Anyone have a built motor using the stock STi crankshaft? - Page 4

all4bspinnin · 08-08-2007, 07:52 AM

Quote:

Originally Posted by PowerLabs

What if you get a used engine block and want to drop forged pistons in it? Do you rehone?

im assuming you would... esp if it has cyclinder scaring

Ive found a 2.5 sti block... all i need now is a crank shaft... i can get the pistons and rods easily...

rjacobs · 08-08-2007, 09:21 AM

Quote:

Originally Posted by all4bspinnin

Does anyone know specifically what he does?

Call him or go on the website and send an email.

314-443-7414
http://www.axispowerracing.net/

I doubt he will tell you exactly what he does, but hell give you a good idea.

**CrawfordPerformance.com** · 08-09-2007, 07:24 AM

Quote:

Originally Posted by PowerLabs

What if you get a used engine block and want to drop forged pistons in it? Do you rehone?

Yes sir

all4bspinnin · 08-09-2007, 10:05 AM

Quote:

Originally Posted by Crawford/I-Speed

Yes sir

so what are the piston/rod specs on a 2.6 ltr using stock crank?

can you get a 2.65 ltr out of the stock crank?

modaddict · 08-09-2007, 10:08 AM

Quote:

Originally Posted by all4bspinnin

so what are the piston/rod specs on a 2.6 ltr using stock crank?

can you get a 2.65 ltr out of the stock crank?

Im not sure they use a 2.6l on a stock crank?

here's from their website:

Specifics on the 2.6 Liter Short Block (S4):
- Crawford Performance designed Billet 4340 rods
- Crawford Performance designed pistons
- Crawford Performance designed Billet Stroker Crank (82.5mm)
- New 2.5 Liter USDM STi Short Block
- Cast Semi-Closed Turbo Block

Note: The Big Valley Team runs a 9.5@150mph with the S4 short block.

modaddict · 08-09-2007, 10:16 AM

Quote:

Originally Posted by all4bspinnin

so what are the piston/rod specs on a 2.6 ltr using stock crank?

can you get a 2.65 ltr out of the stock crank?

you can either bore AND/OR stroke for more displacement. the problem with boring is it weakens the sleeves a little. In these engines, it is IMO, that i would rather have a stroker, than one that is purely bored out. (I have just a little worry about the stock sleeves holding up for years with 25psi of boost)

If you go 1mm over...that's what... .040"?

You can also play the rod/stroke ratio card, with stroking an engine.....or the flame and quench with a larger bore. There's more than 1 way to skin a chicken. they both have pro's and con's. it is then, you leave it up to the people (vendors) that do this thing every day. Day in, and day out.

Flycaster · 08-09-2007, 10:46 AM

Just keep things in perspective: the old adage is, "there is no substitute for displacement", but 0.1 Litre is only a hair over 6 cubic inches. We're talking very big $$$ for very little displacement gain. It's just my opinion, but I think there is much lower hanging fruit on the tree.

***Neanderthal Racing*** · 08-09-2007, 10:52 AM

Quote:

Originally Posted by Flycaster

I think there is much lower hanging fruit on the tree.

i reached through a small hole to grab a piece of fruit once. i was stuck there for hours until i realized all i had to do was drop the fruit...duh (isfh).

all4bspinnin · 08-10-2007, 04:06 AM

Quote:

Originally Posted by modaddict

you can either bore AND/OR stroke for more displacement. the problem with boring is it weakens the sleeves a little. In these engines, it is IMO, that i would rather have a stroker, than one that is purely bored out. (I have just a little worry about the stock sleeves holding up for years with 25psi of boost)

If you go 1mm over...that's what... .040"?

You can also play the rod/stroke ratio card, with stroking an engine.....or the flame and quench with a larger bore. There's more than 1 way to skin a chicken. they both have pro's and con's. it is then, you leave it up to the people (vendors) that do this thing every day. Day in, and day out.

so which one would you go with?

PowerLabs · 08-10-2007, 06:59 AM

I subscribe to the school of thought that says it is money better spent elsewhere.
Don't get me wrong, I would LOVE to have an engine that is sleeved, then bored, and stroked, and then drive that with the biggest turbo I can drive in the street.
Unfortunately though, money being a constraint, you see that those extra $5000 that would go into the boring and stroking would also buy all kinds of other things that would benefit the car much more... Like, say, a really well sorted out turbo kit, meth injector, a nice intercooler, etc etc.

modaddict · 08-10-2007, 07:35 AM

Quote:

Originally Posted by all4bspinnin

so which one would you go with?

If I had the money and decided to increase my displacement? I would keep an OEM bore and put a longer stroke crank in the engine.

this is why:
-You're not weakening the sleeves at all. You have the strongest sleeve possible without actually sleeving the engine with those fancy Darton pieces.

