Your guess appreciated: weak power off boost

[r1de]

Hi All,

A bit of background: '07 2.0T AT6 98k mi, APR 91, no other mods. Have had the cam follower fail twice and am on 3rd cam presently.*

Problem: it seems lately that if I'm driving fairly mellow, and gently begin to put my foot down (D not S), I get almost no responsiveness for many seconds - RPMs slowly increase and then *bam*, the boost kicks in and the engine starts putting out. If I drive harder and accelerate more rapidly, I get better responsiveness. I can't prove this is new behavior, but it sure seems like it; I don't recall this much sluggishness years past or especially following the stage 1 mod. I've had this car for all 7 of its years and it really feels like it's driving subtly more anemically than ever before.

There has been no CEL or other obvious signs/sounds/smells of trouble.

Having been down the cam follower road before (and reading the latest gory threads here), I'm kind of immediately suspecting it's totally blown apart and is the root of all problems I have and will ever have.**

Looking for other guesses or suspicions in the mean time before I have it checked out.

* I'm guessing that since I've had my cam already replaced under warranty due to the follower issue, any more work on that would be out of pocket.

** So I've seen the roller follower solution posted here in years past, and not sure what ever happened to that. I know it was fringe, $$, and pretty big commitment (new cam profile, etc). But what about just redesigning a HFPF itself to use a roller tip, eliminating the follower altogether? That must be crazy and infeasible since I've not seen anyone else suggest it, but just thinking there has got to be some more permanent set-it-and-forget-it fix for the 2.0T FSI, as opposed to just swapping followers every 10k.

[pat_do]

As a tiptronic owner also, I understand your concern.

Note that the TCU (transmission controller unit) adapts to your driving. Meaning, if you do drive fairly 'mellow' then, its shifting strategy will adapt to your style. As soon as you step on it, based on throttle input, angle of the throttle pedal, a mapping will be read and will input certain parameters to the TCU and ECU.

I doubt that it is your cam follower, hpfp or anything mechanical related to the engine head that's causing this. I believe it has to do with the TCU needing to be readapted from times to times.

Also check your diverter valve. I run the diaphragm style and love it; I feel that it is much better than the piston type.

Hope this helps!

Pat

P.S Don't forget, the 2.0T is still a FI engine...when not in boost, it is slow. This is a fact. As a matter of fact, I suggest your buy a boost gauge as it is will provide you with a better indicator of how healthy your engine is.

[jimrobbington]

[IMG][/IMG]Also check your diverter valve. I run the diaphragm style and love it; I feel that it is much better than the piston type.

Better? No. More responsive, yes. But you will always be wondering, "is my dv torn?". Not worth it. Get the dv+, best of both worlds.

[pat_do]

Better? No. More responsive, yes. But you will always be wondering, "is my dv torn?". Not worth it. Get the dv+, best of both worlds.

I'm warming up to the idea. Tks Jim

[allstock]

Also check your diverter valve. I run the diaphragm style and love it; I feel that it is much better than the piston type.

Better? No. More responsive, yes.

Just ordered the piston, now I'm wondering how true is this?

[jimrobbington]

I noticed quite a nice little difference in performance when going back to a diaphragm dv. It is strange that such a part can actually change how the car feels. Obviously it doesn't add power, but the car is quicker to respond to pedal input and quicker to recover boost when letting off the gas and getting back on it.

I noticed an even slighter boost in performance when going from diaphragm to dv+.

[jimrobbington]

You can read my whole thread about my results running all 3 different DVs and quasi- review of each one here if you have nothing better to do.

http://www.audizine.com/forum/showth...rmation-Thread

[allstock]

Very well done write up Jim. I originally planned on ordering the diaphragm rev. with the ideal that it was what the motor was meant to run with, so stick to it. During the call w/ecs I made a last minute decision to go against my gut and go piston. Called them back to cancel - too late - now I have both coming. Anyone in the greater Chicago area want a piston dv??

Jim, the DV+ didn't have clearance issues during the install did it? Totally ECU friendly, no codes thrown? They should give you a free t-shirt for the promotion of their product.

Btw, I attempted a practice run on your wastegate actuator shortening procedure and now know you weren't exaggerating when you said it was tight. As I got a few fingers and thumb around it I couldn't even make a fist. No joy.

[vce1232000]

Had the DV+ nearly 2 years and holding strong.

Here's someone selling a new kit. Not mine

http://forums.vwvortex.com/showthrea...IB-125-Shipped