Help needed...

[OllieH]

Hi folks, as per the title, abit of help is needed. With respect to my previous post http://www.audi-sport.net/vb/showthread.php?92297-Help-Boost-problem!&highlight= with a slow spool problem, I took my car to AMD Technik in Thurrock as I needed to get my geometry checked, so thought I'd kill two birds with one stone. They hooked it up to a laptop and took it for a spin and come back saying they couldn't find anything wrong with it. Now I'm questioning myself as to whether there is something wrong or not. I'm pretty sure before my coilpack problem my car used to make full boost at 2.5k revs, but now it's at 3k+ revs. This problem is starting to do my head in

Anyway, got home and had an idea. Looking at the specs of a completely standard S3 http://www.carfolio.com/specifications/models/car/?car=95502 it says the standard car makes 207 ftlbs from 2200-5500 rpm. So logged group 120 on vagcom and produced the hp/ftlb graph below:

Now, looking at the above graph, I'm not making 207 ftlbs till about 2600 revs! (400 revs later than oem) I have a custom code stage 1 map on the car so obviously my peak torque is going to be higher, but I should still be making 207 at the same revs shouldn't I?? I also logged requested vs actual boost to produce the following graph:

As you can see I'm not making full boost till 3,500 revs, so I'm actually only getting a small window of power.

The help I need is for someone, preferably who has a stage 1 custom code map (but I suppose any will do) to log group 120 and 115 for me on your car so I can produce some graphs from your data and compare to mine. Also anyones contribution to this as to whether its all in my head or not would be great. I really need to get this sorted now as my car just feels so slow at the moment it makes me feel like I don't want it anymore.

Bryzan A4 suggested on my last thread that it could be the wastegate not sealing properly, causing the slow spool. Has anyone experienced this before?

Cheers in advance :icon_thumright:

 

[rossbrownlee]

I have a 2000 APY with K04 turbo on. I have done some logging and graphs. PM me your email and i'll send the excel.

 

[OllieH]

Anyone else? Have just had a look at rossbrownlee's graphs for a standard car and it's not all that much different. Mine does lag behind his abit with regards to requested and actual boost. Anyone with a custom code stage 1 map??

 

[rossbrownlee]

mine is apparently mapped as well although this was two owners ago. I also need to do a couple more runs as have fixed a couple of boost leaks since then.

 

[OllieH]

Yeah you may be right. Just had another look at your airflow and it's around 190, which is 237 HP. My logs were recently showing 190 g/s aswell, until I changed the MAF a couple of weeks ago and it shot upto 200 g/s.

 

[S3 Nattie]

My graph was similar, requested boost used to take a while to get up to pressure.

Changed my N75 to a J and the requested v actual are near enough the same now.

Making the boost as soon as its requested. Maybe something to look in to

 

[rossbrownlee]

yeah was thinking about my maf but it is only about a year old since a recon from audi. was thinking about trying a clean first then see from there. most posters reckon over 200g/s for a mapped S3.
at the moment i'm more worried about the nuclear heat coming from under the bonnet and also about the turbo, much like yourself, it's slooow to spool up.

 

[rossbrownlee]

Changed my N75 to a J

You got a part number for that?

 

[OllieH]

Yeah, bought some circuit board alcohol spray to clean mine but made no difference, so in the end had to bite the bullet and buy a new one. As far as I knew though the MAF hadn't been changed for years. Would have thought yours would be ok if only a year old.

The problem with changing the N75 valve is that if there is a problem, you're not actually fixing it, but just masking it with a valve that asks for more boost than the ecu is requesting.

Just thinking about the N75, if I bypass it and connect a hose straight from the charge pipe to the actuator, I'll be able to see when the turbo spools up with just the actuator boost setting (6 psi?).

 

[S3 Nattie]

Your problem seems related to the actuator or possibly your map.

I would look at your N75 and possibly looking if you have the correct pre load on the actuator.

 

[OllieH]

I tried a working N75 from 1animal1 about a month ago and was still the same. Was thinking about the actuator. Can it be adjusted? Maybe that's why my boost drops off quite abit higher in the rev range.

 

[S3 Nattie]

Ye you can adjust the pre load on the spring. The rod has a nut on it which should be a certain distance from the end of the rod.

I think its 16 or 17 mm. The nut may have come loss and not enough pre load on the spring now.

Worth a check, although not easy to just check lol

 

[OllieH]

Ok, thanks for that. I'll try and have a look. Although, knowing how little room there is, this is easier said than done