Anyone have a built motor using the stock STi crankshaft?

all4bspinnin · 08-04-2007, 12:40 PM

Just as the title says... Im thinking about putting together a built short for as cheap as possible, and i dont feel like spending 2k on a stroker crank. So has anyone put together a block with forged rods/pistons and uses a stock remanufactured crank?

-dave

jays05 · 08-04-2007, 01:01 PM

I'm using the stock crankshaft in my motor.

j87w · 08-04-2007, 01:37 PM

The stock Subaru crank should be plenty for most applications. I wouldnt worry about it at all. But if your shooting for 1000+ WHP your going to need to consider things like that. What are you goals?

Flycaster · 08-04-2007, 01:39 PM

Ditto, but it was a new stock crank. Unless you're planning on upping the redline well past 7.5K, the stock crank is fine.

all4bspinnin · 08-04-2007, 05:16 PM

i dont plan on pushing more than 500hp... and i dont plan on hittin 500hp within the next year...

im really looking to push around 450whp and i would like to rev the motor to at least 7500.... 8k if possible

what about a bigger bore with a longer rod on stock crank?

WOR440 · 08-04-2007, 06:22 PM

I was thinking of using the stock crankshaft in my new motor. I should be pushing 550whp+ on a built motor, but not revving too high.

j87w · 08-04-2007, 08:02 PM

Quote:

Originally Posted by all4bspinnin

i dont plan on pushing more than 500hp... and i dont plan on hittin 500hp within the next year...

im really looking to push around 450whp and i would like to rev the motor to at least 7500.... 8k if possible

what about a bigger bore with a longer rod on stock crank?

IMO the stock crank will suit your goals just fine. Why do you want to rev it to 8k? Just wondering because if it doesnt make power that high then why rev it that high.

Im not to sure what the bore limit is going to be with your app but you can only go so big of a bore before your sleeves become to thin and they may crack. Also you can add a longer rod to increase the rod to stroke ratio (letting you rev your engine higher safer) but I believe you will need longer sleeves to accomidate for how far the piston is now going out(it will have the same stroke but it will have less force on the sidewall)

Goodluck

modaddict · 08-04-2007, 08:36 PM

99% of the "built" motors are on a stock crank. Usually only the strokers get the billet/forged stuff.....there are a few exceptions though.

stock crank is fine for 8k rpm.....the biggest thing is ZERO knock at that rpm....the oil starts to loose flow at that rpm and then you combine it with detonation.....your rods and rod bearings like to hold a party in the oil pan.

***520*** · 08-04-2007, 08:39 PM

^ haha +1.

stock crank here as well.

flatthump · 08-04-2007, 08:43 PM

Is the stocker fully counter balanced?

all4bspinnin · 08-04-2007, 10:47 PM

honestly, 8k is not really a must have... it would be nice but i would be happy with reving to 7k...

im just wondering what all goes into the crank on a built motor, balancing, etc..

i want ZERO oiling issues...

what are people doing with the rods on a stock crank? longer, shorter? Does anyone have a setup they recommend as far as rods and pistons, bore?

modaddict · 08-05-2007, 07:54 AM

pretty much the engine builders combo's are all proven. Crawford, Cobb, Axis etc.... get one of their engine's such as an S3L-h from crawford....."Street stage 3, Long rod, h-beam"

Or a stage 2 from cobb....same thing....forged pistons, long rods, stock crank.

Don't try and reinvent the wheel, buy a combo already proven....you'll be much happier in the end.

