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Dyno blues... Wheres my power gone?

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Old 16 June 2006, 08:34 PM
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Engineer@Uni
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Default Dyno blues... Wheres my power gone?

Hello gents,
I bought a MY05 STi about 11 months back. What a lovely car. 6 months into it I took it round to TSL for a 333 conversion and a "less-unequal" manifold installation. The difference, needless to say, was massive. The mapper there told me I got a good one, and said I should be looking at 360 bhp on Optimax.

Lo and behold, however, I come back to Greece (home sweet home) and gas-up on BP Ultimate (the greek variety has 100 octane and is superior to UK Optimax), dump in 750ml Silkolene octane booster just in case, ramp-up on the rollers and after a few runs, best I got out of the girl was (no wheelspin, 6 peeps sitting on the car) 179 wheel horsepower! a humongous 117 bhp drag and a resultant pathetic 297 BHP flywheel. All this at a very respectable 27 deg C, 69% humidity and sea level.

Now I know the dyno is fine, a stock Ibiza FR got up right after me and made 1 bhp more than manufacturer's claim, so bad dyno is out of the question. HOWEVER, when the dip-stick was removed and the dyno's probe put in it's stead, i got the <ABS> warning light on in the dash. The only thing i can say to explain the pathetic power ( 60 odd bhp down on quote) is that the engine detected low crank-pressure or something and defaulted to a safety-map that was a load down on power.

Honestly guys, I don't believe I did all that modding and gained 35bhp from the factory stated 265, it's simply impossible because the car is signifficantly more potent on the road. Anyone got a light to shine on my plight?

Thanks for taking the time to read the long and frustrated post,

Antonis
Old 16 June 2006, 09:20 PM
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JohnD
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Pity the boost pressure wasn't monitored. I believe that conversion should peak at around 1.4bar? In the UK the Prodrive upgrade (PPP) has a safety feature in the map which pulls back boost (and maybe ignition - I'm not sure) when the charge temp. exceeds a set value. Have to admit, I don't know if that facility is in the map on standard cars of that year. If it is, and was retained after re-mapping, then it could be that charge temps. were high on the runs. I'm sure someone on here will confirm one way or the other?
27C may be mild to you, but it's hot to us in the UK! (just over 80F)
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Last edited by JohnD; 16 June 2006 at 09:22 PM.
Old 16 June 2006, 10:05 PM
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Mo
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Indeed, the temperature at the MAF was probably far higher causing the ECU to pull timing. From the 333's I've witnessed run here in the UK none have provided the claimed figures, bhp is usually close but torque has always been down.
Old 16 June 2006, 11:35 PM
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Andy.F
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Originally Posted by Mo
From the 333's I've witnessed run here in the UK none have provided the claimed figures, bhp is usually close but torque has always been down.
I have found similar. It certainly makes customers have high expectations from us mere mortal mappers
Old 17 June 2006, 09:50 AM
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Engineer@Uni
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Peak boost after ther run was recorded on my boost-gauge as 1.4 which is what the car is mapped to. To be honest after mulling over the facts for a few hours I'm convinced the only logical explanation is that the front-facing fan was failing to produce flow over my intercooler and thus intake charge was way too hot resulting in the ECU dialing in less advance.
Old 17 June 2006, 11:49 AM
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dougwrx
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Originally Posted by Mo
Indeed, the temperature at the MAF was probably far higher causing the ECU to pull timing. From the 333's I've witnessed run here in the UK none have provided the claimed figures, bhp is usually close but torque has always been down.
I have been to a few different rolling road days, with a couple of 333 converions and all of them made the power within a couple bhp+lbft. I think it depends on the rollers.
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