18psi

iTrader: (76)

see keiths build thread because I sure as heck am not about to post dozens of links to prove what we've all already known since 1995

ok,
let me google that for you Dann
http://lmgtfy.com/?q=what+is+boost+creep

18psi

iTrader: (76)

also see my buddy's fastivab25mr (or whatever his sn is) 300whp BP with stock rods that ejected them with ewg and only a can for boost control.
haven't seen much? tune more BP's

PS: my buddy's rods all ejected PAST peak torque. that should blow your mind

nitrodann

Reread what sav wrote, retard.

You failed at being a smartass.

Savington

iTrader: (31)

You should probably post a link, because from where I'm sitting you sound like someone who doesn't actually understand the topic you're attempting to talk about.

e: This thread is basically a clusterfuck of nomenclature. Boost creep (boost rises with RPM, max boost at/near max power) doesn't put any additional stress on rods if it doesn't move the torque peak up. Uncontrolled creep is still not desirable because you can outrun the fuel injectors and it generally means the wastegate setup is pretty ****-poor. Boost overshoot (boost immediately rises beyond the desired level, max boost at/near max torque) is seriously undesirable in all cases and, by definition, is never induced on purpose. Most of you are talking about overshoot, but saying "creep". Dann is talking about creep as I've defined it.

Can we get back to talking about how kludgy exhaust restrictors are now?

Braineack

iTrader: (62)

i dont have time to teach you about inertia loads (tensile and compressive) and how the forces increase exponentially with rpms.

18psi

iTrader: (76)

Are you back to being a complete and utter child and lashing out again?
Are you back to neg propping every single one of my posts again?

Is it that time of the month for you again?
That engine stress doesn't increase past peak load?

Braineack

iTrader: (62)

**** all your strawman semantics arguments. That includes you vlad.

this is what we are discussing:

and I'm the only one who's addressed his question and completely bogus statement and it pisses me off that you're wasting words talking about creep or overshoot or creep vs overshoot.

Nitro's theory is that peak torque on a dyno plot is the peak load of an engine's conponents, so he tunes his cars to increase boost after peak torque to keep the torque output flat to redline.

talk about that.

18psi

iTrader: (76)

But bro, he's tuned so many cars.

..and set so many records

18psi

iTrader: (76)

he would not comprehend how people bend rods by revving past 7k n/a

will not fit into brain

because literally nothing past peak load matters. nothing bro. nothing. no stress on the components, just run ALLOFIT on an upsidedown dyno and your stock rods are fine

Savington

iTrader: (31)

So you're saying that 220ft.lbs of torque at 7000rpm is harder on an engine than 250ft.lbs of torque at 4000rpm? Or am I still confused?

Braineack

iTrader: (62)

in regards to tensile or total inertial loads, yes. total compression or power loads, no.

if you're inducing "creep" to maintain peak torque to redline, you're putting more load/stress on the rods the greater the rpm.

Savington

iTrader: (31)

More tensile load/stress, yes, but not more than a stock motor can handle (unless you rev it past 7k, which nobody has suggested). The compression load is what the stock rods care about, and the peak compression load happens at peak torque.

IOW, if the motor copes with 230wtq at 4000rpm, is 210wtq at 7000rpm going to break it? I think not.

Braineack

iTrader: (62)

i dunno, i suppose. way to ruin it.

nitrodann

Considering the fact that no one here has lost props to me, and I'm 28 props down compared to this time yesterday, and the fact that you are still wrong, I'd say you are projecting.

Dann

Savington

iTrader: (31)

I like you because you never let the truth get in the way of a good internet pissing match

aidandj

iTrader: (5)

My dad did always tell me: "never let the truth ruin a good story"

Corky Bell

Nitro, Hang in there.

Vbad, ??//?????///???

2D: You need V clamp? I Make V clamp. A/O can do both.

Loads: Get a plot of chamber pressure vs crank angle. Multiply piston area times chamber pressure at every degree and plot. At each degree of crank angle, calc the inertial loads. Plot. Add the two loads together for every degree for a total load. Calc column buckling strength of the con rod. Take worst case compressive sum and adjust boost (reflecting pressure load) and rpm (inertial load) to stay below the column buckling load.

It appears nitro has figured this out, its just hard to get past the accent.

Subject for the next thread: In what month of the year do the Aussies drink the least amount of Tequila?

corky

Mobius

iTrader: (2)

Andrew r smart and understand physics.

In terms of compressive loads, 230wtq at 4000 vs 230wtq at 7000 is always going to be harder on the rods, because they have to endure that compressive load for nearly twice the amount of time.

concealer404

iTrader: (3)

While at 7000rpms, they have to endure the force direction change nearly twice the amount of times within a given period.

Braineack

iTrader: (62)

Of course!



I haven't really read up on loads in a quite a while--it's probably been over 10 years.

I was thinking that if you added boost to redline and since tensile load is a function of rpm^2 that the loads would significantly increase as you reach redline, compared to if you held it steady. But that was wrong because that extra boost doesn't really factor into those loads and any increase in boost is really just making up for the loss of combustion pressure due to the speed of the explosions relative to the crank angle and all that business.

Plus I really just wanted to argue about something.


it takes a brave/strong man to admit he was wrong--remember that.