944 NA "EURO" DME BOX
09-30-2002, 01:15 PM
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944 NA "EURO" DME BOX
Does anybody have a source for a euro ( non O2 sensor ) DME control unit for a 944 NA. Or can a US box be properly modified to delet the O2 sensor. I have been told that performance will suffer if you simply unplug the sensor? I am building a SCCA ITS car and want to run leaded racing gas..
Fred
Fred
10-02-2002, 03:29 AM
#2
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Sure, just unplug the O2-sensor and connect a plug #911.612.422.00 in its place. I guess it causes the DME to see some average value or something. You'll probably be a little richer on the mixture, but that'll be fine on a race car.
10-02-2002, 11:56 AM
#3
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FYI, In my 84 944 race car I unpluged the O2 sensor. The car ran fine, but the idle was a little funny. It did not stay stable and rolled a bit. I pluged the O2 back in and it ran the same with no noticealbe difference in on track performance, but had much more stable and uniform idle. I deciced to leave it in.
My motor is an 87 924S unit with corresponding DME for that motor. Motor is 100% stock from stock intake to stock cat and muffler. I run street 91/92 octane gas.
I did hear about NA's making 2 more hp (on back to back dyno runs without the O2 plugged in).
My motor is an 87 924S unit with corresponding DME for that motor. Motor is 100% stock from stock intake to stock cat and muffler. I run street 91/92 octane gas.
I did hear about NA's making 2 more hp (on back to back dyno runs without the O2 plugged in).
10-02-2002, 06:12 PM
#4
Racer
You may want to check out this site:
<a href="http://944dme.tripod.com/" target="_blank">http://944dme.tripod.com/</a>
Check out the power prom link
He can configure the ROW DME to operate as a Euro DME with the improved fuel maps and loosing the O2 sensor.
Todd
<a href="http://944dme.tripod.com/" target="_blank">http://944dme.tripod.com/</a>
Check out the power prom link
He can configure the ROW DME to operate as a Euro DME with the improved fuel maps and loosing the O2 sensor.
Todd
10-02-2002, 11:58 PM
#5
Race Director
[quote]Originally posted by fastfred92:
<strong>Does anybody have a source for a euro ( non O2 sensor ) DME control unit for a 944 NA. Or can a US box be properly modified to delet the O2 sensor. I have been told that performance will suffer if you simply unplug the sensor? I am building a SCCA ITS car and want to run leaded racing gas..
Fred</strong><hr></blockquote>
Fred, why do you want to run leaded fuel? There is no advantage in that. If you can get higher octane fuel in leaded, it still won't help unless you have maps that take advantage of the higher octane. Right now I know of no good chips for our cars for racing. There are enough of us who are building cars for either ITS or 944 Spec (or Cup) that we should band together and try to find someone to do so. I guess there is less advantage to the Spec and Cup guys, but for us ITS guys it's a big deal.
<strong>Does anybody have a source for a euro ( non O2 sensor ) DME control unit for a 944 NA. Or can a US box be properly modified to delet the O2 sensor. I have been told that performance will suffer if you simply unplug the sensor? I am building a SCCA ITS car and want to run leaded racing gas..
Fred</strong><hr></blockquote>
Fred, why do you want to run leaded fuel? There is no advantage in that. If you can get higher octane fuel in leaded, it still won't help unless you have maps that take advantage of the higher octane. Right now I know of no good chips for our cars for racing. There are enough of us who are building cars for either ITS or 944 Spec (or Cup) that we should band together and try to find someone to do so. I guess there is less advantage to the Spec and Cup guys, but for us ITS guys it's a big deal.
10-03-2002, 12:06 AM
#6
Race Director
[quote]Originally posted by Danno:
<strong>You'll probably be a little richer on the mixture, but that'll be fine on a race car.</strong><hr></blockquote>
Richer might mean slower. Aftermarket maps are nearly always leaned out since it makes more sense for the OEM to make the maps rich (safer for the engine in a number of ways). The only way richer would be OK, is if there are enough mods to change VE that the mixture ends up too lean as a result. That may be possible given the results of GRM's project car making more power with an adjustable FPR.
<strong>You'll probably be a little richer on the mixture, but that'll be fine on a race car.</strong><hr></blockquote>
Richer might mean slower. Aftermarket maps are nearly always leaned out since it makes more sense for the OEM to make the maps rich (safer for the engine in a number of ways). The only way richer would be OK, is if there are enough mods to change VE that the mixture ends up too lean as a result. That may be possible given the results of GRM's project car making more power with an adjustable FPR.
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10-03-2002, 02:41 PM
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THANKS GUYS! as for running leaded gas, I have a source for leaded racing gas that is $ 1.00 a gallon less than high octane unleaded race gas. I have had no luck with pump gas when racing with cr greater than 10:1,.. I agree we should ban together to get a chip maker to burn some good stuff for guys wanting to race ITS with a 944
10-04-2002, 01:24 AM
#9
Race Director
[quote]Originally posted by Danno:
<strong>George, have you tried out F.R.Wilk's chips?</strong><hr></blockquote>
No I haven't. Actually, I haven't even started my car yet. I want to get the cage in first and get the interior done. After that, everything that is left is maintenance and bolt-on stuff.
