I was wondering if i put a KB on my stock block with 12psi, how long will my stock block last before the KB eats it?

 

a couple of days tops.....................

 

No one can tell you that man, I blew my block with the eaton and a 4#'r....it's all a matter of tune, luck, and how you drive, weather conditions.....blah blah blah blah.

Some guys have had success....but I think you should count on having to build the block, and quite possibly the tranny.

Aside from that, I would go Works for better quality. The KB is getting to be like and opinion, everybody's got one.

 

Never if u have a good tuner........

 

Things will always break whether they are stock or modded. But at 12PSI your truck should live and long and healthy life. I wouldn't worry. -Mat-

 

the 12 psi from a KB places a lot more stress on your engine than 12 psi from an eaton.

BUT, with a good tune, you should be safe.

DON'T SKIMP HERE.

get a DYNO TUNE from a tier 1 supporting vendor (the big 4 vendors).
Think of it this way, would you rather pay a couple hundred for a Dyno tune or a couple thousand for a new block

 

dyno with different Pullies. Just keep your to the wheels Hp just above the 400/500 mark. GOing higher your engine might not approve

 

I can't argue 12 psi on any engine will cause stress, but I'd much rather 12 psi coming out of the KB than the 12 psi + most people are pushing out of the Eaton. I think if you can tune the kb well, you're in pretty good shape. If the trucks came with twin screws and we pushed the limits of the stock blocks like we are with the eatons, I think you'd see a lot less blown blocks wouldnt you agree?
Shane

 

i dont understand how the kb, eaton or any other blower would cause more stress on the motor at the same 12 psi peak. unless your refering to how much more efficient the kb is at making boost at lower engine rpm's (more boost at lower rpm's)

 

I think what he's talking about, is how forcefull the boost comes on, eaton builds up , KB comes on all at once. so the Instant hit is more stressfull than the gradual. or something like that.

 

Four score and seven beers.

 

does it matter how attractive the scores are? Cause that could be 1 day.

Oh and the eaton makes boost earlier on, the KB tends slightly to build boost. They are both pretty much instant on but the Eaton is more so.

The lb of boost really doesn't matter, in fact, you really want that number to be as low as possible for your application generally. What really matters is how much air you flow. Now normally increased flow increases backflo hence more boost. In anycase, the reason that the KB at 12 psi will make more stress than the eaton is that the KB will make more power. Notice that most people won't say that cranks or rods etc will be good up til xxx HP, thats how you should look at it. Without detonation, without problems, rods and pistons are good up to a certain HP after which they can no longer be counted on. I suppose this will apply to torque as well however I think higher rpms are harder on parts than lower end power (not sure on this one).

So Kb will make more power because it's more efficient, and makes less heat. Therefore your intenerals will take more stress from hp.

As for if we would be grenading blocks earlier or later with a twinscrew, i would say later. The main reason you can't go much past a 6lber is because the eaton generates too much heat to be effective at the top end rpm areas, and heat into the cylinder makes it more difficult to operate without detonation. Without certain octane gas in your area etc, it's just all out hard to do. If you did it with a KB up to an 6lber, you really shouldn't have a problem, and your outlet air will be generally cooler, making your tune easier to accomplish with less chance of detonation. Detonation is what kills these engines, it's what you have to combat. All the way up to the rod breaking point.

Either way, a KB won't grenade your block long as your tune is good.

 

My engine blew with a 3 lb lower pulley and a JL tuned diable chip(for the 3lb lower) back in october 2001. Does that means he was a bad tuner?

 

I am not an expert, but I think it depends on the RPM you turn with that 12psi more then the number itself. IMHO RPM is what kills engines more then boost, yes RPM generally = more power but it's also more engine stress. How many times have you heard of someone blowing an engine up at 2000 or 3000RPM? Most engines generally blow up when they are close to redline, remember that the faster you turn your engine the stress on the components goes up exponentially, not linearly.

At any rate, if you are worried about 12psi, why not shoot for 10psi and see where that takes you? 10psi from a KB should net a substantial amount more power then the same amount on an Eaton due to the efficiency.

EDIT: Forgot to add, the above statement about RPM vs Boost is based on a properly tuned setup as well, detonation or running too lean can blow engines at any rpm or boost level

 

Part of the gain in HP from the KB is because of reduced parasitic drag from the blower. These are just some general figures for an L with a few boltons and 12psi boost: (4#)

Eaton: 540 crank - 80 for blower and acces= 460 flywheel, 400 rwhp
KB: 573 crank - 55 blower and acces= 518 flywheel, 450 rwhp

KB: 540 crank - 55 blower and acces= 495 flywheel, 430 rwhp (maybe 10psi?)

Apten @ 13-14psi?
570 crank - 75 blower and accessories=495 flywheel, 430 rwhp?

Swapping to the KB gives you about a 25 hp cushion before you start stressing the motor more. If you keep the boost levels and RPM down the stock block should last a good while.