Maleficio

You consistently, in every thread, come across as saying that there is absolutely nothing one can do to help his car run better.

You're too hardcore. I just drive the damn thing down "da skreet", and try to enjoy it. And by enjoying it, I mean I like to mess with it and try new stuff.

mark kibort

Sorry, im not going to feed the psydo science. You are not losing any HP to intake tube heat. again, the transient time of the air flowing through it is not long enough. the surface area and distance is not great enough, and the temp change will not be measurable. again, do a quick experiement. take a 2-3' tube. put it in the oven. (Metal tube). get it to 200 degrees. take a shop vac . blow through it. measure , or feel the temps. If you feel 5 degrees, (or measure) thats worth about .25 of a hp. ITS NOTHING! trust me on this. Ive done a lot of this kind of testing with REAL measuring equipment. (like dynos, pressure and temp sensors, etc

Mike Frye

You know there is more than one person on here saying that there is a noticeable difference. There must be SOMETHING to it.

I wonder if it's what you think it is though.

I'm looking at all of the pics here and they look like the tubes are wrapped and also that the end of the tube is sealed to the airbox.

What if the actual effect that you're feeling in traffic is the difference between a kind of CAI setup pulling air from the front of the radiator instead of from around the tubes inside the engine compartment?

Someone said the car starts off and drives more smoothly after idling with it set up this way. That is a noticeable difference. We need to isolate what caused this 'fix' and whether it's truly colder air coming through the entire tube or possibly something else that was changed in the process like sealing up the intake from pulling in air from right above the exhaust manifolds at idle.

When you wrapped the tubes did you seal off the timing belt vent holes too? Maybe it's no longer pulling air from there now as it was before. Just offering other alternative explanations for the fact that you can tell there is a difference in performance, until someone posts some measured temp differences eliminating all other variables.

Randy V

Try this while yer at it:



Makes a noticeable difference in cooling!

dcrasta

That makes good sense. I have noticed on other cars (Turbo and NA) that a lot of so called 'CAI' filters that suck air from under the hood actually decrease performance. A true Cold air intake would pull air from in front of the radiator. Maybe this modification decreases the hot 'behind the radiator' air from being drawn in the 'gaps' in the tubes most people (including myself) have in the intake tubes. Sealing them to the air box should help prevent hot underhood air from getting into the tubes..

mark kibort

That's not true or my intent. I always give my results of the testing I've done or that has been done by others. Trust me, no one has gone against the grain of doing things that OTHERS said wont work than me. (and most have actually worked, but I've proved it by racing and on the dyno, just at real car companies will do. )

the short list:
4.7 liter intake euro conv. mods with and without heads
5 liter part euro (US ljet)
strokers on stock stuff
head and block surface finish/torquing technique
cam mods for the 85cam to S4
pinning intermediate plate for clutch on S2s
brake diameter change, keeping stock calipers
10 wheels up front, on stock body panels
wings, splitters made from cheap stuff
single fuel regulator vs duel on s2s
non pin of rear transaxle
oiling, oil, stock cooling for racing, no accusump
Even the eRAM for the 240rwhp 4.7 928s.


When it comes to things like gearing, or other ideas, I've usually pointed out the trade offs, where no real NET hp gains can be found in all circumstances.

if you want to mess with your car, thats great, but claiming something works that will not , and being called on it is not "hardcore" in my book.

mk

mark kibort

Really??Dont get me started on the "masses" being right. Doesnt the goverment still think that the "Air filter " being clean gives better gas mileage?? (along with millions of people all with their data to testify to this)

Anywyay, there will be NO differnce. all Im asking is someone to take real measurements to prove what I am saying. NO its not like a CAI, as they DO work and can prove lower intake temps. Ive done test on the dyno with a M3 to prove this ,and it was done by accident. closed hood vs open hood where the filter was getting outside air vs underhood air over a dyno run. (5hp) or so.

we are talking about insulating intake tubes which cannot change intake air temps. there is just not enough transient time. Also, there is not a way in heck, that your car will run "smoother" because of this. you guys are smok'n crack if you think a 5 degree temp change is going to do anything noticable.
do the tests under the same conditions, as I ususally do on my tests. Then you can show if the results match the expected gains.

Maleficio

Mark, regardless of your disbelief, I'm going to leave my tubes as they are and continue to enjoy the sustained running quality. Thanx for your input, very interesting stuff.

Maleficio

Mike, I opened the holes for the timing belt vents.

Mike Frye

Easy there Mark, if you read my post again you'll see I'm agreeing with you.

I was proposing another possible solution to the fact that they noticed an unmistakable change in performance after this mod.

