F/I Blowing motors facts

[ajc209]

Originally Posted by FRS Justin

I talked to Pauter rods yesterday (funny you should mention this), and Mario told me,
"The beginning stages of the pull have the most stress on the rod, if you start in 4th around 2000rpm the motor has enough power to overcome the load but the rod takes a beating on the small end. I have seen small end bushing failure result from this. Try to keep the rpm's above 5000 on a hard pull"
So you are 100% correct in what you stated Mr. Raven +1

The inertia in the crank has something to do with reducing stress on the rods at higher rpms. I don't pretend to properly understand it, but that's the principle im told.

[FRS Justin]

[QUOTE=moto-mike;2545126]This is what the rods look like:
QUOTE]THIS IS A PRIME EXAMPLE IF I'M SEEING CORRECTLY!!!! Look at the small end of the DIT rod that bushing looks hammered!!!!!! Mike will you please give us your input on this.


EDIT: Actually after zooming in too 200% they both look hammered on the top of the small end...

[AJPG]

Ok facts
1. FA20 Engine are failing at the rods first.
2. Rods are the weakest OEM component in the FA20.

Variables
1. AFR
2. Timing
3. Coolant temp
4. Oil temp
5. Fuel

Guest that also cloud destroy a built engine with a bat tune.

[BRZ RN]

Originally Posted by FRS Justin

I talked to Pauter rods yesterday (funny you should mention this), and Mario told me,
"The beginning stages of the pull have the most stress on the rod, if you start in 4th around 2000rpm the motor has enough power to overcome the load but the rod takes a beating on the small end. I have seen small end bushing failure result from this. Try to keep the rpm's above 5000 on a hard pull"
So you are 100% correct in what you stated Mr. Raven +1

but i wonder how i keep hearing stories about folks blowing their motor sub 320whp?

[FRS Justin]

Originally Posted by BRZ RN

but i wonder how i keep hearing stories about folks blowing their motor sub 320whp?

My guess factory rods and long low end pulls with a aggressive tune... JMO.....

[AJPG]

It could also be due to "aggressive" driving with poor temp control (oil/coolant) and "aggressive" tune.

[xkalelx]

Originally Posted by BRZ RN

but i wonder how i keep hearing stories about folks blowing their motor sub 320whp?

I would think tuning has more to do these failures than anything.

[denso]

Every knock event is a pain for (the) rods. If you have knock at tuning your engine you'll pull the timing/boost back but you didnt know "how damaged" the rods are from those, maybe particular knock events.

everybody knows that even a stock FA20 got knock - and even N/A FA20s blow holes into the shortblock.

I'm sorry for my bad english

[BRZ RN]

Sometimes im running slow on
N/A on 2nd Gear at 5-7mph in parking lots sometimes it jerks a bit, so thats bad for the rods right?

Sent from my SGH-T999 using Tapatalk

[ajc209]

Originally Posted by BRZ RN

but i wonder how i keep hearing stories about folks blowing their motor sub 320whp?

Becuase the rods wont last once you go much past 250whp. How long they last is a lottery im told with these sintered rods. Could be 50k miles, could be 10k, its down to rod tolerances.

[FRS Justin]

Originally Posted by BRZ RN

Sometimes im running slow on
N/A on 2nd Gear at 5-7mph in parking lots sometimes it jerks a bit, so thats bad for the rods right?

Sent from my SGH-T999 using Tapatalk

No that won't hurt the rods your good...

[denso]

Originally Posted by BRZ RN

Sometimes im running slow on
N/A on 2nd Gear at 5-7mph in parking lots sometimes it jerks a bit, so thats bad for the rods right?

Sent from my SGH-T999 using Tapatalk

At least you tried.

But it is how I said - every knock-event is bad for a rod. No matter of NA or FI. If you didnt get this just leave this thread.

A "good" tune is just a tune that hasnt knocked at the beginning at tuning, maybe it didnt even knocked (or maybe a very little bit). If the rods arent damaged from this they wont fail in future.

If you boost your engine and got knock at tuning it will hurt the rods more than a NA tune yeah, but its the same. If this engine got no damage at tuning your setup the FA20 will last.

Otherwise just tune it that you got the most torque at higher rpms so its less stress for the rods. (Listen to Christian van Koenigsegg... :P)

Thats why Ill go with a "bigger" turbine housing than usual. (and it helps with knock :P)

[fumanchu1]

Originally Posted by RichardsFRS

Agree with Sub. 300whp would be crazy. I would love 200 at the wheels after loss. Can you do that without turbo or blower? Can you buy a small displacement blower or turbo that won't wreck the engines? 300 would be fun but a lil dangerous for the engine

It's fun till the backend jumps and you land spinning tires forever and end up jumping a curb backwards... It's fun as hell but also treacherous is what I mean

[fumanchu1]

Originally Posted by ajc209

Becuase the rods wont last once you go much past 250whp. How long they last is a lottery im told with these sintered rods. Could be 50k miles, could be 10k, its down to rod tolerances.

I'd argue the 250whp figure but definitely the rods are the weak link of that engine, I'm at 300-/+(maybe up to 350) whp and still haven't thrown a rod yet (nothing pointing to the fact I will throw one in the near future), maybe I got lucky, maybe you 250whp dfigure is a bit low... Who know's, all I know is that if I hear knock that's the first thing I'm doing, opening the bitch up to inspect the pistons and rods.