ZCAT3

I have a Cargraphic IC on order and am considering doing the swap myself. Has anyone out there changed their IC? Is this a reasonable DIY? Note - I am a decent handyman, but a beginner with car projects. If anybody has any helpful hints (such as "don't do it") or instructions, I would love to hear them. Thanks.

Jeff 993TT

I've taken my stock intercooler off several times in the past. It's pretty easy, but you have to have some decent tools. Some bolts are on pretty tight.

Here's a general guidelines on taking off the intercooler.

a) Remove intercooler shroud, 8 mm bolts
b) Remove intercooler hoses on both sides, phillips screwdriver
c) Remove the 3 6MM allen bolts on top
d) Loosen alternator housing clamp. There are 2 bolts, I beleive they are 13 mm. You have to be carful that the nuts don't come off the back of the bolts and fall down, or you'll be fishing around for these items in the bottom of your engine tray for a while.
e) Intercooler pulls right off.
f) There are some o rings that I would replace if you have a chance, but not critical. I remember the condition of mine as starting to crack a bit.

If the cargraphics unit is a drop in replacement, which I believe it is, then you shouldn't have any problems reinstalling. Although, from what I remember, the cargraphics unit does not attach to the top of the alternator housing, but I may be wrong.

I've got all the tools and you are welcome to come over to my place and we can figure it out together. I'd be interested too becuase I might do this upgrade in the future as well. I'm in Menlo Park. Or I can come up and look over your shoulder if you don't mind.

Jeff

Here are some pics of the Cargraphics that I found on Rick's (www.993tt.com) site:

Vinnie

Jeff is 100% correct on the install, if I may only add that the Cargraphic's opening for the intercooler pipe may be larger than the factory one and it could be a little difficult to slip on, and second pair of hands might help. If you're interested, this would be a good time to swap to Turbo S intercooler pipes....according to Mike Schatz, it helps maintain boost as the harder pipe will not expand as much as the regular turbo IC pipes. I switched mine, and although I can't say I noticed any difference, I do know they are two different part numbers! :-) And definitely DO NOT DROP THOSE SQUARE NUTS, it took me an hour with magnets and pin lights to find those damn things! Funny thing is that I didn't learn my lesson after dropping the first one, so I dropped the second one too! :-)

Good luck and Hope this helps, I'm sure you'll love the upgrade...especially on your car.

Cheers

TB993tt

Does the Cargraphic I/C work ?
The Cargraphic I/C looks like the one manufactured by TTP in Germany, this is also marketed by FVD. Has anyone seen proof that the I/C works better than the factory unit. For applications up to 540hp, the factory unit is considered the best by RS Tuning. When I had my motor built, I had already bought one of these I/Cs, on the dyno it gave no better cooling than the factory unit. They claim is it flows better, but if the factory unit is good for 540hp, how much more flow do you need ? If you attach a Bosch Hammer to your port and read off inlet air temp (after intercooling) you will find that the TTP/Carpraphic/FVD unit is no better than factory, with ambient temp of 15degC, you will see 55DegC at the top of 3rd gear. Forget the Andial inlet/outlet guages, they are too slow in their reaction times.
I believe that the TTP/Cargraphic/FVD unit does have an effect on a road car by virtue of its size. In a road car one tends to cruise 80% of the time, this allows all the metal (not just the fins/cores) of the I/C to cool down. When you give it some boost, a lot of the heat in the boost air will transfer into the metal of the I/C. This is like a heat sink effect and I reckon this gives you more power/torque for that particular "on boost run" than the stock I/C would have given you (I have more proof of this but would take too long).

ZCAT3

Hi TB993tt - you certainly know more about this than I do. The reason I am switching to the Cargrahic IC is pretty specific to this car. The car had a "Stage 2" upgrade done by Weissach in Vancouver, Canada in December of 1999. Weissach is the North American RUF dealer/distributor. This upgrade included GT1 Turbos, a new ECU, GT2 Fuel Pressure regulator, the larger IC, higher turbo boost (1.1 bar) and some other changes. The ECU was programmed for these changes, of course. The car is now rated at between 500 and 520 HP.

