Short Turbo Temp Sensor?

Talk and Tech about turbocharged 924/944/968 cars
User avatar
Tom
Site Admin
Posts: 8992
Joined: Fri Jun 25, 2021 2:04 pm
Location: Silicon Valley, CA
Has thanked: 947 times
Been thanked: 4040 times
Contact:
Anyone have a current source for a short temp sensor for the turbo? I got my current one at Napa, part #FS158, many years ago and just noticed the wire is frayed where it comes out of the potting material (so not really repairable). It's needed to accommodate the bigger turbo under the intake. Napa is "out of stock" nationally it seems, and I can't seem to find a suitable replacement...

f2158.png
f2158.png (732.24 KiB) Viewed 1000 times

#1

cda951
Posts: 180
Joined: Sun Jul 04, 2021 8:55 pm
Location: Santa Barbara, CA
Has thanked: 136 times
Been thanked: 81 times
Hi Tom,

I wish I had a source for a short temperature SWITCH, which is the important term. When I upgraded to an Evergreen K27 hybrid turbo, I found a VDO-made shorter temp SENDER that fit, but it always had continuity to ground, which would eventually discharge the battery.

One needs to find a temperature SWITCH that fits!
Chris A.
---'86 944 Turbo track rat
---'90 944S2 Cab daily/touring car
---'73 BMW 2002tii road rally car
---'81 Alfa Romeo GTV6 GT car/Copart special
---'99 BMW Z3 Coupe daily driver/dog car
---'74 Jensen-Healey roadster
---other stuff

#2

User avatar
Tom
Site Admin
Posts: 8992
Joined: Fri Jun 25, 2021 2:04 pm
Location: Silicon Valley, CA
Has thanked: 947 times
Been thanked: 4040 times
Contact:
cda951 wrote: Mon Nov 04, 2024 10:11 pm Hi Tom,

I wish I had a source for a short temperature SWITCH, which is the important term. When I upgraded to an Evergreen K27 hybrid turbo, I found a VDO-made shorter temp SENDER that fit, but it always had continuity to ground, which would eventually discharge the battery.

One needs to find a temperature SWITCH that fits!

Thanks and understood. I may have to come up with something new, but we'll see.

#3

User avatar
Tom
Site Admin
Posts: 8992
Joined: Fri Jun 25, 2021 2:04 pm
Location: Silicon Valley, CA
Has thanked: 947 times
Been thanked: 4040 times
Contact:
Well I got lucky and found a good used one in my big pile of old parts :)


Stubby-sensor.jpg
Stubby-sensor.jpg (275.6 KiB) Viewed 945 times

#4

User avatar
Tom
Site Admin
Posts: 8992
Joined: Fri Jun 25, 2021 2:04 pm
Location: Silicon Valley, CA
Has thanked: 947 times
Been thanked: 4040 times
Contact:
Since the short Napa versions are no longer available, I thought I'd see if I could shorten the factory one. I have not yet tested to confirm it still works, though I can't imagine it wouldn't. Turns out the top portion of the switch screws out using a 6mm wrench. Removing that connector piece shortens the piece significantly. Still not as short of the old Napa versions as shown in the last picture, but probably short enough to work for some. After playing with various ideas, I ended up just soldering a wire directly into the port where the connector piece unscrews.

temp-switch.jpg
temp-switch.jpg (567.71 KiB) Viewed 925 times
modified-temp-switch.jpg
modified-temp-switch.jpg (643.6 KiB) Viewed 925 times
temp-swith-compared.jpg
temp-swith-compared.jpg (680.34 KiB) Viewed 925 times

#5

markl951
Posts: 14
Joined: Fri Feb 11, 2022 5:45 pm
Has thanked: 2 times
Been thanked: 10 times
Tom,
I did the same thing but had to make mine a bit shorter. The remaining insulator piece was a bit loose, so I added some JB weld to stabilize it. Works great. To test it, measure continuity between your new wire and the case. It should be open circuit. I carefully heated the sensor end using a small propane torch until my ohmmeter started beeping. Zero ohms is what you want to see. Soon as it cools back down, you should see the open circuit again.
PXL_20240623_234318994.jpg
PXL_20240623_234318994.jpg (103.61 KiB) Viewed 870 times
-mark
near Seattle, WA
85' NA 944 race car / 86' 944 Turbo
23' 718 Cayman GT4 RS
17' Macan GTS

#6

User avatar
Tom
Site Admin
Posts: 8992
Joined: Fri Jun 25, 2021 2:04 pm
Location: Silicon Valley, CA
Has thanked: 947 times
Been thanked: 4040 times
Contact:
markl951 wrote: Wed Nov 27, 2024 5:45 pm Tom,
I did the same thing but had to make mine a bit shorter. The remaining insulator piece was a bit loose, so I added some JB weld to stabilize it. Works great. To test it, measure continuity between your new wire and the case. It should be open circuit. I carefully heated the sensor end using a small propane torch until my ohmmeter started beeping. Zero ohms is what you want to see. Soon as it cools back down, you should see the open circuit again.

PXL_20240623_234318994.jpg
Nice. I tried a small heat gun on mine but couldn't get it hot enough to open. Boiling water doesn't seem hot enough either. I was going to boil it in peanut oil, since that once worked for the oil thermostat, but a torch is a good idea too, as long as I don't ruin it...

#7

Bergerac
Posts: 329
Joined: Mon Apr 03, 2023 3:00 pm
Has thanked: 20 times
Been thanked: 125 times
Has anyone mounted their switch straight into a spare coolant port on the turbo? I have zero clearance under my manifold

#8

User avatar
Darwin
Posts: 317
Joined: Fri Jul 02, 2021 4:17 am
Location: Lompoc, CA
Has thanked: 116 times
Been thanked: 74 times
Is there any drawback to deleting the turbo water pump entirely? Thats what I'm currently running and figured that since I never shut the car off immeidately after hard use, I'd most likely be fine. I just switched to running an NA tank.
1984 VW Rabbit Pick-up - Not stock
1988 944 Turbo S - Really not stock (Chris White special)
2012 VW Tiguan - Kinda stock
2013 Cayenne Base - 6 Speed! Tastefully modified, mostly stock

#9

markl951
Posts: 14
Joined: Fri Feb 11, 2022 5:45 pm
Has thanked: 2 times
Been thanked: 10 times
I ran my car for a while w/o the switch but instead modified the timer circuit inside the relay to run twice as long, roughly a minute vs 30 seconds. It only runs once when you shut the engine off and won't automatically come back on w/o having the switch installed. I don't track my car anymore, so I wasn't too worried about it for street use.
-mark
near Seattle, WA
85' NA 944 race car / 86' 944 Turbo
23' 718 Cayman GT4 RS
17' Macan GTS

#10

Post Reply