MK5 Golf GTI

All Things Mk5 => How to Guides / Troubleshooting => Topic started by: Rob GTI on August 10, 2009, 09:40:12 pm

Title: Power Loss
Post by: Rob GTI on August 10, 2009, 09:40:12 pm

I had my car on a rolling road last week mainly as a health check to see if all was running well. The engine spec is Revo Stage 2, milltek TBE, Forge Twintercooler and Dbilas intake on a K03 turbo. I should really be getting about 260bhp and 310llbs ft torque from this spec, but found I only got 246bhp and 280llbsft torque. which was down from 250/310 from my previous rr session (same RR) which had the same spec minus the intercooler and TBE.

The boost on my Revo settings was upped from 6 to 8 and power went from 245/280 to 250/305 still down on expected power but not that much.

The comments made by the RR operator were that there was no loss of boost through the system proved by the VAG COM logs.

The only thing I can think of is when I fitted the forge intercooler one of the hoses (drviers side) was slightly deformed /squashed (I didn't trim it enough) therefore this could possibly be preventing full boost from flowing around the system?

Any other suggestions greatly appreciated?

Title: Re: Power Loss
Post by: chungster on August 10, 2009, 09:49:40 pm

figures sounds about right to be honest. you won't get much more bhp over Stage 1 unless you fit an aftermarket HPFP and go S2+.

Title: Re: Power Loss
Post by: snapey on August 10, 2009, 09:53:01 pm

Have you got an updated dv?

Luke

Title: Re: Power Loss
Post by: Top Cat on August 10, 2009, 09:53:23 pm

Rob how kinked was the pipe, when i fitted mine the fit was ridiculous i had to cut loads off all three connections on mine, and it still has a slight kink in. If your fit was like mine and you have not chopped it then you could be right.  :smiley:

Title: Re: Power Loss
Post by: john_o on August 10, 2009, 10:01:46 pm

Hi rob,

how exactly did the operator 'know' there wasnt a boost issue? and if not didnt they give you any pointers?
if as you say it was the same RR then yes even given diff days you should be slightly up.

you need to see timing (to see if its pulling it back) and N75 (for a boost issue) etc logs and take it from there......
I assume you are using the same octane fuel?

Title: Re: Power Loss
Post by: jonnyc on August 10, 2009, 10:22:32 pm

Check DV and PCV..

Does it feel slower than when it used to around the time of the last RR session or are you just assuming that its lost power due to the lower figures?

I would say that really the first lot of figures seem very high if the car was only running a map and intake alone..

250hp and 305tq seems about right for your set up.. Fuel pump and stage 2+ will get you the extra that your expecting around 265-270hp 320tq which is the realistic top end figures for a K03 turbo..

Title: Re: Power Loss
Post by: bacillus on August 10, 2009, 11:07:05 pm

Whilst it may not have any bearing on your "problem", IMO if you're not running an uprated HPFP then turn your boost down a notch.

Title: Re: Power Loss
Post by: Rob GTI on August 11, 2009, 09:08:26 am

Thanks for the comments:
A few additional points:

• The car has rev D OEM divertor valve (non-diaphram)
  The forge intercooler pipe was trimmed about 10mm but still squashed about 50% of original dia.
  The ECU had no error codes stored
  Same spec cars have made 260/320 on this rolling road with lower boost settings
  I didn't notice power loss all of a sudden, but can't say I noticed any difference when adding the intercooler or TBE, (I hadn't driven the car for about 2 weeks before the intercooler fitting.)
  I noticed a big difference when the boost was turned from 6 -8.
  The lack of boost loss was explained but I've since forgotton why (it made sense at the time) N75 valve was metioned but I don't know what it does

Title: Re: Power Loss
Post by: bacillus on August 11, 2009, 09:57:58 am

Logging the wastegate (N75) duty cycle can give you an indication as to if a boost leak is present if it's almost 100%.

That being said, on stage 2+ cars the WG duty cycle is usually pegged at a high value without a boost leak being present.

Can you post a pic of your kinked hose as it may allow more ideas on how to improve matters plus post your full revo settings.

Title: Re: Power Loss
Post by: Rob GTI on August 12, 2009, 09:42:42 am

Here is the best shot I could take of the hose, you can see towards the left hand side of the pic where it looks squashed.

(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fs337%2FRobGTIPhotos%2FImage012.jpg&hash=6be26e3d069adfc354f31a8b9a45fa91b96638a6)

My REVO settings are:

Boost - 6
Timing - 4
Fuel - 9

Cheers.

Title: Re: Power Loss
Post by: SteveS on August 12, 2009, 10:25:11 am

surely timing should be 5 unless your on 95ron!?
i turn boost up to 7 too..

Title: Re: Power Loss
Post by: bacillus on August 12, 2009, 05:02:45 pm

Quote from: SteveS on August 12, 2009, 10:25:11 am

surely timing should be 5 unless your on 95ron!?
i turn boost up to 7 too..

Yup, T5 or 6 depending on timing pull with 98/99 RON petrol.

As for your hose problem, you may have to trim off some more but at an angle instead of 90 degrees so that it stretches the left side more than the right of the hose relieving some of the kink.

Title: Re: Power Loss
Post by: Rob GTI on August 23, 2009, 07:41:12 pm

Thanks for replies, not got to the bottom of it yet and don't want to really spend loads on diagnostics to "find" 15bhp. Will post back if I do though.

Title: Re: Power Loss
Post by: john_o on August 24, 2009, 11:07:18 pm

i dunno if you are maybe getting a similar effect to this http://www.mk5golfgti.co.uk/forum/index.php?topic=7083.0 (http://www.mk5golfgti.co.uk/forum/index.php?topic=7083.0) ?

Title: Re: Power Loss
Post by: Rob GTI on September 01, 2009, 10:59:50 am

Cheers,

Just read that and it sounds a very similar problem to mine. I'd even bet we were both talking about the same RR operator!!

I'll ask later this week when I pop in.