RS246.com Forum :: The World's #1 Audi R, S and RS Enthusiast Community

Wagner tuning is developing intercoolers for the C6 together with RS Engineers. First prototypes are done and being tested.

https://m.facebook.com/photo.php?fbid=2 ... n__=%2B%3D

Very interesting - thanks for the heads-up.

According to Ian's HS Marston Intercoolers thread, these are the dimensions of the current RS6 intercoolers:

viewtopic.php?f=47&t=120058

The core sizes are as follow for those interested –
OEM – 225 x 290 x 80 = 5220 cc each = 10.4 litres total
Marston’s – 270 x 275 x 76= 5643 cc each = 11.3 litres total
KWE – 255 x 280 x 95= 6783 cc each = 13.6 litres total

Sportmile – Unknown but much thicker than any of those above Doug said.

The Wagner IC is almost twice as thick as stock, so if it's the same height and width, the core dimensions will go up to:

Wagner - 225 x 290 x 135 = 8809 cc each = 17.6 litres total

Taking a good yardstick, the stock Golf R7 intercooler is 8882 cc, which is pretty generous. The R7 Wagner version is 17056 cc, which is particularly large. Upgrade FMICs are typically 14 to 16 litres volume.

Wagner will have done a lot of design and tooling on these ICs already, so "prototype" isn't very significant IMHO - these are a live product.

This sounds like a good step forwards for the RS6 (and check out the Milletech inlets as well), but look at the design and the position of the ports. It seems like the IC is taking the space occupied by the water heat exchangers behind the IC's - so where are they going to go? Further backwards?

There are two other aspects to consider - ambient airflow and charge airflow. A thicker intercooler will tend to increase the latter, which is always welcome, and probably a great benefit for a tuned RS6. However it also reduces ambient airflow, so the cooling capacity doesn't increase in proportion with the core thickness.

EDIT: This issue is overcome if the aux water radiators are relocated, as the IC is effectively taking the place of what was there before. So it's win-win: you get more cooling capacity AND you get more charge air flow capacity. Both are very important.

Finally, Wagner and RSE seem to have a target in mind. If you do a simple calculation of the IC core volume needed for a 1khp car, you get this sum:

Volume = 10.4 l x 1000/580 = 17.9 l

However, here's the problem with this calculation - it ignores the high boost pressure needed for high outputs. 60 bhp per litre of IC is a OK for low boost engines, but one high boost horse power demands more cooling than one low boost horse power, because the temperatures are higher.

The stock RS6 really doesn't work that hard. It's limited to 650 Nm, which is just 130 Nm per litre. The S6 V10 produces 103 Nm/l, exactly the same as the RS4 or the M5 or the Gallardo or any other contemporary state-of-the-art, naturally aspirated engine (turns out it's really that good). Therefore 0.6 bar turbocharging yields just 26% more torque, which doesn't add up. I think the boost must be profiled to limit the torque.

The short of this is that the stock RS6 intercoolers have quite an easy time, but if you want a lot of power, you need MUCH more cooling.

I never paid that much attention to the V10 in naturally aspirated guise before, but this has been quite reassuring in a way. I thought maybe it wasn't quite a cutting edge engine like the R7's and RS3's that achieve 250 bhp/l and 300 Nm/l, but it turns out that might not be the case after all. You just need the cooling (and fuel and ignition and intake and exhaust and tuning...)

Nick

welwynnick wrote: ↑

Tue Jul 23, 2019 9:25 am

It seems like the IC is taking the space occupied by the water heat exchangers behind the IC's - so where are they going to go? Further backwards?

I'd guess that they'd be deleted as there's little or no room behind them. Actually, there's little or no room anywhere.

Jim Haseltine wrote: ↑

Wed Jul 24, 2019 9:54 am

welwynnick wrote: ↑

Tue Jul 23, 2019 9:25 am

It seems like the IC is taking the space occupied by the water heat exchangers behind the IC's - so where are they going to go? Further backwards?

I'd guess that they'd be deleted as there's little or no room behind them. Actually, there's little or no room anywhere.

Check out Wagner Tuning´s Instagram account. There you can see how they solve it. They delete the ones behind the intercoolers and put a bigger radiator in the front with a modified bumper reinforcement.

