Automobiles Forum banner

Audi Myth busting thread

55K views 78 replies 48 participants last post by  RevItUp 
#1 ·
I figured that now would be as good a time as any to start a thread like this. post up your myths that have been busted, and i can condense them into this original posting.

please only post things you've heard, and tried yourself. i don't want this to turn into a messy thread of every single type of question there is. just one to help keep things straight when it comes to "hey, i heard you should try this...." and know for a fact it doesn't work.

#1. All gasoline Audi v8 blocks are aluminum, no questions asked

#2. You cannot swap rear differential pinion gears from a 5k,200,URS4- into a 4000,80,90, or CQ rear differential housing to convert the car to 3:89 final drive. the pinions are different in a way that you can't even machine them properly to work if you wanted to. you need to use a URQ differential.

#3. You cannot swap internals between a C3 (5k,100,200,v8, URS4, or URS6) and a small chassis B2,B3, and B4(4k,80,90,CQ) steering racks to make a shorter ratio. i just tried this the other day upon hearing it was possible, and the designs are considerably different, along with the angle of the pinion gears being cut different causing the steering to be "notchy". i did check the steering ratios with the different pinion gears in opposite racks by holding them in place, and the steering ratios are certainly not shorter.

#4. You cannot bolt a 4cyl vw/audi engine to an 016(4kq,5kq,200q,urq models) transmission properly. there are european only versions (albeit rare) of the 016 with a 4cyl bolt pattern.

#4.2. You Can bolt a 4cyl vw/audi engine to an 01A (80/90/CQ/C3-100/A6) and to 01E (C3 URS4/URS6/B5 S4

#4.4. You Can bolt all audi gasoline V8 engines to 016, 01E, and 01A transmissions (though some might not have all the bolts on the bottom half of the circle perfect, it does work and has been proven strong enough).

newt said:
If it's an engine part from a car with an RS on it, it DOES NOT necessarily mean it's a better performing part than from one of the other models....
 
See less See more
#52 ·
The RS2 transmission is no stronger than any other wide first gear 01E.

The B5 S4 third gear (EDU code trans) is 1.23 not 1.32.

All 01E's made from 1992 to 2005 have the SAME first (3.50) and second gear (1.89) ratio except for the allroad and European diesels made from 2002 and up.

USA 01E's had either a 4.11 or 4.35 final drive ratio. The 3.89 was European only (2002-2004).

No updated 1-2 collars and syncro rings were installed in production 01E transmissions.

The RS6 uses a 5HP24 which is the same transmission internally as the A8/A6 4.2. The difference is the torque converter size is borrowed from the A8 D2 W12 trans (which also was a 5HP24).

There were a handful of RS2 sedans made for the German market.

Unintended acceleration was found to be caused by idiot drivers pressing on the gas instead of the brakes.

60 minutes modified a transmission in an Audi to give the appearance of going into gear by itself and accelerating, using a compressed air solenoid on the transmission throttle lever. (60 minutes also blew up side saddle fuel tanks on a early chevy truck using model rocket engines to ignite the fuel, after repeated side crash test failed to explode).

There is no such thing as "Cryo-Plating" or "Cryo-Dipping) with respect to strengthening of transmission internals.
 
#54 ·
LOL. Great video. I was laughing through it. I wonder how many takes they had to do before Unser could say all that without busting up laughing. Shift Interlock is a great idea though on many cars. I was at a body shop the other day and some guys 20's Model T was in there. He had a hot rod motor in there and one day he leaned in, turned the ignition to on for some reason as he prepared to roll it forward, and the engine fired, turned over briefly, started, and the car ran through his Garage and took out a 4x4 support. OOPS!

My MYTH Contribution. Hmmm.

Urq Axles ARE swappable diagonally.
84' 4kq Rear Axles ARE the same as Urq rears (or Fronts)
84' 4kq 016's are a closer ratio.
Early Audi wiring DOES Suck.
Mmmm
 
#55 ·
zarati said:
Urq Axles ARE swappable diagonally.
84' 4kq Rear Axles ARE the same as Urq rears (or Fronts)
84' 4kq 016's are a closer ratio.
Early Audi wiring DOES Suck.
Mmmm
I would add 84 and early 85 rear axles are the same as the urq
According to Derracuda the 84 trans differs from any other 4kq trans by a shorter 5th gear.
 
