agree.
Didnt mean to bring any critique...was just wondering about the numbers.


I can see what you were getting at Morghen and I agree that CIS is more than capable of 250hp+ numbers, especially with the K27.

George's motor is healthy now but the foundation has been laid in place for constant improvement with EFI and standalone.
300hp flywheel is definitely in reach with that spec.
E85 is ideal. Pity it's not widely available over here in the UK, otherwise that would be my route. The power from timing alone would probably make it worth it.
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CÚdric  



Joined: 27 Aug 2004
Posts: 1732
Location: Sweden

PostPosted: Tue Sep 10, 2013 4:10 am    Post subject: Reply with quote

Most importantly, where are the youtube vids ??????


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GeorgeV  



Joined: 14 Mar 2010
Posts: 301
Location: Brisbane, Australia

PostPosted: Tue Sep 10, 2013 4:02 pm    Post subject: Reply with quote

CÚdric wrote:
Most importantly, where are the youtube vids ??????


I'm sorry, but I don't have the equipment to make vids of the car while driving.
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Joes924Racer  



Joined: 03 Nov 2002
Posts: 11966
Location: Oregon, Denver Colorado native!

PostPosted: Wed Sep 11, 2013 5:24 pm    Post subject: Reply with quote

Oh no we needs vids.... That thing is awesome.very nice.
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1980 porsche Turbo 931GT Replica
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coldwarvet  



Joined: 13 Jun 2014
Posts: 51
Location: near sandy oregon

PostPosted: Mon Jun 16, 2014 12:41 pm    Post subject: turbo down under Reply with quote

....so refreshing to see THOUGHT applied to a car created in afterthought....
......just beautiful!....you "diggers" are always coming up with the most innovative stuff!...
good go!
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GeorgeV  



Joined: 14 Mar 2010
Posts: 301
Location: Brisbane, Australia

PostPosted: Wed Jul 02, 2014 10:47 pm    Post subject: Re: turbo down under Reply with quote

coldwarvet wrote:
....so refreshing to see THOUGHT applied to a car created in afterthought....
......just beautiful!....you "diggers" are always coming up with the most innovative stuff!...
good go!

Thanks for your kind words. I'm planning on more performance mods soon.
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Joes924Racer  



Joined: 03 Nov 2002
Posts: 11966
Location: Oregon, Denver Colorado native!

PostPosted: Sun Aug 24, 2014 2:43 pm    Post subject: Reply with quote

Wow. I have to give the high fives on your build. Its darn cool.
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1980 porsche Turbo 931GT Replica
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GeorgeV  



Joined: 14 Mar 2010
Posts: 301
Location: Brisbane, Australia

PostPosted: Wed Oct 01, 2014 11:15 pm    Post subject: Reply with quote

Joes924Racer wrote:
Wow. I have to give the high fives on your build. Its darn cool.

Thanks, Joe.
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gabo931  



Joined: 26 Feb 2015
Posts: 21
Location: Puerto Rico

PostPosted: Wed Jul 29, 2015 3:53 am    Post subject: Reply with quote

GeorgeV wrote:
Well, the mods are done and the car is running.

Here's the alternator. Went through 3 of these before settling on a race one. The others could not take the heat. Only charges above 1500rpm, so I need to be careful. The alternator sits between the inlet manifold and the AC condenser.




This is the relay for IC pump.

Bigger breather to reduce blowby.


The finished product.


After many hours on the dyno this is the result.


The car goes like a rocket. When you plant your foot, the front lifts like its going to mono and the acceleration is instantaneous and brutal. You can't hold any gear for very long otherwise you hit the rev limiter very easy - mechanic recommends keeping revs to 5000 due to age of the engine. The boost is set at 16psi, but if you plant it it will max out at 19psi as there are no flow restrictions and the wastegate stuggles to limit the boost. Intake temps after the IC are running at about 40deg cel on a 25deg cel day. The coolant temps stay between 85deg and 90deg. It starts first go, idles beautifully and is very easy to drive in a high gear if you're just tootling around town. The increase is low down torque is very noticeable and makes the car very easy to drive when going easy.

I have a few other things to get done but they are just window dressing. I'm also thinking of going to E85 as it will run cooler, which will help with the temps in Brisbane, and mechanic reckons it will probably increase kw to 200. We'll see.

I want to thank everyone on the board for their inspiration. I would never have undertaken such a venture without the mods I've seen done here on the board. I would not recommend my approach unless you're prepared to spend lots of money. Once you go down this approach, you have to change everything. I think I read a post the other day by Morghen saying exactly this, and my experience backs that up.

Cheers,

G




Hey Man great Build!

May i have more information on the alternator setup? I am planning to build intake manifold with the throttle at the same place as yours but i am having trouble deciding where to place the alternator.

Thanks!
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GeorgeV  



Joined: 14 Mar 2010
Posts: 301
Location: Brisbane, Australia

PostPosted: Fri Jul 31, 2015 12:10 am    Post subject: Reply with quote

gabo931 wrote:

Hey Man great Build!

May i have more information on the alternator setup? I am planning to build intake manifold with the throttle at the same place as yours but i am having trouble deciding where to place the alternator.

Thanks!

The alternator sits on top of the AC compressor and bolts into the block. It is run by the compressor. This was only one of two places to put the alternator, the other was underneath the engine near the starter motor. Because the engine generates a lot of heat, we had to use a race alternator that could take the heat. Although it originally charged only over 1500 rpm, I have had a pulley made for the AC compressor that is the largest that will fit. The alternator now charges the battery at idle.

Let me know if you have any other questions.
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brealytrent  



Joined: 28 Dec 2008
Posts: 413
Location: Coon Valley, WI

PostPosted: Sun Aug 02, 2015 3:27 pm    Post subject: Reply with quote

How 'bout a video of this beast?
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