hillbily1988
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« on: January 18, 2020, 10:50:48 AM »
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I have been playing with this build for a while now,
I have been using tuner Pro to adjust the maps
But I seem to be struggling to find any info on how to get power at lower RPM.
I get no power up unti 3500 when it starts to pull then surges at 4000 all the way to the end of the rev range, I am getting 8psi boost at 2500 and would expect to get it pulling at that point. I have tried advancing and retarding the timing around 2000-3000rpm but makes no difference, just looking for some advice or link me to a post that will help.
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BlackT
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« Reply #1 on: January 18, 2020, 10:55:32 AM »
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Good your post your engine configuration.  BDW even smallest K03-005 bearlly can make full boost at 2500 RPM |
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hillbily1988
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« Reply #2 on: January 18, 2020, 11:03:35 AM »
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AUM with 550cc injectors gt2871 turbo decat 3"
I get full boost at 4000 hence the surge at that point but that's at 18psi
At 2500 I'm getting 8psi I should get more pull, its like theres no turbo until 3500.
Some people run high power just running 8psi max.
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prj
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« Reply #3 on: January 18, 2020, 12:31:26 PM »
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GT2871 does not spool at 2500 on a 1.8T. Not even close, who told you that? Timing should always be MBT, the only thing that can help with spool is cam timing.
A GT28RS made full boost around 3500 RPM on my dyno, so 4000 is not too far off.
Also, is the turbo a china knockoff?
The old GT series are not even produced anymore IIRC.
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prj
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« Reply #4 on: January 18, 2020, 12:36:59 PM »
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Here is graph from a mostly stock S3 with a GT28RS.
Oh and 1.8T won't make any power with 8 psi. On a GT2871 you need a built engine and around 26 psi to make any decent power.
IDK where you're getting your numbers from, you think these engines run on magic or something?
It's a 1.8 liter tiny engine, if you try to extract 200+ hp/liter out of it, of course it's going to have massive turbo lag. And of course it's going to need to run lots of boost.
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hillbily1988
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« Reply #5 on: January 18, 2020, 12:57:50 PM »
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im not looking for miracles, its a cheap build, cheap turbo, cheap manifold.
looking at the dyno graph im getting what i should be, thanks for that.
just thought when i come on to positive pressure i would at least start to feel a power increase and maybe there was something i could do to make it more progressive up until full boost.
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nyet
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« Reply #6 on: January 18, 2020, 01:55:01 PM »
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2.7t swap
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ME7.1 tuning guideECUx PlotME7Sum checksumTrim heatmap toolPlease do not ask me for tunes. I'm here to help people make their own. Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
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Blazius
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« Reply #7 on: January 18, 2020, 02:36:20 PM »
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im not looking for miracles, its a cheap build, cheap turbo, cheap manifold.
looking at the dyno graph im getting what i should be, thanks for that.
just thought when i come on to positive pressure i would at least start to feel a power increase and maybe there was something i could do to make it more progressive up until full boost.
You will never make full boost with 71 below 3.5k even with VVT, unless you are in 5th gear.. My t3/t4 makes half a bar at 3600 or so with VVT and custom setup in 3rd gear. 1.8 is not a big engine anything bigger than t25 based turbo will have some lag. If you want some more flow increase displacement. Also half a bar wont make that much power. The non turbo 1.8 makes 125 hp at 5700 rpm~ with VGM , calculate how much you would make approx with half a bar added on top with gt2871. |
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hillbily1988
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« Reply #8 on: January 18, 2020, 04:12:32 PM »
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Just to be more clear. I'm not after more boost or max boost at lower rpm, I'm not an idiot!
I want to know what adjustments I could make to get a bit more power at lower rpm.
If at 1500rpm (NO BOOST) its like a non turbo
Then at 2500rpm (0.5bar boost) it still feels like a non turbo surely there is something not right and I should be getting more pull, basically gutless up until 3500 (1bar)
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vwaudiguy
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« Reply #9 on: January 18, 2020, 04:44:34 PM »
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Just to be more clear. I'm not after more boost or max boost at lower rpm, I'm not an idiot!
I want to know what adjustments I could make to get a bit more power at lower rpm.
If at 1500rpm (NO BOOST) its like a non turbo
Then at 2500rpm (0.5bar boost) it still feels like a non turbo surely there is something not right and I should be getting more pull, basically gutless up until 3500 (1bar)
Turbo is *somewhat of a* restriction. It's less apparent when it's making boost. |
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« Last Edit: January 18, 2020, 04:47:28 PM by vwaudiguy »
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"If you have a chinese turbo, that you are worried is going to blow up when you floor it, then LOL."
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hillbily1988
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« Reply #10 on: January 19, 2020, 05:43:01 AM »
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That makes sense
If my Chinese wind machine blows up it only cost £79
I can buy 10 for the price of a garrett, I'm only playing around trying to expand my knowledge of cars and how thy are mapped, the complete build has cost me £800 and that includes buying the car so if it all goes wrong im not too bothered, when I get more confident I will invest in better components. Maybe ill change for a gt25 which I assume has the same t25 mount plate?
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prj
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« Reply #11 on: January 19, 2020, 11:22:49 AM »
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You are using china shit + you probably have no VVT or not set it up right and you are wondering why it drives like shit?
Well... lol
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fknbrkn
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mk4 1.8T AUM
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« Reply #12 on: January 19, 2020, 11:34:53 AM »
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Anyway it's cheap talk wo logs
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prj
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« Reply #13 on: January 19, 2020, 02:19:15 PM »
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+1
Also, "can buy 10 for price of a garrett". Yeah, 10 things that have shit efficiency/clearances and will never work right.
GT2871 isn't even made anymore, it's an old design. And the china shit is 99.9% sure going to have worse efficiency than it originally had...
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