Scott Jordan

I just got a Fabspeed tune, and the turbo now seems limited to .4, causing the car not to drive nearly as well as before. I drove about an hour or so before taking this video, but the car was not hot at all. Later in the day it worked fine. Any ideas?


https://youtube.com/watch?v=3eUD0Qu4Igo&feature=share&si=EMSIkaIECMiOmarE6JChQQ

TomF

Something is clearly wrong. With my Softronic tune the guage pegs out very quicky when flooring it with the PSM off and the sport button engaged. I would check with Fabspeed on this.

Petza914

Saw your Facebook post and commented. Thinking you need better Diverter Valves to support the higher boost the tune is commanding. I have the EVOMS Billet versions but there are other choices like Forge, etc and some have different spring rates that come with them so you can experiment with what provides the best performance.

My 09 TTS with Fabspeed stage 2 tune pegs the boost needle about immediately and my aux boost gauge shows I'm getting 50% more boost than before the tune, so about 1.2 bar.

Scott Jordan

Thanks, yea something is clearly wrong. this is when i first picked up the car. see time stamp 3:30; something is clearly throttling the turbo

Crozzer

Did they have you replace the o2 and MAFs prior to applying the tune?

Scott Jordan

no. were we supposed to? No instructions to do so

957austin

From your video, this doesn't look like a boost leak or bad diverters. As you point out, the car is not even redlining when given full throttle. Unless you have a CEL and the car is in some kind of limp mode, I would say this is a bad tune, or it didn't take properly.

Scott Jordan

So, what I don't understand is whether the tune for my car is any different from the tune for any other 955 Turbo S? Why would it be? Fabspeed has sent several files and now again a new one coming soon, but why wouldn't the tune be effectively the same. My car is stock, other than muffler, which they told me self adjusts on the tune. Makes no sense to me.
They didn't give me anything to do or check when installing the tune.

Scott Jordan

I got the new file, but not sure how it will be different.. I sent this to Fabspeed:


Ok. Before I go to the trouble of doing this, can you answer inline:

• how does this tune differ from the 2 other tunes you have provided?
• is this tune somehow custom to my particular vehicle? Other than exhaust, there are no mods on my car, and you said that the exhaust doesn't require any changes to the tune as it will learn?
• do we need to address any of the other issues mentioned in the forums? Seems that there are some valid concerns here?
• Can I do this myself, or do I need to bring to my shop, again... third time btw.
• curious why you had no interest in getting a download of what is happening on my car to tune this properly

Sorry for all the questions, but candidly concerned we have an approach that is logical as it seems we are just guessing here.
Thanks.
Please respond inline.

theprf

Put the stock tune back to verify that everything is OK? That's what I would do.

Crozzer

I have heard that recommendation from a few. Not mandatory obviously, but supposedly good preventative even if no codes. O2 in particular. I plan to just clean my MAFs.

Scott Jordan

Well, Fabspeed answered me basically saying: here's a new file; give it a try. we hope if is better. if not, we will continue to tune a forth time.
I really don't understand how their standard tune for a 955 turbo s wouldn't work on my car.
----

Apologies, our intention is not to make any of our clients feel as though they are being guinea pigged.


This is a new problem for us so please bear with us. The tune should have corrected the previous issues.

If you add in the divertors then the previous tune should hold, but where the car stands the revised tune should still have more output without any over boosting/ causing the shuddering.

Jfrahm

I would look for a boost leak. I believe another test is to disconnect the airlines to the wastegates, then on wastegate spring pressure you should get 0.8 with any tune, just on wastegate spring pressure?
Behavior looks to me like a loose clamp or cracked tube or connector that is opening up under pressure.

Crozzer

this is a good guess, but I think our system might work differently. Maybe the tune raised boost, which subsequently caused something to come loose under the increased boost, so now you can’t make full boost.

However, wastegate and diverter circuits are different and serve related but different purposes.

Additionally, our diverter valves require positive pressure to hold boost, which is delivered via the cycle valve coming off the intake through the control lines to the the diverter valves.

Ambient, or just the spring, does not work. If you have ambient (no extra) pressure in this control line circuit (like say it is disconnected, or a check valve is installed backwards…), then you basically recycle most of the boost and can make about .4 bar on an otherwise healthy vehicle.

a smoke test might help find anything that is open at ambient pressure. A visual inspection of charge circuits might find things blown open at boost by the inevitable oil spray left behind. (Like the notorious driver side charge seal by the diverter valve.) Could be n75 and wastegates. Could be cycle valve and the diverter circuit.

you might find a read through this thread helps sort out some diagnostics. I doubt your issue is the check valve like mine ended up being, but still some decent diagnosis in there.
Turbo Owners - what level boost does your gauge read? Subscribed Search this Thread

good luck and yes this forum has some really helpful folks. Let us know how it is going!