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Old 04-06-2012, 04:30 PM   #81
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Quote:
Originally Posted by Boost Joose View Post
essentially yes....the wheel moves based on rpm/throttle/boost levels


How are we having this discussion when OP doesn't understand what VGT is?
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Old 04-06-2012, 04:31 PM   #82
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Omg, OP just went full retard....
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Old 04-06-2012, 04:31 PM   #83
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Originally Posted by Boost Joose View Post
Yes, surge but a VGT turbo, from my understanding "shrinks to essentially become a smaller turbo for instant responce and then expands as the rpms rise.
your understanding is wrong.
re-read what they do.
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Old 04-06-2012, 04:32 PM   #84
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Quote:
Originally Posted by 18psi View Post


How are we having this discussion when OP doesn't understand what VGT is?
Because we all are obviously envious of the OP's awesome 500rwhp build.
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Old 04-06-2012, 04:34 PM   #85
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Ha, maybe I am....sorry if I mis interpreted. I'm about to leave but I'll read up more later......
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Old 04-06-2012, 04:39 PM   #86
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Quote:
Originally Posted by Boost Joose View Post
Hey dumb fu(k why dont you learn how to interpret english. "many if not most to all drifters go V8 for the response."

In dumba$$ terms: People in the drifing scene that decide to go from a 4 cylinder to a v8 do so for increased response and convienience of having optimal torque at a much broader range.

Can you comprehend that?
You've already established yourself as an abrasive and useless person in general. And I didn't say anything mean to you in my response but you choose to take it there, probably because you are a wal-mart person.

You're lack of good sense shows in your response. Since I know the schools are slacking in teaching your kids good English and syntax I'll go ahead and tell you what you are trying to say:

"Of drift cars that swap a v8, those that do it, do so for the response."

Funny how you jump on my for comprehension, and then quote yourself. If you take the time to really pick apart what you typed, you actually said,"most drifters are running v8's." But hey, we all know comprehension isn't your strong suit.
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Old 04-06-2012, 04:46 PM   #87
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Quote:
Originally Posted by Boost Joose View Post
essentially yes....the wheel moves based on rpm/throttle/boost levels

you do know there difference between a compressor wheel and turbine wheel right?

and you do know that surge has everything to do with the RPM and PR of the compressor wheel right?

and you do know that if you spin the turbine faster/earlier, the the compressor wheel also spins faster and build boost sooner, possibly building boost to the left side of the surge line and becoming very unstable?
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Old 04-06-2012, 04:59 PM   #88
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Wait, BJ is a drifter?

....Well played sir, well played.
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Old 04-06-2012, 08:45 PM   #89
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Originally Posted by Jeff_Ciesielski View Post
Omg, OP just went full retard....
I thought we established that on his intro thread.
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Old 04-06-2012, 08:53 PM   #90
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Originally Posted by 18psi View Post
What a lot of these kids don't understand too is our motors can't even CONSUME the 25psi or whatever it is, from a large turbo, at 2500rpm.

Stick a 30r+ car with mbc set to 25psi in 5th gear at 2k rpm and go W0T. See how much surge you get.
Ask me how I know
Wait. Serious time.

18psi please tell how a 30r+ could see 25psi at 2000rpm in 5th? On a miata motor Without flat shift or any tricks. Even with the best fuel i am not sure it is possible.
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Old 04-06-2012, 09:41 PM   #91
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It wont, obviously.
It will try, and surge like a motherfawker.

This is me in a 3076 miata on e85 running *ALL OF IT* in 5th gear at low rpm (filming buddies bp-t festiva vs skyline)

he wasn't even flooring it at all, and listen to how bad it surges.
when he got on it at 2k (different time) it sounded like a friggen sprinkler head and car was shaking violently.
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Old 04-06-2012, 11:02 PM   #92
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So wait is the lack of exhaust flow/low rpm that causes surge or what exactly...

I know it's not enough rpm on the compressor but say we do find a way to keep it spinning... then what?
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Old 04-06-2012, 11:10 PM   #93
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Quote:
Originally Posted by triple88a View Post
So wait is the lack of exhaust flow/low rpm that causes surge or what exactly...

I know it's not enough rpm on the compressor but say we do find a way to keep it spinning... then what?
No, I think you've gotten a bit mixed up on what surge is.

Surge is when you have high pressure and low mass flow out of the compressor. If you look at a compressor map, it is basically when you go to the left of the surge line on the map. It happens when the turbo is spinning fast enough to deliver more air than the engine can take in.
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Old 04-06-2012, 11:21 PM   #94
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Quote:
Originally Posted by Rara View Post
No, I think you've gotten a bit mixed up on what surge is.

Surge is when you have high pressure and low mass flow out of the compressor. If you look at a compressor map, it is basically when you go to the left of the surge line on the map. It happens when the turbo is spinning fast enough to deliver more air than the engine can take in.
Which causes a breakdown of the airflow through the compressor. Its like an airplane wing stalling. The compressor is a wheel of wings.

Wikipedia takes this mostly in terms of a jet turbine engine, but the concept is the same. http://en.wikipedia.org/wiki/Compressor_stall
It looks a lot more violent in airplanes.
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Old 04-06-2012, 11:25 PM   #95
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Originally Posted by Bryce View Post
Which causes a breakdown of the airflow through the compressor. Its like an airplane wing stalling. The compressor is a wheel of wings.
Exactly. Another way to look at it is air is quickly alternating between moving through the compressor normally, and getting forced through the compressor backwards.

Severe surge can potentially damage compressor wheels pretty badly too.
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Old 04-06-2012, 11:38 PM   #96
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antisurge housing ftw

the big bitch in my avatar never surges.
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Old 04-06-2012, 11:43 PM   #97
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If you've never experienced it, compressor surge is pretty horrible.
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Old 04-07-2012, 12:29 AM   #98
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Soooo we need something to allow some of the flow to escape so the turbine can spin at a good rpm?
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Old 04-07-2012, 12:44 AM   #99
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Quote:
Originally Posted by triple88a View Post
Soooo we need something to allow some of the flow to escape so the turbine can spin at a good rpm?
That could potentially help. If airflow through the compressor can be maintained, the AoA on the blades will be effectively reduced warding off a stall condition. Jet turbine engines have a vent valve in the compressor section for this purpose.
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Old 04-07-2012, 12:53 AM   #100
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Quote:
Originally Posted by Boost Joose View Post
The point of these VGT turbos are to have a small turbo at low RPM(like a 2554) and the flow and power of a big turbo in high RPMs(like a 3076)
Wait, what?!?
No, no, no...
If that's how they worked it would be the magic bullet. It strictly helps spool.
The solution you want is right above...

How come I feel I'm wasting my keystrokes?
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