JHM C5 A6/S6 4.2 Development

**A62TURBO** · 10-07-2010 12:51 PM

^^^^ hahaha lol that made my day

**G Men 08** · 10-07-2010 03:41 PM

Originally Posted by beemercer

Teaser... what might these be...?

that looks like it may be...

A fun time!!!

**pismojeff** · 10-07-2010 04:00 PM

looks like it might be $2500...

**khalimadeath** · 10-08-2010 12:38 AM

Originally Posted by pismojeff

looks like it might be $2500...

x2

**IRS6I** · 10-08-2010 05:50 AM

Dan,

Awesome works and performance you guys are doing keep up the good work.

I would like to pick you brain on one point with these engines if possible? I am in the process of rebuilding a C5 4.2 and want to upgrade the rods/pistons. The rods arent an issue but with the pistons what is the procedure when it comes to the bores when installing aftermarket forged pistons and new rings? I ask as these engines use a Alusil bore.

I would appreciate any information you can supply.

**A4edwin** · 10-10-2010 05:24 PM

never got a response. what benfits will dp's give my car? will there be a big diff like the turbo cars? or will it be 5hp and a slightly louder exhaust.

**G Men 08** · 10-10-2010 06:00 PM

my guess, Edwin, is option B. Unfortunately.

**beemercer** · 10-10-2010 09:49 PM

Originally Posted by A4edwin

never got a response. what benfits will dp's give my car? will there be a big diff like the turbo cars? or will it be 5hp and a slightly louder exhaust.

Well it depends on the downpipes. I have modded stock downpipes on my A6. They are 2.5" throughout with highflow cats located downstream (closer to the catback). They definitely add a healthy amount of power and torque if you have the supporting mods, such as a 2.5" x-pipe catback, S8 cams, S8 intake manifold.

I'm gonna throw it out there, my A6 (formerly Dan@JHM's A6) feels faster than my 05 S4 did. For reference my S4 did 328whp/300wtq on 93oct on a Mustang and my tune is a stock Euro S6 file.

I'm hoping to get a baseline dyno before the header install, so there may be a nice before and after graph or everyone.

**khalimadeath** · 10-11-2010 12:25 AM

diff comp to handle the cams?

**beemercer** · 10-11-2010 12:48 PM

^Mine is running a stock Audi file from the European S6, primarily for the manual swap, though it should correct for the cams since the S6 uses the S8 cams iirc. JHM or VAST should be able to set you up with the Euro S6 file.

Once the headers go on I will be working with JHM to dial in the tune based around the Euro S6 file. Should be decent power gains in it.

**Scotty@Advanced** · 10-11-2010 01:46 PM

Originally Posted by beemercer

^Mine is running a stock Audi file from the European S6, primarily for the manual swap, though it should correct for the cams since the S6 uses the S8 cams iirc. JHM or VAST should be able to set you up with the Euro S6 file.

Once the headers go on I will be working with JHM to dial in the tune based around the Euro S6 file. Should be decent power gains in it.

I don't recall exactly but I'm pretty sure the S8 intake cam is unique to the S8 and the S6 uses an S8 exhaust cam and an A6 4.2 intake cam.

The better file to use is a Euro S8 with a manual, it's got 20 horses over the S6. Did you use the S8 rockers when you swapped cams?

**A4edwin** · 10-11-2010 04:59 PM

i have a milltek exhaust. no chip yet. def thinking about the jhm tune and the tip tune i'll more than likely want a little more. guess i'll want to see some dyno numbers. 1/4 mile numbers really don't do it for me. i'd like to see where the powers at before i drop coin.

**beemercer** · 10-11-2010 05:18 PM

Originally Posted by Scotty@Advanced

I don't recall exactly but I'm pretty sure the S8 intake cam is unique to the S8 and the S6 uses an S8 exhaust cam and an A6 4.2 intake cam.