The car was later traded in for a new 996TT. While the Porsche dealer had the car, they decided to remove the larger IC and sell it. They then re-installed the stock IC. We plan to use the car on the track for a few DEs, but will mostly do street driving. In doing the PPI on the car, I discovered the IC change in speaking with the tech at Weissach. Like you, they said the car should be fine with the stock unit (meaning no damage would be done), but they felt the car would not be at peak performance without the larger IC. So I then spoke to 2 other people I consider epxerts in this area: Steve Weiner, one of the resident experts on this board; and my personal mechanic. The responses I got were varied. Steve W (admittedly the most conservative of the bunch) said "I would not use the car in its current configuration without a
larger Cargraphic IC. No exceptions. We do our 480 HP GT-2 package here and I will not do this upgrade without that. That boost level will trigger a whole bunch of knock sensor activity, especially with your gasoline, that will result in
much reduced performance. I'm afraid not many tuners take into account the regional
differences in fuels." My mechanic shared Weissach's opinion - the car will be o.k. with the stock IC, but performance will be better with the larger IC. Given the cost of the car, I did not want to mess around and I want the performance I paid for.

TB993tt

ZCAT3
The question is still: Does the Cargraphic I/C work ?
The engines with the 540hp I refer to have similar mods as yours but run higher boost mid range, and they make do with the standard I/C without knocking.
FYI I still use my I/C 'cos I think it works via the "heat sink" theory.
If you are having to pay for this I/C I would ask to see proof that it does what they say it will do - ther's no way they'll have that proof, unless someone plugs a hammer in to your car and does a back to back max intake temp run in say 3rd gear before and after fitting the I/C (ambient temp and air press must be the same on the two days.) I'd love to hear the results <img src="confused.gif" border="0">

ZCAT3

TB993tt - I can try a few tests with my G-Tech before and after install, but that's about the best I can do (no 4 wheel dynos near by). I am going on the recommendations of the experts I deal with. I do not expect more power, just less lost power. You are in the U.K., so it should be noted that the best readily available fuel we have available in California is 91 octane - barely sufficient to run a stock 993tt. I think this is the main reason the larger IC is highly recommended. If you want, you could e-mail Steve W your question as he may have a real answer for you.

Vinnie

It is my opinion that on a hot day, running DEs the larger IC should help keep the intake temperatures down, which will help stave off potential detonation and give you more power. BUT I'm not saying more than what a stock intercooler would give if operated at optimal conditions. Just more power in higher temps and racing situations where the car is under load for extended periods of time. With that said, I'm sure the stock IC would work fine, but at the cost of power and coupled with just 91 octane fuel, its just too risky for me with this car and detonation. Cooler (more dense) air equals more power and heat is the worst enemy to our air cooled engines. I believe Fuel even plays an important role in cooling our cars as it helps cool the pistons (I could be wrong here, its just a theory). Just my $0.02, and probably worthless.

Regards,

Rick in Portland

TB993TT,

Who told you that the Andial digital readout is too slow? I installed the dual readout and it reacted just fine. It was interesting to see how fast the temp climbed when on boost.

As far as the I/C being better than the stock one, all I can say is that I saw over 100-degree temp drop on a track day. The Car Graphic unit worked very well. By its design, it should be better as it has much more of a cooling cross-sectional area. I was quite happy with this cooler.

Also, it has a different bracket to mount onto the fan housing. The overall fit is tight, but everthing clears just fine.

Rick

TB993tt

Rick
No one "told" me that the Andial digital readout is too slow.
Get your mechanic to plug a Bosch Hammer into the footwell port and set it to read air intake temperature. Now do a run in 3rd or 4th gear on full boost up through the revs to 6000+rpm. Watch the Andial intake temperature and compare it with the more accurate, faster reading Hammer readout, taken from one of the engines own ECU sensors. You will see that the Andial unit cannot "keep up" while the Andial guage might reach 45deg C (or degF equivalent)before you have to come off the boost, the Hammer reading will go up to 55 -65degC momentarily -this is the real air intake temp. It is this "temerature/boost curve" which makes it difficult to compare intercoolers.
As for your 100degF temp drop - firstly the guage issue, your Andial guage would not have shown you the actual "real time" temerature your intake air reached -secondly without doing back to back testing (using a Hammer) with the same variables (or by comparing times) -it is impossible to make statements about which I/C cools best.
Your comments on "by-design" and "cross sectional area" are straight from the manufacturer's /distributors sales manual and after reading the above surely you would take them at face value until you have satisfied yourself conclusively.
For the record, I have both the Andial guage (fitted and being used -for amusement) and the Cargraphic I/C (fitted and used for its "heat sink" value -see above)

Rick in Portland

My comments about the cross-sectional area didn't come from any sales pitch. I am an engineer that has to deal with thermal issues daily when designing IC's.

