mdvaldosta

Its not the boost thats hard on the engine, its the cylinder pressure. Boost is kinda directly related to cylinder pressure, but there are alot of other factors. Generally 8 psi is considered the max "safe" amount on the rods, but alot of people feel 10 psi is ok as well. Sure there are some people running more boost, even 14psi on a stock block, but the rods are just powder'd metal cast weak rods that will bend or break under too much pressure - especially when you combine pressure + rpms.

Alot of people say you can run more boost with the KB than a centrifugal supercharger (like vortech) because the boost comes in faster and you don't rev as high as the vortech units. You can honestly run damn near 500 hp on the stock rods and a safe tune as long as you keep the revs down. On the stock rods NA their said to be safe till 6500, with a 400hp car their not safe past 6k.

jdaniel

This being the main reason Im scared to get a blower. I have a LEADFOOT!!! There is no way in hell I would be able to keep off it!

callmecobra

ive heard the opposite md, since the kb boosts instatly, it creats a sudden strain on the motor. while on other hand, the centrifugal builds up, and is easier on the motor.

jdaniel

I drove a '03 Cobra and the boost is there INSTANTLY!!! As soon as you press the gas the boost gauge shoots through the roof! Its awsome!

mdvaldosta

It may be that way with the pistons nomo but its not that way with the rods, its more hp at higher rpm's that are hard on rods - and the rods are the weak link in the mod motors (assuming a safe tune for the pistons's sake). The cranks virtually NEVER break, and the pistons only really have trouble with bad tunes, so the rods are what I'd be worried with.

callmecobra

yeah, your totally correct about the rods at high rpm's. but i would think that instant boost, would cause strain on the entire motor, when it first hits hard?

w11988

I guess I should have said something like 14# is too much to run safely or for very long. Even with a great tune, I don't think you would run too long be bending a rod at 14#. Of course if you beefed up the bottom end and have a good tune, 14# would be fine, but upgrading your rods and pistons is definitely a different story than stockers. Sorry if I wasn't clear.

ricekiller2003

I have a MAC Pro Chamber Exhaust (with no cats) and I love it. It has a very deep and authoritative sound...but the biggest thing was the perf. gain! I could not get my car past a 14.3 on the quarter (silencer removed) with the stock exhaust. I got the MAC Pro Chambers and Dynomax Race Magnum Mufflers all installed at the same time. I ran a 14.1 for my lowest times and ALWAYS stayed UNDER 14.3 consistently after that...great mod.

The cheapest way to make your car run high 12's...

Rip off the exhaust after the headers. Remove the silencer and put a K&N in there. Get a cheap, basic bottle of nos, remove the rear seats and spare tire, ice the intake and warm up the tires hard!

A supercharger would work too. 8 - 10 psi sounds about right on a stock engine. Anymore and you'll be getting forged internals put in your NEXT engine.

mdvaldosta

I see your reasoning, the low rpm high boost amounts working against the pistons would put alot of pressure on them. Both ways may be hard on the engine, but I can certainly say that all the rod failures I've ever heard of have been at high rpm with high hp engines, and the KB doesnt recommend running over 6k rpm - besides the power starts dropping off then anyways - and with a centrifugal the power is gonna continue to increase virtually no matter how high you rev - which makes it more tempting to rev high.

2002stang

So whats the opposition?

I see lots of people with these vortechs, I do drive to work everyday, after i get the s/c Ill probally get a cheap beater, but ill still drive to work somedays.

Essentially, Im not hurting anything aslong as i dont Exceed 8psi? Whats wrong with punching it everynow and then?

I just want to know before i save for this, if this is going to do damage even under moderate levels or will it still be a overall safe side for normal and some enthusiast driving.