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Old 03-10-2015, 12:44 AM   #81
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Quote:
Originally Posted by nitrodann View Post
Thats correct.

Ive never seen overshoot on an MX5 with a T2x turbo or EFR using competent boost control, and CERTAINLY not with only the wastegate can for boost control.

Dann
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

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Originally Posted by Savington View Post
Someone should probably explain the difference between boost overshoot and boost creep. I'm pretty sure Dann is referring to creep (boost rises with RPM regardless of wastegate spring pressure), while everyone else is referring to overshoot (boost rises rapidly past the wastegate spring pressure which creates torque spikes that can damage stock engines).
ok,
let me google that for you Dann
http://lmgtfy.com/?q=what+is+boost+creep
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Old 03-10-2015, 12:48 AM   #82
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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
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Old 03-10-2015, 02:30 AM   #83
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Reread what sav wrote, retard.

You failed at being a smartass.
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Old 03-10-2015, 03:18 AM   #84
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Originally Posted by 18psi View Post
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
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?
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Old 03-10-2015, 09:19 AM   #85
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Originally Posted by nitrodann View Post
What is the point and why.

Seriously, spell the point out and justify it.
i dont have time to teach you about inertia loads (tensile and compressive) and how the forces increase exponentially with rpms.
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Old 03-10-2015, 09:55 AM   #86
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Quote:
Originally Posted by nitrodann View Post
Reread what sav wrote, retard.

You failed at being a smartass.
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?
Quote:
Originally Posted by Savington View Post
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.
That engine stress doesn't increase past peak load?

Last edited by 18psi; 03-10-2015 at 10:41 AM.
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Old 03-10-2015, 10:00 AM   #87
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**** all your strawman semantics arguments. That includes you vlad.

this is what we are discussing:

Quote:
Originally Posted by nitrodann
Seriously, why do we give a **** if we get 5psi of creep past peak torque?
Quote:
If its past peak torque then its not putting any more stress on any components than peak torque already did. Which is why its called -peak- torque.
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.
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Old 03-10-2015, 10:06 AM   #88
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But bro, he's tuned so many cars.

..and set so many records
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Old 03-10-2015, 10:13 AM   #89
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talk about that.
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
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Old 03-10-2015, 05:14 PM   #90
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Originally Posted by Braineack View Post
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.
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?
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Old 03-10-2015, 05:48 PM   #91
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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.
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Old 03-10-2015, 06:05 PM   #92
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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.
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Old 03-10-2015, 06:41 PM   #93
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i dunno, i suppose. way to ruin it.
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Old 03-10-2015, 07:10 PM   #94
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Quote:
Originally Posted by 18psi View Post
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?
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
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Old 03-10-2015, 07:23 PM   #95
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i dunno, i suppose. way to ruin it.
I like you because you never let the truth get in the way of a good internet pissing match
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Old 03-10-2015, 07:25 PM   #96
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My dad did always tell me: "never let the truth ruin a good story"
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Old 03-10-2015, 10:46 PM   #97
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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
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Old 03-10-2015, 10:59 PM   #98
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Quote:
Originally Posted by Savington View Post
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.
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.
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Old 03-10-2015, 11:03 PM   #99
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Quote:
Originally Posted by Mobius View Post
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.
While at 7000rpms, they have to endure the force direction change nearly twice the amount of times within a given period.
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Old 03-11-2015, 08:15 AM   #100
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Quote:
Originally Posted by Savington View Post
I like you because you never let the truth get in the way of a good internet pissing match
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.

Last edited by Braineack; 03-11-2015 at 09:16 AM.
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