Steve - didn't you write it down ?
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">thanks for the AN fitting number, I was looking for them</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Anyhu, 12mm/1.5 adapter, Aeroquip# FBM-2246. <img border="0" title="" alt="[Wink]" src="wink.gif" />

 

thanks i did not , now i will

<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />

 

-Amen Nicole re the notion of prefering the ability to breathe to a 0.1 second reduction in 0-60 times!

The vast majority of the light aircraft I have flown have been powered by air-cooled 5.3 liter four cylinder engines. Most all of them have updraft carburetors- which means that the carb is mounted below the engine, a relatively cool area. Carburetors use venturis to draw in fuel by lowering air pressure in the throat of the device-a phenomenon that also drastically lowers the temperature of the air entering the engine's intake tubes.

This effect is so pronounced that in humid climates it is possible for the throat of the carb to ice over and cause the engine to fail. Since this means that you are landing whether you like it or not [a rather un-good situation if you are half-way to the Bahamas...], there is a provision to add heat to the air entering the carburator. The heat comes from a heat exchanger that fits around the exhaust pipe, and when it is engaged, it is not untypical to see a 5% drop in engine RPM! Hot air entering an engine certainly can make a difference.

I have to wonder if those thin plastic tubes actually make much difference- they sure don't seem to have the ability to thermally isolate the incoming air, and it looks like this air is drawn in over such frigid items as the AC condenser, the top of the radiator, etc...

Normy!
'85 S2 5 Speed

 

Normy, etal:
Tests have been done with insulated intake tubes, and there was a slight HP gain made with them. I believe it was Lou Ott who first tried them.

Also, don't the GTS models use insulated intake tubes? I think they're there more to reduce noise, but they also probably lower the intake temp a bit. :^) YMMV.

Seat of the pants measurements vary widely from one seat to another. The only valid and reproducible tests are done on a dyno. Although I'm not from Missouri, I still think you'll need to show me (with a dyno run output) that what you've done actually improves HP and or torque. Till then, you might as well claim you caught Moby Dick while lake fishing. Again, YMMV.

 

Porken: There are not too many Trabants or Wartburgs left on German roads these days. After the reunification, most East Germans have spent their lifetime savings on getting Western cars (French Renault being one of the most popular brand, probably due to it's good value). Today, few people would want to deal with the shortcomings of the old 2-stroke engined cars - not only because of their engines, but also because they are all 40 or so year old designs, with little safety and other modern conveniences.

PS: Air in Dresden was already getting better when I was there last in 1992. But they had also started charging for parking in the city...

 

Funny how your expenses expand to fit your income...

My girlfriend (who was born in Slovakia), long before the 'Velvet Revolution', dreamed of owning a Ford Escort, instead of a Trabant like others who managed to buy cars.

Now she drives a convertible SAAB (with a self-terminating timing belted Opel V6 ).

 

Hi all,
Ed R.- the later 928's have the snorkel thermal wrap. I think the Big 3 sells them for other cars.

I had thought the Venturi in the snorkel was to help with low RPM cylinder filling by speeding up airflow. My S4 snorkels have holes in them, last time I looked. Think they were facing down.
Possibly Porsche Engineers worry about water ingestion and put in drain holes.

About K&N: last time I had both K&N and stock
filter side by side, I could see light throught the K&N and not through the stock. Try it yourselves.
Maybe I just had a looser cotton weave K&N.

Does anyone have any real temp readout of the engine bay temps?
Many of those VW K&N cone filter upgrades have their cones sucking in engine bay air.

Ernest
Dreaming of that Tim Supercharger upgrade kit

 

PorKen: LOL I have one of those Saabs, too! Mine just isn't convertible. And it self terminated already - while in custody of the the Saab dealer
for a rattle. Of course they didn't take me seirous when I told them it's coming from the timing belt... Has your girlfriend's engine terminated itself? Was it still under warranty then? I now have all the tensioner upgrades, and they said it was unlikely to happen again. I like the car very much otherwise.

Ernest: The holes in the intake tubes are supposed to go on the connectors to the timing belt cover. The problem with the K&N filters is the oil that creates a film on the thin wire in your mass air flow sensor - then it produced incorrect readings and needs to be replaced ($$$). Cleaning it is big risk as the wire is so thin. With the oil, the K&N apparently has less flow than the stock filter. But then again, I've heard that's irrelevant, as the 928 engine never needs as much air as the filter can flow...

