stage 1 unicorn developments - TT 2.0 tfsi

Mr Grey

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Afternoon all...

I am new to the forum and this being my very first post

I have recently had my car remapped with Unicorn Developments in Stockport, friendly staff and what appeared to be a good service and positive reviews.

However at the end of the power runs and mapping process I was told that the cars diverter valve would need replacing as I wasn't gaining the full amount of boost I needed to get to.

The results on paper looked good though, my car is a 57 plate 2.0 tfsi TT and the only modification is a Miltek Quad exhaust set up (not all the way through to the down pipe though) which was added by the previous owner.

On my initial power runs I was told the car is running above the stock power of 200bhp and was at 223bhp due to the exhaust.
After the Map was added it came out at 248 bhp and torque from 230nm to 290nm ...but it was marked up on my print out as - boost leak diverter valve.

The owner Rick said he would help me get the diverter valve changed for a reasonable fee, and also mentioned to add 99 ron fuel as on the day of the map I had unfortunately had to use 95ron Tesco fuel as they was out of stock on the 99ron....I was told that my fuel timing was off because of this and to just go back to the 99 gear and it would sort itself out?
fast forward a couple of weeks now and I had called a few times and spoke to lady on reception at Unicorn to get my car back in for the DV to be fitted to fix the small issue.. after 4 separate calls and promises of calls back I heard nothing :(
So I decided to have the DV replaced elsewhere, I took it to a VAG specialist in Manchester and I got a call back on the day of fitting to say my DV was in perfect working order? not tears or damage to the spring or diaphragm and they said it looks like new, I asked them to go ahead and change it anyway for peace of mind with exactly the same revision model they had just taken out.
So I am still left with a problem on the car not getting to optimum boost requirements for the map I think and down a few quid on a job that didn't need doing sadly.

On driving the car it doesn't feel that noticeably different from before really.
Does anyone know where I go from here to solve this issue, I spoke to a place called Awesome GTI who were very helpful but they talked me through what they do on there map process and checks involved prior to adding a map and logging that is done to identify any small problems so they can be fixed on the day prior to a map being and to ensure the problem is correctly diagnosed which sounds good but to late now I have already had it done and left scratching my head on what's required putting right. I am hoping someone with more knowledge than me on boost issues could help?

I was going to call Unicorn back but after several attempts and speaking to them they have yet to call me back so kind of given up on that one :(


many thanks in advance for any advice and input.
 

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Hello Mr Grey,

Chloe sent you a quote at the beginning of last week after we returned from our week of being closed to fit the DV and replace the faulty thermostat.

Thermostat is quite a bit more than the DV fitting as it involves the removal of quite a few parts.

The car is currently performing well below par as it isn't able to make the boost it should be. It's like me asking you to blow up a balloon with a hole in it - not easy!

Your car was logged on the Dyno before tuning, the issue is that a small leak from the DV will often not show itself when the car is not mapped, as its not making as much boost and therefore will not leak!

Now if you have had the DV replaced and it is still not boosting as it should, then there are two possibilities.

1. - the turbo is not making the boost in the first place - possibly due to a week actuator, or the wastegate is not sealing.

2. - the turbo is making the boost but it is leaking out somewhere other than the DV - for example a faulty pipe, loose hose, split intercooler etc.

These cases are both much much rarer and more complicated and expensive solve than a faulty DV, so we always recommend replacing this first, even if you don't think it is at fault.

Thanks, Rick
 
Hi Rick,

Thanks for the reply, i have checked back through my emails and text messages and have definitely not received a quote through, checked my spam also?
I have had both the diverter valve and thermostat replaced now and cannot notice any differnece.
If i am being completly honest it felt good on the drive home and a little faster but not blown away as so many people rave about after a remap. . a few days on and it somehow feels like the map is no longer on the car and its back standard?
I am not very technical when it comes to all this and know enough just to scrape by.. possibly like others who own sports cars.
I am willingh to fix what needs fixing but dont want to start fixing lots of things that dont need fixing, are you able to help with a diagnosis of the problem? I would pay an hours dyno time or something and maybe with your data logging and expertise we could shed some light on where the problem lies? Just extremely unhappy to have been have spent a lot of money on a map that everyone raves so much about only to find the car feels no different ..
 
I'll see where the quote went but i guess it doesn't matter now!

I'm happy to put you on the Dyno but there really isn't much point. I am looking at your log as I type, and I can see that the boost that the ECU is requesting isn't being made. So, the car is being asked to do something but it isn't able to manage it.

The reason(s) why this is happening are covered in points 1 and 2 in the post above. It's a mechanical issue, and no amount of fiddling of the ECU is going to help.

The first thing to do is to check for leaks in the intake system, and if that doesn't fix it then you start having to look at the actuator and then turbo. It could be any one of these things, and you have to work through them systematically starting with the easiest/cheapest first. Unfortunately it's impossible to say this is the cause of the fault (low boost) and it's going to cost this much to fix.

You say that the car felt better but no doesn't seem to. That could well be that the fault is getting worse - which isn't actually a bad thing as it makes the cause easier to find.

You could leave the car with is for a morning and we could spend a couple of hours going over it to see if something can be spotted and fixed.

Rick
 
Thanks Rick, i would greatly appreciate this if i could drop it off with you to see if you can spot anything,.. again many thanks i can drop it with you tomorrow morning if thats ok?
 
Ok great, i will see you wednesday, thanks for the swift reply and have a pleasant evening.
 
Whoops that was a quality repair by somebody, hopefully the car is making a good deal more power than it was before.