#56 ·
scottmandu said:
The RS6 uses a 5HP24 which is the same transmission internally as the A8/A6 4.2. The difference is the torque converter size is borrowed from the A8 D2 W12 trans (which also was a 5HP24).
Is this true? So the internals (clutch packs, the number of clutch disks in one pack, diameter of them, all the shafts and so on, are the same in any other 5hp24?) So basically only the bellhousing + torque converter puts this tranny into "stronger then other 5hp24" league?
My a8 3.3tdi has allso 5hp24 with big bellhousing and big diameter TC, as the rs6 and w12 but I tought it was beefed up internaly as well...
 
#57 ·
scottmandu said:
There is no such thing as "Cryo-Plating" or "Cryo-Dipping) with respect to strengthening of transmission internals.
uhhh yes there is.

http://www.nwcryo.com/motorsports_gears.html

and there is a scientific explaination why.

Residual stresses and retained austenite.

After having installed a RS/RA analyser at a big name transmission manufacturer I was surprised to find that their quality gear components are coming out of heat treat and ready for production with a Retained Austentite measure of 20-30%. If these were aircraft components well.. the shit would be hitting the fan.

The science.. Austenite is a crystal form that Iron takes while cooling from liquid iron to solid. Typically Austenite is only stable above 900ish Celcius, meaning below that it wants to convert into martensite. Of the Crystal forms, martensite generally takes 90% of the Iron which is a cubic body centered crystal (5 atoms 4 perimiter one center) when iron is cool. However when cooling and heat treating austenite crystals which are face centered cubic (4 atoms no center atom) can be retained below 900C.
Since this austenite is unstable below 900C and it is retained in the part we can see that something is up... that something is a change in VOLUME of the crystal forms. since martensite is BCC and composed of 5 atoms and austenite is FCC and composed of only 4... IF austenite were to be unstable and be convinced to convert to martensite there would be a volume change of the crystal, and thus big changes in stresses inside the part.

This is why airplane parts which are designed to operate from 200F to -100F must have very very very low retained austenite. If a temperature swing and load stresses causes the austenite form to convert to martensite, stresses in the part change and can allow structural failure. Parts such as heat treated items like bearings, gears, shafts, ect would all be very succeptable to this.

So now we know the how... now to know the why.

If we can bring our steel parts to a controlled temperature swing and make the austenite crystals change into martensite crystals in a controlled environment then we can allow our parts to reduce the austenite form as much as possible then we can reduce the likelyhood of uncontrolled volume changes.

This does nothing to point out the fact that the physical differences in strength, brittleness, elasticity, ect is different between martensite and austenite too.

this however does not work for austenitic metals such as our famed stainless steels and nickel based alloys.
 
#58 ·
the_natrix said:
scottmandu said:
There is no such thing as "Cryo-Plating" or "Cryo-Dipping) with respect to strengthening of transmission internals.
uhhh yes there is.

http://www.nwcryo.com/motorsports_gears.html

and there is a scientific explaination why.
Your correct and totally glazed over my point. It's not called "Cryo plating", or "Cryo dipped" as nothing is plated or nothing is dipped. It is called Cryo Tempering, or cryogenically treating.
 
#59 ·
- Unattended Acceleration: There was never any proof to show that this actually happened other than a few instances (but not one resulting in an accident). The truth of the matter is the brakes on the older 5000's were much better than acceleration so if you held the brakes and the gas both to the floor the car would go nowhere. Originally the 4000/5000 used a standard transmission brake pedal on the automatics which was very small compared to the American cars at the time so the first recall was to make this larger. After this didn't work they put the shift lock in all cars and still had problems after this. All cases brought against Audi were lost in court as the car had no issues and it was the drivers fault in each case. We did see one locally where the car was having work done on the cruise and upon start-up the car started revving to about 5,000 rpm. The car was left as-is and the local VW rep was called and they sent the crew to find that the wrong clip was installed causing binding. Audi made no changes to the car other than the brake pedal and shift lock-out yet the problem went away. Lesson learned, never believe what anyone tells you especially if they heard it on TV. This is fiction.

