Product Reviews

JHM Tuned Audi B7 S4 – Review

B7 S4 on the Dyno

I had been wanting a JHM tune for a while after reading countless positive reviews on Audizine, but it used to be that the only way you could get tuned was to remove your ECU and ship it to JHM. I’ve had too many bad experiences shipping car parts, plus I didn’t want to cut my ECU out, so I was THRILLED when my favorite local tuner, GoodSpeed Performance Lab, became an authorized JHM dealer and could flash my car on-site. I was the first car that GoodSpeed flashed with the JHM tune (thanks Jon for the honor!), and I thought it’d be neat to get some before & after dyno results on their MAHA AWD dyno as well…

B7 S4 on the Dyno

Before we get into the numbers, let’s talk about gut feeling and “butt dyno” results first. I really love the tune, as it’s woken up the car and makes it feel like a whole new animal. The throttle is way more responsive. First and second gears feel like a different car, as the car revs fast and takes no prisoners. The entire powerband feels stronger too, and I found myself unable to resist hammering the gas at every chance I get, and it is now way too easy to hit triple digits on the freeway. When you shift gears the torque is there right away and it almost feels like you launch through each gear shift. I was warned by a good friend who has had this tune for a while that “you’ll have to re-learn how to drive the car” and he was spot on, especially lower gears as the car is way more responsive and wants to RUN. From a drivers perspective, this tune put a huge, ear-to-ear grin on my face and has made my car way more fun to drive. I think the change in driveability and responsiveness is far more impressive than the numbers when it comes to this tune, but let’s talk numbers, too:

JHM Dyno Graph B7 S4

JHM Dyno Graph B7 S4

The car gained about 10-12 whp at peak and about 20 ft-lbf of torque at peak. But as the dyno graph shows above, it’s not just at peak where the gains are made – the gains are consistent across the power band, especially with the torque. I think the torque is a lot of what I’m feeling with this tune, as this car wants to “get up and go” right off the line. The tune also increases redline a bit (as you can see the two “after” lines go further) too. The car put down 321 hp at the crank and 235.8 at the wheels for those interested, as well as 252 ft-lbf of torque to the wheels and 297 ft-lbf of torque at the crank. Those numbers may sound low to you (after all, Audi claims these cars make 339 bhp at the crank) but part of that is due to the difference in dyno machines – the MAHA AWD dyno is probably the most conservative dyno on the market, which means its going to read a lot lower than say a Mustang dyno (more common). I’ve also never seen or heard of a B6/B7 putting down 339 hp at the crank in bone-stock mode, so it’s likely Audi may have over-estimated these numbers a bit. Also note that I’m on 91 octane gas as 93 isn’t available here in Arizona, and generally speaking the 91 gas we get here isn’t that good either, so these numbers would be better if I had better fuel to test on.

Other relevant mods to the car: piggie pipes (pre-cats only), Milltek resonated exhaust, K&N filter, and an 034 Motorsport MAF Hose.

I’ll probably be doing 2.5″ catless downpipes next, just to try to eek out a little more performance out of the current setup. JHM recommends having at least piggie pipes and an exhaust with an X-pipe to run this tune, so I’m probably at the very lowest end of modifications you should have before getting this tune. Further down the road I hope to do their intake manifold, crank pulley and several other parts, and I’ll have the car dyno’d again to see those gains. So far my performance mods have been minimal, as I came from an A4 so the 100+ hp & torque gains were sufficient compared to what I was previously accustomed to with the 2.0T.

Brilliant Red B7 S4 - JHM Tuned

All in all, I couldn’t be happier with my decision to get the JHM tune. The car feels so good, almost as if it were bumped up an entire performance class (think S4 to RS4) in terms of road manners and throttle response. The tuning process was super easy (the tune itself took about 30 minutes, not including dyno time) and being able to get tuned at a dealer without any mailing in the ECU funny-business makes this an easy decision.

Updated 12/26 with better dyno graph – Thanks Jon!

Nick Roshon

Nick has been an Audi owner and fanatic for the last 10 years, and started Nick's Car Blog in 2009 to share DIYs and pictures of his A4. Currently he drives a 2012 Audi TT-RS, and has previously owned a B7 S4, B7 A4, and an 82 Audi Coupe (GT) LeMons race car. In his day job, Nick is a digital marketer and lives in San Diego, CA, USA.


  1. I’m considering down pipes, exhaust and the chip upgrade but I wanted to check and see what your thoughts were since you already made the investments. What was your total HP gain with the down pipes, catback, and chip? If you could do it again would you do anything different? Have you heard of “Xs Power” downpipes? How much did it all cost? Do you know any good connections in the PA area? Thank you Chief!

  2. Jon – I think those mods are a great way to start in terms of bang for the buck. An exhaust is a must both from a performance and a sound standpoint. The downpipes are another big power adder – I did piggie pipes ( but those XS Power ones look nice too. I wish they were 2.5″ throughout instead of being necked down to 2.25 at the end, as a lot of exhausts are 2.5″ so it would be nice to have a 2.5″ exhaust throughout.

    I might do a different exhaust in hindsight. My Milltek resonated exhaust is VERY quiet. I really like the STaSIS and JHM/FI exhausts for our cars.

    HP gains are tough to say as I never got a true baseline measurement – all I had was before and after the tune above, but in both cases I already had piggie pipes and an exhuast. Your numbers will also be much higher since you have 93 gas versus really crappy 91 gas here.

    Next up for me performance wise is a JHM Lightweight Crank Pulley and a JHM Intake Manifold or Intake Spacers to free up a little more HP…

  3. I wanted to get your input on the performance mods you have completed so far. I am planning on doing the pipes, chip, exhaust, & MAF hose. If you could do it again would you do everything the same? Overall how many hp’s did you gain? I thought our cars were 342hp stock; you indicate otherwise and that makes me sad. I appreciate your feedback! There is so much info out there these decisions are a pain in the ass.

  4. Nick, Thanks buddy! I reposted my question bc it did not show up on my side…whoops. Keep up the good work!

  5. No worries Jon. My car did dyno a lot lower than Audi claims is factory (and that was with a few mods, nonetheless) but the MAHA dyno is the most conservative dyno there is – I could go get re-dyno’d on a Mustang and show 10-15% higher numbers, but my car wouldn’t really be any faster so at the end of the day it’s just different ways to measure the same thing. I was really just interested in gains from certain mods so as long as I keep using the same dyno I should be able to evaluate.

  6. Nick, does this tune require removal of the ecu? I had heard that it may be possible to flash using the obd port using JHM cable. JHM doesn’t seem to accept to ecu’s for programming anymore. The nearest dealer is 500 miles away so I would be flashing it myself. Thanks

  7. Yes, they do have a program where you can flash it yourself with a cable. Some people have found it more difficult than others, but it’s certainly DIYable. I’d give JHM a call – I believe they charge a fee to rent the cable or you can buy one if you plan to do a lot yourself. They also be planning on adding a dealer near you sometime, so it wouldn’t hurt to ask first.

  8. Thanks nick, I had gotten some info from them but haven’t heard from them regarding removal of the ecu

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