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Discussion Starter · #1 ·
Just got back a little while ago from GRD Performance here in the Chicago area where we ran our R32 on their DynaPack AWD hub dyno. The DynaPack hub dyno is considered one of the most accurate dynos available and is unique from the more common "roller" dynos (DynoJet and Mustang) in that you remove the wheels from the car and attach the DynaPack pods directly to the hub:

PLEASE READ CAREFULLY:
The goal here is for us to get a baseline dyno number for our stock R32. The dyno numbers below can NOT be compared to any other dyno run or any other R32 as there are far too many differences in individual cars, individual dynos, weather, conditions, etc., etc.
Also, the following dyno info is taken from an AWD dyno and is NOT comparable to the numbers you get on a regular FWD/RWD dyno run as there is more driveline loss associated with routing power from the engine crank, through the transmission and through the AWD driveline. We also are not going to draw any conclusions as to what kind of crank horsepower our car is making as there is NO reliable rule of thumb as to the driveline loss. Even the stock horsepower that VW quotes is suspect as we have it on reliable sources that the R32 and TT3.2 indeed make the same horsepower (we'll try and confirm this on this dyno in the future) even though VW markets the R32 with 240hp and Audi markets the TT3.2 with 250. Either way, we can't simply take the 240hp VW claims and divide it buy the hub horsepower we got on our car as the R32 may not be making a true 240hp stock.
So, again, our goal here was to see what kind of horsepower and torque our R32 is getting down to the hubs on a DynaPak dyno as a baseline for further modifications. We also wanted to see what affect on power disconnecting the exhaust flapper valve would have. The stock R32 exhaust has a flapper valve built into it that is activated by a vacuum line. When the flap is closed, the exhaust is much quieter up till about 3,000 RPM where it will open up to allow more flow through. This is reportedly built into the exhaust to help the R32 pass noise regulations in a variety of different markets. We had heard reports that disconnecting the vacuum line to the exhaust would potentially free up more power. So we did a few runs bone stock and a few with the exhaust flapper valve vacuum line disconnected and plugged.
Bone stock our R32 put about 208.2 horsepower to the hubs. Torque on the stock car peaked at 206.4 lb-ft. The dip you see in the curve is most likely the variable intake manifold kicking in.
With the exhaust flapper disconnected peak horsepower went up to 212.3hp and torque was up to 210.9 lb-ft at the hubs.



We'll have a complete article on this along with a few comparison dynographs from the same dyno in the future. For instance a stock WRX puts around 159hp and 178 lb-ft of torque to the hubs on this same dyno. A stock B5 Audi S4 (twin-turbo V6) puts out 200hp and 225 lb-ft of torque (although you have to look at the graphs as the S4 makes more power under the whole curve than the R32).
Anyway, that's where we stand right now. We'll have to see what we do next from here...

-jamie
 

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Re: VWvortex R32 Stock Dyno Numbers ([email protected])

Quote »
We also are not going to draw any conclusions as to what kind of crank horsepower our car is making as there is NO reliable rule of thumb as to the driveline loss.


 

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Re: VWvortex R32 Stock Dyno Numbers (Thinman61)

That is great. http://****************.com/smile/emthup.gif
 

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Re: VWvortex R32 Stock Dyno Numbers ([email protected])

Quote, originally posted by [email protected] »
With the exhaust flapper disconnected peak horsepower went up to 212.3hp and torque was up to 210.9 lb-ft at the hubs.

This is impressive. http://****************.com/smile/emthup.gif
I didn't think there would be any gain at all.
 

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Discussion Starter · #9 ·
Re: VWvortex R32 Stock Dyno Numbers (ValveFloat)

Quote, originally posted by ValveFloat »



DynaPack annoyingly refers to their numbers as "flywheel" numbers which is in reference to the hub flywheel numbers, not the traditional flywheel or crank. The numbers presented are torque and horsepower at the hubs.
-jamie
 

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Re: VWvortex R32 Stock Dyno Numbers ([email protected])

Jamie--
I was just visiting GRD tonight and they told me about your dyno run (though I didn't know it was your car). Pretty impressive performance!
Have you discussed any mods with the guys at GRD? Apart from the HPA turbo kits (I would have to rob a bank
), they told me that there wasn't much currently available.
 

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Re: VWvortex R32 Stock Dyno Numbers (boomgarden)

http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif
but i have a question. How do these numbers compare to the ones EIP got on their R32 in fwd mode on a dynojet dyno.
http://forums.vwvortex.com/zerothread?id=1292565
You guys got 208 in AWD mode and they got 214 in FWD mode? Does that seem right? Are the differences in dyno's brining the numbers closer together? Just checking, please dont think im trolling cuz im all for the R32.
.
Seneka
 

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Re: VWvortex R32 Stock Dyno Numbers (Seneka)

Quote, originally posted by Seneka »
http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif
but i have a question. How do these numbers compare to the ones EIP got on their R32 in fwd mode on a dynojet dyno.
http://forums.vwvortex.com/zerothread?id=1292565
You guys got 208 in AWD mode and they got 214 in FWD mode? Does that seem right? Are the differences in dyno's brining the numbers closer together? Just checking, please dont think im trolling cuz im all for the R32.
.
Seneka

