Joey's Totally Predictable DD

[.RJ]

Its something unique to the V8 in the B7 S4 - because the timing chain was moved to the back of the motor, because otherwise it wouldnt fit in the engine bay - and cant be serviced with the engine in the car.

[SlimKlim]

Ah right, I thought you were talking about the 4-banger. Given the power you can make with a K04 swap is more or less the power you get from that V8 I think I'd go that route instead. Considerably cheaper insurance and gas bills too.

[SlimKlim]

I got my little android phone gauge set back up in anticipation of the tune. Unfortunately the ECU in the MKV doesn't let you read nearly as many parameters as the MKVIs, I can't get oil temp, pressure or exhaust gas temps, all I can get is coolant/intake temp.

I can use it to estimate hp/tq and catch 40-60 and 60-80 times, which will be really interesting to see the before/afters. Right now my 40-60 time is 3.1s and the best guess at whp/wtq is 164/174, assuming the car+me+gas weighs 3300lbs. I'd like to make it read the numbers at the flywheel but I don't understand math well enough. Maybe If I try setting the vehicle weight to 0? I dunno, I can mess around with it this week, but even if I can't get it accurate I can always figure out the percentage it improved after the tune.

[SlimKlim]

Tune installed. Sweet baby-makin' Jesus a little boost makes a lot of difference. hock:

The initial throttle response does feel a little sharper, but you do get more of the "elastic throttle" sensation because it takes a couple seconds for it to sweep all the way up to ~18psi. It will happily convert your tires into smoke in 1st and 2nd gear if you turn traction control off, but it's not as bad as I imagined, pretty much the same as when it was stock, if you want to keep traction you need to short shift and roll onto it gently in 2nd.

The RPM range feels much more linear now and it doesn't choke down quite so much at high RPMs but ~3k is still its happy torque zone. The only reliable data I was able to capture before and after is a 40-60 trap time of 3.1s stock and 2.4s after the tune. Maybe even more impressively, it'll do it in 2.7s staying in 3rd gear. It's definitely a little slingshot now. :thumbup:

EDIT: I do need to bleed my brakes rather badly now. I have a can of ATE sitting around but I haven't had time to get it in the car. All the extra go made me realize how badly I need some more slow. hock:

[RawrImAMonster]

Hell yeah, tunes make such a big difference in turbo'd cars. Such a nice feeling when you first get on the throttle with all the extra power.

[WRXtranceformed]

You guys are making me want to pull the trigger on a tuneeeeeeee

[SlimKlim]

Both of you guys are operating on an entirely different playing field than I am.

Getting over ~250ft-lbs feels like warp drive for me, and that's like what, half of Lee's stock power?

[SlimKlim]

Well the tune roasted an ignition coil. Started stuttering hard under heavy load. Some diagnostic work with my handy little bluetooth scanner and $20 at Advance and she's right as rain again.

...except I think the diverter valve might be on it's way out. WOT upshifts from 3rd gear don't feel as fast as they should be but I don't think it's the transmission because it isn't harsh or clunky, it slips into gear fine but then seems to take its time building up boost, and I'm also occasionally hearing a turkey call sound when shifting or letting off the throttle after going WOT.

I'll keep driving it before I order any parts to see if I can better identify the problem but if it does turn out to be the DV I'm not sure if I want to get the Forge or do an OEM replacement. The Forge kit relocates it higher in the engine bay, presumably for more sweet wooshy noises, and it's allegedly more durable than the OEM one. However given that I'm only stage 1, an OEM replacement will probably last until well after I sell the car, so maybe I'll save the money. :dunno:

[davej]

i might have the stock DV's from the S4 in a box somewhere, they were working fine, but i swapped them for 710N's when i got my tune. you're welcome to them if you want to try one out.

edit: nevermind, not the same part at all. good for the 2.7 or 1.8, in case anyone else can use them.

[SlimKlim]

Thanks, no worries. I did some reading and I don't think my car has the latest OEM style DV. In '10-'11 they went to a piston style that allegedly performs much better. That's only $60, and as far as I can tell the Forge DV is just an over-engineered option that will hold crazy amounts of power and it relocates it to be much louder in the cabin.

[youtube]2EdDflM5Osk[/youtube]

Seems like it would actually be kind of obnoxious, not worth the money for my purposes. I gotta take the long way home and get on the highway so I can do some pulls and see if I notice boost leaking. It's pretty tough to test issues like this when your commute is all 35mph roads and you need to be a full chuff in 3rd to create the symptoms.

