Just wondering if I had the stock crank polished and all would it be able to hold 15psi of boost. Not all the time. Just once in a great while. Kinda on a budget

 

I was up to 18 on mine. It never broke, and lasted for over a year.

 

I would think it could do it. Stock cranks are tough. Just make sure the pistons and rods are forged. What is your compression ratio gonna be?...

 

If you only unleased the that much boost every once in a while, and as CrazyLT1 stated, if you have forged pistons and rods, then it might hold up for quite a while. There is a possiblity that it might not though. I think the odds are in your favor that it will last for a while, but you would still be taking a risk.

 

Usually around or over 550 RWHP is where you have to begin worrying about the stock crank

 

Then why did you say you think he could do it? 15psi on just about anything is going to be over 550rwhp.

 

15psi coming from what?, what else is done to the motor? Heads/cam? Compression ratio? 15PSI from a 60-1 turbo might hold, but 15psi from a 91mm wouldnt.

 

why would you chance it ????? all that time and money into the shot block to save $400....

save time and money and do it once.......

 

Honestly, its alot more than 400. Thats why people dont do it. One of the biggest problems is the main caps. Without converting to a 4 bolt splayed set up..running a forged crank is useless. The caps still cant take that much power. And doing that is alot more. Figure a little over 500 for the crank, 200 for some decent caps, 100? for studs, and about 450 in machine work..thats about almost 1100$

 

I no the cost because i did it....is it really worth the money saved ??? I am making 15lbs of boost.....do you think i would trust a stock crank @686rwhp.....it could cost you everything in the end.......and that bill will be over the $1000 mark

Save your money and do it right the first time.....i took a full year off to do my car.....and that was the best thing i did .....

 

Yes, def. Unless you have someone like me. Before I bit the bullet and went with the good stuff, I was going to build just a basic small boost engine to kinda practice on. Next year im going with a 6speed and 10psi so I really dont have to make much power. Plus its going to be 99.99% street car. Im going to go to the track maybe 2-3 times all summer. After the summer is over I plan on redoing EVERYTHING (except the turbo kit itself)..bigger turbo, better motor,and a 3speed auto. That way it will be a track only car. I know im rambling..but in my car..i wanted to "learn" on a cheaper setup. Im only loooking to making 550rw so a stock crank woulda been fine. Id feel MUCH better about myself blowing a 2,000$ short block as opposed to blowing a 5,000$ short block.

 

There is no evidence that proves an aftermarket crank is any stronger than a stock crank. Me and a friend work on boosted LT1's all the time. NEVER seen a stock crank break. Have seen the crank "walk" a couple times on stock 2 bolt mains, but this was also around the 630 RWHP mark....but the crank itself was fine.....

 

I agree. And was the cap walk with studs? or bolts.

 

The cap walk was with just the stock bolts. I think that 2 studded caps can be stronger than 4 bolt mains

 

With stock caps?..where can you get stronger 2bolt caps?