Just different dynos on different days using different ways to drive the measuring rollers. In reality, the comparison means nothing.
Jon
 

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Re: VWvortex R32 Stock Dyno Numbers (N2N)

well only reason i asked is 214 x 1.17% for average FWD car driveline loss is 250. so with them putting haldex in fwd mode they are seeing no more drivelline loss then a regular fwd car. (using integras 17%, seems to be close for other fwd cars).
and with the awd numbers showing fairly low for awd loss too. Just trying to see whats going on.
Seneka
 

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Re: VWvortex R32 Stock Dyno Numbers (Seneka)

Awesome figures Jamie
http://****************.com/smile/emthup.gif
 

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Re: VWvortex R32 Stock Dyno Numbers (Seneka)

Quote, originally posted by Seneka »
well only reason i asked is 214 x 1.17% for average FWD car driveline loss is 250. so with them putting haldex in fwd mode they are seeing no more drivelline loss then a regular fwd car. (using integras 17%, seems to be close for other fwd cars).

1.17 is a little misleading. It's actually represents the inverse of a drivetrain "loss" of about
14.6%. 214 / .854 = 250
FWD dubs usually use a 13-15% correction factor.
214 / .85 = 251
But then even when the R32 is in FWD mode, it's still spinning the extra mass
of the propshaft, and trailering around the unloaded rear drivetrain. Can't
compare to any other FWD dub *directly*.
Also EIP's FWD dyno was a best of 218 whp, 220 lb-ft with the valve mod.
http://www.houseofthud.com/car...o.jpg
If you want to compare *any* of the dynos we've seen to any others,
then this one makes more sense, because it's a 2 wheel Dynojet dyno
model 248, and there's lots and lots of other dyno graphs out there
from the same model dyno.
Quote »

and with the awd numbers showing fairly low for awd loss too. Just trying to see whats going on.

What's going on is that you absolutely cannot compare the numbers from these two different
types dynometers. Period.
Consider this. Each wheel + tire weighs in at 48 lbs. On an AWD chassis
dyno that's nearly 200 lbs of spinning mass with the very worst possible moment of
inertia. This has a huge negative impact, particularly on inertial dynos, but
also any load based dyno that is letting the revs increase steadily.
The dyno above has the wheels/tires removed, eliminating that factor entirely.
Helps explain why it shows the highest WHP numbers of any AWD dyno for the R32
we've seen so far. (Neuspeed's AWD Dynojet run was 190whp, and a load based AWD chassis
dyno was 174whp. etc.. )
ian



Modified by Daemon42 at 10:12 PM 3-16-2004
 

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Re: VWvortex R32 Stock Dyno Numbers (Daemon42)

yah im following you. Trust me im all for the great #'s. One question, why does a 227hp wrx put out 160awhp on the same dyno? Thats what im trying to understand. With the fwd dyno, considering a reasonable loss u see the hp as 240-250 where it should be. But with the awd dyno it seems like its not losing as much as it should. maybe thats where im going off. maybe he was talking about the wrx on a chassis dyno? (mustang)?
seneka
 

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Re: VWvortex R32 Stock Dyno Numbers (Seneka)

I spoke with Anthony (95GLX) and he has dynoed his car as well but on a Mustang AWD dyno.
Based on his numbers and comparing them to my results, I estimate that 15% loss is pretty close to accurate in FWD and about 25% for AWD.
To further support these estimates, I will be dyno testing my car on an AWD, Twin 248 Dyno-Jet setup very soon (same dyno that we have and tested with in FWD). I will post the results and we should be able to find out the specific loss from the AWD vs FWD.
-Rich
 

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Discussion Starter · #19 ·
Re: VWvortex R32 Stock Dyno Numbers (eiprich)

One thing I didn't mention yet because I don't have answers yet is an interesting thing that happened during our testing...
We went through a lot of the data plots and one of them was a torque graph showing the difference between the front two and rear two pods (so front vs. rear output at the hubs). At low RPM at the start of the run the Haldex system went to an immediate 50/50 split of power between front and rear wheels. However, as the run progressed in both RPM's and MPH (speed) the Haldex system progressively and very evenly started to divert power back to the front wheels ending with about 90% of the power to the front wheels at redline.
So is the Haldex system programmed to push power back to the front wheels at high speeds (90 mph) and high shaft rotation? It could do this to prevent an overheat condition in the clutchpack, but that's speculation on my part. I have emails into contacts at VWAG and at Haldex to try and find out what the story is. Meanwhile I've been contemplating what this means on the dyno run. The Haldex coupling was still putting about 10% power to the rear wheels at the end of the run, so there is still driveline loss through the main shaft, clutch pack and rear drivetrain components and I'm not inclined yet to say that driveline losses would be closer to FWD - in reality *if* there were any changes it would probably meet in the middle somewhere unless the Haldex system is extremely efficient.
I'd like to go back to the dyno and do some more testing. One that I'd like to do is to run the car through a typical fourth gear dyno pull and when the haldex starts to divert power to the front, back off on the throttle (and thus speed and RPM's) to see if there is a progressive return of power to the rear as speed decreases *or* if it is related to perceived slip or continuous perceived slip conditions in some way and instantly goes back to 50/50 split.
Either way I wouldn't read much of anything into the above yet till we do some more testing and get answers from some people on how the Haldex system behaves.
-jamie
 

