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why flutter tried to kill me

- - - - - flutter bov evo turbo help boost

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11 replies to this topic

#1
GeeKz

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Possible Repercussions from a flutter setup…
I love the sound of my evo3 engine’s flutter. A lot of people who have heard it also admire the tone of my flutter, even. :drool: To the point that it has constantly sways me to keep it that way rather than to change the setup to this day! Well, that was until a couple of weeks ago.

Basically I’ve grown to love the way it handles, drives and sounds. the flutter of the evo sounds heaps better than the bov sound i had on the wrx which is remiscent of a plastic bag full of water being thrown on the ground when shifting. :thumbsdown:

Lately I’ve been doing a bit of travelling for work. Lately having to travel to the yarra valley quite often as of late. Anyone whos ever been there will tell you that there are many corners that are quite fun to tackle and find your and your vehicle’s limits!
Many different road surfaces and angles and terrains. . You basically feel like a real like rally driver!
I remember when I still owned my wrx I tackled that same route once before and realised how much fun it could be! Which is a crap load of fun!
After reminiscing the wrx’s performance, I thought and wondered how my new baby would take these same corners. Would it perform as well as the (lightly modded) wrx?

ONLY ONE WAY TO FIND OUT!


A few days later I took my car to find out. That morning it was freezing cold almost. It was all of about 5 degrees celcius with hard rain! However my lil beast just kept sticking like borat on the naked fat guy.

Constantly taking corners at above 100kms to a lot more. On 24psi of boost on my exits. It just kept sticking and sticking! Being that it’s a private road at 5am(so no laws were broken) I just kept pushing and it wouldn’t fail me at all. Being that its all private it didn’t need to let up on the accellerator on the corners…. So I’m shifting quick and its always engaging the next gear and on boost quickly after each flutter. Possibly even going airborne on at least two occasions. LOL. Or at least it felt like it did.
So I make it to work feeling more confident in my car’s abilities more than ever.


Okay long story short, after work being that there was a slight possibility that there may be other vehicles around so I’m a lil reluctant to tackle each corner as I did that morning. But on one of the “S” turns I decided to give it a little gas. I enter the S turn at about 70kph on 3rd then go fourth when I felt the need to… after a bit I ease off the gas as I felt I was going a lil quick and I didn’t want to speed and endanger anybody’s lives. However when I eased off on the gas, my car starts to lose traction and I feel it start to spin on as I exit the S turn. Fortunately I had decent instincts and after a little slide left and right I recover without any dramas. I wasn’t too sure if my passenger even felt it at the time but I knew what was going on but and took it in my stride. Fortunately it all worked out.
However for the next 24 hours it was weighing on my mind how it couldve happened the was it did. Being that I took it much harder in the morning and in the morning it was much more wet as it was still raining heavily at the time in the morning. In the afternoon it was only about 30 to 40 percent on the road that was wet. So it really didn’t make too much sense. When I came to the realisation that it must have been during the instance when I backed off the gas and the engine did it’s fttt-ffftt-ftt-fttt-fttttt.
As I have noticed and been told and if I’m not wrong that is caused by the air going back into the turbo blades and causing the compressor surge right? Well I’ve noticed that if I shift quickly and engage the next gear quickly before the compressor surge causes the compressor stall its fine but if I’m too slow the engine either shudders or stalls depending on if I’m clutching still or starting to engage a gear. But I believe that it must’ve shuddered and that’s what made me lose the traction. That’s what I think happened anyway. Any insight into my situation will be much appreciated.
What worse is that I lost a lot of faith in my car’s and my abilities after that incident. Does anyone know if theres any bov that makes a similar noise as that of the flutter? As it sounds awesome. But I’d rather be alive and have my car in one piece and still have fun than lose any of them for a cool sound, but if I could have all four, it’d be better than awesome.

Sorry for the long post. I just thought I ought to explain how I got into this situation.

#2
EV0300

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Tbh I dont like flutter I think it sounds tacky, I am actually quite happy with my evo x bpv. But if yoy must have the flutter I dont think that there is any bov that wilk give you the se sound

#3
jack be nimble

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I think you had throttle off oversteer.
When you were keeping the throttle pinned you were keeping the car either neutral or light understeer. But when you backed off, it upset the cars balance and made it light oversteer.