If you want to build it yourself, Crawford sells the S3l packages in pieces, and you assemble it.

crystal_Imprezav · 08-05-2007, 09:57 AM

Stock crank w/ a jdm oil pump modified with an extra shim and slightly deburred/ported will be plenty good. At around 500whp is where you should be considering sleeves vs no sleeves. IMO the crank would be the least of your worries at those power levels. The only reason I would upgrade the crank was either 1) to get more displacement or 2) to get a lighter rotating assembly. Otherwise, if you were really paranoid, you should get some extra drilling done on the crank. My 2 cents

crystal_Imprezav · 08-05-2007, 09:59 AM

As for bore. If your going to use a new block casting stick with the stock bore of 99.5. The stock bore and hone that comes from the factory will be better than any machine shop can produce. If rebuilding a used block, go with 100 overbore and make sure they are using torque plates on the bore/hone.

all4bspinnin · 08-05-2007, 06:02 PM

Quote:

Originally Posted by crystal_Imprezav

As for bore. If your going to use a new block casting stick with the stock bore of 99.5. The stock bore and hone that comes from the factory will be better than any machine shop can produce. If rebuilding a used block, go with 100 overbore and make sure they are using torque plates on the bore/hone.

gotcha, now what kind of displacement increase is a 100mm bore? I plan on doing this...

deburred/shimmed crank (like u said), forged pistons and rods, ARP headstuds... who makes a goodrod bearing? Anything else i should be considering? So dont worry about sleeves since im shooting for around 400-450whp?

i can get rods and pistons at cost price since a good friend of the family works for a major performance distributor. Due to the "hookups" i have im pretty sure i'll be able to put this block together for less than 2500

08-04-2007, 12:40 PM	#1
all4bspinnin Spec C Club Car: 06 BLACK STI!!! Fav Mod: Annual Bonus!! Location: jax, FL Posts: 1,375 Join Date: Jul 2006 Trader Rating: (2)	Anyone have a built motor using the stock STi crankshaft? Just as the title says... Im thinking about putting together a built short for as cheap as possible, and i dont feel like spending 2k on a stroker crank. So has anyone put together a block with forged rods/pistons and uses a stock remanufactured crank? -dave This ad is not endorsed by this member. Please register or login to hide this ad.

08-04-2007, 01:01 PM	#2
jays05 Spec C Club Car: Blue 05 STI Fav Mod: Synapse FMIC Location: Upstate NY Posts: 1,721 Join Date: Nov 2004 Trader Rating: (0)	Re: Anyone have a built motor using the stock STi crankshaft? I'm using the stock crankshaft in my motor.

08-04-2007, 01:37 PM	#3
j87w Senior STI Driver Car: 06 STi Location: New Mexico Posts: 393 Join Date: Oct 2006 Trader Rating: (1)	Re: Anyone have a built motor using the stock STi crankshaft? The stock Subaru crank should be plenty for most applications. I wouldnt worry about it at all. But if your shooting for 1000+ WHP your going to need to consider things like that. What are you goals?

08-04-2007, 01:39 PM	#4
Flycaster S204 Racer Posts: 3,008 Join Date: Apr 2004 Trader Rating: (0)	Re: Anyone have a built motor using the stock STi crankshaft? Ditto, but it was a new stock crank. Unless you're planning on upping the redline well past 7.5K, the stock crank is fine.

08-04-2007, 05:16 PM	#5
all4bspinnin Spec C Club Car: 06 BLACK STI!!! Fav Mod: Annual Bonus!! Location: jax, FL Posts: 1,375 Join Date: Jul 2006 Trader Rating: (2)	Re: Anyone have a built motor using the stock STi crankshaft? i dont plan on pushing more than 500hp... and i dont plan on hittin 500hp within the next year... im really looking to push around 450whp and i would like to rev the motor to at least 7500.... 8k if possible what about a bigger bore with a longer rod on stock crank?

08-04-2007, 06:22 PM	#6
WOR440 STI Driver Car: 05 STi Fav Mod: <---- Agile Tuned STi Location: Altoona, PA Posts: 244 Join Date: Jan 2006 Trader Rating: (0)	Re: Anyone have a built motor using the stock STi crankshaft? I was thinking of using the stock crankshaft in my new motor. I should be pushing 550whp+ on a built motor, but not revving too high.