The better file to use is a Euro S8 with a manual, it's got 20 horses over the S6. Did you use the S8 rockers when you swapped cams?

Scott, I appreciate your input, I know you have tremendous experience with the timing belt 4.2's. I did not do the cam swap on my A6 (I bought it form Dan and had JHM do the work prior to shipping), but I do not believe that the S8 rockers were installed, only the intake and exhaust cams. Any idea in the difference in the rocker ratio between the A6 and S8 rockers?

I will see how a worked over Euro 6MT S6 file works out, I'm confident in JHM's programmer's ability to make it work, he did build this afterall *skip to 0:23 for the fun stuff

http://www.streetfire.net/video/audi...nce_148031.htm

**eagledubg** · 10-11-2010 06:36 PM

ive never seen this video before but it makes me smile knowing i have a 4.2 which will become my next project car..cant wait to see what vast comes up with

**G Men 08** · 10-11-2010 06:56 PM

hey now, Would an RS6 benefit from the s8 cams and intake?

**Vinchenzo51** · 10-11-2010 07:34 PM

so you think that now since JHM owns a C5 maybe SOMEONE will FINALLY make a decent boost gauge mount for us. i just ordered a B5 passat pod and am going to fiberglass it into my steering column cover... i would LOVE to just bolt something in place

**khalimadeath** · 10-11-2010 10:44 PM

i watch this and see $$$$$$$shiny$$$cool$$$$$looks fast$$$$$$$$$$$$$$

if that makes any sense lol

**beemercer** · 10-17-2010 12:40 PM

**UPDATE**

Car started this morning right around 9:40AM. We need to finish up the work and get the car back together, but all seems well. I have to say, open headers are quite LOUD AS FUCK ahaha.

There were a lot of little modifications that needed to be done to fit the headers perfectly... luckily VAST's fabricator (the installation was done with their assistance) is an artist with his tools and got them in flawlessly.

Hopefully I'll have some videos up soon of the car running. I'll also have some thoughts on how well they are working soon, should be driving 900miles back to Massachusetts early tomorrow morning.

**Gumby** · 10-17-2010 07:44 PM

^very cool! can't wait to hear what it sounds like compared to the B6/7 S4s with headers.

any larger pictures?

**EinSchnellAudi** · 10-17-2010 08:09 PM

Originally Posted by beemercer

**UPDATE**

Car started this morning right around 9:40AM. We need to finish up the work and get the car back together, but all seems well. I have to say, open headers are quite LOUD AS FUCK ahaha.

There were a lot of little modifications that needed to be done to fit the headers perfectly... luckily VAST's fabricator (the installation was done with their assistance) is an artist with his tools and got them in flawlessly.

Hopefully I'll have some videos up soon of the car running. I'll also have some thoughts on how well they are working soon, should be driving 900miles back to Massachusetts early tomorrow morning.

Know who is excited to (literally) hear the results?? This guy :)

**beemercer** · 10-20-2010 10:07 AM

Originally Posted by Gumby

^very cool! can't wait to hear what it sounds like compared to the B6/7 S4s with headers.

any larger pictures?

It's very similar since the headers are essentially the same (the A6 actually has less engine bay room horizontally, so there was a slight redesign.. same size primaries, same collectors though, same restrictive head exhaust ports :D). With the catback off it was brutally loud, but now with a custom x-pipe, some resonators and magnaflows it is surprisingly subdued. The tone with headers is much cleaner than the log manifolds since the airflow experiences less restriction and variance. It is quiet at idle, but deep, clean and loud under hard load... exactly what I like.

Also less drone on the highway.

And I have a ton of pictures on my camera, just got home from the 16 hour ride so it may be a little while.

Originally Posted by EinSchnellAudi

Know who is excited to (literally) hear the results?? This guy :)

I'll try to get a few flyby videos asap.

