K04 Turbos
11-21-2000, 05:22 AM
#1
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K04 Turbos
<center><img src="http://pictureposter.audiworld.com/AudiWorldPics/2000/Mvc-704f.jpg"></center><p>Just a quick note.......there are many out there who say that the K03 and K04 turbos are junk...outdated...etc. Some of those same people say that they can't produce over about 1.3 bar of boost.
We have our ECU set to run 1.4 bar boost on our S4 race car...but after our 4 hour race at Virginia (Motorola Cup), the boost started to gradually drop of...down to 1.1/1.2 bar at Las Vegas(Speedvision GT). When we were testing our low boost problem on our S4 car at the San Diego race...we found out that the electric divertor valve/cycling valve (which is what we call it on 944 turbos...same function) was leaking when the solenoid was closed. In essence, we were putting boost pressure onto the wastegate valve all of the time when we were boosting the engine. A new valve was not available from Audi.
I installed a Porsche 935 manual boost pressure regulator (had it in my tool box since our 924 Carrera GTR-962 IMSA days...actually had it as a spare for my 924 Carrera GTS street car) and mounted it right next to the shift lever so that the boost was cockpit adjustable. In practice sessions, the little K04 turbos would produce 2.0 Bar boost. I didn't run the car at those levels, but would accelerate...watch the boost gauge go up to 2.0 Bar...back off the throttle...turn it down...etc. until I achieved the 1.4 that we wanted use for the race. I was impressed that they would produce that much boost.
These turbos were used when we got them from Audi Motorsport. They went through about five sprint races, two test days and one four hour race...and still were boosting just fine.
May the Turbo Force be with you...........Don
We have our ECU set to run 1.4 bar boost on our S4 race car...but after our 4 hour race at Virginia (Motorola Cup), the boost started to gradually drop of...down to 1.1/1.2 bar at Las Vegas(Speedvision GT). When we were testing our low boost problem on our S4 car at the San Diego race...we found out that the electric divertor valve/cycling valve (which is what we call it on 944 turbos...same function) was leaking when the solenoid was closed. In essence, we were putting boost pressure onto the wastegate valve all of the time when we were boosting the engine. A new valve was not available from Audi.
I installed a Porsche 935 manual boost pressure regulator (had it in my tool box since our 924 Carrera GTR-962 IMSA days...actually had it as a spare for my 924 Carrera GTS street car) and mounted it right next to the shift lever so that the boost was cockpit adjustable. In practice sessions, the little K04 turbos would produce 2.0 Bar boost. I didn't run the car at those levels, but would accelerate...watch the boost gauge go up to 2.0 Bar...back off the throttle...turn it down...etc. until I achieved the 1.4 that we wanted use for the race. I was impressed that they would produce that much boost.
These turbos were used when we got them from Audi Motorsport. They went through about five sprint races, two test days and one four hour race...and still were boosting just fine.
May the Turbo Force be with you...........Don
11-21-2000, 05:35 AM
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They can't be bone stock turbos, can they?
I have always heard that the K03/K04 can only produce so much hp. It sounds like yours are producing much more than everyone says they are capable of.
The limitation I have always been told is amount of air that the little turbos can push. Basically it is just an air pump. So much CFM can flow through it. Don't you at some point hit a wall where you cna't force through anymore air?
What sort of hp are you pumping out of your S4?
The limitation I have always been told is amount of air that the little turbos can push. Basically it is just an air pump. So much CFM can flow through it. Don't you at some point hit a wall where you cna't force through anymore air?
What sort of hp are you pumping out of your S4?
11-21-2000, 05:53 AM
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Re: They can't be bone stock turbos, can they?
Bone stock K04's. We have not dyno'd the car.....but at 1.4 Bar boost we can run on the straightaways with most of the Vipers/993/996/Corvettes up to about 130 mph...then they start pulling away from us.
11-21-2000, 08:26 AM
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I know race fuel . . . but . .
but it is still an air pump is it not? Do you know what the K03 and K04 are rated at hp wise? How far beyond said rating do you think you cna safely push each turbo? Also how much air can they each push?
I am about to install a large FMIC onto my 180TTQ along with the 225TT intake and exhaust manifolds.
I am about to install a large FMIC onto my 180TTQ along with the 225TT intake and exhaust manifolds.
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11-21-2000, 09:00 AM
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Race CAR...
<center><img src="http://www.3k-warner.de/english/images/pics/baupr_tabelle.gif"></center><p>Clearly the K04 CAN push that much air, because in this application, it is. But I guarantee that it is running well outside of it's efficiency range, and therefore, developing a ton (how is that for a measurement) of extra heat. So, even if the turbo holds together (Audi Sport magic? Luck? Don's clean living?), you are paying a high price for diminished returns.
With that said, remember that this is a race car, so a) it is expected to push the limits of it's systems to extract every possible ounce of performance, and b) I assume there are beefed-up cooling systems to help deal with the extra heat (bigger rad, oil cooler, etc.). Are those the stock intercoolers? Hmmm, seem a little wimpy to me.
Back to the K03/K04. These are low-pressure turbos designed to spin-up quickly for low lag and therefore, really good...STREET performance. So, what does this have to do with a race car? I bet that 130+ mph Viper/Vette problem on the straights wouldn't be so bad with a single K27/K28 like the good old days. Oops, tipped my hand.
"Old-School Boy"
With that said, remember that this is a race car, so a) it is expected to push the limits of it's systems to extract every possible ounce of performance, and b) I assume there are beefed-up cooling systems to help deal with the extra heat (bigger rad, oil cooler, etc.). Are those the stock intercoolers? Hmmm, seem a little wimpy to me.
Back to the K03/K04. These are low-pressure turbos designed to spin-up quickly for low lag and therefore, really good...STREET performance. So, what does this have to do with a race car? I bet that 130+ mph Viper/Vette problem on the straights wouldn't be so bad with a single K27/K28 like the good old days. Oops, tipped my hand.
"Old-School Boy"
11-21-2000, 09:24 AM
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How could that chart be accurate?
Jimmy:
According to the chart, the K03/K04 have a performance range of 60-140 Kw which equates to 80 - 187hp! A Stock 180TT comes with 180 and a stock 225TT comes with 225! Each car has either exceeded the limits or is at them.
I based this on various places that said 1 Kw = 1.341 hp
Just multiply 60 * 1.341 = 80.46hp!
Please tell me what I am doing wrong! I am sure the 1.341 is the wrong number, but that is all I can find.
According to the chart, the K03/K04 have a performance range of 60-140 Kw which equates to 80 - 187hp! A Stock 180TT comes with 180 and a stock 225TT comes with 225! Each car has either exceeded the limits or is at them.
I based this on various places that said 1 Kw = 1.341 hp
Just multiply 60 * 1.341 = 80.46hp!
Please tell me what I am doing wrong! I am sure the 1.341 is the wrong number, but that is all I can find.