JHM Tune Issues - B8.5 RS5

Hello all,

It’s been roughly a month of running the JHM stage 2 tune and I’ve noticed a few things.

1st - startup idle is rough and jumpy, when reversing after startup the car seems like it just doesn’t want to.

2nd - Jumpy and clumsy when driving normal, holds gears longer than it needs to, feels overall just bad.

Once the car is in dynamic it feels rock solid, with an occasional SLOW upshift.

Any idea what the reason could be?

I have not done a throttle body calibration since I don’t have the tool.

Always a great idea to do the throttle adaption. That has almost always good results. Now that the throttle is more sensitive and no delay that adaption makes a big difference if your unit is even slightly out.

Cold starts JHM has done what they can to keep the motor in the lowest possible friction moment while also working to keep the oil pressure up. This reduces motor ware during the most critical part of the motors life and that’s on cold start. The colder out it is the better the chance the JHM ECU is fighting a battle to keep the rpm down the TQ down but the oil pressure up. Best thing you can do is start and drive as soon as possible. It isn’t a good idea to let any car sit and “warm up” start and drive.

I had a client who was having similar issues. He calibrated the throttle bodies and we checked everything. In the end, it turned out to be dirty air filters! He replaced both (actually went to K&N panel filters) and his issues went away.

With that said, it’s not unheard of for the throttle bodies to go bad on these cars, especially in the rest of the world (non-US) cars. So throttle body adaptation is a good start (Ross Tech VCDS) and I’d also look at spark plug replacement if that hasn’t been done in 20K miles or so. These cars are surprisingly hard on plugs.

Also, on the slow upshift, the DL501 does not like indecisiveness…it likes you to be committed. So if it holds a gear, it’s expecting you to ask for maximum acceleration. So if you go wide open throttle through a few gears, then go neutral in the next gear, it’s still in “race” mode so to speak. After 30 seconds, it’ll shift into the next gear. You can get around this by simply using the paddle even in S mode.

In Drive mode (not dynamic), the shifts even under part throttle happen later (about 2900 rpm) so the car isn’t trying to shift into 7th gear at 40mph and 1700 rpm. Removes all responsiveness from the car. And again, if you want to hyper mile it, just use the paddle and shift into a higher gear.

Do make sure you are servicing the car’s transmission on time too. Don’t skimp on that as old fluid can affect how the car operates.

There’s also a transmission cooler kit out there that does wonders and works very well with the JHM stage 2 tune. Link here: https://redmistracing.com/ols/products/rmr-transmission-cooler-for-the-audi-rs5-b8b85-2010-to-2016

On the cold start, you can also throw your fuel trims out of whack by having the car sit and warm up. Really bad thing to do. I usually try to get the car moving by the time the fast idle settles if not before. That’s often a struggle as I start the car with the garage door closed so my neighbors continue to like me :). If you have a Ross Tech VCDS, you can go in and clear the trims to “start over” so to speak. Your first cold start will be rough but it’ll smooth out after. I’d check everything else first though.

Ok I’ll look into that! I don’t have a ROSS VCS cable so maybe that’s something to check.

Filters are clean, just replaced. Car has had every service done even the 85k mile recently.

Awhile back I did have a trans malfunction that required me to pull the car over since it wouldn’t drive. After I cycled it went away and have yet to see anything else.

Could this be an underlying trans issue?

Could be but usually when it goes away, it’s a voltage issue. The CAN bus is very temperamental and it needs a proper amount of voltage for the modules to communicate. If it dropped below a certain threshold, for whatever reason, you can get an error but it usually causes your dash to light up like a Christmas tree.

So if it’s JUST a trans malfunction, best to get a scan otherwise we’re just guessing. The Ross Tech VCDS is the best thing out there, here’s the one you want: https://store.ross-tech.com/shop/vchv2_ent/

The model year will also help and with a VCDS scan you software and hardware of thr transmission

Ok, it’s a 2013 and I ordered the VCDS scanner.

Any VCDS mods that you recommend?

There are a bunch! You can find a lot of them here: https://www.a5oc.com/threads/complete-vcds-vagcom-mod-list.28600/

Did someone manage to enable the battery state of charge view on a >2012 ?

Not sure but there are bluetooth/smartphone battery monitors available which will list the percentage charge and voltage level.

I’m a dealer for Antigravity batteries and we have them for lithium ion as well as normal lead acid. And they’re cheap!

What are the best plugs for the RS 5 B8.5?

OEM is fine, I use NGK Rutheniums. You can get those off of www.rockauto.com for a decent price.

Thanks, looks good. How often would you replace them. I’ve seen recommendations for time or mileage. Thanks again!

I think the OEM recommendation is every 35,000 miles or so? I tend to replace them every 25,000 but I usually do “performance” maintenance above and beyond what Audi recommends. I actually have a set of Rutheniums that arrived today and I’ll swap them in this weekend. Been a bit since I’ve actually wrenched on my own car!

Anyone know what the latest version of the JHM Stg2 tune it? I flashed over a year ago and wondering if they have done any tweaks to it or the TCU side of the tune. I am running the Catless & SAI delete tune.

I think it’s 17.9? I’d have to log in and take a peek. I haven’t flashed anyone locally in a while. There’s only one other RS5 in town so not a lot of people to flash in person. That sounds wrong. But I digress…the only changes have been to the ECU side, TCU side is the same I believe.