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Water-to-air intercooler installation - 81 931
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Mike9311  



Joined: 14 Dec 2004
Posts: 986
Location: Chicago-ish

PostPosted: Tue Dec 22, 2020 9:41 am    Post subject: Reply with quote

It was a loose, spur of the moment, style of test on a warmer day and oh so long ago.. as in last century long ago
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1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2130
Location: MI

PostPosted: Tue Dec 22, 2020 11:34 am    Post subject: Reply with quote

I like the lag.. It makes the “drivability” fun, and keeps me on my toes..
You feel the 2670 lag is much more Cedric? Makes me wonder what a k27 would feel like..
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 2104
Location: Somerset, UK

PostPosted: Tue Dec 22, 2020 5:28 pm    Post subject: Reply with quote

Fasteddie313 wrote:
I like the lag.. It makes the “drivability” fun, and keeps me on my toes..
You feel the 2670 lag is much more Cedric? Makes me wonder what a k27 would feel like..


Small lag differences between the K26 2660 6.10 and the K27 3257 6.10 on my car. Bigger wheel takes a little more time to spool. Biggest difference is the K27 has top end legs. Big legs. When it comes on boost, its strong all the way up to top end in big gears on the highway.
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252


Last edited by Carrera RSR on Tue Dec 22, 2020 7:03 pm; edited 1 time in total
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Cdric  



Joined: 27 Aug 2004
Posts: 2077
Location: Sweden

PostPosted: Tue Dec 22, 2020 6:56 pm    Post subject: Reply with quote

Fasteddie313 wrote:
I like the lag.. It makes the “drivability” fun, and keeps me on my toes..
You feel the 2670 lag is much more Cedric? Makes me wonder what a k27 would feel like..


Quite hard to compare since I had the intercooler added at the same time. But in the logs it builds boost earlier now than it did before, and its very responsive when going on and of the throttle, which is something i like for hard driving.
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chuck21401  



Joined: 20 Feb 2005
Posts: 322
Location: Annapolis, MD

PostPosted: Fri Dec 25, 2020 5:32 am    Post subject: Reply with quote

I replaced the thermostat and installed a low temperature fan switch.

The car is running cool again. This pic was taken after a 30 min ride with a number of boost runs.



The nice thing about the 924 turbo is that you have to move at least three other parts to accomplish any task. To remove and replace the fan switch, I had to remove the air box and put the headlights in the up position.



Based on Dan's advice in this thread, I went with a 82C thermostat and 75C fan switch. http://www.924board.org/viewtopic.php?t=41044







The fans have yet to come on. The radiator is warm but apparently not hot enough to kick on the fans. Air temps last night were around 30F degrees and today it's around 50F
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Last edited by chuck21401 on Fri Dec 25, 2020 5:49 am; edited 1 time in total
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chuck21401  



Joined: 20 Feb 2005
Posts: 322
Location: Annapolis, MD

PostPosted: Fri Dec 25, 2020 5:43 am    Post subject: Reply with quote

Mike9311 wrote:

When you hop out of the car, pop the hood and put your hand on the exhaust side of the intercooler and then the throttle body side. You should notice a big difference.


Here are some pictures after 30 minute runs. Last night the air temp was around 30F. Today the air temp is around 50F.

Last night




This morning



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chuck21401  



Joined: 20 Feb 2005
Posts: 322
Location: Annapolis, MD

PostPosted: Fri Dec 25, 2020 6:10 am    Post subject: Reply with quote

The air temp sensor I bought isn't going to fit.

I had hoped to connect it to the 1/8 NPT 27 port which is meant for water/methanol injection.



But it turns out the sensor probe is a big thing...other hoses and a hard pipe are in the way. I disconnected the hose pictured below in an attempt to do a test fit. No joy.



Here's my question...if I connect the sensor to the overboost port (switch is currently not connected; the wire is grounded to the block)...would that give me an accurate reading? I just need an adapter to go from 1/8NPT to M12 1.5.



Another idea would be to tap into the stock S2 temp sensor (93160612300) which is not connected. Anyone know the threads on the stock sensor? Apparently those are NLA...I figure I could sell that one (assuming that it works...would need to figure out how to test it) and connect the new probe there?


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GregSC  



Joined: 19 Jul 2008
Posts: 99
Location: Lovely, KY

PostPosted: Mon Jan 11, 2021 6:21 am    Post subject: Reply with quote

Hey Chuck,
I can confirm that a M14x1.5 plug fits into the space vacated by the stock intake air temperature sensor. Also some of the factory literature I have mentions that as the appropriate size.
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chuck21401  



Joined: 20 Feb 2005
Posts: 322
Location: Annapolis, MD

PostPosted: Wed Jan 13, 2021 4:44 am    Post subject: Reply with quote

GregSC wrote:
Hey Chuck,
I can confirm that a M14x1.5 plug fits into the space vacated by the stock intake air temperature sensor. Also some of the factory literature I have mentions that as the appropriate size.
.