- Audi 5000 Turbo catching fire on hills: This is one of those odd problems that only happened in a few places in the world. If you fill your Audi 5000 Turbo in Hope, B.C and then drive up the Coquihalla Highway there is a good chance that the car will catch on fire and burn. We had this problem when I worked for Audi and a customer would fill the tank full to the brim at a sea level and then get on it going up a mountain. As they were gaining altitude the fuel would start to expand then run back through the vent system and piss out on the turbo would cause a fire to start. The people knew there was a problem and stopped on the side of the road where the fire would keep burning and destroy the car. Audi had a hard time figuring this one out as it only happened in a few places in the world and only if you filled the tank until it is was literally pissing fuel out the filler. Audi did a few recalls to modify the evap system which corrected the problem. This one is fact.
 
#60 ·
scottmandu said:
The RS6 uses a 5HP24 which is the same transmission internally as the A8/A6 4.2. The difference is the torque converter size is borrowed from the A8 D2 W12 trans (which also was a 5HP24).
The D2 A8 and C5 A6 4.2 use the 5HP19, not the 5HP24. Are you saying the torque converter is what makes the difference between a 19 and a 24 and the internals are the same? :?
 
#61 ·
MikkiJayne said:
The D2 A8 and C5 A6 4.2 use the 5HP19, not the 5HP24. Are you saying the torque converter is what makes the difference between a 19 and a 24 and the internals are the same? :?
Uh, what? I don' tknow about the C5 chassis, but the D2 most certainly did come with the 5HP24. In fact, this is the very 5HP24 I just pulled out of my motor donor/parts pre-facelift D2 A8:


 
#62 ·
I heard a new one this weekend. I was driving my fiancees dad around in the 93 s4 and stuck my foot in it to pass a car and after he wanted to tell me that it is "very bad to rev the engine that high. The motor can be damaged by revving it that high." Mind you all that I revved it to about 5500.
 
#63 ·
ur20v said:
Uh, what? I don' tknow about the C5 chassis, but the D2 most certainly did come with the 5HP24. In fact, this is the very 5HP24 I just pulled out of my motor donor/parts pre-facelift D2 A8:
Yes my mistake :p The FWD D2 (with 2.8 V6 and 3.7 V8) had the 5HP19. Obviously the V8 Quattro D2s did have the 5HP24 :thumbsup:
Dunno about the V6 Quattro D2s, but I don't really care either cos they're a bit rubbish.

I know non-V8 C5s had the 19 too, but will defer to others on the 4.2.

:cheers:
 
#65 ·
Apriliapilot said:
I heard a new one this weekend. I was driving my fiancees dad around in the 93 s4 and stuck my foot in it to pass a car and after he wanted to tell me that it is "very bad to rev the engine that high. The motor can be damaged by revving it that high. Mind you all that I revved it to about 5500.
It's not an old American V8. Mine loves to spin and it sounds so good.
 
#66 ·
higher rpms increase internal engine stess exponentionally. Did I spell that right? obviously cars with a high rev limiter are engineered to deal with those stresses but if you ran one engine at lower rpms for it's life and one at higher obviously the one with higher rev's would have more of a tendency to have the possibility of damage.
 
#67 ·
Apriliapilot said:
I heard a new one this weekend. I was driving my fiancees dad around in the 93 s4 and stuck my foot in it to pass a car and after he wanted to tell me that it is "very bad to rev the engine that high. The motor can be damaged by revving it that high." Mind you all that I revved it to about 5500.
My response would have been.....

If you live your life by being Mr. cautious you are certainly in for a boring uneventful life. The manufacturer put the red checks and electronic limiter to prevent engine damage and I'll stay below that, but I am certainly not going to stop my engine from singing out and having fun. Rev limit is 6700, and I plan to bounce off that once a week.

And a piece of testimony is my audi's have always done so once a week, and have had a long and fruitful joyous life.
Hell even my ford does it occasionally LOL
 
#68 ·
the_natrix said:
Apriliapilot said:
I heard a new one this weekend. I was driving my fiancees dad around in the 93 s4 and stuck my foot in it to pass a car and after he wanted to tell me that it is "very bad to rev the engine that high. The motor can be damaged by revving it that high." Mind you all that I revved it to about 5500.
My response would have been.....

If you live your life by being Mr. cautious you are certainly in for a boring uneventful life. The manufacturer put the red checks and electronic limiter to prevent engine damage and I'll stay below that, but I am certainly not going to stop my engine from singing out and having fun. Rev limit is 6700, and I plan to bounce off that once a week.