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Re: VWvortex R32 Stock Dyno Numbers ([email protected])

That is a bit odd about the torque transfer, but I think I can explain it.
Start with the tech information on Dynapack's web site.
http://www.dynapackusa.com/f1.htm
Notice they say that being a true load based brake dyno, that they
control the exact rate of accelleration. To simulate an inertial dyno pull, you
specify the start rpms, the finish rpms and most importantly, the interval
over which you want to accellerate.
So what?
Well, it means that the dyno has to *allow* the hubs to accellerate.
It's perfectly capable of holding the hubs to a fixed rpm, but to
simulate a traditional 2000-6500rpm dyno pull, at each moment
along the way it measures the brake horsepower, and then regulates
the braking force to allow the engine to accellerate to a higher
rpm at a pre-determined rate. A quote from the site
"Once the Ramp Time is chosen, the vehicle will accelerate at that rate regardless
of the throttle position (above a minimum of course). Having total control over the
rate of acceleration opens up a new world of tuning and diagnostic possibilities and it
is a benefit that none of our competitors offer."
Means you could do the whole pull at 1/2 throttle, and it'd still accellerate from 2k to 6.5k
in a user specified interval.
So how's this apply to Haldex? Well, if you dig through the technical information
on the Haldex Traction site, they say that Haldex can maintain a full lock between
front and rear at virtually any speed, but it needs a small rpm difference between
input and output shafts of about 1-2 rpms (higher the load the greater the rpm difference
required to maintain lock). Now let's say that at the start of the run the engine is turning
at 2000 rpms and you're in 4th gear (ratio of 1.1:1 and final drive of 4.24). That means the front
driveshafts and the propshaft going to the input of the Haldex unit is turning
at 428 rpms, with a road speed of 428 rev/min * 6.5 ft/rev * 1/60 sec/min = 46 ft/sec or 31.6 mph.
At 6500 rpms the front axles and propshaft are turning at 1393 rpms
for a road speed of 1393 rev/min * 6.5 ft/rev * 1/60 sec/min = 150 ft/sec or 102 mph
The dyno is now essentually set to regulate the road speed at all four tires from
31.6mph to 102mph. This works fine at the front hubs because they're always driven directly from
tranny and front diff.
But the Haldex needs that 2rpms difference between input and output shafts to maintain
full lock to the rear.
If the output shaft needs to turn 2rpms slower than the input for full lock (50/50 split on the dyno)..
then it's turning 426 rpms at the start of the run and 1391 rpms at the end.
426 rpms = 31.4 mph at the rear hubs
1391 rpms = 102.7 mph at the rear hubs.
Notice the difference between front and rear road speeds.
At the start.. .2 mph and at the end .7 mph.
It's subtle, but remember this dyno simulates the inertial run by regulating
the hub speed so that it stays glued to a specific accelleration curve. If the
hub speed drops below the curve, it reduces the load on it, allowing it to speed up.
If it moves above the curve, it increases the load to keep the speed down (all the while
actually measuring how much load it has to apply.. and that is a direct measure of
the torque output at the hubs).
The problem is, that as the road speed increases, the rear end wants
to turn little slower than the front under the same load, so as the
rear hub speeds fall below the accelleration curve, it's reducing the load
on them more and more to keep the speed up. If the dyno maintained
the same load front and rear, then the rear hubs would be
turning .7 mph slower than the fronts at the end of the run at full
lock. With 90% of the load at the front, and only 10% at the rear, the
torque transfer demands are lower so now Haldex is presumably successful
at keeping the rear wheelspeed matching the front, or at least
with a much lower rpm difference than the full 2 rpms required for
maximum haldex engagement.
So there's two ways to look at this.
1. It's a quirk, perhaps even a flaw of the Autopilot mode of the dyno because of the way
it tries to match speed at all 4 wheels at once. Might see if one of the other modes
would avoid the issue. They'd undoubtably see the same thing running say.. an
AWD Porsche with its viscous coupling to the front (no center diff), and it could
be even worse because a VC always allows *some* significant slippage (has to, to keep
the fluid hot and viscous). There may be a setting to allow a larger rpm difference.
Make sure the R32 uses it.
2. Or one could argue that this test represents a more accurate representation
of what Haldex is really doing in the real world switching between AWD and FWD
as it speeds up. Except that it most certainly is not running a 50/50 split in 4th gear
on the highway if you roll on the throttle at 2000 rpms. Too much traction at the front
for that, no rpm difference between input and output shafts at the Haldex unit, thus
no significant rearward torque transfer. 1st and 2nd gear.. yes.. 4th.. no
That's my take at least. Might want to run it by the dyno operators, or even Dynopack
and see what they think. Just tell em that Haldex needs a small rpm difference
between input and output to maintain lock, and see what they say.
ian


Modified by Daemon42 at 2:04 AM 3-17-2004
 
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