Has anyone removed the air conditioning system from the car and if so what is involved? I never run my A/C and from a simplicity standpoint and weight savings, I'd like to get rid of it. Anyone know the amount of weight saved by removing the compressor and associated hardware and any implication of loosing the the A/C which is used to power the fuel cooler on the TT/GT2? There is no fuel cooler on the GT3 or Cup cars, btw. Anyone know if the fuel cooler is actually operating when the A/C is turned off and is in fact really necessary?

Thanks....

 

When the air conditioning is turned off the fuel cooler does not have any cooling. The european cars (ROW) don't have this feature. Weight saving can be important, pump, hoses (underside), condensers (2) and hardware removed probably represent close to 100 pounds! I saw Kevin post on Rennlist and he's talking about 30 pounds of saving… Hum, may be I'm off a little bit lol!!! But about the a/c coming on and off to cool the fuel ??????

I am correcting this sentence about fuel cooler. "The essential companion" book mention there are a fuel cooler installed on ALL 996 turbo…Sorry about this mistake

 

I would love to get hard data on this, both on the weight savings and operation of the mysterious fuel cooler. Seems there is a lot of conjecture on both fronts. 100 lbs seem excessive however. I was thinking about 40-50lbs myself but would love to hear from someone who's removed and weighed the stuff. I think on 997GT3s the factory delete option was about a 60lb savings if memory serves me correct.

 

Just by curiosity I went and search different forums. A guy with a 930 save 30 kg (66 pounds removing the a/c system. Of course we are talking about stripping everything, condenser, evaporator, desiccator, expansion valve , compressor, hardware and all the lines under the car and in the front compartment. Admit it is far from 100 pounds But I'm talking about a good clean-up , Interesting subject I have to admit….


http://www.911uk.com/viewtopic.php?t...er=asc&start=0

 

I know you're building a monster track machine pwdrhound -- but I've never seen anything massacre resale ability like pulling the A/C. Even if there's a .001% chance you'd ever sell it, I'd leave it in.

Also -- why haven't you gotten a cup car yet They don't have all this pesky stuff you're removing

 

You're looking at a max weight reduction of 40 lbs I'd say. I've removed an entire a/c system from other sports cars, and they've all come in from 30-35 lbs. With our cars, there may be a slight bit of added weight since we are rear engine and the lines run to the front of the car vs a front engine setup, but we're talking aluminum lines that don't weigh much.

 

I'm not ever going to turn my car back into a daily driver and if I ever sell it, the person that will buy it will not be for daily duty but rather as a no holds barred track car which is still legal to drive on the street. In that case, A/C delete would be a bonus. In 4 years of ownership, I have only run the A/C a couple of times so it has no value to me. I still haven't decided 100%, but on a 997GT3RS the A/C delete is a highly sough after option.

As far as a Cup car, I thought about it briefly but the $1500/hour operating cost of one is too rich for my blood (just tire wear will set you back $250 for each 25 minute session). 996 Cups are reasonable priced buy not any faster then my car. A well driven 997 Cup is slightly quicker but comes at a much higher cost. On top of that, it is a lot more fun chasing down a Cup in my "street" car than the other way around. That's the challenge. Plus, I have the option of still driving my car on the street from time to time if I choose. I actually put almost a 100 street miles on the car this past weekend which is probably my quota for the month. With the shock compression turned way down it was fairly doable (but not all too enjoyable )

 

Wondering why? You can buy a nice 996-997 Cup car with spares for $80K and up. I'd much rather race a Cup car with all the right stuff than put 10s of thousands of $$$ in my Turbo and never quite get there. Then, worse, end up with something that I can't return to stock and sell for going prices or sell at any price as a 996 Turbo racer that hardly has any market at any price.

Maybe I'm missing something. I have a decade of very serious racing in my past and much longer building racing machines.

 

I think you are right in the ball park with the weight saving estimate.

Looks like according to this document from PAG, A/C delete on a 997GT3RS is at least 15kg/33lbs:

...vielen Dank für Ihre E-Mail vom 03. September 2009 und Ihr damit verbundenes
Interesse an den Produkten unseres Hauses.

Nach Prüfung durch die
Fachabteilung möchten wir Ihnen mitteilen (after checking with the various in-house departments), dass wenn Sie Ihren Porsche
911 GT3 RS
so ausstatten, wie in Ihrer E-Mail beschrieben, Sie auf einen
Gewichtsvorteil von ca. 50 kg kommen (weight savings totalling 50 kg)
- Leichtbauscheinwerfer ca. 5kg, (lightweight lights)
- PCCB ca. 15 kg Ersparnis gegenüber Stahlbremse, (vs steel brake)
- Lithium-Ionen-Batterie ca.10 kg Ersparnis gegenüber einer
Bleibatterie
- ohne Klimaanlage ca. 15 kg Ersparnis, (A/C delete)
- ohne Radiosystem ca. 5 kg Ersparnis). (radio delete)

I would imagine it is comparable on our cars. That is a pretty substantial amount of weight to be lugging around without using it at all in my case. I have also come across a post where identical 996GT3s (one with A/C and one with factory A/C delete) and the difference was 61lbs as measured on identical scales (see post 17, 21, and 25 below):

http://rennlist.com/forums/997-gt2-g...options-2.html

I tend to believe the 33 lb. figure. I think 61lbs is a bit unrealistic and a result of scale error or other small differences in the two cars.

 

Curious what is your tire cost for 25 min session? How is a Cup car more costly than yours on a minute/hourly basis?

Is fuel that much more? How about brake pads? Other expendables?