**Dan@JHM** · 10-20-2010 10:15 AM

Originally Posted by beemercer

**UPDATE**

Car started this morning right around 9:40AM. We need to finish up the work and get the car back together, but all seems well. I have to say, open headers are quite LOUD AS FUCK ahaha.

There were a lot of little modifications that needed to be done to fit the headers perfectly... luckily VAST's fabricator (the installation was done with their assistance) is an artist with his tools and got them in flawlessly.

Hopefully I'll have some videos up soon of the car running. I'll also have some thoughts on how well they are working soon, should be driving 900miles back to Massachusetts early tomorrow morning.

You mean JHM ;)

**beemercer** · 10-21-2010 11:00 AM

Originally Posted by Dan@JHM

You mean JHM ;)

Whoops my bad, I had been up since the day before when I typed that

**Pete_R** · 01-30-2011 09:04 AM

Hello.

Can anyone help me with my Audi S6 2000 Avant Tiptr. Engine code AQJ.
What is the difference between those catalysts.
4B3 254 500 X
4B3 254 550 X (AQJ)

and

4B3 254 500 CX
4B3 254 550 CX (ANK)

I was planning to replace my downpipe+cat with Milltek sport cats+DP.
but Milltek Cat and Downpipe assembly fits only 2001-2003 models with ANK engine

**redneck truck** · 01-30-2011 10:23 AM

Looks like nothing is different. Why didn't you create a new thread for your question?

**SpooldYou** · 01-31-2011 03:33 AM

JHM makes awesome products. Jay and Dan are great guys and straight up. Only thing im mad about is that I bought a 2.7t instead of a 4.2

**redneck truck** · 01-31-2011 04:48 AM

Good thing is, lots of guys still swear by the 2.7. I'm sure you could always sell yours when your envy reaches critical mass :-)

**SpooldYou** · 01-31-2011 06:07 PM

Good point. Only thing I hate about the b6 s4 there isn't any room.... at all. A6 4.2 shoulda been my first choice.

**beemercer** · 01-31-2011 06:10 PM

Damn, realized I haven't updated this in a while... lemme pull some pictures together

**A4edwin** · 02-05-2011 09:00 AM

Waiting^^^^

**beemercer** · 02-05-2011 01:10 PM

Well here's a writeup of the parts added from October..

Just thought I'd start a thread to post up some pictures and thoughts on my new JHM Headers. Also installed were Stern Street Density Motor Mounts and a JHM oil filter relocation kit.

Product Information:

JHM Longtube Headers:

Full 321 stainless steel, hand tig welded with laser cut flanges and merge collectors. Uses an equal length designed specifically tuned for the Audi 4.2L V8. V-banded intermediate pipes that can be ordered with high flow cats. Included are new exhaust manifold gaskets and new mounting hardware.

JHM Oil Filter Relocation Kit:

Because of the less than convenient location of the stock oil filter on the C5 4.2L V8's it was necessary to relocate it. This was achieved using an oil filter relocation kit readapted to the Audi 4.2L motor. Basically there are two manifolds, each with an inlet and outlet fitting. These manifolds were connected with rubber line (later kits will utilize steel braided line), allowing the oil filter (the filter is actually a Mustang filter, $4 each instead of $16 :D) to be mounted underneath the airbox and out of the way of the headers.

(Picture will be added later)

Stern Motor Mounts:

The standard B6/B7 S4 mounts fit perfectly. Included are resistors that plug into the wiring harness to eliminate any check engine lights.

Pictures:

Stock exhaust manifolds with custom piggie pipes. The precats were removed from the stock downpipes and HFC's placed downstream. It's clear the stock exhaust manifolds were designed with space considerations at the top of the list.

Both headers pre-installation. Notice the equal length design and long primary length designed to optimize low end torque production.

Passenger side header before installation. Notice the thick laser cut flanges and focus on gentle bend radii.

