BruceP

Just get PSS9s and call it at day. Adjust it all you want. It's the best option for the street. Better than factory X kits. But it may be out of your budget since it sounds like you want to go bits and pieces which I wouldn't recommend.

Hi, Bruce.

Budget is certainly not the issue, as you may recall from past exchanges, Ben. And deciding to stay with factory springs and sways does not equal going "bits and pieces".

"Best option for the street" isn't helpful, but thank you. What "best" and which "street" are the key questions for suspension choices if you really care about performance.

Of course I remember that of course budget is not an issue for ya. That's why we're all still driving 996s and especially for you, an MK1 996 with the beloved Boxster headilghts that receives all-season beating.

And what of performance? Aside from getting responses like "this worked great for me," trying to come to some sort of meaningful suspension/handling conclusion around "performance," especially over the internet, is a sisyphean challenge.

My point is, all these options will be just fine for the daily 911: ROW M030, Bilstein shocks with OEM springs, PSS9s, etc. For those on a budget, go with the new aftermarket shocks with factory springs options. If you have more money to spend, PSS9s are a no brainer. If you have no budget, then heck handle your business and go for a full Moton setup.

Thx for reading, buddy. :)

You keep skipping past the part where I don't want to lower the car.

Just get PSS9s and call it at day. Adjust it all you want. It's the best option for the street. Better than factory X kits. But it may be out of your budget since it sounds like you want to go bits and pieces which I wouldn't recommend.

Hi, Bruce.

Budget is certainly not the issue, as you may recall from past exchanges, Ben. And deciding to stay with factory springs and sways does not equal going "bits and pieces".

"Best option for the street" isn't helpful, but thank you. What "best" and which "street" are the key questions for suspension choices if you really care about performance.

Bruce,

I am also struggling with the same options. Tirerack.com has a set of 4 for $808, Shox.com has them for $829

I'm doing it. As far as I can tell, the car will stay drivable for my purposes, with a better ride AND better handling, all for just a few hundred more than just replacing the rears alone with OE shocks.

People get caught up in the excitement of a lower, stiffer car, often not realizing that this will only improve performance if the pavement is smooth. The job of a suspension is to keep the rubber on the road. On my roads, that's about travel and rebound damping. No bragging rights for me, but I think I'll be happier.

I went through this decision on the front not too long ago, but the dealer warrantied the original shock. Otherwise I would have gone for the Bilstein HD shocks. I think the Bilstein sport shocks have a shorter travel. The HD shocks are sportier shocks than OEM and have a lifetime guarantee.

shox.com has a buy-3-get-one-free Bilstein deal right now. Unclear from the Bilstein web site and shox.com if it applies to all shocks, or just the Bilstein truck shocks.

Good scoop. I ended up calling Bilstein in the US, because there's no support to speak of in Canada, and you're exactly right. The HDs are the direct replacement. Thanks for chiming in!

If you put stiffer shocks on the rear then you will somewhat "unbalance" the car.

If it were me I would go with sport shocks all the way around and keep the handling balanced.

Sorry if I wasn't clear. That's exactly what I'm thinking to do. Sounds like you'd endorse the shocks for my purposes?

The rear shocks on my car are showing signs of leakage. I want to replace them.

I've thought about upgrading the suspension, but ended up rejecting the idea. The car is a four season daily driver, and the roads and parking lots in this city are brutal. I don't want to lower the car, and I don't want to radically stiffen the ride.

Rather than just put new OE shocks in the rear, I'm thinking of replacing all four with Bilstein's sport shocks, which are a straight replacement for the OE pieces. My experience with these in the past is that I'll get a bit more stiffness and control when they're loaded, and a bit more compliance over little bumps vs. OE. This seems like the right answer for my driving reality.

Anybody had any experience with these? Again, I'm not talking about Bilstein's PSS9/10 kits. Just the dampers. TIA, as always!

A hundred years ago, there was a legend about the necessity of keeping the rpm's elevated on the 356 Porsches of the day, and I believe that stemmed from the original 356 Carreras having roller-bearing cranks, and that the higher revs regimen was to counter any potential damage to those roller bearings from lugging the motors. Do you think that might apply to the M96's IMS bearing as well?

