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Author Topic: Puzzling dyno run - possible small boost leak??  (Read 2380 times)

Offline berg

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Puzzling dyno run - possible small boost leak??
« on: December 31, 2011, 04:50:24 pm »
Hi guys,

Been over to Awesome today for first RR session since went stg 2+.

Last year on Stg 1 it averaged about 304bhp and 341 lb ft.

Soooo.... today it averaged 306 bhp  :scared: but average torque of 411 lb ft  :rolleye:!

The car drives very well and feels a lot faster than when I was at stg 1 so how can I only be getting 2bhp more but with such high torque figures?

I had F9 which I know is lean for 2+ but was told not dangerous when logged as no timing pull of note. So they dropped it to F5 and did another run which brought the AFR down but also the torque with BHP staying pretty similiar?

I have the revision D fitted but no other uprated silicone hoses so only cause put forward could be a small boost leak on a pipe somewhere? Please correct me if I am wrong though, but seeing as BHP and torque are linked can one actually be so low with the other so strong? :confused:

Will try scan log up too when get chance but any thoughts in meantime appreciated, looks like a call to Carl or Kev on Tuesday might be needed!

Many thanks.
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Offline PDT

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Re: Puzzling dyno run - possible small boost leak??
« Reply #1 on: December 31, 2011, 05:19:05 pm »
Replied by PM  :happy2:

Bhp and torque are linked, torque is the amount of force the engine can create, bhp is a measurement of the rate that it can make it.

If you do the maths using the physical dimensions of a K04 tfsi turbo, using 'normal' fuel I cant see much more than 380ft/lb being realistic. I Have never seen higher than 380ish ftlb on a realistic dyno.
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Offline PDT

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Re: Puzzling dyno run - possible small boost leak??
« Reply #2 on: December 31, 2011, 05:20:15 pm »
How was the RPM calculated for the run? Got a graph?
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Offline berg

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Re: Puzzling dyno run - possible small boost leak??
« Reply #3 on: December 31, 2011, 10:21:27 pm »
Quote from: PDT on December 31, 2011, 05:20:15 pm
How was the RPM calculated for the run? Got a graph?


thanks dave,

will post up graph tomo
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Offline damoegan

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Re: Puzzling dyno run - possible small boost leak??
« Reply #4 on: December 31, 2011, 11:06:42 pm »
Awesome's rollers are renowned for giving high torque figures..
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Offline vRSAlex

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Re: Puzzling dyno run - possible small boost leak??
« Reply #5 on: January 01, 2012, 12:40:02 am »
What's the wheel bhp?

It's about time tuners just used whp only.
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Offline RobH

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Re: Puzzling dyno run - possible small boost leak??
« Reply #6 on: January 01, 2012, 01:15:42 am »
Quote from: BDMAlex on January 01, 2012, 12:40:02 am
What's the wheel bhp?

It's about time tuners just used whp only.

Does whp take the "lottery" out of it?
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Offline bacillus

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Re: Puzzling dyno run - possible small boost leak??
« Reply #7 on: January 01, 2012, 11:25:37 am »
Quote from: RobH on January 01, 2012, 01:15:42 am
Does whp take the "lottery" out of it?

It bypasses the need for a calculation to get the flywheel bhp...
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Offline PDT

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Re: Puzzling dyno run - possible small boost leak??
« Reply #8 on: January 01, 2012, 11:56:36 am »
Quote from: BDMAlex on January 01, 2012, 12:40:02 am
What's the wheel bhp?

It's about time tuners just used whp only.

Have been saying this for years, but European markets like big numbers so flywheel numbers are what matter. Also the cars manufacturers all quote flywheel so that's the measurement of choice for tuners.

Different story in the USA, but again their wheel hp figures are usually massively inflated.
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Offline Janner_Sy

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Re: Puzzling dyno run - possible small boost leak??
« Reply #9 on: January 01, 2012, 12:03:20 pm »
Quote from: PDT on January 01, 2012, 11:56:36 am
Quote from: BDMAlex on January 01, 2012, 12:40:02 am
What's the wheel bhp?

It's about time tuners just used whp only.

Different story in the USA, but again their wheel hp figures are usually massively inflated.

That is so true, their WHP normally equates to our flywheel Hp.

Is it possible on the dyno dynamics rollers to show both the fly and wheel Hp curves?
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Offline RSam84

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Re: Puzzling dyno run - possible small boost leak??
« Reply #10 on: January 01, 2012, 12:05:28 pm »
i know that on my Rs when i was running standard pipes they were sucking themselves closed whilst under boost! replaced with Silicone pipes and improvment was amazing.
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Offline chungster

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Re: Puzzling dyno run - possible small boost leak??
« Reply #11 on: January 01, 2012, 12:37:43 pm »
Quote from: Janner_Sy on January 01, 2012, 12:03:20 pm

Is it possible on the dyno dynamics rollers to show both the fly and wheel Hp curves?

Absolutely! You just need to ask for it. Depending on which DD outfit you go to, they will give you it by default.

I have to say, looking at my WHP on a MAHA vs WHP on DD, it is a lot more believable.

My WHP figs:

MAHA - OE Map but with CBE - 228bhp (300 FWP!!!)
MAHA - OE Map with CBE / TT / TIC - 242bhp (323 FWP!!!)
DD - OE Map with CBE / TT / TIC - 251 bp (297 FWP)
DD - Revo S1 with CBE / TT / TIC - 272 bhp (321 FWP)

might ask JKM for my stock run WHP back in 2010!

Just done some calcs on Excel to calc my stock WHP based on the FWP @ JKM :signLOL:

267 FWP I got. on the DD runs above, I lose round 15% of my FWP to get WHP. That would put my totally stock WHP @ 225 bhp. So the Milltek CBE gained me 3bhp!  :grin:

In total I've gained 47bhp @ the wheels (55 bhp @ Flywheel based on DD WHP>FWP conversion)

 :driver:
« Last Edit: January 01, 2012, 12:51:03 pm by chungster »
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Offline berg

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Re: Puzzling dyno run - possible small boost leak??
« Reply #12 on: January 01, 2012, 02:53:12 pm »
silicone pipes on the list me thinks
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Offline PDT

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Re: Puzzling dyno run - possible small boost leak??
« Reply #13 on: January 01, 2012, 04:32:48 pm »
If there was a boost leak it would affect the peak torque more than the peak power, you are hitting peak boost (more boost = more leakage) at the same point as peak torque.

I think the car is probably fine, and the dyno results are the cause of your concern. Get a 2nd opinion from a known realistic dyno (any dyno dynamics) and ask them to datalog the car during the run.
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Offline berg

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Re: Puzzling dyno run - possible small boost leak??
« Reply #14 on: January 01, 2012, 09:52:01 pm »
cheers dave, looks like you or statllers will be getting a call.

suppose if am coming up your way could give andy carroll a lift as apparently he is homesick  :signLOL:
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