Detail on the passenger side header showing the oil filter relocation manifold and the busted up stock motor mounts. The motor mounts were replaced with stern mounts. The oil filter had to be relocated in order to gain sufficient header clearance.

Driver's side header wrapped. It is only necessary to wrap the headers slightly past the inner CV joint. Also it is recommended to wrap the headers on the car, I helped install a set of S4 headers and it can be difficult to get the nuts started with the wrap already on the headers.

Thoughts:

JHM Longtube Headers:

Just picking up the headers before installation you realize they are a great piece. The installation does require a a motor drop and a bit of custom work, so keep that in consideration. We had to shave down a bit of the driver's side transmission mount (a triangular piece that bolts onto the subframe and tranny. We also had to cut one of the hard coolant lines on the passenger side of the engine and splice in a piece of rubber hose. The retail header kits will include a premodified pieces that you can bolt on and then send back your core.

As far as the benefits I'll start with the lame ones first. Slight improvement in gas mileage; I drove 1000 miles from home to Detroit to get these installed and kept note of the miles/tank on each leg of the trip and noticed maybe a 7% gain in mileage (from about 450 miles per tank to 480 miles). Another nice benefit is the drone... it's a lot less noticeable. Now obviously a V8 with no cats and a less than stock catback is going to exhibit a bit of drone, but compared to my old catless downpipe/stock exhaust manifold S4 there is a lot less drone and just a generally cleaner, deeper exhaust note. As far as the power, it's definitely there. Down low the car pulls like a beast, basically once you hit 2.5k rpm the tuned length design comes into play and all the extra low end torque just starts killing it. The acceleration at 3k rpm with headers feels like how it used to feel at 5k rpm without headers. I suspect that the tune is holding the car back at the moment, especially up top, so once I get the tune worked I'll add some more thoughts.

JHM Oil Filter Relocation Kit:

Well this was more a means to an end than anything, but still it is a well designed product. I've provided some feedback on it to JHM, so expect a slightly revised setup. Could be a nice piece for guys even without headers so you can relocate the filter to a more convenient spot. Where I have mine mounted, I can unbolt the filter side manifold and pull the whole filter out from where the headlight is (remove the headlight), and uncrack the filter with it hanging out in front of the front bumper.

I believe next oil change I'll be replacing the rubber line with braided steel line and most likely adding an in-line oil cooler.

Stern Motor Mounts:

Great product, definitely recommended. I went with the street density, which, true to the name, are definitely great for a street car. I can not notice any vibration of harshness at idle and under light cruising, only during heavy load and hard deceleration (engine braking).

Despite the almost nil vibration, they do their job dampening the motor incredibly well. Because of the manual transmission swap on my car, there used to be horrid longitudinal engine movement.. pretty much every time I shifted above 4k rpm it felt like the motor was going to come out of the radiator. This was despite the 034 transmission mounts and Apikol rear differential mount. With the mounts installed there is still a degree of driveline movement, but its significantly improved.

Future Plans..?:

In the process of dismantling and removing the motor I noticed a few areas that are a definite 'needs improvement'.

The first piece to be reworked will be the stock inlet piping from the MAF housing to the throttle body. There is a hard plastic piece that has a pretty obvious constriction in it, which just amplifies the rather small diameter in general. The plan is to replace the piping and elbows all the way from the throttle body to the MAF housing with either aluminum tube and silicone couplers, or a single 4-ply silicone inlet pipe. Hopefully this should be complete within a few weeks.

Next is reworking the current tune. As of now my car is sitting with a slightly reworked European S6 tune, which primarily was intended to provide a steady idle with the S8 cams and manual swap and to pass California emissions. The tune is not a power tune, and is definitely holding the car back up top. I'll be logging the car on WOT pulls to see if the throttle plate is closing slightly (JHM's programmer, an A6 4.2 owner himself, suspects this). Hopefully with a stronger tune the top end pull will match the low end push.