All I know is, that I'm having a ball keeping the revs elevated on my MY '05 M96 equipped C2S!

This engine hates to be lugged. No engine is happy so far from peak efficiency as this engine is below 3000rpm. This one tells you so, too, in vibration, fuel economy, tailpipe emissions. Heck, Porsche tells you straight up you can run the motor up to 4500 rpm stone cold. I don't doubt that an M96 engine CAN be poodled around at 2000rpm and that lots of people do. But I don't think that makes it a good idea.

And you can't help but notice how many engine failure stories have occurred at very low speeds. My .02.

I was the guy that started that 'Stupidest Money' thread. I think that many Porsche owners take themselves too seriously.

Porsche mostly acquired its status baggage in the 80s, when it became the darling car of 'achievers'. Before that, Porsche's were more oddball and quirky than they were straight up status symbols. Since then, its image has been a product of the people who drove them, not the other way around.

I think if you can't just tell people what you drive, then either you hang around with the wrong people or you might not be comfortable enough in your skin to drive something so extroverted.

EDIT: I say this as someone who truly loves Porsches, by the way, including my own little plain-jane C2!

So about $380 USD each..just the parts?! Sheesh!! Wow.

Could be worse. I wasn't that fussed about it. Porsches are cheap to buy, but not cheap to own. This has always been true. A lot of guys aren't ready for that. I like to fix these things right, I don't mind paying for it, and I've never had a single repair item that exceeded the equivalent of a single monthly payment on a newer one. I'm not complaining. (But you'd be surprised at the heat I've taken in 'other' forums for not being upset about maintenance costs!)

If the bet is that your coolant temperature will stay below 215F while in traffic....I'll take that bet. :D

I don't think any practical mod would produce that result, actually, though I know you feel differently. But I'll be happy with any improvement, and delighted if I never saw the far side of 105C except in the very worst circumstances.

The rads were $425CDN each. I did both of them as a precautionary measure. They also sent the AC condensers out for reconditioning. I'm going to bet this solves it.

On the BMW cooling system topic, I was so paranoid about this that when I bought my 04 Range Rover last year, I put a significant amount of money into replacing every failure-prone cooling system component!

EDIT: Here are a couple of pics of the rotted rads.

Yeah, you can say that again. That plastic neck snapped on my 528 and cost $3k worth of engine damage...warped head, pulled block threads that had to be helicoiled, etc, etc. Until this happened to you, I'd not have though of it either, but of course those rads are just collectors for everything, as low as they are, but then I don't drive the 996 in what little snow we get, here in Richmond. I thought most all rads cooling portions are finned aluminum nowadays, so I'm surprised it doesn't happen more often up north. BTW, how much were the rads?

Like we said, radiator cleaning is normally the culprit, in your case, it just wasn't leaves, but the result is the same. Salt is nasty stuff on aluminum. Would definitely pay to hose out the rads in wintertime to get the salt out. Glad you found it before you sprung aleak!

As I may have mentioned somewhere in this thread, the rads were 'clean' in the sense that debris had been removed. The corrosion developed in the outboard lower corners of the rads, which are of course behind the AC condensers. Regular hosings might help, but I suspect the only way to prevent it would have been to regularly remove the bumper cover and separate the rads and AC condensers as some here do from time to time.

It was somebody else's car for six winters, so caveat emptor. But this is the first car I've owned with aluminum rads. Never would have occurred to me. (That said, I like this problem better than BMW's plastic rads and the fun way they fail!).

Sorry to bump an old thread, but I thought I'd share what looks like the real problem may have been.

There was significant corrosion in both radiators. It was bad enough that when my indie started to clean out the corroded material, one rad actually started to leak. I'm replacing both rads and refurbing the AC condensers, and I'll bet that cools things down.

My car is driven year round, even on salty, slushy days here in Toronto. It was interesting to me that the body and chassis are still in wonderful shape for all the abuse. Never imagined it would be the rads that would complain first.