They seem to be taking it pretty seriously, and if RS Engineers are involved, I wouldn't be surprised if we see one thousand bolt-on horse power pretty soon.

I'll be interested to see what RS/TTH/THT get out of this, in particular the shape of the power curve, which often reveals a lot. The stock IC is a bottleneck, so these should help open up the top end.

https://www.facebook.com/RS-Engineers-1 ... LtRBGDyDWv

There's a video with some CAD of the new installation at 20 seconds here:

https://www.youtube.com/watch?v=-v-Ezi87380

It looks like you have to buy a new bumper beam and two new water radiators to fit behind it:

Wagner have launched their new RS6 C6 intercoolers, though only on their German and US websites, and they're not available until next month.

As you'd expect they're quite expensive given that there are two new auxiliary coolers and a new bumper beam - 2490 Euros or dollars

I estimated they would be 8809 cc each, and they actually come out at 8730cc. They're larger than any other coolers for the C6, or B5 or C5 for that matter.

I wonder what THT / RS Engineers have been able to make with them?

https://www.wagner-tuningshop.de/produc ... 01146.html

Nick

I'll hopefully be running these if the Wagner UK can get a kit for me before my cars built.

I've been holding off as long as possible and spoke with UK Wagner who told me they were guessing they'd be out near the start of this year, so I waited and will get in touch again before I leave the car in to be stripped down.

Looking forward to seeing what they are like along side the TTE1000s

Some tuning companies don't provide much information about their products, but Wagner aren't one of them. Their product range is very broad, and they tell you pretty much everything.

Observation No1: If you look at their other products, they use a tube and fin matrix measuring 64x41x6.5cm for a VERY wide range of intercoolers, ranging from the Skoda Octavia 1.8TSI to the Porsche Macan. That has a volume of 17.0 litres, vs 17.4 l for the new RS6 cooler. In fairness, almost all Wagner upgrade intercoolers fall within the range of 14 to 17 litres, and it's only the Porsche 911 turbo and Nissan GTR coolers that are any bigger - around 22 litres.

Observation No2: Intercoolers need to do two things - provide high cooling capacity, while minimising flow restriction at high flow rates. So far it's been assumed that the stock coolers do restrict airflow for tuned cars, though S4Player did get 1028 bhp on stock coolers on his car. Wagner have published a pressure / flow comparison for the stock and upgrade coolers. They plot airflow in grams per second against mbar pressure drop, and measure up to 175 mbar, or 2.53 psi. The stock coolers measured 272 g/s, and the Wagner coolers measure 297 g/s, which is only 9% more. I thought the improvement would be greater than that.

However, if you look at all the other figures that Wagner give for stock and upgrade coolers, you'll see that 272 g/s is actually a very good figure, so the stock cooler were never that bad after all, which kind of bears out S4P's experience. He got a bit more top end power from his Marstons, but not that much more. In fact, the coolers that don't' flow well are the FMICs, as they have longer air channels - typically 600mm vs 300mm.

There seem to me to be three modern cars with particularly great tuning potential - RS6, GTR and Porsche Turbo. They have a number of things in common - deep breathing top ends and strong bottom ends are pre-requisites, but also none of them use cross-flow intercoolers. They all have relatively short intercoolers with high flow capacity. The GTR does have two FMICs, but they're configured like side mounts, with the charge air flowing vertically downwards, rather than cross-wise. It never really occurred to me that SMIC's were an asset to the RS6.

I think in due course the new RS6 C8 will have great tuning potential - it's gone back to SMICs, and other reasons.

Nick

welwynnick wrote: ↑

Sun Jan 12, 2020 7:05 pm

I think in due course the new RS6 C8 will have great tuning potential - it's gone back to SMICs, and other reasons.

Nick

And so it begins. THT got 796 PS and 1107 Nm from a stage 1 tune on new C8. Good numbers for a tune only.

Audi must have realized that SMICs were an asset to earlier RS4 / RS6's etc. Porsche have known this all along.

https://www.facebook.com/THTPerformance ... =3&theater

Nick

Well, I got bored with social distancing, and thought I would try and find out what made intercoolers tick.

So I took advantage of the information that Wagner Tuning published, and compared some intercoolers.

