limits on lb7 rods?

[RENODMAX]

Torque kills stuff. Its not necessarily just "having the fuel" to bend rods, its how/when that fuel is injected and combusted (or not). I also think it is a balancing act making rods and pistons survive. I have seen broken or poorly calibrated injectors open too soon and ignite dodge cr pistons (400 some cc/min flow) which is way more fuel than you will be injecting. Straight rods and melted slugs With lots of fuel I would be more worried about pistons really shitting the bed. I think you are over fueling that 4088 and could at least upgrade it to a 4094 to cool it down as that 4088 is a relatively hot blooded thing, so take into account that the more fuel you put through an injector it gets exponentially hotter.

 

[SteveFord]

Ask Trent lol

:secret:

 

[paint94979]

The fact that I have a big single probably helps a lot

 

[SteveFord]

The fact that I have a big single probably helps a lot

What the hell happened to your avatar!?

 

[McRat]

I normally defuel tuning under 2500, and sometimes all the way up to 3000. IIRC, when we ran the GT45, it was ~800rwhp at 1200ftlb, but peak power was 4400rpm? Dunno, I'd have to look it up.

When racing, you don't need big power under 2500. And 1200ftlb is still lots of bottom end for launching.

The original fantasy I had 6 years ago was running a stock long block at 750rwhp by keeping the torque low, and HP peak up high. Many of our Casper engines were fairly low torque. Even at 750rwhp, it took a good number of passes before we started bending the rods. Obviously I didn't detorque it enough.

Big chargers are your friend if you're going to try and run big power on a stock longblock.

 

[x MadMAX DIESEL]

good read so far. Would an s472 be a "big enough single" on the stock bottom end to help alot?

 

[McRat]

As a rule of thumb:

2.6" charger 3600 rpm peak HP
2.8, 3800 peak HP
3.0, 4000 peak
3.2, 4400 peak.

The higher that peak is, the better your HP/TQ ratio is.

If you could peak at 5252, you could have HP=TQ, or 1200HP at 1200ftlb.

 

[dieselson]

On our last motor, we ran a gt4088r turbo, duel fuelers, on the highest tune for about 1 1/2 years, with 80+ 1/4 mile runs and a dyno run to 618. When we tore it down to do the head gaskets, and decided to use a new motor, we tore apart the old motor and found that the rods weren't bent in the slightest, and the pistons looked good too. I definetly believe that tuning plays the biggest role in helping your engine live, because my dad was, by no means, easy on that truck. Hopefully this new motor should be good, dyno'd 654 whp so far with no problems at all as of yet and only thing done to it is head studs and C grade gaskets.

 

[jonathancasey19]

On our last motor, we ran a gt4088r turbo, duel fuelers, on the highest tune for about 1 1/2 years, with 80+ 1/4 mile runs and a dyno run to 618, and when we tore it down to do the head gaskets, and decided to use a new motor, we tore apart the old motor, and found that the rods weren't bent in the slightest, and the pistons looked good too. I definetly believe that tuning plays the biggest role in helping your engine live, because my dad was, by no means, easy on that truck. Hopefully this new motor should be good, dyno'd 654 whp so far with no problems at all as of yet and only thing done to it is head studs and C grade gaskets.

Thank you for that info! I appreciate the feedback from everyone. Good read x2

 

[ChevyDieselLLY]

Yea the less torque the better with my stock turbo I dynoed 590 and 1100. So who knows what I was making with the twins.

 

[Mike_S]

How in the world did you tune your torque so low?

RPMs my friend, more RPMs.

 

[x MadMAX DIESEL]

So who all is running 4k on the street? And is the general consenus that torque down low breaks or bends rods. And High cylinder pressure from long injection duration what kills the pistons whether cracking or just melting?

 

[Drholliday]

So who all is running 4k on the street? And is the general consenus that torque down low breaks or bends rods. And High cylinder pressure from long injection duration what kills the pistons whether cracking or just melting?

If I'm over 60% throttle I hit 4k on the street.

 

[x MadMAX DIESEL]

If I'm over 60% throttle I hit 4k on the street.

Have alot of run time on your new engine setup, still stock bottom end right? dyno or track times?

 

[Drholliday]

Have alot of run time on your new engine setup, still stock bottom end right? dyno or track times?

Stock bottom end, 40k-50k with the S475, about 5k with the dual fuelers. I'm up to 120k on the motor total. With as hard as I drive it I won't be upset when it does blow.

 

[MrUPS]

Good stuff guys keep it coming. opcorn:

:teknology:

 

[Righteyeblind]

I ran 4100 rpm with my s472 with some logs at shifting at 4300rpm. My twins didnt need near that much rpm.

 

[whitetrash21]

I run 4k rpm on my race tune, use it sometimes on the street. This is an LLY, same crap you LB7 guys are dealing with though.

 

[Chevy1925]

ive been debating having trent run my tune up to 3600rpm but i dunno if the power will drop off that high. hhhmmmmmm

 

[bullfrogjohnson]

So who all is running 4k on the street?