Thanks again to those who were interested. And if you winter drive your car in salt and crap, maybe something to keep an eye on that you might not have thought of.

Bruce.

I am thinking of installing brake dust shields for a my99 996.

Any suggestions for where to purchase and if they

are effective. Any caveat's?

Thanks

bolobar

These can impair brake cooling, which is why I've never considered them. This might be academic if a car was strictly a boulevard cruiser, but it's enough to deter me. YMMV, of course.

I live in Las Vegas...hot hot hot in summer. My 2000 6speed never moves above 180 (by the gauge) even w/AC. I cant help but wonder if Porsche tested their cars in desert climates? If they did the car should not overheat or run too hot. It would seem to me that if a car is running too hot then something in the system is not working as designed. I really dont get the whole discussion.

Echo perryinva's comments. I think the car is built to do what it does brilliantly, which is go fast. When my car is doing that, it's happy as a clam in any conditions. I don't think that Porsche failed to test the car for hot climates, but I bet they didn't give too much thought to designing it for sitting still.

To clarify my issue, the car is not overheating in the opinion of its designers (the warning light has never come on). It's ME who isn't comfortable with the operating temps when it's idling in traffic.

Regarding your temperature gage, I don't think mine "moves above 180" either. Problem is, on that gage, "180" covers a lot of territory. I use the OBD to get the actual temperature, if I really want to know. I'm pretty sure I've seen 105C on the OBD without the needle on the gage moving past the "180".

My original question was quite simple: Will the third radiator lower the coolant temperature appreciably in stop and go driving conditions? Three pages later, it doesn't look like anybody knows for certain. That kind of gave me my answer.

Well, I'm a little confused here. From the first post I thought that your fans were running continuously, but the temp still stayed above 215F which is about 102C, in stop and go traffic. (It doesn't specifically say that, but that is what I thought.) In which case MR 1999s fix will not work, even he has to agree with that.

(And for the record, there is no way that turning the fans on sooner or constantly will yield a lower final coolant temperature any lower than if the fans kicked on at 215F and stayed on. Period. That is Thermo101. It WILL prevent the temperature from ever reaching 215F, or even exceeding whatever that final temperature is, but it will be the same pre or post mod. I run under the reasonable assumption that 215F max is no big deal, and there is nothing really to gain keeping the coolant constantly at 180F, at the expense of more wear & tear on the fans and the parasitic loss of the load. Using your logic, why not just hard wire the fans and keep them running all the time the engine runs?)

But when you say that the cooling system is running normal, do you mean that the fans are cycling on and off all the time in traffic? In that case, Mr 1999s fix will work exactly as he has stated, the coolant will be a more constant lower temp on average, as it will do what you stated works, move more air through the radiators. I have a 2002, and they don't seem to have the same cooling issue, as the fans infrequently turn on even in stop and go city traffic in 105F air temps. And as you stated, when the fans kick in, the temp drops very quickly, which is why I didn't suggest a higher rate fan. The ones you have work. On an aside, I had done the clutched fan delete on my BMW a few years back to "gain" a bit of HP back, as I really didn't think that the apparant small amount of air did much. I shortly re-installed it as it made a huge difference in the number of times the electric fans came on and their duration. The clutched one is much quieter and suffices for normal use. It doesn't take much air make a difference. It almost seems like the 996 with this cooling "issue" could benefit from an additional lower (quiet, less load) speed on the fans.

Hey, Perry, let me be really clear. Sorry if it seems terse, but there's a lot of broken telephone on this thread:

In high ambient temps, sitting in very slow or stationary urban traffic, the temp as displayed by the OBD can exceed 105C. This is within Porsche's parameters. But I worry about it anyway, hence the original question.

When I say the system operates as designed, I mean: The rads are clear. The coolant is less than two years old. The coolant level is correct. The coolant type is correct. The expansion tank cap is new. The fan relays turn the fans on, and switch to high speed when they are supposed to do so (102C or AC on).

This means that in the conditions described above, the fans are already on high speed at all times, but I'm still operating at 105 to 108C.

When I say that the temperature drops quickly with air flow, I mean that it does so when the car starts moving again.