I took the dimensions (in cm) and flow rate measurements and looked for trends and correlation. I calculated the frontal area, as seen by the ambient air passing through, and the cross-sectional area, as seen by the charge air passing across. I also calculated the volume of the intercooler matrix, which I think is the most important overall parameter from the point of view of cooling capacity and flow capacity (it's also consumes cost and space). I then compared the parameters against each other. Sometimes there were no significant trends, but a few combinations looked interesting.

Area/length is an arbitrary measure of the shape of the IC - whether it's short and fat, or long and thin. It's the number of sq cm total cross-sectional area seen by the charge air, divided by the cm length of the tubes the air has to travel down. It predicts that thin IC's have small area, low A/L and high restriction, and short IC's have high A/L, low restriction and low pressure loss. It's analogous to an electrical resistor, or a thermal conductor, where charge or heat flow through a material is proportional to the cross-sectional area, and inversely proportional to the length of the conductor. Do heat exchangers behave in a similar way?


Quantity: 1 = FMIC, 2= SMIC
Length = distance travelled by charge air through heat exchanger matrix
Width = width of SMIC or height of FMIC
Thick = thickness of heat exchanger matrix
Total W = total width (double for SMIC)
Area = Thick x Total W = area of matrix as seen by charge air
Volume = length x thick x total W
Inlet = inlet port diameter in mm
Outlet = outlet port diameter in mm
OE g/s = mass flow rate of stock IC
Mass flow rate = Wagner IC


So is there a correlation between flow rate and the size and shape of the IC?
It's not a direct relationship, but it's fairly good.
Broadly speaking, the higher the A/L the higher the mass flow rate.
Large IC's are better than small IC's.
SMIC's have higher flow than FMIC's.
Large charge air ports flow better than small ports.
The BMW M4 is a water cooled chargecooler, and flows well for a small matrix.
Neither of the BMW 335d coolers flow well for some reason.
The EVO IX exceeds expectations due to it's large inlet / outlet.
The RS6 has the highest flow of any stock IC (Edit - correction - that would probably be the Porsche Panamera)
The highest flowing IC's aren't necessarily the ones with the largest matrix - they need short tubes and large ports, too.

Wagner took all these measurements at a pressure differential of 175 mbar or 2.5 psi, which is quite a significant drop.
By contrast the max pressure drop across paper air filters is usually about 5-10 inches of water, around 0.3 psi.

So what's the significance of mass flow rate? BHP roughly equals 1.1 x flow rate in g/s.
And the pressure drop increases with the square of the flow rate (or roughly the square of the power).

Nick

Edit - just realised I should have included the OEM IC dimensions as well; they're all valid data points.

Here's the data with the OEM sizes added (minus the GTR and EVO which I couldn't find easily). It makes for a clearer trend:

My car is currently at RE Performance getting these fitted. I will need to get a map tweak to take full advantage but will sure be interesting to see how they perform. I’m also getting some 3.5” decat pipes fabricated. (Current primary cats in place)

Spec of car currently is
TTH 950
REP Gearbox
Aquamist HFSv3
Milltek Res Catback
Super sprint Seconday Cat Delete
As is its running 843bhp (not ps) at I believe 1.2 bar and 820ftlbs.

Final figures with upgrades I’m hoping for is 860-880 same torque but sustained over longer revs.

I will post dyno once done but will be at least 5-6 weeks with current lockdown regs.

Well, well. KWE didn't want to be out-done by Wagner, so they've introduced an EVO 2 version of their existing upgrade SMICs that are even bigger:

https://www.ebay.co.uk/itm/Audi-RS6-4F- ... 0290.m3507

The KWE high-performance intercoolers have the network dimensions: 255x280x160mm = 22.9 litres / pair (which is up there with the biggest Porsche and Nissan upgrade IC's)

By "network" I think they mean "matrix". It's so new there's no pictures and nothing on their website yet.

4.59 litres per litre is more than double stock, and area / length = 29cm, so it's off the scale. It means the flow restriction should be low as long as the inlet & outlet are big enough.

Nick

From the Advert -

"The fans in front of the coolers and the water coolers behind the coolers are now gone, it becomes a large one in the middle

Water cooler from Mishimoto installed, this is as large as the 2 series water coolers but has 50% more volume."

So sounds just the same as the Wagner offering but no word yet on whether it also includes a new front crash bar too like Wagner.

I’ve just had these fitted to mine along with hybrid turbos and 3” system

Will be getting mapped next week