08-04-2007, 08:36 PM	#8
modaddict Spec C Club Car: 04 Crawford STi Fav Mod: CP35r 440whp Posts: 2,008 Join Date: Jun 2006 Trader Rating: (3)	Re: Anyone have a built motor using the stock STi crankshaft? 99% of the "built" motors are on a stock crank. Usually only the strokers get the billet/forged stuff.....there are a few exceptions though. stock crank is fine for 8k rpm.....the biggest thing is ZERO knock at that rpm....the oil starts to loose flow at that rpm and then you combine it with detonation.....your rods and rod bearings like to hold a party in the oil pan.

08-04-2007, 08:39 PM	#9
*520* STi > EVO... Wait what??? Car: 03 EVO Fav Mod: stock :( Location: Michigan / Saint Louis Posts: 12,397 Join Date: Oct 2005 Trader Rating: (1)	Re: Anyone have a built motor using the stock STi crankshaft? ^ haha +1. stock crank here as well.

08-04-2007, 08:43 PM	#10
flatthump Enginerd Car: The Spaze Mobile Fav Mod: Tuning Location: South O.C., Ca Posts: 13,025 Join Date: Jan 2006 Trader Rating: (5)	Re: Anyone have a built motor using the stock STi crankshaft? Is the stocker fully counter balanced?

08-04-2007, 10:47 PM	#11
all4bspinnin Spec C Club Car: 06 BLACK STI!!! Fav Mod: Annual Bonus!! Location: jax, FL Posts: 1,375 Join Date: Jul 2006 Trader Rating: (2)	Re: Anyone have a built motor using the stock STi crankshaft? honestly, 8k is not really a must have... it would be nice but i would be happy with reving to 7k... im just wondering what all goes into the crank on a built motor, balancing, etc.. i want ZERO oiling issues... what are people doing with the rods on a stock crank? longer, shorter? Does anyone have a setup they recommend as far as rods and pistons, bore?

08-05-2007, 07:54 AM	#12
modaddict Spec C Club Car: 04 Crawford STi Fav Mod: CP35r 440whp Posts: 2,008 Join Date: Jun 2006 Trader Rating: (3)	Re: Anyone have a built motor using the stock STi crankshaft? pretty much the engine builders combo's are all proven. Crawford, Cobb, Axis etc.... get one of their engine's such as an S3L-h from crawford....."Street stage 3, Long rod, h-beam" Or a stage 2 from cobb....same thing....forged pistons, long rods, stock crank. Don't try and reinvent the wheel, buy a combo already proven....you'll be much happier in the end. If you want to build it yourself, Crawford sells the S3l packages in pieces, and you assemble it.

08-05-2007, 09:57 AM	#13
crystal_Imprezav Spec C Club Car: Slow 05 STi Fav Mod: Loping Idle Location: Chewy's Garage Posts: 1,881 Join Date: Mar 2005 Trader Rating: (12)	Re: Anyone have a built motor using the stock STi crankshaft? Stock crank w/ a jdm oil pump modified with an extra shim and slightly deburred/ported will be plenty good. At around 500whp is where you should be considering sleeves vs no sleeves. IMO the crank would be the least of your worries at those power levels. The only reason I would upgrade the crank was either 1) to get more displacement or 2) to get a lighter rotating assembly. Otherwise, if you were really paranoid, you should get some extra drilling done on the crank. My 2 cents

08-05-2007, 09:59 AM	#14
crystal_Imprezav Spec C Club Car: Slow 05 STi Fav Mod: Loping Idle Location: Chewy's Garage Posts: 1,881 Join Date: Mar 2005 Trader Rating: (12)	Re: Anyone have a built motor using the stock STi crankshaft? As for bore. If your going to use a new block casting stick with the stock bore of 99.5. The stock bore and hone that comes from the factory will be better than any machine shop can produce. If rebuilding a used block, go with 100 overbore and make sure they are using torque plates on the bore/hone.