Hi All

After getting a remap last year on my vRS TFSI, I have an intermittent problem with the boost pressure. Sometimes when I change gear, the boost pressure gets very low - see attached pic. I have tried several solutions together with the tuner, but the problem is not solved yet - I think we have tried 5-6 different remaps, but still with the same problem. The latest revision is based on a remapped Leon TFSI with same mods as mine, and apparently the remap shows no issues on the Leon, but it does on mine.

The problem can be provoked by rapid gear change and repressed by slow gear change. Sometimes I also get the problem randomly when changing to third/fourth to overtake, which is really annoying...

I have the newest revision diverter valve and there are no fault codes, so please help

BTW. When I use the standard map, there are no issues at all.

I really appreciate help on this

Thanks in advance

Edited 12 June, 201213 yr by saksager

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A quite big drop in pressure...

I was wondering if there is some sort of torque limiter eventhough mine is a manual gearbox? I have heard of similar issues with Golf GTI DSG. Anyone knows if I can see if there is a torque limiter with VCDS? Then I hould be able to detect if I "hit the roof".

Thanks

What stage is that map? Are you running an uprated Downpipe?

Hi. It's a complete Milltek, so I guess uprated? It's this downpipe: http://www.awesome-gti.co.uk/product.php?xProd=6043&xSec=306

It's a custom map, so i don't know which stage, but dyno shows 267hp with too little cooling, so I guess it is stage 2 - 2+ (does it sound right?) No HPFP, which would be required for stage 3 as far as I know...

Have you uprated the diverter valve??

The diverter valve is also from awesome and a OEM revision D (latest revision at least): http://www.awesome-gti.co.uk/product.php?xProd=13242&xSec=305

It makes pressure so it's not the DV.

Have you tried a map with less boost? You seem to be running a lot of boost which creates heat which the ECU senses and cuts the power, that's if you're not going into overboost which doesn't always throw a code. Have you got any more logs, block 118, 230, 031.

Are you running a forge blow off valve spacer by any chance?

Who's map is it?

I don't have a valve spacer. The map is from Landberg.dk - perhaps not known in UK

martziniuk -> can you look through the logs if I make them and tell me if something seems wrong? Would an S3-intercooler help if it is heat issues?

There is no torque limiter on the manual box. Your running a stage 2 equivalent map. I'd be surprised if you weren't getting fuel cuts running boost like that.

Post the logs up especially block 230.

Perfect. I'll make some runs and post it. I'll see if I can make it today, but at the latest tomorrow.

Thanks.

4th gear if possible.

I made the logs - 3rd and 4th gear logs.

Does it give indication to what is wrong?

Thanks in advance.

Octavia TFSI 4th gear 12062012.csv

Octavia TFSI 3rd gear 12062012.csv

Imo You're getting fuel cuts, there is a massive deviation in rail pressure in the 4th gear log (29bar!!), 3rd rail pressure is fine but in higher gears the engine needs more fuel so rail pressure drops. Is it bad in long pulls in 6th?

You're running too much boost IMO, you can either get your tuner to tone the map down or try a HPFP upgrade.

For what it's worth I never ran boost like that on stage 2+ and I had a proven 280bhp.

Edit. It's running a bit lean too, a richer mixture would help to keep things cool.

Actually I haven't noticed it in 6th gear, but 5th for sure. What boost pressure did you have in your stage 2+? Is my boost particularly bad in some rev range?

With regards to the HPFP fuel upgrade, are there other options than the APR, Autotech and KMD? Which one is sufficient if I don't want to change turbo?

On the 4th gear log from 2360rpm-3280rpm, thats where the rail pressure drops badly so if the map was toned down there it would be better. I would consider a deviation of 6 bar on requested rail pressure to actual rail pressure within spec.

Mine ran at 1.3 bar but tapered off. If you don't want to upgrade the pump tell your tuner and if he won't listen go elsewhere. APR are supposed to be the best pump as it's fully rebuilt and tested before being sent back, the others are in DIY kit form.

With regards to the pump, I haven't been able to find any before/after HPFP dyno graphs for a K03, but it seems as if it is a massive performance boost for most people, so perhaps I should consider at least the internals for the pump - I use the car every day, so the APR HPFP is really not an option :(

In case, there is a pump failure, what will happen? Not even the APR nor the OEM is bullet proof, but some suggest, the APR is the best, but will pump failure cause major damage or "just" the pump itselves? Do I need a new cam follower just to be sure the wear is at minimum?

Another thing in regards to the fuel pump... Since I think I'll stick with the K03-turbo, will I then stress the pump less than if I did a K04 conversion? My thinking is that while a lot of K04 converted engines do have the APR pump, I might be just fine with internals if I stress the pump less...

If you ran at 1.3 bars, did you then loose a lot of torque? Mine is around 420Nm or 308lb/ft and I really like it Do you by any chance have an old log of your car? - then I could take that with me to the tuner...

I am in constant dialog with the tuner, and they are also puzzled, but I think I'll ask them if they would consider lowering the boost pressure.

Last question... If I fit some sort of HPFP (rebuilt or internals), would I then require new map or is it plug and play?

The APR pump can be bought as a new unit but it's expensive. As you say no pump is bulletproof but I've not come across an APR failure yet. I would fit a new follower they're cheap enough. It's up to you what you do really but just keep an eye on the oil level to make sure it doesn't increase. You'll only gain about 10-15bhp with the fuel pump but the midrange pull will last longer. I spiked at 320lbft which leveled off to 290-300lbft but my car ran perfect

Pm me your email and I'll send you logs and a dyno tonight.

Well, 10-15hp is actually more than I hoped for Will I see the results directly after bolt-on or do i need a remap?

Also, is the fitting straight forward? Seems as if but there might be complications?

Edited 13 June, 201213 yr by saksager

I think it would help a lot with your current map but when they map for the uprated pump they up the pressure the pump works at, instead of 110bar max as in your logs it would be 130 bar. What year is your car? Some early ones come with a banjo connection which is a little bit harder but yeah fairly straight forward.

It's a 2006 model - I saw a guide somewhere and it seems doable in a reasonable time frame...

Sorry for the thread revival, but did you ever resolve this? Having a very, very similar issue myself.