boopity

I know the mild hybrid is supposed to help the torque curve and reduce turbo lag. for anyone who has driven both with and without the mild hybrid, did you notice a difference?
How about reliability? have you see any issues?


*EDIT*
More likely it was the switch from an IHI turbo to a Garrett turbo that makes a difference, not the mild hybrid battery.

SMac770

No, that's not how Audi uses the MHEV in general. VAG is strictly about efficiency cost, and the primary purpose of the MHEV is to improve stop/start scope of operation. The 12v BAS is only a 1.7 bhp motor, capable of 5.3 ft-lbs. Now, the 48v BAS on the V6/V8, that's got some actual juice to it. But the 12v BAS, no. Just to spin up / spin down the crank.

ptmdsharp

What the OP is describing is exactly how it works in many volvos. They used to have 2.0 that was both supercharged and turbo charged. They dropped the super charger, which was supposed to reduce turbo lag, and replaced it with a battery to play the role.

I have a 2018 that predcates MHEV and haven't compared. I disabled the auto-stop start, haha, so MHEV wouldn't help me in that regard. That said,I love the engine. Quick, good gas mileage and turbo lag is barely noticeable IMHO.

boopity

I was misinformed by information in another thread I guess. Thanks for the help guys. If the only improvement is start/stop, then I may go for a b9 instead of a b9.5 just so I can get the MMI wheel.

142 guy

You are mixing B9.5 / B9 which is a body style refresh with engine changes. Up to 2020, the B9.5 was not mild hybrid. The 2021 got the mild hybrid with the DPAA engine.

The DPAA engine with mild hybrid in the 2021 and later A4 has 13 more hp than the earlier CYMC engine and gets a nudge better fuel consumption in the EPA / Transport Canada ratings, so those are two positive things The belt starter system is pretty seamless in its start / stop operation so you might want to give it a try before dismissing it. As an observation, you don't need the hybrid / Li Ion battery stuff to do a belt drive starter. You can find Audi marketing documentation on line which has videos describing the operation of the hybrid part of the scheme in the A4. I find those videos a little opaque as to what the hybrid part of the scheme is actually doing.

boopity

With the switch to MHEV, audi also replaced the IHI turbocharger with a Garrett turbocharger. That is most likely what is responsible for the better torque curve and reduced turbo lag.

KevinB656

I couldn't wait to get rid of the B9 MMI wheel. The touch screen on my B9.5 is so much easier to use. Plus, the screen is considerably bigger. The B9.5 also has a significantly upgraded MMI system.

boopity

There are after market upgrades such as rsnav that allow you to have a bigger touch screen, and keep the MMI wheel.