Thanks, good to know. I bought two adapters... M14 x 1.5 Male to 1/8-27 NPT Female and M12 X 1.5 Male to 1/8-27 NPT Female...depending on where I decide to mount the sensor. I'm also trying to figure out where to mount the gauge in the cockpit. I'm leaning towards fabricating a bracket to mount it on the tray below the glovebox on the passenger side.

In other news I cleaned up the wiring for the intercooler pump and heat exchanger fan. Both are controlled by a dash mounted switch. I ran a separate wiring harness with a relay and fuse.

My dashboard is already cracked so I figured one more hole would not make a difference.




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Mike9311  



Joined: 14 Dec 2004
Posts: 986
Location: Chicago-ish

PostPosted: Fri Jan 15, 2021 1:12 am    Post subject: Reply with quote

Nice, I like it! I also like the idea of being able to turn it off for starting. The CS is always on but the silver '82 is by switch. They both need some wiring TLC
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
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chuck21401  



Joined: 20 Feb 2005
Posts: 322
Location: Annapolis, MD

PostPosted: Mon Jan 18, 2021 8:57 am    Post subject: Reply with quote

chuck21401 wrote:

I ordered the intake temperature gauge...



On hindsight, a flush mount gauge wasn't the best idea...I'm having trouble figuring our where to put it.

So for now I'm going to have a custom aluminum panel made and see how it looks. I read about this website https://www.frontpanelexpress.com/ on a thread on RENNLIST here https://rennlist.com/forums/944-turbo-and-turbo-s-forum/655024-custom-under-radio-gauge-panel-pics.html .

If it looks too home grown I'll have to think about something different.
I suppose I could delete the radio and replace it with a panel holding the MBC and the intake air temp gauge. But I don't want to lose my radio yet.

So this panel will be attached to a bracket on the right side of the center console. With any luck, it should look something like this (the grey circles are M3 studs on the back of the panel):



I'm going to switch the setting on the gauge to the Fahrenheit scale. The colonies have yet to fully embrace the metric system.

The Front Panel Express website has software to design and then preview the panel.




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Last edited by chuck21401 on Mon Jan 18, 2021 9:42 am; edited 2 times in total
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chuck21401  



Joined: 20 Feb 2005
Posts: 322
Location: Annapolis, MD

PostPosted: Mon Jan 18, 2021 9:34 am    Post subject: Reply with quote

Mike9311 wrote:
Nice, I like it! I also like the idea of being able to turn it off for starting. The CS is always on but the silver '82 is by switch. They both need some wiring TLC


FWIW, I used this Hella wiring harness to run the pump and the fan.


https://www.amazon.com/HELLA-357211011-ValueFit-Wiring-Harness/dp/B016VAHX8E

I replaced the red switch with this switch that lights up with just a small green dot.
https://www.amazon.com/HELLA-H61923001-Green-Rocker-Switch/dp/B000COD53S/
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2130
Location: MI

PostPosted: Tue Jan 19, 2021 12:12 pm    Post subject: Reply with quote

That temp sensor looks more like an EGT than something you would want to use as an IAT..
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 2104
Location: Somerset, UK

PostPosted: Tue Jan 19, 2021 7:26 pm    Post subject: Reply with quote

Looks like bolt on thermocouple?

I used two of those bolted my head. Never gave temp readings I was expecting. Also relatively slow to react to temp changes compared to the IAT sensors I have installed pre and post IC.
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252
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chuck21401  



Joined: 20 Feb 2005
Posts: 322
Location: Annapolis, MD

PostPosted: Wed Jan 20, 2021 11:56 am    Post subject: Reply with quote

Interesting discussion about intake air sensors. Found some interesting chatter about the different types of sensors any how fast they react on a RX7 turbo forum: https://www.rx7club.com/single-turbo-rx-7s-23/intake-air-temp-sensor-1137070/

Other link of interest I found while searching:

https://www.auberins.com/index.php?main_page=product_info&cPath=5_24&products_id=167

http://thesensorconnection.com/thermocouples/all-thermocouples/air-probe-thermocouple

The gauge and sensor in my car will be more for entertainment and reference purposes; it will not be used as part of an EFI system or something. Hopefully it will be reasonably accurate and fast. We shall see.
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