S6 AAN: I want TORQUE!!!

[Giacomo]

Hello,
I'd like to improve the torque of my S6.
The car is manual 5 gears stock engine, 100'000 miles, just chip-tuned with Ultimot 280 hp chip. Nothing else.

I'm going to install a K26 turbocharger, wagner EM and substitute kats with direct pipes.
I already have this parts since a lot of time in my warehouse, and I know that something better could be done. For example Volvo K24-7400 turbocharger, but I already have this K26 and don't want to keep it making dust.

It could be enough for me, I'm just afraid to destroy the rods of my engine, because the same set up on my other car, Urquattro RR, made a rod come out of the engine after 250 km. See the picture.

So, what do you think? Was my RR engine defective and so me unlucky, or do I have to expect to destroy this AAN also?

I'd like to change the chip from Ultimot to PRJ's, will it be enough? I know PRJ is a good tuner! But what was wrong on RR? The rods or the chip?

[macspring]

The difference between the RR and the AAN is that the RR uses a distributor with a rotor arm, where as the later AAN's do not. I think of spark hop, more especially if the incorrect rotor arm is mistakenly bought and fitted.

Just my tuppence. Others will know more.

[UrS4boy]

Why do you think a K26 will solve your problems? It is not the right turbo for a 20VT AAN/ABY/ADU as a daily driver. Way more lag down low than either a K24-7000 or K24-7200.

Get a K24-7000 tune by Prj with a 3 Bar MAP sensor and see if you like that first.

[andy10v]

What k26 are you fitting?

A stock k26 from a 10v will be laggier and less power iirc.

[Giacomo]

I have bought it refurbished: it was from a porsche 944 Turbo S.

[Giacomo]

Why do you think a K26 will solve your problems? It is not the right turbo for a 20VT AAN/ABY/ADU as a daily driver. Way more lag down low than either a K24-7000 or K24-7200.

Get a K24-7000 tune by Prj with a 3 Bar MAP sensor and see if you like that first.

I'll try this first. Thanks

[Giacomo]

Also I'd like to change the gearbox from manual 5 to manual 6.
I know that many manual 6 fit on AAN.
Its own OEM 6 gears, S6 Plus DGU gearbox, RS4 B5 gearbox, S8 DGV gearbox...
Which is better? I like short gear ratios a lot!

Also, another project is to re-build the OEM engine of the Urquattro RR. I want to keep the OEM head (with OEM engine number), which was not damaged, and use something stronger inside the motorblock, STARTING FROM THE RODS.
I don't know which brands are good quality/price, what do you suggest? What else do I need? Crankshaft? Rod bearings? Where can I get a new motorblock?
Thanks!

[caterpillar]

change the exost piping and boxes to at least 3"..3,5" (89mm) and downpipe.... and the torque will come as a sjedgehammer...!!!!!

[Giacomo]

sorry, I don't understand your slang.
I understood only "downpipe".
What are "boxes"? And what is "exost piping", the exhaust system?

[UrS4boy]

change the exost piping and boxes to at least 3"..3,5" (89mm) and downpipe.... and the torque will come as a sjedgehammer...!!!!!

Not unless you are already making big hp. On a stock C4 AAN, the gains are minimal, especially for the cost. Best bang for the buck = Stage 1 Software with stock 2.5 Bar MAP sensor = 260 hp. Next best bang for the buck = Stage 1+ software with 3.0 Bar MAP sensor = 280 hp. After that, there are gains but the cost per hp (or Nm) increases more and more.

[Quattronaut]

I'll try this first. Thanks

IMHO- why? I know Prj´s reference, but right now you have a stock hardware motor with a good working map from Ultimot, if I have understood it right. And now, you want to change that- but no hardware changings, only another map done by Prj?

Sorry- senseless in my opinion. The differences won´t be very big. Don´t even know, if there will be differences, because I don´t know Prj´s and Ultimots exact maps- but Prj will do a reliable map, respecting the limits of the motor, and Ultimot chips are wellknown, and running in a lot of cars, so they also do a good job. There can´t be too much difference in here. Spending a lot off money for at last no difference?
With 280hp and around 400nm torque the stock turbo is maxed out. For really more torque, you need another turbo- do you have some infos about your K26?

The broken rod on the RR coul be ignition failure- but COULD. Rods are killed by early high torques...but I didn´t here of them breaking with an normal stock mapped car. Nobody can tell you, why that happened.
Maybe the ignition failde, maybe the map is bad, maybe something else.

The 6speed gears do not have great difference in gear ratio compared to the 5speed ones...first and last gear are nearly equal, only thing is, the 6speed ones are nearer to each other from 3-5. Don´t know, if that improvement is worth the money and work, either...

[Giacomo]

You seem to be the voice of my conscience. I like and agree with your comments, they're very rational.
But first of all, I like to try different parts (hardware and/or "only" software), just for curiosity.
For the gearbox, I was just curious to know if somebody knows better than me what is different between the gearboxes I mention. I know that between 5 and 6 gearboxes, on S6, only the intermediate gear ratio ar different, but maybe a gearbox for RS4 or S8, which are designed for 380 and 360 hp, could stand better other extra upgrades in the future. Or RS4, which gears should be 15% shorter than S4, could improve the sensation of torque. Same for S6 plus gearbox, which has last gears shorter.
At last, when RR engine rod breaks, it was running with Ultimot step 1 and K26+wagner EM. (the same K26 that maybe I'm going to fix on S6: the RR has been repaired with a "hybrid" engine bought from Tobias with AAN motorblock, RS2 metal gasket and ABY head with distributor - no coils, and it's running with its own K24 now).
I driven the RR stock for 30000 km, then turn to K26+wagner+ultimot1 and after 250 km (two hundred and fifty) pushing the 4 gear on highway a rod say bye bye.

[Giacomo]

Which is the strenght of the stock RR rods? 600 Nm?
Could a K26 at 2,5 absolute bar generate such a torque?

[Quattronaut]

Which is the strenght of the stock RR rods? 600 Nm?

Don´t know numbers; there is no technical data like this afaik; dangerous is not only the torque itself, but having it at low rpm and kicking in very hard.

Could a K26 at 2,5 absolute bar generate such a torque?

K26 at that pressure should give around 430-460nm, I estimate.

IMO-from mapped RS2 upwards, rods are in danger. Good mappers ask, what is done to the motor, and I guess, on a stock hardware RS2, they map a bit into "rod safety" compared to a motor with upgraded rods.

As the K26 should be more laggy than the RS2 turbo, I would think, it is safer, because it does not kick in as hard and early as the RS2 one does. Alas I do not know, what kind of K26 it is...but maybe, the RS2 charger is capable of more power and torque.

Let me have a look to that gearbox stuff tomorrow- don´t promise, but maybe I find some datas.

[Giacomo]

Some pics of the K26, hope all these numbers helps.