I'm sure the hammer is a better tool for reading the temp spikes. However, if the thermal couples are placed properly, you should be able to get a fairly accurate reading with the Andial unit. What I was interested in was the delta between the input and the output of the IC, and there is no question that the CarGraphic IC is doing the job. Most of the time I was seeing the charge air temp out of the IC just a degree or two above the outside ambient temp.

I believe Andial installs their modified IC for the higher-horsepowered TT's.

Rick

ZCAT3

TB993tt -

I suggest you e-mail Steve Weiner at Rennsport Systems at porsche@rennsportsystems.com as he strongly recommends the Cargraphic IC. I know from past experience that Steve and his shop do not recommend spending money on upgrades unless they are proven (by them in their own shop) to work effectively. Steve can likely shed some light on the results they have seen from this IC.

TB993tt

Rick
Sorry, I have to take issue with you again. I am trying to ascertain whether the Cargraphic I/C provides cooler input air than the stock I/C. Your comments about cross sectional area of irrelevant as it is obvious by looking at the Cargraphic I/C that it is bigger than stock -this should make it more efficient, but does it ? The placing of the Andial thermal couples is not really the issue, they are not as fast reacting as the ones read by the hammer we are not talking temp "spikes" here we are talking temp curve. Your "delta" between input and output air is therefore not the correct figure for this reason so again it proves nothing about this I/C.
"there is no question that the Cargrahic I/C is doing its job"
What exactly does that mean??
Obviously the thing works - my question at the top remains.
You say you mostly see the charge air temp out of the I/C a degree or two (Farenheit) above ambient - even with the slow reading Andial guages I find this hard to beleive. Are you saying in a run in 4th gear from 2000 to 6500 rpm the guage only shows 2deg above ambient - NO WAY - even the Secan GT2 EVO I/Cs don't cool that well.
I don't understand your comments re the Andial I/C ? what has that got to do with the relative efficiency of the Cargraphic unit to the stock one ?

Jeff 993TT

[quote]Originally posted by Vinnie:
<strong>this would be a good time to swap to Turbo S intercooler pipes....according to Mike Schatz, it helps maintain boost as the harder pipe will not expand as much as the regular turbo IC pipes. I switched mine, and although I can't say I noticed any difference, I do know they are two different part numbers!</strong><hr></blockquote>

Vinnie, I got a quote for the upgraded Turbo S pipes.

993-110-633-56 Left $180.00
993-110-632-56 Right $174.00

Yikes! I'll probably do the upgrade if I change my stock intercooler though.

Jeff

Rick in Portland

It's not worth it arguing about this, because we have different opinions. However:

1. The Andial readout unit I had in the car didn't seem slow at all displaying the temp. In fact, you could observe how quickly the temp would rise as soon as you got on boost.

2. When runnng hard, the temp would rise and then level-out at some high temp reading. At that point I would see what the difference was between the input temp and the output temp of the IC.

3. At the track I would see a difference of over 100 degrees between the input and the output of the CarGraphic IC.

4. On the freeway, I would see the output temp of the IC a few degrees above the outside ambient temp even when I would floor it to redline. This was the part that I was most happy with.

5. Here's something I noticed that made a big cooling difference. I was running the Turbo "S" tail until I decided to sell the car. When I put on the old tail, I noticed that the intercooler was not nearly as effective. The output temp was somewhere around 10-30 degrees higher with the old tail while pushing it on the freeway.

6. My comment about Andial's Intercooler is that even they seem to think that it is necessary to use something other than the original unit on their high horsepowered Twin Turbos.

Talk to Steve Weiner about this intercooler and his observations with the one that was in my car.

Rick