My S6 work in progress with dyno figs and pics

[JP]

I normally try to stay away from too much forum banter and draw my own conclusions from experience. But on this occasion I'd thought I should share my experiences as I found the following findings incredibly informative especially as I did a dyno pull as an impromptu got nothing to do on a sat afternoon thing. Infact I found the results so intriguing that I thought it be nice to post up for others to learn from.

First of I'm running an AAN 1996 S6 that I bought earlier this year. It had a complete service history except one worrying thing that was the cambelt change 2 months prior to my purchase which was done by a tire and exhaust place.





So I figured lets play safe do a headgasket change the lower front pulley and give the car a once over at Quattronics as after previous dealings I felt most comfy with the car there. I'm glad I did as the tire exhaust place had used an impact driver on the front pulley and partially cracked the keyway. On a whim I figured might aswell give the head a refresh and went for a nice recon job which I guess could be considered as a stage 1 head if you had to label it involving some swirl polished/back cut valves, bowl work and seat work. Wouldn't really classify it as a ported head but flow figures backed up to have approx a 10% gain across the flow range on intake and exhaust. Coupled with a 7A exhaust cam.

Stripped ready for the refreshed head clamped with ARP's


Well impressed with the honing marks still being there after 163K miles and no lip on the bores


The valves


Refreshed head with new tapered guides, viton stem seals and ofcourse the valves.


Head back on with 7A exhaust cam fitted


On recommendation I also went for a Bilstein B8 and H&R lowering combo, which Corey set up to my driving style on his alignment equipment. Giving me some extra camber on the back to make a tad more responsive for cornering the tank. Almost forgot there was a quickshift kit sneaked into there just to make sure I got proper use of the close ratio 6 speed box

pretty much how the car now sits lowered with a light tint

[JP]

On the long run I'm looking for possibly a slightly bigger turbo and remap to suit so innevitably the exhaust had to be done aswell which was carried out the other week which I was well happy with being a 3" system made up totally custom using a sports cat and two box's. My request was that it could be as straight as posible and I don't think they could've achieved better. As it's pretty much a straight pipe for most of the car. Which I have to say sounds the nuts I also have to say I felt a bit bad as they promised drive in drive out not realising that my request was so far from their jig setup that I didn't leave till well into the early hours of the morning so a thumbs up on customer service on that one.







I decided whilst the car was up in the air to do an oil change aswell as it smelt a bit fuelly. Corey suggested getting the injectors cleaned as they had a 170K miles on them and may have irregular spray pattern causing a rich run on one of the cylinders. So I went to check these on sat morning on an ASNU injector cleaner and sure enough 2 injectors had a bit of a sharp spray instead of a nice fan. A quick flow test before and after cleaning not only showed the improved spray pattern but also a 15% gain in flow which I was well chuffed about. That means your injectors are theoretically loosing 1% of flow every 10K miles so worth thinking about on these motors that are clocking up the years and miles.

So having sorted the injectors on saturday morning I decided to go for a good old drive for a couple of hours to let the ECU settle itself enjoying an array of motorway and countryside around the south Beds area. With the missus and kids out for the day and evening I made a couple of impromptu calls and booked myself in for a rolling road session that afternoon. As I figured it would be nice to have a before and after for when I finally bit the bullet and chose my final route and went for the remap.

So the car was strapped down to a 4WD Dyno Dynamics set up. All the tire pressures checked for 40psi (factory is 44 but I feel it doesn't drive nice that way as I like a bit of squeel on the sidewall before it lets go).

This is the bit that shocked me as I knew the ECU had some scope for relearning but other than the small spike in the powergraph when the car skipped a little as it came on full boost the tq and hp was well smooth to the extend the operator commented on how smooth it pulled. Not only that the AFR ratio's we're hitting perfectly between 12:1 and 13:1 on full boost with as smooth a curve as the power.

Now I wasn't actually expecting any gains, if anything a slightly irregular fueling curve due to the changes to the motor as it has not been remapped and is running standard boost and intercooler setup. The power run was literally to get a baseline before further mods. Basically the engine's done 170K miles only had 10% flow gain from the head (a proper ported job sees 25%+ gains) a 7A cam and 3" exhaust system which if anything was going to bring it back to what factory spec states. Admittendly each change you could feel an improvement in throttle response and the way it pulled through the gears. Well as you can see it made 33hp over standard at the flywheel.





