S3 Low BHP?!

[JaseS3]

Hello all,

I'm new to the forum but have been reading a lot of your posts over the past few weeks since I got my S3 8L (reg 2000), some great info so far so thanks for that but now I need some help please! (Sorry for the massive first post but I'll trying to give as much info as possible)

I got VCDS and tried to work out how much power the car has but as the car has a revo remap (so the previous owner told me, but no proof) block 120 didn't seem to work well (result was about 170 bhp) so I estimated power using both MAF g/s and butt dyno but they are both reporting about 200bhp which I know is near standard but nowhere near what I would expect with a remap, I would think the prev owner had lied but the boost readings lead me to believe it is remapped so I;m at a loss!

I have a forge DV & k&n panel filter. I can hear the turbo spool up but cant seem to hear anything from the DV, not sure if thats normal?

I've tried driving with the MAF disconnected and it idled a little smoother from cold but no noticeable difference besides from that, N75 duty looks normal to me but I'm not expert so charts below & the car does have an ESP light on due to lat accel sensor electrical fault but I suspect it will not be related?

Any help is massively appreciated!

Butt dyno:


BHP calculated from MAF with KM:



Requested boost vs actual (first run):



Requested boost vs actual inc N75 graph (second run):

 

[<tuffty/>]

Need to try that picture attachment again dude as it failed epically

<tuffty/>

 

[JaseS3]

Doh! thanks tuffty, looks ok now but the images are small unless I click on them, if thats a problem let me know and I'll try again.

Also I forgot to mention that not long after I got the car it was hesitating for a second about at about 4-5k with WOT but I ran some redex through it and it has seemed ok the last few days, not sure if that cured it or if it's an intermittent fault thats just not acting up at the minute. It didn't seem to happen when logging for the above charts though.

 

[badger5]

4k before getting full boost?

am I reading it right? if so its some 500rpm slower than I would expect to see

 

[JaseS3]

Hi,
From one of the runs where actual max'd:
RPM / Load / Requested / Actual

3200	185.7	2360	2250
3800	177.4	2270	2300

From the other:
RPM / Requested / Actual

3440	2360	2300
4040	2330	2320

So yes it looks like actual isn't peaking until about 4k, any ideas what might cause that or what I could look at / log next to find out? Could it be due to the revo map? (if it has one).

 

[slowcoach3]

I know your trying to determine the cars power but have you also done a full scan to look for fault codes dude?

 

[badger5]

leaks most common... or if its plain tired and cracked internally, that makes them laggier

 

[JaseS3]

Yeh I checked for fault codes strait away bud but there are no engine codes, only the acceleration sensor code.

Something new just happened on my way home though, I cruised home at about 70mph and when I hit the slow roads I noticed a very noticeable wooshing sound which started at the same time as the turbo spooling up and go louder when I let off the accelerator, almost like a quiet dump valve but it was also 'wooshing' a bit while still accelerating. I tried to log it in VCDS as I had the laptop with me but it stopped! and obviously the logs are the same as before...weird! Could it by that my DV is sticking? I also noticed the small tube coming off the side of the air box is a little loose, not sure if that matters or what it's for though?

I hope it isn;t just cracked and knackered in side :-( Do the boost figures indicate to you guys that the car may be chipped? Just thinking that if it is chipped then loosing that much BHP (260ish when chipped? down to just over 200) would be a big loss just for being old and worn? ...Just guessing here though (and hoping!)

Thanks for the help so far guys

 

[JaseS3]

Ok so I did a visual check for air leaks and can't see anything obvious besides the air box tube mentioned above so maybe a smoke test is needed but I'm thinking it may be related to the woosh sound from earlier today and if it was a split pipe or something I presume it would happen all the time.

Is there anything anyone can think of that would only sometimes cause that wooshing noise?

 

[badger5]

visual test for leaks = 99% flawed

find a garage with smoke tester dude..

 

[JaseS3]

Ok thanks badger I'll have a ring round and try to find somewhere, hopefully somewhere local does it.

 

[kwistof]

Where abouts are you located Jase?

Maybe someone local to you from here can recommend a place....you'd be surprised how few garages have smoke testing machines considering how useful they are!

 

[Lewis.]

Where abouts are you located Jase?

