Boost problems, few soloutions - thoughts on ideas required.

[DBP]

Hi all,

I recently went to a RR day and my car didn't get what I wanted. On the graph it showed a huge spike. JKM said it was the map. I went back to the mappers and they took a look and said nothing in the chart shows the graph I am getting they tried a different map but it is still there.

A few solutions discussed where...

New N75 valve

Yellow DV spring

New N75 race valve

removing all the n112/n279/SAI

What do you think on these solutions? Also what else should I try?

[rk696]

Does it have any surging or other problems? Reason I ask is that I had surging on my map, and it turned out that the N75 was sticking and causing an overboost/underboostcycle. Got a new one and it's perfect.

IMO, a ECS 'race' valve will just make the boost spike worse.

Edited 31 May, 2012 by rk696

[DBP]

Does it have any surging or other problems? Reason I ask is that I had surging on my map, and it turned out that the N75 was sticking and causing an overboost/underboostcycle. Got a new one and it's perfect.

IMO, a ECS 'race' valve will just make the boost spike worse.

Thats what I thought! I said that to him and he said a chap he done a remap for prior had a manual controlled one with a ball bearing in it? It has the surging now. Where did you get your valve from?

[Guest BigJase88]

Surging is a 1.8t problem on even the stock map which is highlighted from a remap with a tuner who's unfamiliar with the engines

I suggest you take it to r-tech

[rk696]

Jase is right. Some 1.8T's exhibit the surging from the factory, but some don't. It seems to be a bug in the ECU's software that a remap makes worse. By the look of it, it depends on the software and version of the ECU, which there are a lot of. Contrary to what people believe, not all 1.8T 180's have the same map and ECU. Have you only just mapped the car or has it had it for a while? Has the surging always been there?

The one with the ball bearing in is called a MBC (Manual boost controller). It lets you set the boost manually, but the ECU can have a hissy fit if it's not set up properly. The N75 is there so the ECU can control the wastegate, and therefore the boost pressure.

I got my valve from Sere Motors in ireland. It was about 40 quid posted. Part number is 058 906 283 E.

Edited 31 May, 2012 by rk696

[collyb]

im currnetly having this same problem,,after a remap to my 03 vrs octy...im finding the surging kicks in at 3000rpm and continues across to 5500-6000rpm,,almost like an on/off boost type feeling... i tried contacting the guy who remapped my car but he said he only gave a 7 day money back guarentee on his maps,,and this started happening to mine around ten days after the remap,,,he claimed he had remapped a 1.8turbo audi a4 the previous day and had no issues with it,,im wondering would it be my n75 valve also???

[rk696]

It could be an N75 problem. That's exactly the problem mine had. If the problem wasn't there when you had the map put on, I doubt it will be a mapping issue. Who did it out of interest?

Oh, and to everyone on this thread - The surging issue with the factory 1.8t map was at part throttle, not full throttle, I've just remembered. My car has spent hours on the dyno at Shark performance for them to solve the problem. They suggested a new N75 to fix the full throttle surging, and they were spot on with the diagnosis.

[collyb]

it was a local mobile mapper,,has quite a good rep here in ireland to be honest,,, when i had the map put on at first the problem deffo wasnt there as he left me test drive it for 30 min before i paid him and told him i was happy,,plus i would have surely noticed it...is there any way to test the n75 valve? i have a diagnostic tool but its a very basic one and shows no codes currently stored on the car

[rk696]

Not really without Vag-com. The N75 runs at high frequency and turns on and off a few times per second. As they get old, they slow down and the plunger inside sticks which causes the ECU to sense too much boost and over-compensate for it, causing the surging issue.

Try and find a local member who is willing to try their valve on your car, or just replace it anyway - At least you know it definitely isn't that causing the problem then.

[missingmyvrs]

Hi all,

I recently went to a RR day and my car didn't get what I wanted. On the graph it showed a huge spike. JKM said it was the map. I went back to the mappers and they took a look and said nothing in the chart shows the graph I am getting they tried a different map but it is still there.

A few solutions discussed where...

New N75 valve

Yellow DV spring

New N75 race valve

removing all the n112/n279/SAI

What do you think on these solutions? Also what else should I try?

if your mapper suggested a race n75 ( no such thing anyway) then you need to go somewhere else as he hasnt a clue!!!

surely said mapper would have diagnostic to check car for faults etc etc ??? if not again you need to go somewhere else !!!!

to many numptys getting into mapping that clearly havent got an idea about what there doing!!!

[DBP]

if your mapper suggested a race n75 ( no such thing anyway) then you need to go somewhere else as he hasnt a clue!!!

surely said mapper would have diagnostic to check car for faults etc etc ??? if not again you need to go somewhere else !!!!

to many numptys getting into mapping that clearly havent got an idea about what there doing!!!

This is what he meant

http://www.awesome-gti.co.uk/product.php?xProd=11033&xSec=294

Actually listed as "race"

As for going somwhere else .... I already spent my money ages ago I have had it on for a good 6 months?

For ages I did have a notch from where the turbo died off and the engine changed over but that hasn't ever bothered me. But when I was at JKM they rolling roaded it and said it was the map from the peaking shown on the graph.

So I have taken it back and they tried a map for a golf GTI running much bigger boost but turned it down for mine and now I get this bunny hopping feeling but only in 4/5 under full load.

TBH my car has had 155k on the clock so that N75 valve isn't going to last forever.

They guys who done mine are a large German specialist mainly BMW's.

[rk696]

My N75 was faulty at 49K and 8 years. At 155k, yours has done pretty well I think. Mine does have a slight surge as the turbo peaks, but it only does it once, then it's smooth to the redline. Before I got a new valve, it would be pulsating all the way to 6000RPM.

p.s. The ECS Race valve is supposedly a re-badged valve from the old Audi 5cyl engines. Think Audi Quattro etc. They were designed for a much larger turbo than the k03s, and as such, they recat too slowly, causing a boost spike as the turbo spools.

[DBP]

I bought a new N75 direct from Skoda at £47 and it sorted all my boost surging problems so now I am a happy camper! When I pulled it off there was a little bit of oil in it.

The only downside to the new valve is the fact the car doesn't feel as ferocious as it did before.

[HtecElite]

I've got Surging and it can be clearly seen on the graph the dyno prints out.

N75 from skoda is being replaced, im just trying to find out what variant i need.

Also going to do a smoke test to hunt down any boost leaks.

Edited 1 July, 2012 by HtecElite