S4/S5 tuning EA839 engine


Registered User
Hey guys, just finally got my car mapped and going through the development work myself on my MY17 Audi S4 B9.

Started to use process to build a more powerful car from the ground up that is reliable, strong and OEM drive.

after running some tests on increasing the power yesterday I found With the new S4 engine we are just finding out limits that restrict the engine from producing the big power we all crave.

The first restriction seems to be around intake temperatures due to a small intercooler the air temperatures already exceed 60° and when mapping struggle to keep the temperatures below 70°. This means that power is limited for a remap around 410 bhp. Any tuning company offering more than 410 bhp from this engine in my opinion is seriously jeopardising then the longevity of the car or lying about their figures.

Why is intake temperatures important? In modern turbocharged internal combustion engines the cooling of the air after the compression stage is the standard technique to reduce temperature of the engine intake air aimed at improving cylinder filling (volumetric efficiency). At present, standard values for optimum performance is intake air temperature in the range 30-70°C. With the new EA839 engines in the S4 etc... running above 60° as standard, changing the Intercooler is a must and a dirty trick by Audi to restrict the power.

If any of you guys are interested in finding out more please shout up.

I have mapped mine now to 410bhp with an OEM drive that’s so much smoother and refined to drive.


Well-Known Member
Bronze Supporter
That sounds good. As more people come out of warranty there will be more mods to come. How much torque is the gearbox rated for? Should up your servicing of oil in the gearbox now.


Registered User
Very misleading is the gearbox but looks like 700nm on the ZF 8HP55AF according to Ross Tech. I’m sure the gearboxes have limits in their on ECU, I’ve seen the max speed limit go off but I will report back the more I find.


Registered User
What a lot of people in America have said the other restriction is the turbo inlet elbow which is restricting air flow into the turbo. Im currently running a Jb4 piggy back with front mount intercooler. Decat downpipe and panel filter. I also have WMI. I think I’m running around 480bhp got to go back to the dyno. Before the wmi and Decat I was at 441bhp.

where in the country are you?

keep up the good work.


Registered User
Leicestershire bang in the middle.

yeah I looked at that and ordered the ECS replacement straight the way, Audi have definitely restricted the airflow coming in as they over boost on the way out.

I have changed the air filter to that racing line replacement foam filter too, with that on and no map mine ran 380bhp standard


Registered User
There is a thread somewhere on aftermarket turbo chargers if you perform a search...


Registered User
RE That 60 quid ECS item: I'm really not convinced the first 8 inches of pipe is a turbo inlet restriction, the remaining 12" worth that connects to the turbo itself looks to narrow yet further.

Get some dragy times up. Adverting a power number tells us nothing about the real world performance of your map.