 

Nicole - her's hasn't died, although I complained about a grinding noise from the 'new' tensioner about 12K after the 66K TB replacement and they replaced it for labor cost only. The only bad thing so far was the oil cooler gave out and puked quarts of oil into the coolant system. Working on her car gave me the confidence (and the metric tools!), to buy a 928! If you're over on SAABNet, search for V6Vert for my NG/GM SAAB exploits, I have a MOAB there too...

I've heard the best way to clean the hot-wire is to steam clean it.

Fortunately, the L-jet cars have no problem with oil on the barn door.

 

looks like its worth a try but then should we worry about cool air not being drawn to our Timing Belt? No tubes to provide the flow of air? Dave

 

Porken, I like the way you made that framework and was able to use the factory hold-downs. I really don’t care if you really get a + or – in Hp. This nice little project shows us your willingness to explore your imagination and have the ability to follow though with it.

 

urnott~1 - I had a problem with this too, I finally decided it wouldn't make much difference? The design of the intake tubes is, in theory, designed to extract air from the TB area.

T_Max - thanks for the kudos.

To be sure, I'm not actually claiming an overall horsepower boost, although on the imaginary dyno, one would think this to be good for a few HP on the top end.

I'm relating the usable power or increased response, ie. pedal down = go, I've gotten from this, on my car. I'm unsure if it would help on an unmodified car, especially one without an open exhaust.

 

Ken,

Wouldn't the bungy cord weigh less than the frame you made plus stock rubber straps. Surely you've lost performance potential here!

Forget the butt-o-meter and the dyno, what is 0-60 or 0-100 before and after? Simple departure from speculating on the effect.

 

I have long pondered this intake problem. I have followed each mod that I have come across.

I have come to the following PERSONAL conclusions.

1) The original tubes were for noise reduction of intake scream and clean venting for the TB housing.

2) You can't get cool air to stay cool as it passes through heat retaining plastic while passing over a hot radiator and a heat generating power plant.

3) heat rises, thus heat soaking the tubes.

4) the air does not race through the tube so quick that it doesn't have a chnace to heat.

5) metal and plastic are efficient heat retainers.

6) Induction tubes are not insulated or sealed at joints.

7) the 928 engine is packed in a small space with limited ventilation/circulation around the engine.

8)The intitial induction design is at best, adequate to supply the air to the engine.

So what does all this mean and what is my point?...read #8 again.

I can bet that it is not my imagination, that when it is cooler outside, not cold, say...60 to 75 degrees, my car runs with more snap to it. There is no lag.

If this was only my personal experience, then there would not be this long ongoing debate or search for a better air delivery system.

I don't think PorKen has done anything but allowed his intake to be LESS restrictive. There is a possibility that without the tubes or even airbox cover, cooler air is being drawn from the closest points to the outside of the vehicle, so it would be best to have a better filter.

The only way to measure this is with a temp gauge below the filter.

I think the only way to fix this issue is to get rid of the airbox completely and "Y" from the AFM or MAF with an inline filter at each intake, running to the lower sides of the vehicle. The question is, how do you do that without destroying the car.

 

Dan Perez - I don't recommend the bungy route for extended use, it does not seal the air filter well all the way round.

I don't have any good launch areas nearby, and I'm not comfortable with using a stopwatch. This might push me over the fence on buying a G-tech though...

I'm surprised no-one else, that I could find, has tried this simple excercise for comparison. I did a limited search before this and found only air box lid hacking posts. Someone else could easily duplicate my 'testing' with their own bungy or even a piece of rope.

My results I attribute to shortening/straightening the intake tract before the throttle plate, irregardless of temperature. Similar in principle to my dream system of individual throttle bodies.

928ntslow - Good points. One could piggy-back a multimeter to the wire from the L or LH air temp sensor... Running N/A through tubing would reduce the air speeds no matter where it goes?

On my expermiment list is putting an aluminum sheet over the underside of the hood all the way up to in front of the radiator(s), perhaps then even down to below the bumper, to funnel a large amount of cooler air to the air box. My MOAB would be revised to be closed except at the top where there would be a large central opening sealing to the hood panel for a ram-air effect.