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Old 04-25-2014, 03:34 AM   #1
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Default Why does it feel slower at WOT than at partial throttle?

I've been curious about this feeling for some time. My car seems to accelerate slower under WOT than under partial throttle. I've searched for the similar issues but only found a related topic with e90 BMWs. Any clue what may be going on?
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Old 04-25-2014, 09:11 AM   #2
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placebo effect.
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Old 04-25-2014, 10:02 AM   #3
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Faster? Or spooling faster?

Ive noticed that rolling into the throttle seems to make a turbo spool a little faster than just punching it. More noticeable with extra big *** turbos like Hondas tend to run.
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Old 04-25-2014, 01:27 PM   #4
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^ Yep. And some tiny turbos get awesome surge issues along the same lines.

Also, check your throttle linkage.

And your maps vs data logs, Seen maps with a timing drop at a certain MAP/IAT that often roughly corresponds to WOT vs 80% throttle. If cold weather tends to move that 'optimal throttle point' lower, then you may have your culprit.
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Old 04-25-2014, 01:41 PM   #5
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Quote:
Originally Posted by Braineack View Post
placebo effect.
Could all this is based on buttdyno data. However, the car use to feel much more alive before. Or maybe I got used to it

Quote:
Originally Posted by Full_Tilt_Boogie View Post
Faster? Or spooling faster?

Ive noticed that rolling into the throttle seems to make a turbo spool a little faster than just punching it. More noticeable with extra big *** turbos like Hondas tend to run.
I don't have any data with regards to spool. It just feels that the power delivery is faster. My churbo could be be consider somewhat big. 2871-ish journal.

Quote:
Originally Posted by Sparetire View Post
^ Yep. And some tiny turbos get awesome surge issues along the same lines.

Also, check your throttle linkage.

And your maps vs data logs, Seen maps with a timing drop at a certain MAP/IAT that often roughly corresponds to WOT vs 80% throttle. If cold weather tends to move that 'optimal throttle point' lower, then you may have your culprit.
Timing seems fairly constant and matches with the values I have in my spark table.
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Old 04-25-2014, 02:05 PM   #6
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I can think of some reasons part throttle feels faster:

1. better tuning at lower TPS. (Richness isn't conducive to power)
2. increased intake flow velocity from throttling the airway leads to better mixing which could lead to better torque
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Old 04-25-2014, 02:08 PM   #7
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what does your spark and fuel map look like at part throttle vs full? leaner + tons of timing = faster
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Old 04-25-2014, 02:28 PM   #8
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This is what I have now. Spark and fuel seem very constant. However, this is at WOT and I don't have anything for partial.
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Old 04-25-2014, 02:34 PM   #9
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there is a drastic difference in timing

also are you using an mbc?
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Old 04-25-2014, 02:51 PM   #10
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Quote:
Originally Posted by 18psi View Post
there is a drastic difference in timing

also are you using an mbc?
Drastic from lower kpa to higher kpa or the actual read from the log vs map input?

No mbc it's all wastegate.
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Old 04-25-2014, 02:57 PM   #11
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your map is triggering a difference of 5* between part throttle and wot.
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Old 04-25-2014, 03:41 PM   #12
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Your fuel map is a mess, dude.
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Old 04-25-2014, 03:50 PM   #13
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Your fuel map is a mess, dude.
Agreed. I am in the process of changing a few key components on my set up so tuning is going to have to wait for now.
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Old 04-25-2014, 06:13 PM   #14
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Quote:
Originally Posted by buffon01 View Post
Could all this is based on buttdyno data. However, the car use to feel much more alive before. Or maybe I got used to it

no it's more like: if you're at 200kPa at 50% throttle, and 200kPa at 100% throttle is a difference in regards to engine load?
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