TB993tt, these are interesting data you posted. Are you stating that at 160kph the OEM IC was already heat soaked (41) vs. CTR IC (31). The difference you show is huge and I assume these were tested on a 997 GT2 on a same car, correct? Was the EGT recorded on the car with OEM IC vs. CTR IC as well?

 

Guys!! u still wasting ur time with that Toby LOL!!

 

I have been around long enough to know that you are spouting the theory without haviong spent hours watching IATs in turbo cars in a probably unhealthily obsessive way
If you had experience tesing intercoolers you would know that one thing about factory intercoolers (from 993 onwards) is that they are very resistant to "heat soak" from the 993tt onwards they have always been exceptional in recovering very quickly with a road airflow through them. I am particularly experienced in watching 993tt IATs and the stock inertcoolers recover from heatsoak in seconds.
The 996/7tt ones are similar, they are quite thin and cheap with crappy end tank arrangements but do not really have the mass to heat soak....anyway regardless of whether YOU think they are heatsoaking in my graphs I watched the IATs and if you ask any of the tuners who frequent forums to log IATs on stock 997GT2s you will see that in regular driving they run at ~20degC above ambient, you can call it heatsoak or whatever but this is the level they run at........ my expensive intercoolers run around 5-10degC above ambient this is how it is....... the moot point and one more interesting is what the "cheap" aftermarket intercoolers run IAT at on GT2s - where is that data

Oh dear, you say you are an engineer ? Good engineers do the testing and observe for themselves - I realise I am a bit obsessive about IAT and have watched far too many IAT readings in silly situations, the worse being on my recent 1.5mile airfield day where I had to smuggle the laptop past the scruiteneers looking for loose items in the cockpit and check it was reading whilst getting up to 195mph which is quite hard work......yes my I/Cs were only 22DegC above ambient then as well.....


Brett, you need to get some more hands on testing time before stating all the known factual stuff - watch a few 0-190mph IAT runs then come back to me ..... My tests have been confirmed by the guy who builds the most successful Porsche turbo race engines in the world.....

 

Art, I wouldn't describe it as "heat soaked" - you will doubtlessly have seen the stock intercoolers, they do not have much mass so do not classically "heat soak" like a big heavy aftermarket intercooler. Driving around in what I would describe as a "normal" manner which is on and off the throttle, bit of boost but not going silly, the IAT on the stock car was 41DegC - this is a 23DegC ambient day so it is running at 18DegC above ambient which from my testing is about right for the 997GT2 in normal driving conditions, it is not heat soaked it is just the IAtemp they run at. In contrast in the same driving conditions my intercoolers run at between 5 and 10 degC above ambient - and it goes from there.....

When you get on the boost the stock ones' IAT rockets upwards from the 41DegC and mine does also but obviously from a lower base.....

I get what Brett is trying to describe ie proper scientific testing conditions but achieving those on public roads is not really possible and I have enough experience watching IATs that I know what I am doing. I know an EVOMS700 996tt customer shared some IATs with me and they looked promising but understandably most IAT "runs" only go up to about 130mph whereas as you can see from my 170 run on the previous page the real heating starts after this....

Yes same car same tune, didn't record EGTs

 

This discussion prompted me to produce a chart which I had been meaning to do for a while:

I mentioned on a recent airfield day I managed to sneak my laptop into the cockpit (under the prying eyes of the scruiteneers) and record IAT data for 1 run.
I also logged the run on a Driftbox, you can see it on the chart below, went a maximum of 194mph is 30.06s.

Sorry for if this tweaks your scientific methodology Brett but I stuck some numbers into excel basically I read off from the Drifbox numbers the elapsed time for every 10mph increment and noted to IAT from the Durametric at that precise moment. Wrote it all down, stuck it into excel, trimmed the scaling and it comes out as below:

The left scale is IAT in degC and if you mulitply the left scale by 10 it is also speed in mph. Bottom scale is the actual elapsed time.

It was a 13 DegC ambient and sitting with engine idling on the start line for 5 minutes "heat soaking" it was reading a steady 20.2DegC before the acceleration started.

Note the engine is tuned on an expensive engine dyno using a water cooled intercooler to give IATs as my tuner experienced with my intercoolers. The engine was boosting at between 1.4 and 1.6bar for this run on its modified VTGs.....

What I found particularly interesting is how the IAT levelled off at very high speed and with 1.49bar pumping into it for 4.4s from 185mph to 194mph the IAT actually dropped from 38.2 to 36.7DegC - That gents is a Porsche tuned for the Autobahn !

 

Ugh.

I have been building and tuning Porsche's (and other high performance cars) for over a decade. I spent years as a tech traveling with Porsche race teams to various road courses in the US such as Road America, Road Atlanta, Watkins Glen, Mid-Ohio, Sebring, Daytona, Lime Rock, IRP, Putnam Park, etc. I have built, tuned, and maintained cars that race in ALMS, PCA, HSR, and SVRA. I am an AEM factory trained and certified engine management system tuner, and have tuned hundreds of cars over the course of my career. I have analyzed literally thousands of 15-channel real-time engine parameter datalogs from the various cars I have tuned over the years, including hundreds of datalogs from modding, tuning, and racing my own 993. Your 3 little excel charts of only IAT vs. speed are laughable.

Your understanding of heat transfer fundamentals and testing is severely lacking, and your assumptions about me and my experiences couldn't be more off-base. It’s hilarious that since you clearly have no grounds to back up your statements on a factual scientific merit, you try and pin me as a book worm and insult my lack of “hands on experience” instead. Looks like that didn’t work out so well either, I thought you would have gotten the hint with my last post.

