3 Performance Upgrades Garanteed
12-28-2004, 08:34 PM
#1
Burning Brakes
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3 Performance Upgrades Garanteed
In the past year of ownership I have had the experience of repairing/restoring my car to it original condition. As far as the engine is concerned it is stock and I have not added any aftermarket performance upgrades. I have done repairs after which I have noted a marked increase in performance and my car is running much better than it did a year ago. Here is a list of upgrades you can perform or check that if they are not up to what Porsche intended you are loosing power.
1. New vacuum lines - You really think those 15 year plus rubber connectors are doing their job? Think again. I installed a MySwiss vacuum line upgrade that uses new silicon tubing with brass barbed connectors and I truly felt much greater eagerness in my acceleration and overall running.
2. DME Temp Sensor (NTC) - I recently had a DME wiring harness meltdown and when I removed the connector for the NTC half of the sensor came off. Somehow it had melted or deteiorated and was not functioning. There are two temperatrue sensors and just because you have temp indication on your instruments does not mean that your NTC is functional. There is one for the instruments and one for the DME. Along with my great replacement wiring harness from 944Ecology I asked for a replacement NTC sensor. Since the DME was not getting this signal it was running the emergency map which is geared toward keeping the car running and not performance. I am also looking forward to better mileage because the DME defaults to a cold or rich mixture with an open NTC. Surprising I passed California emissions in this condition.
3. Throttle Position Sensor - This switch is mostly known for its importance at idle. Included in the sensor is another switch at about 2/3 throttle position that is used for the DME called wide open throttle (WOT). It indicates to the DME that the driver is serious about acceleration and dumps in more fuel. I knew my WOT was bad so I had George at 944Ecology send a position sensor along with the harness. I can now feel the point at which the DME gets this signal and there is a noticable increase in power from the engine that pushes me further back in my seat.
With these three items performing correctly my car is running much much better and I am no longer regretting purchasing an S instead of an S2. I am sure this information is old material to the older Rennlist members but I see so many noobs that I thought I would post about it for them. Half the battle for more performance with these cars is to insure that they are running at factory specs first. 2. DME Temp Sensor (NTC) - I recently had a DME wiring harness meltdown and when I removed the connector for the NTC half of the sensor came off. Somehow it had melted or deteiorated and was not functioning. There are two temperatrue sensors and just because you have temp indication on your instruments does not mean that your NTC is functional. There is one for the instruments and one for the DME. Along with my great replacement wiring harness from 944Ecology I asked for a replacement NTC sensor. Since the DME was not getting this signal it was running the emergency map which is geared toward keeping the car running and not performance. I am also looking forward to better mileage because the DME defaults to a cold or rich mixture with an open NTC. Surprising I passed California emissions in this condition.
3. Throttle Position Sensor - This switch is mostly known for its importance at idle. Included in the sensor is another switch at about 2/3 throttle position that is used for the DME called wide open throttle (WOT). It indicates to the DME that the driver is serious about acceleration and dumps in more fuel. I knew my WOT was bad so I had George at 944Ecology send a position sensor along with the harness. I can now feel the point at which the DME gets this signal and there is a noticable increase in power from the engine that pushes me further back in my seat.
12-28-2004, 09:18 PM
#4
Burning Brakes
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I hope to install the MySwiss vacuum line kit this week. Great info - thanks!
In notice that my car smells a bit rich most of the time yet I passed emissions. I'll have to check the things you mentioned.
In notice that my car smells a bit rich most of the time yet I passed emissions. I'll have to check the things you mentioned.
12-28-2004, 09:57 PM
#5
Burning Brakes
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MySwiss originally developed his kit for the Turbo but he also sells one for the NA that is less expensive.
There are procedures in the factory service manual for testing the NTC and wide open throttle switch.
good luck
There are procedures in the factory service manual for testing the NTC and wide open throttle switch.
good luck
12-28-2004, 10:36 PM
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Vaccum leaks will kill these cars. I discovered this within an hour of buying my first 944. . . A very small, hairline crack in one of the stock "Y" connectors by the fuel pressure dampener made the car lurch and buck so bad I thought it was going to knock my fillings out. The leak was so small and unnoticeable I didn't realize it until later. The moment I fixed it the car ran like brand new.