This is typical of cars with fatter than standard rear sway bars or mods that increase rear end grip.
Your car sounds to be very well tuned suspension wise, although it will take balls to drive hard knowing it will oversteer if you back off!!
You could tune it out with smaller rear bar, fatter front bar, or something to increase front grip/ reduce rear grip. Though it will make your car power understeer it will be safer if you not concentrating or if someone else is driving
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4g93t jumbuck conversion. PRANGED 18/3/12, CHECK MY MEMBER RIDES Page 11. no serious human injuries.
ON THE ENGINE STAND. g4cs 2.4l + Gt35r. PLUS: auto conversion + Awd coming.
thanks for parts and help: BMGTZ, EVOCPE, cwolf, Benozi, Jamo-GSR, 1JUM2NV, RXVII..much appreciated, cheers guys.
Aerodynamics are for people who can't build engines. —Enzo Ferrari
REMEMBER: you cant polish a turd, but you can roll it in glitter.

#4
JayRome

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I think you had throttle off oversteer.
When you were keeping the throttle pinned you were keeping the car either neutral or light understeer. But when you backed off, it upset the cars balance and made it light oversteer.

This is typical of cars with fatter than standard rear sway bars or mods that increase rear end grip.
Your car sounds to be very well tuned suspension wise, although it will take balls to drive hard knowing it will oversteer if you back off!!
You could tune it out with smaller rear bar, fatter front bar, or something to increase front grip/ reduce rear grip. Though it will make your car power understeer it will be safer if you not concentrating or if someone else is driving


agreed to above...

also a lil insight to your flutter....

our Karmen Vortex AFM/MAF are extremely sensitive compared to Voltage AFM/MAF sensors. so a slight change in pressure/vac in the lines and you will notice while you are driving (leaks, size of cooler pipes etc).... Flutter can disrupt the Sensor readings as can a BOV set to Atmospheric, even a BOV with a really stiff spring thats plumbed back into the intake can do it...... usually causes a slight hesitation in power on back off. As soon as the throttle snaps shut, it takes the engine a split second to regain power again... or on some rare occasions, the engine dies while coming to a stop after a little burst...

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#5
D3bb4

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Compressor surge... can keep the throttle open because of the buildup of pressure in the pipework, so that's plausible. As is the above statements. Would expect throttle off oversteer if it was sudden especially.

#6
evo-gsr

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WTF ....over 100km/h in hard rain at 24psi....What's your name mate - Sebastian Vettel??
Private road at 5am but other cars possibly travelling on this same road, after work....
Farking LOL!!!!!!!

Edited by evo-gsr, 30 April 2012 - 10:19 AM.

[qoute name="BMGTZ" post="331212" timestamp="1467451744"]I don't know anything ...
Trust in the master of taxis.... He will set you straight[/quote]

#7
ENGINR

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WTF ....over 100km/h in hard rain at 24psi....What's your name mate - Sebastian Vettel??
Private road at 5am but other cars possibly travelling on this same road, after work....
Farking LOL!!!!!!!


I was thinking the same thing...
"I got an idea, an idea so smart my head would explode if I even began to know what I was talking about." - Peter Griffin

#8
evo-gsr

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^ Yep...sounds like a load of bullshit to me.
[qoute name="BMGTZ" post="331212" timestamp="1467451744"]I don't know anything ...
Trust in the master of taxis.... He will set you straight[/quote]

#9
ENGINR

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^ Yep...sounds like a load of bullshit to me.


Get outta my head!!!! I was thinking that too!!!! :P

Have just been re-reading the original post and all I can think is that the loss of traction happened because the driver was driving like a dickhead and this crap about private roads at 5am in the morning is trying to make out that driving like a dickhead is OK in this instance.

If you're really serious about finding out why your EVO behaves the way it does and whether you should have faith in how it handles or does not handle - book in for the next WRX or SAU club Deca skid-pan day and go hard out there in a controlled environment that will really test your 'decent instincts' and awesome driving ability.

Edited by ENGINR, 02 May 2012 - 06:35 AM.

"I got an idea, an idea so smart my head would explode if I even began to know what I was talking about." - Peter Griffin

#10
evo-gsr

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[qoute name="BMGTZ" post="331212" timestamp="1467451744"]I don't know anything ...
Trust in the master of taxis.... He will set you straight[/quote]

#11
ENGINR

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^ That's awesome!

"GO! SPEED RACER! GO!"
"I got an idea, an idea so smart my head would explode if I even began to know what I was talking about." - Peter Griffin

#12
jack be nimble

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I thought it was so obviously happening on the open road that it didn't rate a mention...
Go speedracer.. Lol
4g93t jumbuck conversion. PRANGED 18/3/12, CHECK MY MEMBER RIDES Page 11. no serious human injuries.
ON THE ENGINE STAND. g4cs 2.4l + Gt35r. PLUS: auto conversion + Awd coming.
thanks for parts and help: BMGTZ, EVOCPE, cwolf, Benozi, Jamo-GSR, 1JUM2NV, RXVII..much appreciated, cheers guys.
Aerodynamics are for people who can't build engines. —Enzo Ferrari
REMEMBER: you cant polish a turd, but you can roll it in glitter.



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