If I can't convince myself it's the DV I can always lift up the passenger corner, rip out the wheel liner and pull out the existing DV to inspect it for tears. Sounds like it only takes a few minutes to do.

[RawrImAMonster]

I doubt it would be that bad. My Active Autowerke BOV is venting to the atmosphere and is pretty loud with the windows down. With the windows up, you can't really even hear it.

[SlimKlim]

Huh, maybe they have a mic in the engine bay for that clip or something. Still, it's $140 more and the upgraded OEM style one should last indefinitely if the one I have does turn out to be bad. I've found some threads where people have symptoms like me, and are, like me, wondering if their DV is bad, but the people replying say that if the DV is out you probably won't hold more than 5-8lbs of boost at all. I haven't found anyone that had just my symptoms and resolved them with a new DV. Hopefully getting some more seat time in will make it easier to figure out.

[SlimKlim]

Ok I came home over lunch to liberate the puppy from her kennel and took a route that allowed for some hoonage. It consistently spikes to right under 20lbs and holds 16-18 consistently. However, on WOT upshifts I hear a fluttering sound, the boost drops to maybe 10psi and takes a couple seconds to scroll back up. Once or twice it felt a little uneven, like a slight surge in boost, dropping a little bit and then climbing again, but most of the time it's just shift-drop to 10lbs-fluttery noise and scrolling back up to full boost in a couple seconds.

Initial googling says the fluttering sound is normal. I can't tell if I'm just being a paranoid new parent and it just takes the turbo a little bit longer to reach it's new maximum boost, or if something is actually acting up. :dunno:

[SlimKlim]

Ran it by my friend who installed the tune and got some internet feedback and decided to just replace the DV with the updated piston style. I definitely don't have the symptoms of a fully shot DV, but something doesn't seem quite right, the fluttering sound right after an upshift seems to be the giveaway.

So anyway, ordered for $60, will be installed as soon as it shows up and hopefully it will scroll up to full boost faster and maintain it better during shifts.

[Mike]

This has escalated quickly... GL with that!

[Ken]

Ok I came home over lunch to liberate the puppy from her kennel and took a route that allowed for some hoonage. It consistently spikes to right under 20lbs and holds 16-18 consistently. However, on WOT upshifts I hear a fluttering sound, the boost drops to maybe 10psi and takes a couple seconds to scroll back up. Once or twice it felt a little uneven, like a slight surge in boost, dropping a little bit and then climbing again, but most of the time it's just shift-drop to 10lbs-fluttery noise and scrolling back up to full boost in a couple seconds.

Initial googling says the fluttering sound is normal. I can't tell if I'm just being a paranoid new parent and it just takes the turbo a little bit longer to reach it's new maximum boost, or if something is actually acting up. :dunno:

Yeah, can't say that I've experienced that.

I'll use this as an excuse to test mine at WOT however to compare.

[SlimKlim]

Yeah actually that would be nice. Pop off a few WOT upshifts for me and report back. I'm not getting the "DSG fart" right now because the boost drops off so much, that's got to be the problem. Do you have a boost gauge? If so let met know roughly how long it takes to sweep to full boost after pinning the throttle too, I'm not really sure what I should expect considering this is my first turbo car and it's only just now *really* using that little turbo.

I don't really know how the DV works, but I'm theorizing that it's still fully opening or closing or whatever it's supposed to do to allow it to hold boost, but it's sticky or something is torn causing it to do it much more slowly than it's supposed to.

[Ken]

So I definitely get that little pop/fart in between shifts when at WOT. Unfortunately I don't have a boost gauge so I can't definitively tell you what the boost is doing but it feels normal when compared to the Evo; definitely a lag but nothing out of this world.

DV sounds like it could definitely be the culprit from my limited turbo knowledge.

[SlimKlim]

Yeah sounds like it. I'm also getting a chirping/barking sound every once in a while when I let off the throttle after hitting full boost. I assume that shouldn't happen. At any rate the updated style one will be here tomorrow, I'll install it Friday or Saturday along with all the other little maintenance items that are due on it.

[JustinG]

The flutter sounds should be your wastegate opening/closing rapidly to regulate boost though. So the wastegate may be sticking open causing the sudden drop in boost?