And a piece of testimony is my audi's have always done so once a week, and have had a long and fruitful joyous life.
Hell even my ford does it occasionally LOL
Thats more or less what I said, but in a slightly more diplomatic way. I did also use some of the weirdos on who think its acceptable to double (or triple) the original hp these engines had after driving the crap out of them for more than 150k miles here as examples (i neglected to mention the number or broken rods/blocks though). I do have to be somewhat understanding, as he is from Brazil his experience with cars/engines are with 1liter to 1.6liter engines made out of sugarcane.
 
#69 ·
CorradoGuy said:
- Audi 5000 Turbo catching fire on hills: This is one of those odd problems that only happened in a few places in the world. If you fill your Audi 5000 Turbo in Hope, B.C and then drive up the Coquihalla Highway there is a good chance that the car will catch on fire and burn. We had this problem when I worked for Audi and a customer would fill the tank full to the brim at a sea level and then get on it going up a mountain. As they were gaining altitude the fuel would start to expand then run back through the vent system and piss out on the turbo would cause a fire to start. The people knew there was a problem and stopped on the side of the road where the fire would keep burning and destroy the car. Audi had a hard time figuring this one out as it only happened in a few places in the world and only if you filled the tank until it is was literally pissing fuel out the filler. Audi did a few recalls to modify the evap system which corrected the problem. This one is fact.
Wellll, actually that would be a myth as well... That was happening here in CO as well. Word is there were ~30 cars that burned here, all of which were kept VERY quiet by Audi. These were all 5000T/Q, 200T/Q with CIS right around the time of the unintended acceleration hysteria, except this was a REAL problem. It got to the point that there was a TV crew outside the dealership that most of these cars (by coincidence) came from about to report on these fires. Audi went to great lengths to stop that. It took many (useless) recalls, like the big rubber shield around the injector lines. The symptoms were always the same. After long uphill runs (like on I70 from Denver to the Eisenhower Tunnel), the car would develop a miss, loss of power, smell of fuel and then fire. This usually happened with cars with about 30k miles. Audi sent engineers who loaded the trunks with bags of concrete and drove I70 repeatedly trying to recreate the problem to no avail. Finally this happened with the service manager of the dealership driving a customer car. It ended up burning to the ground. Audi quietly replaced the customer's car, and flew the burned car back to Germany before the insurance company or anyone else could get at it to dissect the car to find out what happened.

Along with the next (and last) recall parts kits for these cars were taped 5 Viton injector seals, seemingly added as an afterthought. These were the true fix for the problem. This was shared with those attending the Urq25 celebration here in CO by someone who was involved the whole time along with some other great stories from back in the day, like people hot rodding Michele Mouton's '85 Pikes Peak winning car around Denver after the event.
 
#71 ·
Myth "you can't run a bov to atmosphere on a cis car".

Truth. I have been running a hks ssqv since I bougt my car 2 years ago. ( sorry I know most of you hate the tuner noise but they work great and hold varied levels of boost with out any adjustments)

Myth "stock head gasket on 10vt 5cyl will not survive more then 10 psi."

Truth. I have been running 14-21 psi on 200000mi plus head gasket for 2 years
( it will probably blow up this week now that I said something)

Myth "multiplying your horsepower output is bad for your car"

Truth It is really bad for stuff! my drive shaft center bearing has been completely destroyed
In under a year.
 
#73 ·
No problems and it has been 2 years. Fuel economy is the same. No stumbling or stalling at any point. I don't even kill spark plugs. Bov has one major advantage, no double pass through the turbo. Heating charge air twice is not on my list of things to do. Also blowing the cis door in reverse with 20psi seems like a bad idea. So I'm still going with myth.

On the flip side cis won't run with a bov that is open under idle conditions. That is important and I forgot to put that.
 
#74 ·
FACT: Even to this day audi will bend over backwards if you claim unintended acceleration on a new car. Had a customer with a 3.0 CVT who didn't know how to drive it back his new car into a couple of other cars. Audi payed for all the damage to his and all other cars without question. He just murmered those magic words.

Also I have had remote start on my 80 (auto) for about six years and the car still has not managed to drive away on its own yet .
'
 
#75 ·
Myth: An issue free 01a trans can take high hp for a pretty long time as long as it is not abused or sets a spinning wheel back down during hard acceleration.

Truth: A perfectly wonderfully functioning 01a can be turned into noisy scrap within a couple of thousand miles of abuse free enjoyment. Meaning nothing rough, just some full throttle blasts with slow shifting between the gears.

Enough folks have tried the myth approach and seen the truth now.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top