Realizing that I can't manipulate too many variables in the system, I wondered whether the increased surface area and system capacity offered by the GT3 center rad made any difference at all.

That's my story. To me, the three reasonable answers would be: Yes, it will help. No, it won't make any difference. Or, stop worrying and trust Stuttgart. ;)

Thanks,

Bruce.

Fans go to stage 2 (high speed) all the time the AC is on.

I know, and this is why I'm skeptical about the value of the 'fan mod'. Under the conditions I'm talking about, the fans are running on high most of the time anyway.

Not sure if this applies to all years, but there is an exact duplicate of my options sticker in the owner's manual or the service book... forget which, but it's there. Exactly the same sticker as the one under the hood.

Have you checked both radiator fans to feel if they are moving about the same amount of air? Easy to tell if you stick you hands right in front of the front tires. (Turn on the AC or you'll have to wait until summer..) Could you have a weak motor, or part of the resistor is bad on one, and that it simply is not moving enough air? The fan runs at two speeds, but is dependent onte resistor to do that. You may only have one speed.

Perhaps you have a defective T-stat that's not opening all the way? I've never understood going with lower temp t-stat, as the stock one should be full open at well below 95C. Full open is full open. AFAIK, a lower temp T-stat does not open more than the stock one. Same thing if fans are already running. Running them sooner does not keep the top temp cooler. If fans are running, then the system will reach the same equilibrium temp, regardless of when they turn on. What you may gain, is less of an excursion before they reach equalibrium. This doesn't sound like Bruces problem. I assume you've done a coolant change, and the system was properly bled. You might try Water Wetter, or as Brad inferred, a larger or additional oil cooler. though the 3rd radiator might be less expensive than the oil cooler. It's certainly cooler looking.

As I mentioned in my original post, the cooling system is entirely working as designed. I'm pretty familiar with the car by now and comfortable with this stuff. Have actually been through a fan failure, so I know how that goes. They're both clean and working fine.

I share your view on the fan mod. It might work for some, but the coolant temperature rises and falls so quickly with this car that I don't see how prophylactic cooling is going to make much difference in the traffic I drive in, other than letting the engine run cooler for a minute or two longer.

A real fix doesn't exist, frankly, IMHO. If you look at how they deal with this stuff in police cars and taxis and military vehicles, the only variables you've got are surface area, air flow and system volume: More rad, more fluid, more air. We can add only a little volume and surface area, and can only control airflow with motion. The dream solution would be a fan design that moved more air, and fan motors that can deal with the load.

Do you like make things more completcated than necessary? :o

It works for ALL. Street or track. It is not that the fans do not push enough air. It is the fact that they do not turn on soon enough to full speed.

I disagree with you. That's my right. My own experience tells me that your suggestion will not work for my needs, and your aggressiveness does nothing for your credibility.

Have you checked both radiator fans to feel if they are moving about the same amount of air? Easy to tell if you stick you hands right in front of the front tires. (Turn on the AC or you'll have to wait until summer..) Could you have a weak motor, or part of the resistor is bad on one, and that it simply is not moving enough air? The fan runs at two speeds, but is dependent onte resistor to do that. You may only have one speed.

Perhaps you have a defective T-stat that's not opening all the way? I've never understood going with lower temp t-stat, as the stock one should be full open at well below 95C. Full open is full open. AFAIK, a lower temp T-stat does not open more than the stock one. Same thing if fans are already running. Running them sooner does not keep the top temp cooler. If fans are running, then the system will reach the same equilibrium temp, regardless of when they turn on. What you may gain, is less of an excursion before they reach equalibrium. This doesn't sound like Bruces problem. I assume you've done a coolant change, and the system was properly bled. You might try Water Wetter, or as Brad inferred, a larger or additional oil cooler. though the 3rd radiator might be less expensive than the oil cooler. It's certainly cooler looking.

As I mentioned in my original post, the cooling system is entirely working as designed. I'm pretty familiar with the car by now and comfortable with this stuff. Have actually been through a fan failure, so I know how that goes. They're both clean and working fine.

