Crank lightening, not knife edging - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

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Old 04-23-2010, 02:21 PM   #21
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Quote:
Originally Posted by Stealth97 View Post
Just get the cast SOHC protege crank, its like 10 or 11lbs lighter
beat me to it... they work fine for n/a applications and low boost. plenty strong enough.

sohc 1.8, 91.5-94 (don't want a small nose...)
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Old 04-23-2010, 02:34 PM   #22
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I just don't see it doing much. Enough to notice anyway. I'm with Jason on the flywheel comment.
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Old 04-23-2010, 02:38 PM   #23
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Originally Posted by therieldeal View Post
beat me to it... they work fine for n/a applications and low boost. plenty strong enough.

sohc 1.8, 91.5-94 (don't want a small nose...)
Even N/A I think I would greatly prefer our forged and nitrided crank.
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Old 04-23-2010, 10:35 PM   #24
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I've been running the SOHC crank for three years now, had it balanced along with the rods, sees 8k RPM's on occasion, its super smooth. Half the counterweights make for less windage loss as well.
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Old 04-23-2010, 11:35 PM   #25
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Like other state, the more you leave the stock engine the better which they got their own magic.

Although many of you do not listen to this...

It is the same blcok of a competition Mazda 323 GTR pushing more than 300 HP, backj in PR who have done 10s the crank is stock...\\\\


IMO, leave it alone, the crank in stock trim is bullet proof.
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Old 04-24-2010, 01:03 AM   #26
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Im next inline at Cardelli's for my 1.6 crank.

Are you doing this also Nick?
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Old 04-24-2010, 02:03 AM   #27
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The loss in spool is due to some type of inertia situation I am not bright enough to explain. Mine had a **** ton taken off of it. 7 or lbs.

I saw no gains at all. It just looked cool and sounded smart. if budget is a worry, I would pass..
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Old 04-24-2010, 01:18 PM   #28
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Loss in spool is kind of a myth.
The car may show less boost at a given RPM in logs in say 1st, but car accelerates faster.
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Old 04-24-2010, 01:23 PM   #29
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Quote:
Originally Posted by railz View Post
Im next inline at Cardelli's for my 1.6 crank.

Are you doing this also Nick?
No, my motor has been together for about 6 months or so.
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Old 04-24-2010, 01:33 PM   #30
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Rebello in Northern CA?
Yes, out of CA. And I see I had the incorrect spelling. It is indeed Rebello. My bad.
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Old 04-24-2010, 03:43 PM   #31
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Quote:
Originally Posted by JasonC SBB View Post
Loss in spool is kind of a myth.
The car may show less boost at a given RPM in logs in say 1st, but car accelerates faster.
It's a shame boost vs. RPM is so easy to log, since it's really not a good way of measuring anything. What you need to log is torque vs. time or RPM vs time.
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Old 04-25-2010, 01:41 PM   #32
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Bingo. Load a dyno as if a Miata weighs 3500LBs and a 35R will spool like 2860 in terms of RPM.


The lighter crank means you are probbably spending less time in 1st, 2nd , etc gear, which will slow your spool a bit. Basically you have less time at a decent load state to spool the turbo. So chances are the perceived boost threshold will be higher, despite the car accelerating better.

From what I can see the weights are for driveability and NVH reduction more than for the engine itself, like the balance shafts you see in a lot of I-4s.
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Old 05-05-2010, 03:59 AM   #33
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Rebello has been doing Datsun work for many many years and is one of the Bay Area's and maybe one of the nation's best 4/6 cyl machinists/engine builders.

They built a wicked n/a 2.4i setup for my friends 510 datsun that screamed.
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