 

Read my post #7 directly above... Probably the same reason a ton of guys spend $100-130K on a 997GT3s and then spend another 20K to make them track worthy instead of buying Cup cars for almost half the price. Why do guys spend 10s of thousands on their cars on this forum trying to make them go faster in the 1/4 mile when they could probably buy an actually drag racer for much less money and be even faster? Same logic. I think it boils down to the fact that for me it's a lot more fun build a car I can drive to the track and pretty much outrun any car I come across and then have the option to hop in it and drive it home while the rest of the boys are loading their "race" cars on a trailer. Granted, I don't drive it to he track anymore since I bought a Featherlite but I do have the option to if I want. If I had the budget to actually race, yes, a Cup car would be a ball, but to run one in the black group at the Porsche DE, not so much so. Incidentally, I have found that wheel to wheel racing in a Spec Boxster is a ton of fun. I have done several 12 hr Enduros this year in a Spec and had an absolute ball!!

 

I buy a set of NT01s for $1000 per set and get 25 sessions per set. That breaks it down to $200 of tire wear per day ($50 per 25min session). On a Cup I'd be at $1000 per day ($250 per 25min session). Engine rebuild cost on a Cup is about $30-40K every 100hrs. I run about 1.5 hours per day which breaks it down to about $600/day for engine reserves on a Cup. I am at 100 track hours on my engine and will be doing a preventative rebuild this winter with a $15000 estimate cost which breaks down to $225/day. I am not even including the gearbox but the cost of a sequential 997 gearbox rebuild will be equally eye watering compared to ours. As far as fuel goes, you have to run race gas in a Cup which at $10/gallon will be $250 for the day. I can run street gas at $100 per day.

Just considering the three items above, a Cup would run me $1850/day versus $525/day for my car. Other consumables like brake pads are roughly the same for both but PMNA parts costs on other items are downright scary. So, the cost of running a Cup is about $1325/day more than on my car barring any other repairs on the Cup which can widen that $$ gap in a hurry. Since I do about 30 track days per year, that would amount to $39,750/year more to run the Cup compared to my car at a very bare minimum. Factoring in a gearbox rebuild, probably closer to $45K more. Disregarding all else and ONLY looking at tire wear, you are looking at an EXTRA $24,000/year in tire wear on a Cup compared to my car. Most guys that run these cars will tell you to budget about $2000/hour operating cost on a Cup which would work out to $90K/year for me. Like I said, too rich for my blood as this is only a hobby...

 

^^^well let no man say pwdhound hasn't thought about running a Cup.

To be honest, I had no idea the operating costs were so high. 40k/yr is like buying an E36 M3 and crashing it every 3rd time on track

 

+1

Thinking to myself, couldn't one lower the rev limiter by say 500-600 RPM and drastically extend the motor service life?

Also how about using the same tires that you use on the Turbo?

Not trying to argue, just curious. I understand you have your reasons for wanting to remove the AC and I'm ok with that.

 

Nick, I'm sure all sorts of things can be done but a large chunk of power in Cup motors lies in the upper end of the RPM range. That's where these cars live. I'm sure if you dropped the limiter 600 rpm or so, you'd be leaving a huge chunk of performance on the table probably putting you in the realm of well driven GT3s or cars like mine. At that point, why even run a Cup? These cars are race cars and thus are not designed with economics in mind. Race teams don't really have budget constraints, certainly not the same ones that I have. A race team in many cases will run two 25 minute session on a set of $2300 sticker slicks and toss them because the performance is no longer there after that.

Regarding tires, Cups run metric sized tires which are totally different from what we run on Turbos or ever 997GT3s. 997Cups run 27/680-18 rear race slicks that are close to 27" tall for example. There are no other non race or DOT tires manufactured that would work on these cars. The suspensions and set up of the whole car in fact is based around these tires. This is part of the reason Cup cars will never become mainstream. They are race cars and unless you are racing, they just don't make sense. This is the reason GT3s and modded cars like mine are relatively popular and fun at the track. With the right track prep and modifications, you can have a car that will get you close to the performance of a Cup while still reasonably economical to operate. Unlike a Cup car, I can run my car at the local DE, lapping day, NASA time trials, and still take it to lunch on the weekend.

To me, the fun part of this hobby is seeing how much performance I can extract out of a "street legal" platform. We're looking at various other tweaks this winter to pick up some time, with aero being one and some additional weight loss being another part of that equation. I'm still running the factory RUF exhaust which is rather heavy at 53lbs. I am currently in the process of having a custom exhaust made that will shed about 25lbs off the rear of the car. If I can combine that with another 35lbs for the A/C that we are starting to see some quantifiable gains especially considering I'd be loosing 50+lbs from the very rear of the car. This would put me right at 3100lbs with fuel ready to run while still looking absolutely stock. Resale doesn't concern me as this car is a write off for my auto parts business. My car is 90% track and so far from a TT that the only potential buyer would be another track junkie looking for a fully sorted track weapon. Certainly not someone that wants a car with to do C&C with...

Researching this a little more, we can actually do this mod and still make it rather easily reversible. Essentially, we can remove the heavy rear A/C compressor and the front A/C radiators leaving the lightweight aluminum piping in place. The piping would basically be capped off. This would provide the bulk of the weight loss of around 25-30lbs and still make it easy to reverse. In the rear, a 996 Cup pulley and belt would be installed in place of the stock serpentine belt. Another added benefit of getting rid of the front A/C radiators would be slightly better airflow through the main engine radiators resulting in better engine cooling.