I share your view on the fan mod. It might work for some, but the coolant temperature rises and falls so quickly with this car that I don't see how prophylactic cooling is going to make much difference in the traffic I drive in, other than letting the engine run cooler for a minute or two longer.

A real fix doesn't exist, frankly, IMHO. If you look at how they deal with this stuff in police cars and taxis and military vehicles, the only variables you've got are surface area, air flow and system volume: More rad, more fluid, more air. We can add only a little volume and surface area, and can only control airflow with motion. The dream solution would be a fan design that moved more air, and fan motors that can deal with the load.

You know, I know it's a popular mod and a lot of folks have had overheating issues (maybe '00 specific), specially on the track, but I've NEVER had overheating issues, let alone high temps in my car with the standard 2 radiators, even on the track during the middle of the summer at places like Buttonwillow and Thunderhill, which get 100 degree temps in the summer ambient.

I will say though, every time I wash the car, I spray high pressure water at the radiators to keep them clean.

Oh, and it's a C4s.

I agree that the cooling system works brilliantly when there is airflow through the rads, as would be the case on a track. The problem is sitting in traffic. Indeed, it might only be a problem in my head; the car is working as designed. I just don't think the car was designed with the stresses of urban commuting strictly in mind.

Regarding the model year, I think that I've read that the early 996s had only one temperature sensor, located at the engine. The later ones had a second sensor at the rads, and the OBD read out the average of the two readings, thus making the later cars appear to run cooler than the earlier ones did. C

The target coolant temperature is 90C - 95C. You cannot run at that low of a temperature if moving in slow traffic without getting more air past the radiators.

I'm sure you're right. The only really correct, effective fix would be fans that moved more air.

You know, I know it's a popular mod and a lot of folks have had overheating issues (maybe '00 specific), specially on the track, but I've NEVER had overheating issues, let alone high temps in my car with the standard 2 radiators, even on the track during the middle of the summer at places like Buttonwillow and Thunderhill, which get 100 degree temps in the summer ambient.

I will say though, every time I wash the car, I spray high pressure water at the radiators to keep them clean.

Oh, and it's a C4s.

I agree that the cooling system works brilliantly when there is airflow through the rads, as would be the case on a track. The problem is sitting in traffic. Indeed, it might only be a problem in my head; the car is working as designed. I just don't think the car was designed with the stresses of urban commuting strictly in mind.

Regarding the model year, I think that I've read that the early 996s had only one temperature sensor, located at the engine. The later ones had a second sensor at the rads, and the OBD read out the average of the two readings, thus making the later cars appear to run cooler than the earlier ones did. C

Or you can keep your coolant temperature below 200F at all times by doing my simple fan mod. Cost is virtually nothing.

I am familiar with the mod. As mentioned earlier, I don't believe it's an answer for me. When the car is hot and stationary, the fans are already running anyway. When the car is moving, it cools down quickly and doesn't run as hot. Thus, being able to manually activate the fans is not helpful.

Bruce,

I live in Houston, TX so I have seen temps upto 112 C (on my 2000 996 C2, I can get the coolant temp on my AC display).

I track the car quite a bit and installed the 3rd radiator. In stop and go traffic over 70 degrees F ambient, coolant temps creep over 100 C, even with the 3rd radiator, so I decided to do the radiator mod. Still waiting on the relay for the toggle switch, but with that I guess the temps should stay in the safer sub 100C range.

Let's see if the next step needed is the LN thermostat.

Joost

Yes, I get my coolant temps the same way. This is where I got my observation about the importance of airflow, because as you already know, the OBD readout is really accurate and instantaneous.

To the other posters, thank you. Some replies: Yes, the rads have been cleaned out. Toronto hot is hotter than you might think, just not for as many months! Appreciate the comments about track performance, but as I mentioned originally, the car cools just fine when it's in motion. The issue is exclusively when it's idling in traffic. I totally believe the car could run without fans... I'd be a happy guy if I could commute to work at 200kph!

It sounds like this might be a good mod, just not a transformational one.

Thanks, guys.

So, Brad, should I take that as a yes? The 3rd radiator is useful for cooling in my situation?