Maybe someone local to you from here can recommend a place....you'd be surprised how few garages have smoke testing machines considering how useful they are!

The Audi workshop next door to where I work don't even own a smoke tester an my S3 has similar lacking power issue and can't really see any issues with it. Where can you buy smoke testers are they mega bucks?

 

[kwistof]

If you have a play with google there are a few guides on how to make your own smoke tester up......doesn't seem to expensive though.

As I said above there are very few places that I know of that offer a smoke test, so it doesn't surprise me Audi don't have one. I suppose the majority of cars don't have as complicated breather systems as we do on our 1.8t engines; so probably isn't a great demand for garages to have them.

I had issues with my car for a while and the local garages around my area didn't have smoke testers so didn't get to the bottom of the breather pipe that was split. That only became apparent when I went to Bill's and he found it in a few minutes if that!

 

[JaseS3]

I'm in Grimsby bud, east midlands. We have a lot of small garages round here but not so many specialists as such...if anyone knows anywhere close(ish) though that would be great. Otherwise I have seen a guide on testing with pressure and soapy water while searching about so I might give that a go, if I can't get a smoke test that is. Worth doing or will I be wasting my time?

Also it's still baffling me why the car would start making a wooshing noise on boost and letting off the throttle yesterday but now its completely silent again besides from initial turbo spool and exhaust of course. Sounds like a vac leak as suggested but not sure why the noise would appear then disappear, with my DV not usually making ANY noise at all it's making me think it's sticking and yesterday maybe it moved a bit, made the noise and then stuck back into the original position. Guess I won't know for sure until the smoke test to rule out the leak.

Out of interest is it a small job to strip a forge 007p down to check it or from the info I've given am I totally barking up the wrong tree even considering that?

 

[Lewis.]

I'm in Grimsby bud, east midlands. We have a lot of small garages round here but not so many specialists as such...if anyone knows anywhere close(ish) though that would be great. Otherwise I have seen a guide on testing with pressure and soapy water while searching about so I might give that a go, if I can't get a smoke test that is. Worth doing or will I be wasting my time?

Also it's still baffling me why the car would start making a wooshing noise on boost and letting off the throttle yesterday but now its completely silent again besides from initial turbo spool and exhaust of course. Sounds like a vac leak as suggested but not sure why the noise would appear then disappear, with my DV not usually making ANY noise at all it's making me think it's sticking and yesterday maybe it moved a bit, made the noise and then stuck back into the original position. Guess I won't know for sure until the smoke test to rule out the leak.

Out of interest is it a small job to strip a forge 007p down to check it or from the info I've given am I totally barking up the wrong tree even considering that?

This sounds similar to my issue. When I picked up the car and for a few days after it went like a rocket, but then it kinda felt a bit slower. It's not that noticeable but it's definitely not running as normal. Its been remapped so was super fast, and now it's still fast but not at full performance. It's hard to pin point it too as I can't see any split pipes, no fault codes are brought up when scanned but it just isn't picking up as quickly as it should, not seeming to boost fully. Annoying but not the end of the world, although I would like it sorting!

 

[badger5]

£25 for basic smoke test here... invaluable piece of equipment.. gets used pretty much every day.
ALL VAGs have leaks.. (well seems that way at times , lol)

yea, expensive, and if the garage owner is tight for £ or plain ignorent of the time they will save "them", then they dont buy them. I thought twice or more as mine cost me >£600 but its an essential tool for me.

 

[JaseS3]

If you ever get to the bottom of it Lewis let me know and I'll do the same but it sounds like we already know it's a leak.

Badger I was tempted to drive to yours as £25 would be well worth it but I just did a quick google maps and it's waaay to far unfortunately...back to plan A then, find somewhere near(ish)

But in saying that I just had a thought, having I made a rookie mistake here as when I did the but dyno I expected to see about 250-260 hp (due to the remap and other small mods) but I'm now thinking that the 250-260hp would be at the flywheel where as the butt dyno prob measures bhp at the wheels? Therefore I may not have a big issue like I was thinking as I would be loosing a fair bit of power through the gearbox etc. I still think there may be a leak but not as big as I first thought. Am I correct in thinking the hp quoted on remaps is at the flywheel and the butt dyno measures at the wheels?