From what I can tell, FR's chips are basically just European maps mainly. I'm looking for something even more aggressive to take advantage of race gas and designed with a header and CAI in mind.
I wish we could switch to a MAF, but unfortunately, the rules forbid that.
<strong>George, have you tried out F.R.Wilk's chips?</strong><hr></blockquote>
No I haven't. Actually, I haven't even started my car yet. I want to get the cage in first and get the interior done. After that, everything that is left is maintenance and bolt-on stuff.
From what I can tell, FR's chips are basically just European maps mainly. I'm looking for something even more aggressive to take advantage of race gas and designed with a header and CAI in mind.
I wish we could switch to a MAF, but unfortunately, the rules forbid that.
10-04-2002, 03:33 PM
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In reference to running high octane leaded/unleaded fuel ina stock NA car...
The advantage is that under harsh (HOT) racing conditions, the knock sensor wont retard the timing...no knock detected...no retard.
As for the O2 sensor...round file it. The computor goes into open-loop status after 2500 rpm effectively "removing" it anyway. Aside from running alittle fat at idle,it WILL NOT run any richer under race loads.
Might as well remove the exhst restriction the sensor provides.
I'd caution from getting too agressive with maps/chips. These cars are'nt gonna make power above the stock redline if utilizing the stock intake tract and stock camshaft. All it "may" (maybe) do will take away some bottom end torque.
The advantage is that under harsh (HOT) racing conditions, the knock sensor wont retard the timing...no knock detected...no retard.
As for the O2 sensor...round file it. The computor goes into open-loop status after 2500 rpm effectively "removing" it anyway. Aside from running alittle fat at idle,it WILL NOT run any richer under race loads.
Might as well remove the exhst restriction the sensor provides.
I'd caution from getting too agressive with maps/chips. These cars are'nt gonna make power above the stock redline if utilizing the stock intake tract and stock camshaft. All it "may" (maybe) do will take away some bottom end torque.
10-04-2002, 05:05 PM
#11
Race Director
[quote]Originally posted by QUICK'44:
<strong>In reference to running high octane leaded/unleaded fuel ina stock NA car...
The advantage is that under harsh (HOT) racing conditions, the knock sensor wont retard the timing...no knock detected...no retard.
</strong><hr></blockquote>
It's my understanding the NA does not have a knock sensor - at least the early cars. Is this inaccurate?
Also, I know the advantage of high octane. The question was "why leaded?" and that was answered.
[quote]Originally posted by QUICK'44:
<strong> I'd caution from getting too agressive with maps/chips. These cars are'nt gonna make power above the stock redline if utilizing the stock intake tract and stock camshaft. All it "may" (maybe) do will take away some bottom end torque.</strong><hr></blockquote>
Why would adjusting the maps, even agressively, take away any bottom end? A good set of maps should find power throughout the rev range unless Porsche programmed them on the edge, and that I doubt. Then again, the flapper door AFM probably is not accurate enough to get really aggressive.
<strong>In reference to running high octane leaded/unleaded fuel ina stock NA car...
The advantage is that under harsh (HOT) racing conditions, the knock sensor wont retard the timing...no knock detected...no retard.
</strong><hr></blockquote>
It's my understanding the NA does not have a knock sensor - at least the early cars. Is this inaccurate?
Also, I know the advantage of high octane. The question was "why leaded?" and that was answered.
[quote]Originally posted by QUICK'44:
<strong> I'd caution from getting too agressive with maps/chips. These cars are'nt gonna make power above the stock redline if utilizing the stock intake tract and stock camshaft. All it "may" (maybe) do will take away some bottom end torque.</strong><hr></blockquote>
Why would adjusting the maps, even agressively, take away any bottom end? A good set of maps should find power throughout the rev range unless Porsche programmed them on the edge, and that I doubt. Then again, the flapper door AFM probably is not accurate enough to get really aggressive.
10-06-2002, 07:20 AM
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"The advantage is that under harsh (HOT) racing conditions, the knock sensor wont retard the timing...no knock detected...no retard.
Uhhh.. I agree with George here... Only the S2 and later NA cars had a knock-sensor. And relying on one to ride the edge of detonation is not really effective anyway. First because the amount and time that ignition is retarded under knock-detected conditions really take away from the performance. It's better to have timing adjusted to never knock at all, but closer to the edge than stock. Second, at high-RPMs, the knock-sensor isn't effective because of interference from valvetrain noise.
"As for the O2 sensor...round file it. The computor goes into open-loop status after 2500 rpm effectively "removing" it anyway."
Only under certain conditions does the DME go into open-loop mode. It is actually possible to stay in close-loop using O2-sensor feedback and dithering all the way up to redline. It's only under full-throttle (clicks WOT switch on TPS) AND you have the flapper-door swing open with a certain velocity higher than the pre-programmed threshold, that you will enter open-loop operation.