Obviously the information I found interesting was the fact that a correctly modified head does make a difference on a turbo'd car and I sort of wish I'd gone the whole way with it now as I'm curious to what the engine is actually capable of on a standard turbo with a remap. What I actually found most interesting is that the ECU was capable of relearning to such an increase within it's standard parameters without a remap

[Jamo]

What turbo is on the car? you figures look far up the rev range to be a K24 and you have a boost spike on the run although re-reading you have a 7A cam.

I'd take the 7A cam out for a stock turbo but that's my preference.

Nice car now what you really need is a nice homefry chip to push you closer to 290 bhp :mischeif:

[JP]

Still the standard K24 turbo on the car. I also have the old cam still so I can always change back if desired. Still deciding whether to actually go the full hog and stick some rods in with a better head and a K26/27 hybrid or stay sensible.
At the moment the clutch is slipping on it under load so when changing that over instead of dropping the box I may go the other route and remove the engine and change the head for a full blown one and do the rods. Although the labour costs involved in that I would be tempted to rent a car for a couple of days and do a driveway job when the weather picks up.

[twoqu]

The turbo looks like its a K26. The K24 has the info tag on the backplate not the compressor housing. A red tag indicates that it is a factory exchange item. If you can read the numbers, post them to aid identification.

[JP]

Ah I know what that might be I had an old K26 on the shelf of my Audi 200 that we originally fitted at the same time to it but on start up we discovered the seals had gone and it was burning oil big time so we reverted back to the original K24 which came on the car. Totally forgot about that as it was back in April/May when those where taken. The pic showing the turbo will be from before it was started up the first time. Obviously it needing a rebuild is why I was contemplating the K26/27 option having a partial core on the shelf.

Just pulled out the mobile phone camera, have to say learned something new about the tags on turbo's today.

[Acidburn]

Nice results and glad you put up the thread as it was well wrote out etc, and I enjoyed reading it and hearing what you had done.

Just wondering was that a OJZ exhaust system? Looks like it and the workmanship is spot on.

[JP]

^^^^ thankyou. The exhaust was fabricated from scratch using 3" pipe, prebend mandrel sections and magnaflow box's by quattronics. When they said it was drive in drive out I was a bit shocked to see that they were using a TIG for welding. (probably why it went a tad into overtime)

[Acidburn]

Good to see they stayed on and took the time to sort it out properly, looks a nice bit of kit, what do you think of the noise? and from what I can see its a twin box system. Had any flames out yet

[JP]

I chose a twin box system as I've driven single box's before and feel it's too uncivilised for the type of car. Even now you'll get some people trying to figure out where the rumble is coming from as the S6 is such an unlikely candidate to the untrained.

At idle there is a lovely burble quite discreet, from 1500-2200rpm it's almost silent then the rumble starts coming back, by the time you get to 3300-3500rpm it goes into a full blown rasp when you floor it. As a guideline it sounds something like the attached clip. Although the sound is a battle with the massive Dastek fan they had (apparently hits 100mph+ wind speeds) and the fact the mic seams to be overloading slightly.

[Acidburn]

nice video and sounds like most RR vid's i've seen.

What I might try is to get it so I get a twin box system with one box removable so if its too much I can put a second box back in.

[UrS4boy]

Two things:

1. You are putting too much on that valve job. No way you gained 33 hp on just head work. Not even with the 7A cam.

2. Check your passenger side carpet at the tunnel to see if it's been cut (up high, under the dash). I really suspect that you car has been chipped, e.g. Stage 1, 2.5 Bar MAP.

Not meant to bash, just to point out some potential errors in your assumptions.

(I could be wrong).

[JP]

^^^ one of the reasons I made this post is specifically because I found the findings very interesting myself. The car runs a perfect 2.1 on the electronic dash gauge and the passenger footwell carpet is untouched, so the ECU underneath remains untouched aswell.

[EspenW]

Dyno Dynamics dynos are known as heart breakers, that is, they produce low power figures compared to other dynos like the Dynojets, etc.
However, flywheel figures generated from a rolling road will always be a guesstimate at best. How much power was actually measured (at the wheels)?

[JP]

I haven't got a printout showing wheel power, but will give the guys a call tomorrow to see if they have got them saved on file. I know that the first pull they did the car climbed on the rollers big time and pulled an eratic 290, they strapped her down harder and reduced it to a still erratic 281 after which they threw on another strap which finally stopped it lifting at the back and did 2 back to back runs both with smooth curves one of 263.1 and one of 262.9.