I’m sorry that this discussion had to plummet to a penis measuring contest about who was more experienced, but your patronizing attempt to discredit my experiences ticked me off.

Carry on.

 

So you've not been into this stuff for long enough to remember the fun had by Porsche turbo race teams which led to the comissioning of the $25K Secan intercooler for the 993 GT2 racers ?

Sorry but from your earlier posts it seems you do not have experience in this particular area. Apart from your 993 how many other race turbo Porsches have you worked with ?

Patronise my "little excel" charts but I can and have created loads of data, these were just to share with interested parties not for some abject analysis, I do this for fun - just how much Porsche turbo intercooler data have you analysed ?

 

Unbelievable.

You just cannot fathom that somebody with tangible real world experience specific to this area disagrees with you. You are still trying to discredit my statements by implying my experience isn’t specifically turbo Porsche related. Once again you are dead wrong, amazing you haven’t figured this out yet from all of the posts I have made so far.

How about this. Save for a very fun old McLaren, every single one of these cars I am referring to in this post was a Porsche. More then I care to count right now, some NA, some boosted. Here is a good question. How many Porsche turbo cars have you actually tuned? And by tuned, I mean used a laptop (or other means on the older cars) to write the actual fuel and timing (etc) mapping for the car, and then systematically datalog and test the results? You are trying to claim Porsche turbo omniscience because you spent some time watching an IAT readout. Give me a break.

Now, you can try and turn this into an interview session all you want, I have made my educational and professional background clear. At the end of the day, YOU interjected with claims about a superior magic aerospace intercooler that cost $13K. You have been trying to justify the ridiculous price tag with condescending remarks since, and your own graphs show that the “data” you used for these assertions is grossly flawed. I posted specific questions regarding your methods, and you decided to attack the messenger instead of the message, because that is all you can do.

The redundancy here is mind numbing, have a nice day.

 

So like I said you do not have experience in Porsche turbo racing and the role intercoolers play and have played in the last 15 years ?

The "aerospace magic" with its ridiculous price tag funnily enough is used by the real Porsche turbo race teams - like this car below, I suppose you could tell them of your vast experience and spout all the theory, which of course is easy to come by just like learning to tune some obscure AEM management system - jeez do me a favour - these proper turbo cars run with Bosch Motorsport ECUs - you can do those as well can you - for race turbo application ? didn't think so - there are loads of wannabes like you out there



And you should let these idiots know about intercooling also........fools all fools

 

I love how you ignore the pertinent questions about your actual experience since you are the one making claims here.

Did you build the cars pictured? No.
Did you tune the cars pictured? No.
Have you spent over a decade working as a Porsche tech on track cars? No.
Do you have any academic understanding of thermodynamics or heat transfer? No.
What did you do then? It looks like all you did was pull out your checkbook, and then post pics of cars that other engineers built, tuned, and tested. And you are calling me the wannabe, hilarious.

I have never said that other race teams (who are full of qualified engineers) didn't know what they were doing, quite the opposite in fact. I did say that your "data" was junk and the claims you are making to justify your lighter wallet are incorrect. I tried to explain why, that went over your head so you instead tried to attack my level of experience.



How about this data log from a 993 turbo during a sprint session. See that yellow Load line? That’s boost. See that blue Air Temp line? That charge air temps post IC. Should I put this into an excel chart so you can understand it? Strange, ambient on this day was 89 degrees F (32 deg C), and according to this data log the max air temp this car saw was 122 F (50 deg C) even after a hard 20 minute session (the time scale is not exact due to the sampling rate) on a road course. That is a max increase of 33 degrees F (18 deg C) over ambient. This custom intercooler that I designed and fabricated didn't cost $13K, shouldn’t those charge temps have been much much higher than that? Hmmm, I guess all that testing and development work paid off afterall... As I said before, I have analyzed literally thousands of data logs just like this one.

You want to talk about older Porsches? I love talking about old Porsches. Here are some old pictures of cars I worked on that raced in the various sanctioning bodies that I previously mentioned. I’m sure you will recognize the Fabcar built “last” 935. It was amazing seeing this thing carry the nose when coming up the hill at Lime Rock on boost.
At the shop:

At the track:


And of course the 962 that replaced it back in the day. Here it is at the shop pre-restoration, just after it was purchased from Mr. Valentine himself:



At the track post all of our hard restoration work:



A very potent 3.4L build, Carrera manifold, twin plug, group B cams, K29 hybrid, etc, that I built and tuned. This went into a 930 chassis that was setup for track and street entertainment with piggyback fueling for when the CIS leaned out up top:



This ground up build of a widebody RS track car was a fun little project:


This Porsche powered Royale was a real treat to work on, especially when we had to separate the car at the firewall in the pits to get to the leaking chain housings:


I also never said that AEM was the only standalone I have worked with, far from it. This 3.8 RSR for example ran an EFI Technologies ECU that I tuned. But it’s NA, so I guess that doesn’t count. It’s 964 twin brother however did run a Bosch ECU.
You can also see both of these cars in the background of the first Royale pictures parked under our awning.


But you are probably right. I have never even been to a race track or touched an intercooler, let alone actually seen a P-car in person. I have plenty more pictures of all of the various projects I worked on and the tracks we raced them at (which I previously mentioned) that I have never uploaded since they are on film, but even though this has been greatly entertaining I am done wasting my time on you. I will just hold my breath and wait for you to post some data logs from all of Porsche track cars that you have personally built and/or tuned oh omniscient one.