We were actually experimenting with modifying the DME code to run open-loop all the time using pre-programmed fuel-maps to remove the automatic enrichment that occurs under open-loop mode (it really is too rich at some places). But we would've had to datalog all operating ranges under all load levels (256 data-points). Also this would have had to be done for each and every single car's configuration since upgrading just the air-cleaner would've changed flow-conditions to throw the pre-programmed map off.
Uhhh.. I agree with George here... Only the S2 and later NA cars had a knock-sensor. And relying on one to ride the edge of detonation is not really effective anyway. First because the amount and time that ignition is retarded under knock-detected conditions really take away from the performance. It's better to have timing adjusted to never knock at all, but closer to the edge than stock. Second, at high-RPMs, the knock-sensor isn't effective because of interference from valvetrain noise.
"As for the O2 sensor...round file it. The computor goes into open-loop status after 2500 rpm effectively "removing" it anyway."
Only under certain conditions does the DME go into open-loop mode. It is actually possible to stay in close-loop using O2-sensor feedback and dithering all the way up to redline. It's only under full-throttle (clicks WOT switch on TPS) AND you have the flapper-door swing open with a certain velocity higher than the pre-programmed threshold, that you will enter open-loop operation.
We were actually experimenting with modifying the DME code to run open-loop all the time using pre-programmed fuel-maps to remove the automatic enrichment that occurs under open-loop mode (it really is too rich at some places). But we would've had to datalog all operating ranges under all load levels (256 data-points). Also this would have had to be done for each and every single car's configuration since upgrading just the air-cleaner would've changed flow-conditions to throw the pre-programmed map off.
10-06-2002, 09:08 AM
#13
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[quote]Originally posted by Danno:
<strong>We were actually experimenting with modifying the DME code to run open-loop all the time using pre-programmed fuel-maps to remove the automatic enrichment that occurs under open-loop mode (it really is too rich at some places). But we would've had to datalog all operating ranges under all load levels (256 data-points). Also this would have had to be done for each and every single car's configuration since upgrading just the air-cleaner would've changed flow-conditions to throw the pre-programmed map off.</strong><hr></blockquote>
What we need (hint hint) is something like the module avalable for the Honduhs. They have a package that allows you to reprogram the ECU essentially the same way as you would a stand-alone ECU. Pretty slick. IIRC they aren't cheap, but they are cheaper than a true stand-alone ECU. This way folks with the knowledge and inclination could custom program their DME on the dyno. It should be possible to even use input from a MAF or MAP. Geez, this would even make it possible for folks to turbo a NA 944 since engine management is the single biggest hurdle. And of course it would allow me
to create maps for my race car.
<strong>We were actually experimenting with modifying the DME code to run open-loop all the time using pre-programmed fuel-maps to remove the automatic enrichment that occurs under open-loop mode (it really is too rich at some places). But we would've had to datalog all operating ranges under all load levels (256 data-points). Also this would have had to be done for each and every single car's configuration since upgrading just the air-cleaner would've changed flow-conditions to throw the pre-programmed map off.</strong><hr></blockquote>
What we need (hint hint) is something like the module avalable for the Honduhs. They have a package that allows you to reprogram the ECU essentially the same way as you would a stand-alone ECU. Pretty slick. IIRC they aren't cheap, but they are cheaper than a true stand-alone ECU. This way folks with the knowledge and inclination could custom program their DME on the dyno. It should be possible to even use input from a MAF or MAP. Geez, this would even make it possible for folks to turbo a NA 944 since engine management is the single biggest hurdle. And of course it would allow me
to create maps for my race car.
10-06-2002, 09:17 AM
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Take a look at Huntley Racing's website. They have a black box that allows you to modify the factory DME air\fuel mixture to remap these values. I have no personal experience with the product but am interested since I am in the process of converting my 930 CIS system to 3.2 Carrera DME
10-06-2002, 12:59 PM
#15
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[quote]Originally posted by garrickl:
<strong>Take a look at Huntley Racing's website. They have a black box that allows you to modify the factory DME air\fuel mixture to remap these values. I have no personal experience with the product but am interested since I am in the process of converting my 930 CIS system to 3.2 Carrera DME</strong><hr></blockquote>
Is that the Link fuel controller and the spark controller? If so, they will not work for me. In SCCA IT racing we can modify anything inside the ECU (DME) box, but piggybacks and other such methods are not allowed. We (and those running 944 Cup and 944 Spec) need to actually reprogram the chip rather than alter the signal to it. Of course, a stand-alone system that fits completely inside the DME box, that uses the OEM connectors, and doesn't require a controller outside the box would do the trick ever so nicely.
<strong>Take a look at Huntley Racing's website. They have a black box that allows you to modify the factory DME air\fuel mixture to remap these values. I have no personal experience with the product but am interested since I am in the process of converting my 930 CIS system to 3.2 Carrera DME</strong><hr></blockquote>
Is that the Link fuel controller and the spark controller? If so, they will not work for me. In SCCA IT racing we can modify anything inside the ECU (DME) box, but piggybacks and other such methods are not allowed. We (and those running 944 Cup and 944 Spec) need to actually reprogram the chip rather than alter the signal to it. Of course, a stand-alone system that fits completely inside the DME box, that uses the OEM connectors, and doesn't require a controller outside the box would do the trick ever so nicely.