Max power and torque in stock internals ??

[Rocco]

hi friends

do you know how many power and torque could be hold in our engines with stock internals and reliability ??

450hp limit with 9.3:1CR ??

600nm of torque could be too?


surelly with 9:1CR or less could be better for more power true?

of course always talking about to use 98Ron fuel

it would be nice to see and share the many experiences of us with our engines working with different powers and torque ...without upgrading internals

[QuattroFever]

I've read on here a while back that 550nm is as far as you want to go if you want to maintain some reliability. Anymore and your gambling everytime you nail it. Im sure there are some crazy swedes or norweigans that have made 650nm and I've heard tales of horrendous boost spikes but the stock motor took it.

Im trying this out at the moment before i swap my bottom end to see what it's capable of. Im currently on 1.3bar on a gt3071. Feels like 500nm @ about 3200-3500rpm.

Old stock setup was apparently 440nm high boost + high timing MRC'd and this is def. More torquey already by a fair margin.

[prj]

I don't understand why every month there is a new thread on this topic.
This has been discussed to death.

The last time here:

http://www.s2forum.com/forum/showthread.php?t=47697

You won't bed rods with torque or hp, you will only bend them with knock!
Map it with a safety margin, and you will not have any issues. There is nothing "crazy" about this, it is just proper mapping.

[Rocco]

thanks Dmitri

[QuattroFever]

I don't understand why every month there is a new thread on this topic.
This has been discussed to death.

The last time here:

http://www.s2forum.com/forum/showthread.php?t=47697

You won't bed rods with torque or hp, you will only bend them with knock!
Map it with a safety margin, and you will not have any issues. There is nothing "crazy" about this, it is just proper mapping.

EDIT: its in the link. No need to drag it out here.

[EspenW]

Update to my comment in that other thread:
I thought I was running right under 2.2bar, but seems that I have been running 2.5bar (at least for a while). Thus, I just got a new 2.5bar gauge

[Thuppu]

You won't bed rods with torque or hp, you will only bend them with knock!
Map it with a safety margin, and you will not have any issues. There is nothing "crazy" about this, it is just proper mapping.

So you say there is no power limit for the stock internals?

[quattrofrank]

Well, the problem is the torque on lower rpm`s. But in my mind to change the rod`s is a good guarantee to avoid damaging your engine if you want to be close to 600nm. I mean, its not cool to have a car wich you cannot floor on the highway beacuse you are afraid of bending the rods.

[EspenW]

We discussed this in the other thread (and a bunch of other threads), but here goes: The "problem" with torque at lower rpms is that high cylinder pressure at low rpms is the easiest way to introduce knock and preignition. In addition, the opposing load from inertia is much lower at low rpms, so detonation at higher rpms is safer since the piston inertia pulls the conrod hard in the other direction, equalizing some of the shock load.
Double your torque and peak compressive load (occurs around 15 degs ATDC) on the rods goes up by only approx. 20%. However, detonate, and peak load can spike by more than 1000%. Preignite so peak cylinder pressure peaks before TDC, and you got the inertia of the car and drivetrain pushing against the gas load. That spells trouble.
I'm currently at 2.5bar at 3600rpm and well over 600nm at the wheels. Reason why I don't bend anything is that I don't detonate on E85 (effective octane of 115+).

[prj]

So you say there is no power limit for the stock internals?

Well, it is not really possible to bend the rods with just normal operation...
But the more power you have, the smaller the margin for error.

On a k24-7200 it's pretty hard to bend rods unless you do really stupid things (or have a 3B ).
The stronger rods are just insurance. In case you or your tuner screw up the mapping or for some reason you suddenly lose fuel pressure during hard boost... or whatever...

And remember, even then, motronic will drop all the boost and pull lots of timing almost instantly.

Where problems happen, is when people have those "cool" boost controllers, which boost 2 bar when there is heavy knock.

[quattro84]

Respect to those who keep on explaining in these threads. It's useless IMHO to repeat it over and over again about when and were rod buckling occurs.

Still, the safe mapping is one part of the job. Keeping the engine up in good shape after mapping is as vital to ensure engine knock doesn't occur due to deterioration of the fuel- or ignition system. Be sure to have some margin in the mapping work to overcome for instance lower fuel quality (E85 quality in NL isn't constant, have heard of deviations up to E50 quality...)
Have seen guys running in excess of 500hp with dodgy sparkplugs/fuelpumps/plug leads and supply voltage drops complaining about the mapping itself...