Another area that could use some work is the stock snub mount, or front motor mount. Mine was actually torn straight through, and so I just removed it. I suspect it was torn because of the design... placing the dampening material for a mount normal to the movement

. I wonder if a stiffer material could actually provide some dampening, or if it'd be necessary to redesign the brackets? I have an idea for a modified bracket that I'll sketch out soon.

After that I'll be looking for a spare motor to have the heads ported and reworked and the bottom end built. Shown below are the untouched exhaust ports of the stock head. Based on some of the results with B6 S4 headwork (JHM is in the process of getting a spare head set ported for Jay's car), there could be some 30whp locked up in headwork when coupled with S8 cams (which essentially have the same lobes as the S4 chain timing cams) and the other supporting intake and exhaust modifications (headers, S8 IM, 2.5" X-pipe exhaust, inlet piping). The built bottom end will be a little ways off, but hopefully it'll be coupled with either a 200 shot, a 2.2L twin-screw, a big centripetal blower, or two snails mounted on top of the tranny... all projects in the works on S4 4.2's.

**jaycurn** · 02-05-2011 02:39 PM

Nice update Beemercer!! Keep us posted on your car!

**beemercer** · 02-05-2011 05:54 PM

^Thanks, for tonight I decided to go clean the engine bay and reroute a lot of wires that we kinda put in place hastily during the motor reinstallation.

I spent a good 1.5 hour cleaning up the passenger side valve cover (you can see the filth in one of the pictures). Thinking I'm gonna pull them off and polish them.. looked easy enough to get them off.

I'm also measuring out all the inlet pieces to get started on that project, hopefully ordering the silicone next week. I'm also considering making a fiberglass ramp piece to install in the lower bumper behind the foglight to feed some more air to the cone filter.

Oh and one more, I actually received the first revision of my tune a few months back. It needs some more work to work around the SAI readiness codes, but for now it's great. It's based on a European S6 box-code, which means it's natively a tune for a manual. I had JHM's software writer liven up the gas pedal a lot to aid in rev-match downshifting. It also definitely helped with some more power, the car is a lot stronger up top. I can swap the chips to get a before and after acceleration log comparison, but I first need to replace a main O2 sensor (tomorrow afternoon hopefully).

**redneck truck** · 02-05-2011 08:38 PM

I'd love to see the English translation of the throttle control table for our cars. I imagine it's more of a conversation between the throttle pedal, the engine computer, and the throttle body, where they jabber back and forth and decide whether they're going to heed your input or not.

**beemercer** · 02-05-2011 11:33 PM

So quick update on the tune, the SAI delete is possible.. so hopefully soon I'll have that added to the tune. Once the readiness codes get set properly for SAI I may look into block-off plates and removing all of that junk off the back of the motor, but I'm sure if that'd be worth it. Any thoughts from anyone who's done it before?

**redneck truck** · 02-06-2011 06:56 AM

I deleted my SAI months ago. Still haven't passed inspection, but my buddy working on the SAI delete, secondary O2 delete, TCM delete, 6MT throttle program has found a way to force readiness on all systems that are no longer operable. Engine bay is cleaner without SAI hoses, I JB welded the hole in the air box up, removed the kombivalves and had my buddy make me some block off plates. Simplified the vacuum lines when I removed the vacuum control valve - got a trouble code for that one that a resistor would probably fix, but I'd rather the computer know the system isn't working than think it is, at least for now.

I'll see if my buddy wants to make you some too, since I've got the valves off the car I can hand them to him and ask him to copy the flanges.

**redneck truck** · 02-06-2011 06:57 AM

Also, the back of the motor is a lot easier to work on without kombivalves in the way. When I go to replace my front o2 sensors they will be more accessible, and I had a much better time troubleshooting and fixing oil leaks back there. The Touareg motor has a rubber hose between the valves instead of a metal hard pipe, so that might make things easier for someone who wanted to retain the system, but I'd just as soon remove it.