Thread: VE 4CW crankshaft max load

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2011-08-01 03:33:28

#61

cory

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Man that knife edged crank looks nice.

I took my 4crw to 10k last year no problem..

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2.0 218/153- 12.9@106
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2011-08-01 04:09:21

#62

Denismo

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thanks. what load? how much hp?

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gti-r
500hp sr20ve+t rnn14 build in SLOOOOWLY progress http://www.sr20-forum.com/turbo/38423-sr20ve-t-gti-r-500hp.html#post493785

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2011-08-01 14:17:01

#63

cory

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All last season. Bit it was only drag. Making 270whp 190ftlbs

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2.0 218/153- 12.9@106
2.3 270/190- 11.6@116
2.4 285/210- 11.5@118
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2011-08-02 02:57:18

#64

b12sr20ve

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Originally Posted by Denismo

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1. we used the 4cw crank into sr20ve n1 and rewed 9k. used 300v motul. it was fine on the 1/4mile races. then we changed to motul x8100 and used the car as the daily drive. we damaged the bearings on the 7k rev. can't find out if the oil or the 4cw crank is the reason?

2. my friend has put 4cw sr20de crank in the 1.8 gti-r engine. he reved few races up to 8700 rpm. 570whp. he says everything is fine. we are now putting the sr20ve head to rev more. we will show you the bearings in the winter, when we will rebuild the engine.

3. we have put the 4cw crank into another 300whp gti-r, because we havent found the 8cw or rnn14 one... sooner or later I will give you the statistics.

the theory is right the 8cw is more reliable due to the harmonics. even the heavier crankshaft, flywheel is more reliable due to harmonics. there is the theory of machines that I have studied in the university. the counterwheights are the flywheels of the crank without them we will have

/\-----/\
--\---/--\
---\-/----\

the saw

with the flywheel we have the following characteristics

/\/\/\/\
I
I

the heavier the crank wheights and the flywheel and the lower(smaller) the tooths of the saw.

it is the "theory of the mechanics"

Remember one thing : not the static load kills the bridge, but the harmonics and the sign different loads.

the second and the odd order harmonics are the worst

because we have the increased load in the resonance points. in the resonance point we have the summ of few periods POTENTIAL energy : it is the result of few periods of the kinetic energy.

interesting.....

question. on your sr20ve n1 that revved 9k, was the crank oem specs or was it lightened?

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2011-08-02 02:57:47

#65

b12sr20ve

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Originally Posted by cory

Man that knife edged crank looks nice.

I took my 4crw to 10k last year no problem..

wow 10k

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2011-08-02 03:25:49

#66

donttazmebro Online/offline status of donttazmebro is unknown

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it was already discussed and proven that 2nd and 3rd order harmonics are the downfall of the 4cw crank. Most people going will quote nismo running them in their race cars or discuss how their motor is fine for drag racing or having fun daily driving.

Nismo has a team of people that tear down a motor after each race.
Amateur road races have seen uneven bearing wear on 4cw cranks

For the casual driver it's not that big of a deal.

but i still run a gti-r crank in my NA VVL build along with a fully 16ve flywheel and stock crank pulley because of all the things that could go wrong, i don't want my bottom end to be one of them

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2011-08-02 03:36:33

#67

cory

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I know its off topic. But hows your motor doing? Is it even running? I remember you having some issues

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2.0 218/153- 12.9@106
2.3 270/190- 11.6@116
2.4 285/210- 11.5@118
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2011-08-02 22:30:05

#68

donttazmebro Online/offline status of donttazmebro is unknown

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Originally Posted by cory

I know its off topic. But hows your motor doing? Is it even running? I remember you having some issues

yep it's running, as strong as ever.

things to come:
oversized valves
new big ported head
custom IM
larger secondary injectors

ive been tuning and bpu'ing the IX in the meantime

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IX MR vs VVL guess who's faster

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2011-08-03 08:58:32

#69

Autech

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My 10krpm 4cw is stil running, without an issue.....

Id still love for mr Miko to come up with actual evidence.

Good post Denismo! Put the math down on paper over various rpm..you will see soon how the frequency overlaps and how you will reach a certina rpm ( i think it was near 6k) that there was no ill benefit from running the 4cw.

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2011-08-03 10:07:15

#70

P10

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Last 3 motors i have built
N/A race motors

1st 8 c/w ballanced no lightening, did approx 20 races, no issues

2nd 4 C/W ballanced no lightening, approx 15 races, ran bearings after oil pickup fractured and broke off. no issues up to that time

3rd 8 c/w Ballanced, knife edged ran bearings after 3 meetings

Im going to knife edge a 4C/W for my next turbo motor, its going to be pulled down every 3 meetings any way and bearings are cheap.

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