Ditto on a 951 - there's more vaccum junk on those cars than words can do justice to. Replace the entire mess. In my recent "why don't I have boost" saga, I replaced every single POS plastic hose in that car with the purosil / brass "T" setup. Works great. I now have the same setup on the n/a car. Nary a problem nor hiccup. Well worth the money. I suspect the myswiss ones are just as good.
Ditto on a 951 - there's more vaccum junk on those cars than words can do justice to. Replace the entire mess. In my recent "why don't I have boost" saga, I replaced every single POS plastic hose in that car with the purosil / brass "T" setup. Works great. I now have the same setup on the n/a car. Nary a problem nor hiccup. Well worth the money. I suspect the myswiss ones are just as good.
12-28-2004, 10:47 PM
#7
Burning Brakes
Jon, excellent advice - sounds like you have that nice S of yours back on the road after that last meltdown ! I have replaced all the items you mention, and together these fixes do indeed bring back that smooth new-car feel !!
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12-28-2004, 11:05 PM
#8
Burning Brakes
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Originally Posted by brad-cam
Jon, excellent advice - sounds like you have that nice S of yours back on the road after that last meltdown !
I must have toasted that as well because that power steering wire was melted to the oil pressure wire in several places.
12-28-2004, 11:08 PM
#9
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Vacuum lines, TPS, DME temp sensor - 10-4.
Just to add, I noticed a nice improvement after I cleaned my injectors with carb cleaner, an air compressor and my battery charger. I think the procedure is on clarksgarage.com.
Just to add, I noticed a nice improvement after I cleaned my injectors with carb cleaner, an air compressor and my battery charger. I think the procedure is on clarksgarage.com.
12-28-2004, 11:17 PM
#10
Burning Brakes
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Originally Posted by FRporscheman
Vacuum lines, TPS, DME temp sensor - 10-4.
Just to add, I noticed a nice improvement after I cleaned my injectors with carb cleaner, an air compressor and my battery charger. I think the procedure is on clarksgarage.com.
Just to add, I noticed a nice improvement after I cleaned my injectors with carb cleaner, an air compressor and my battery charger. I think the procedure is on clarksgarage.com.
12-29-2004, 12:54 AM
#11
Burning Brakes
Jon, your idle problem is puzzling, especially since you replaced the TPS. Hopefully the chip helps, but I'm not sure exactly how it will, as the stock chip should work fine too. Did you put a vacuum gauge on it during idle to ensure there isn't still a vacuum leak ? Will it not idle at all, or does it
stumble, or cut out intermittently ?
One more thing - on the fuel injector cleaning, I had excellent service from www.witchhunter.com.
stumble, or cut out intermittently ?
One more thing - on the fuel injector cleaning, I had excellent service from www.witchhunter.com.
12-29-2004, 01:26 AM
#12
Burning Brakes
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Originally Posted by brad-cam
Jon, your idle problem is puzzling, especially since you replaced the TPS. Hopefully the chip helps, but I'm not sure exactly how it will, as the stock chip should work fine too. Did you put a vacuum gauge on it during idle to ensure there isn't still a vacuum leak ? Will it not idle at all, or does it
stumble, or cut out intermittently ?
stumble, or cut out intermittently ?
My thinking on the chip replacement is that perhaps the shorted wire damaged the ISV control? Why I think a chip will help is only based on Pete944's success with this solution for the same problem. He had shuddering on his S2 and it was corrected with a new chip install.
12-29-2004, 05:15 AM
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I had a sudden oddity at any acceleration on a road trip so when I got home I replaced ALL the vacuum lines with silicon ones. I eliminated the rubber with extreme prejuduce and it was all better. So replace all that mess, it isnt too expensive but make sure to secure the ends with small zip ties like on the fuel pressure regulator.