I was also asking for real measurable, repeatable temp readings.

The lack of these readings doesn't prove that their mods didn't have an effect. It doesn't prove anything.

Sitting there at your desk telling more than one person that the change in performance they reported feeling is a figment of their imagination without knowing everything that might have changed isn't very objective.

I'm just postulating that maybe you're both right:

I don't think the air could possibly remain in a plastic tube long enough to get heated up.

I also don't think that more than one person imagined a similar change when doing similar work.

My theory that will accommodate both of these opinions is that maybe something else is at work here.

You said CAI works. I'm saying that maybe they sealed out the inevitable under-hood air that gets into the stock setup when those flimsy plastic tubes are pushed into the ends of the air box when they taped them on. (on at least one there is a rad cover as well).

76FJ55

Mark I think your idea that heat soak will negate the benefit is incorrect. Not that there is necessarily enough dwell time in the tube for the ID tube temp to have a profound effect on IAT. The thermal wrap on the tube will most likely reduce the ID temp of the tube. This is due to the reduced thermal conductivity of the insulated tube. I think you are being distracted by the idea of heat soak. Maybe another example will help clarify (or just ad to the confusion, we’ll see). This example will hopefully be easy to identify with.
Example:
Take a thermos (one of the nice stainless steel ones) and fill it with hot water just below its boiling point. Put the lid on it and set it on the table.
Now Take a nice quart sized stainless steel pan and fill it with hot water as well, put a lid on it and set it on the table next to the thermos.
Now wait a few minutes or so, enough time for thermal equilibrium (heat soak) to occur.
With out using the handles (insulated to keep you from burning your hands) pick each one up.
You will most likely notice that pan is painful to hold, where the thermos is most likely warm but unlikely to cause you harm.
The decrease in thermal conductivity allows for a greater change in temperature across the insulated material as equilibrium. This is similar to what is happening when the intake tubes are wrapped with insulation. The outside of the insulation reaches equilibrium at a temperature close to that of the engine bay and the ID of the tube reaches an equilibrium temperature closer to that of the intake air. As the insulating value decreases (or thermal conductivity increases) the ID and OD temps more towards each other OD temp goes down and ID temp goes up.
So, if you are trying to minimize heat input in to the intake air you want an intake system with the maximum insulating value you can have any time the temperature around the OD of the system is higher then the intake air temp.
A few materials in order of conductivity
High conductivity
Copper
Aluminum
Steel
Titanium
Plastic
Fiber Glass
Low conductivity.
This is why radiators are typically made of copper or aluminum,
Fiber glass is used to insulate things such as headers and you attic
And why we wear coats in the winter.

hacker-pschorr

You don't have "winter" in Oklahoma.

Hell, we don't break out the "winter coats" until February. And that's only because it takes that much longer to shovel a path to the grill.

auzivision

Perception versus reality can get blurred with expectations.

I agree it could be something else, but will never agree that the air in the intakes has enough time to heat up significantly enough to make a real measurable difference.

Then again, if it makes someone feel better doing it, there is nothing wrong with that.

Jim M.

Once again the all knowing MK is letting his big mouth overrun his brain.

I measured my temps at the top of the stock aircleaner using a Fluke digital probe, accurate to 1/2 degree F. I took my measurment over about a 4 week period both before and after my mods. Measured it in the mornings on the way to work, and again on the way home, recorded the temp of the Fluke and the outside thermometer on the car. Any inaccuracy in the Porsche temp gauge is irrevelent since I was only interested in the difference. However my temp gauge has always been close to radio reports. All measurments were done at highway speed, althought my notes show temps in the high 170's when stopped in traffic. These quickly cooled down when I got going again.

The 31F drop was after the insulation addition compared to before the insulation addition on similiar ambient temp days. Some days I didn't get to 31, but most times in the mid to high 20's in temp drops.

The point of all this is; there is some heat gain to the inlet air from engine temps and sucking air from the top of the radiator even while driving. Originally I had a piece of aluminum to shroud the radiator, but it became so heat soaked that it would burn your hand and I felt it wasn't accomplishing anything. On my GTS I built the fiberglass shroud to go over the top of the radiator. Now my inlets draw air from in front of the radiator without the added heat, and the fiberglass doesn't get nearly as hot as the aluminum one did.

I did my measurments based on some tests Louie Ott did to accomplish similar results. Those of you who know "Professor" Ott know he is through with his analysis.

dcrasta

If thats the shroud in the pic I think you should sell them, nice looking and functional.

Thanks for the data also. Seems like you have done your homework