Why does the 915 ROW has an oil cooler?

[livi]

When the US version does not ?

[Rory Mckenna]

Hey Livi,
I would think because the Euro cars are driven at higher speeds for prolonged periods of time on the Autobahn.. and the US.. that doesn't happen. I could be wrong.. but i think i am on target.

[livi]

That might be it. I thought perhaps it was because the ROW engines produces slightly more power that is delivered through the box to handle.

[wolf]

vee have more of zee power and zee tork here my dear fellow doctor. zee 915 was at the end of handling this; otherwise we would have had the 3.3 (from zee turbo)

[livi]

I guess thats it. Much obliged, boyzz!

[richde]

Originally Posted by Rory Mckenna

Hey Livi,
I would think because the Euro cars are driven at higher speeds for prolonged periods of time on the Autobahn.. and the US.. that doesn't happen. I could be wrong.. but i think i am on target.

When were speed limits lowered in the US?

You want extended high speed cruising? Try New Mexico or Arizona.

Most things people think about the autobahn have not been true for me. It's not very widespread, is not all unlimited and it's been difficult whenever I've been on it for the last seven months to really blast on down the highway. Too many slow moving trucks and slow drivers that are not afraid to pull out into the passing lane while traveling 60 or so MPH while you're bearing down on them at well over 100.

[1982911SCTarga]

I don't buy that differences in driving style were why ROW cars got transaxle coolers. All 911s are road cars. Hey, at least we got the extra front A/C condenser and blower.

Has anybody got hard comparisons of mileage lifespans between a cooler-equipped and non-cooled 915 transaxle? How much does having one extend the life of the gearbox?

Brian

[stevemfr]

above all, not all RoW 915's have coolers...

[livi]

Originally Posted by stevemfr

above all, not all RoW 915's have coolers...

I meant specifically the Carrera models (84-89), which IIRC all have oil coolers in Europe, but not in US or Japan. Sorry I was not clear on that.

I believe it has to do with (as stated previously) the assumption that 231 bhp was on the verge on what the 915 could handle.

[Rory Mckenna]

Originally Posted by richde

When were speed limits lowered in the US?

You want extended high speed cruising? Try New Mexico or Arizona.

Most things people think about the autobahn have not been true for me. It's not very widespread, is not all unlimited and it's been difficult whenever I've been on it for the last seven months to really blast on down the highway. Too many slow moving trucks and slow drivers that are not afraid to pull out into the passing lane while traveling 60 or so MPH while you're bearing down on them at well over 100.

Rich,
I agree.. The Autobahn as it once was.. is really no longer.. There are far to many STAU in Germany these days. I didn't get to do too much fast driving while I was stationed in Baumholder there...I think it was done because there is more potiental to drive at higher speeds than here in the US..
Yeah there are places here you can ramp it up...but not legally as it could be in Germany..

[RarlyL8]

I have one of those trannies and asked an old timey mechanic about it. He told me that the Euro cars are beat on more than in the US so the tranny needed a little insurance as the power levels climbed. They are also geared differently than the US versions.

[Bill Verburg]

There is a history of neglect as far as oem performance parts for US cars

[jorian]

"Why does the 915 ROW has an oil cooler when the US version does not ?"

Because Charles Kieffner doesn't like towing.....

[Hugh R]

I have an ROW with a trannie cooler. It because Americans want the lower hp car with less performance. Its because Americans didn't say WTF when the EPA and the rest of the gubmit said, you don't know what's good for you, but we do, and the American public said okey, dokey.

Its why $30 throw away cell phones that I use in Prague, will work in Germany, England, France, Italy, Slovinia, New Zealand, Canada, Russia, and a bunch of other countries, but my US Verizon phone will only work here and in NZ.

[jthwan22]

Really, I never notice it. Anyone have a picture?

[RarlyL8]

[svandamme]

coz Europeans engine brake, snot-rev, and use the synchro's for what are meant to be used,
Porsche knows it , and tries harder

while Amerihkans make a whole lotta hoopla about doubleclutching, revmatching
while generally frowning upon things like engine braking and what not
Porsche knows that too and figures they can cut costs because of that

[stevemfr]

Originally Posted by livi

I meant specifically the Carrera models (84-89), which IIRC all have oil coolers in Europe, but not in US or Japan. Sorry I was not clear on that.

I understood it that way, too. My 231hp '84 Carrera (WPOZZZ91ZES...) didn't have a cooler. Why, I can't say. The car was stock and had about 18kkm's on the clock when I bought it mid '85. I had other 231hp Carreras on the lift in the early 90's that did not have a cooler either (I worked at a P shop just outside of Munich). I never delved further - just assumed it was an option. Possibly early Carreras did not have the cooler standard? The shop I worked at (indy), we weren't seeing many late Carreras yet - those still went to the dealer.

As far as performance neglect goes, the 204hp SC didn't have a tranny cooler standard in Germany with the 'bahns, why should P have reduced the profit margin on its 217hp US Carrera by adding a cooler for people driving 55mph? While I can't quite follow the cell phone to tranny cooler argumentation above, driving in the US was def. different - especially back then (less Staus on the 'bahn in the early/mid 80's) - regardless of how much of an outlaw you were in the US. I purchased my '84 over here (Europe) and drove it for several weeks before importing it to the US, and I did one Frankfurt Airport / downtown Munich run in under 2 1/2hrs despite traffic. That is an average of over 100mph for 2 1/2hrs. I was in my early 20's back then and my driving was - shall we say - very spirited. Back in the US I never managed more than a spurt here and there despite my spiritedness. There was simply no need for a tranny cooler for the average P driver.

[javadog]

The 915 gearbox was originally designed for an input torque of 25 mkg. When the SC was introduced, it slightly exceeded this maximum figure and you'll recall Porsche changed a few things on the gearbox, the biggest change being the reversion from using magnesium castings to aluminum again. As the 911SC was developed, the ROW cars gained torque.

When the Carrera was introduced, it produced around 28.6 mkg of torque. In the early 80's, Germany opened some new stretches of Autobahn and the traffic was still light in certain areas. There were only a few small cars you had to worry about and trucks kept to the right lanes. I remember being able to really fly at times. In fact, driving at night in the rain was a little unnerving, as the trucks were gone and the slow lane moved along at around 80mph, which was well above the speed a 911 would hydroplane on the tires of the day. Not fun.

Anyway, the more power you transmit through a gearbox, the hotter it will run. I suppose Porsche figured that cars for certain markets had the potential to put a lot of heat into the gearboxes, so they put coolers on some of them. Keep in mind that ROW cars went to some markets that had strict speed limits, not unlike ours. Most countries had a speed limit of around 50mph, give or take.

They made other changes too, such as strengthening the top 2 gears and the side plates on some versions. Actually, there are many little differences in the 915s built for different markets. We'll probably never know the reason for all of the changes. Given the speed limit in America, Porsche correctly figured that we'd only be able to put a fraction of the rated torque through a 915 for more than a few seconds at a time, so it was pointless to add the cooler.

JR

[GrantG]

I think track use would generate more heat than Autobahn use (especially with optional LSD). Too bad the cooler wasn't even an option here