-It will solve the high rpm oiling issues. Aftermaket cranks are drilled different and suposedly have better oiling characteristics.

-You're talking 1300-2k for an aftermaket crank (with a small increase...the bigger the increase in stroke, the costlier the crank)

This is just my opinion. You'll find lots who agree, and lots who disagree.

***Neanderthal Racing*** · 08-10-2007, 09:49 AM

the reason why i didn't do a cobb pro stage2 is i could not afford its 2.65 billet crank at that time. cobb was generously willing to build me a pro stage 1 with the stock crank and for that, i am eternally grateful. god bless trey cobb and jeremy.

so, to increase displacement we settled on an overbore that would bring us to almost 2.6L and still leave some service room with the sleeves when the time comes.

there is an upside and a downside to everything. the upside of an overbore is you aren't affecting piston speeds which helps with spool.

here are a couple of useful articles on bore vs stroke:

http://findarticles.com/p/articles/m...9/ai_n15614621

http://en.wikipedia.org/wiki/Stroke_ratio

http://www.hotrodders.com/forum/big-...ke-103595.html

all4bspinnin · 08-10-2007, 09:59 AM

Quote:

Originally Posted by Neanderthal Racing

the reason why i didn't do a cobb pro stage2 is i could not afford its 2.65 billet crank at that time. cobb was generously willing to build me a pro stage 1 with the stock crank and for that, i am eternally grateful. god bless trey cobb and jeremy.

so, to increase displacement we settled on an overbore that would bring us to almost 2.6L and still leave some service room with the sleeves when the time comes.

there is an upside and a downside to everything. the upside of an overbore is you aren't affecting piston speeds which helps with spool.

here are a couple of useful articles on bore vs stroke:

http://findarticles.com/p/articles/m...9/ai_n15614621

http://en.wikipedia.org/wiki/Stroke_ratio

http://www.hotrodders.com/forum/big-...ke-103595.html

excellent, thanks!

id like to build a motor that would spool a gt30 ungodly fast and still be reliable... i'll research and find the best compromise of the two...

im thinking pretty much like what you built..

***Neanderthal Racing*** · 08-10-2007, 01:06 PM

Quote:

Originally Posted by all4bspinnin

excellent, thanks!

id like to build a motor that would spool a gt30 ungodly fast and still be reliable... i'll research and find the best compromise of the two...

im thinking pretty much like what you built..

here's the pro stage1 page of cobb's site. tell jeremy you want the "big bore" (aka "the cutn edg monster")
http://www.cobbtuning.com/products/D...id=2263&v=more

08-09-2007, 10:46 AM	#52
Flycaster S204 Racer Posts: 3,008 Join Date: Apr 2004 Trader Rating: (0)	Re: Anyone have a built motor using the stock STi crankshaft? Just keep things in perspective: the old adage is, "there is no substitute for displacement", but 0.1 Litre is only a hair over 6 cubic inches. We're talking very big $$$ for very little displacement gain. It's just my opinion, but I think there is much lower hanging fruit on the tree.

08-10-2007, 06:59 AM	#55
PowerLabs Professional STI Driver Car: 2006 Corvette Z-51 Fav Mod: Buying a new car. Location: All around the US Posts: 429 Join Date: Mar 2007 Trader Rating: (0)	Re: Anyone have a built motor using the stock STi crankshaft? I subscribe to the school of thought that says it is money better spent elsewhere. Don't get me wrong, I would LOVE to have an engine that is sleeved, then bored, and stroked, and then drive that with the biggest turbo I can drive in the street. Unfortunately though, money being a constraint, you see that those extra $5000 that would go into the boring and stroking would also buy all kinds of other things that would benefit the car much more... Like, say, a really well sorted out turbo kit, meth injector, a nice intercooler, etc etc.

08-10-2007, 09:49 AM	#57
*Neanderthal Racing* GT R US Car: CUTN EDG project Fav Mod: $20. mudflaps from auto zone Location: my cave Posts: 5,847 Join Date: Dec 2003 Trader Rating: (1)	Re: Anyone have a built motor using the stock STi crankshaft? the reason why i didn't do a cobb pro stage2 is i could not afford its 2.65 billet crank at that time. cobb was generously willing to build me a pro stage 1 with the stock crank and for that, i am eternally grateful. god bless trey cobb and jeremy. so, to increase displacement we settled on an overbore that would bring us to almost 2.6L and still leave some service room with the sleeves when the time comes. there is an upside and a downside to everything. the upside of an overbore is you aren't affecting piston speeds which helps with spool. here are a couple of useful articles on bore vs stroke: http://findarticles.com/p/articles/m...9/ai_n15614621 http://en.wikipedia.org/wiki/Stroke_ratio http://www.hotrodders.com/forum/big-...ke-103595.html