Max rpm our 7.3's can effectively turn

[TERRCO]

I see a blown up 7.3 in your future.

 

[lincolnlocker]

again are you asking about a bone stock motor or upgraded top end? or fully built? dave already said he has proof of over 6k... highly doubt thats a stock motor.

live life full throttle

 

[85_305]

Oh sorry, a mostly stock motor I suppose.. maybe w/ upgraded valve springs and pushrods. I dont care about a fully built motor because I'm sure w/ enough time and money it can certainly be done... especially w/ other means of injection.

 

[under pressure]

Its gonna take alot of head work and everything else to see 6000...

I wouldnt recommend 4000 on a stock tuned truck... At minnimum the top end needs addressed.
Your making less power at 4000 rpm then you were at 2500 rpm.

 

[Arisley]

:whs:

I once saw 4500 in my truck, it sounded sweet and it was still pulling, but it was sluggish.

 

[85_305]

But what I'm saying is, the mathematical equation for horsepower is
hp = torque * RPM / 5252

With that being said, higher rpm=higher hp.... if the setup can handle it. So in theory, if we could spin more rpms in our 7.3's, our potential for greater hp goes up. Those guys dragging hi-hp 7.3's... what rpm do they shift at?

I'm not saying I want to run 6,000rpm... but anything more than the stock redline... is that possible or even worth it?


I'm not good at explaining things (hence why I'm not a teacher), but what I'm saying is this.

Every auto manufacturer and anybody that mods cars aims for a healthy amount of rpms.

For instance... TPI camaros start wheezing after 2-3k rpms... direct injected corvettes were built to handle 5-6k rpms.

ferrari/Lambo are 12k rpm motors....
Built hondas are 8-12k rpms motors...
Built cummins are 5-6k rpm motors....
6.0/6.4's are 4-4500 rpm motors when tuned (I I think..)
Volkswagen diesels spin 6k-10k rpms....

7.3 powerstrokes turn 3800rpms..............

All I'm trying to say is that properly increasing RPM will in theory increase hp... so while the rest of the aggressive automotive community works to increase rpm's because with rpm's comes horsepower, it seems as though RPM's aren't really talked about on a 7.3

 

[golfer]

So is 4,000rpms a relatively safe rpm for these motors, assuming you have the proper fueling and timing for those kindsa rpm's?

sure...100% safe. guaranteed.

we've taken bone stock engines with bolt ons to 775hp AT 4100rpm...stock cam, stock heads, heads never removed, etc..200k mile forged rod engine..simply out of the frame, and onto our engine dyno.

 

[under pressure]

Giberish

 

[85_305]

sure...100% safe. guaranteed.

we've taken bone stock engines with bolt ons to 775hp AT 4100rpm...stock cam, stock heads, heads never removed, etc..200k mile forged rod engine..simply out of the frame, and onto our engine dyno.

And does a properly setup 7.3 shifting @ 4100 rpms produce more useable power than say, using stock 7.3 shifting points @ 2800-3100rpms?

 

[Hotrodtractor]

I see a fair number of upgraded motors get disassembled after failure have valve imprints on the pistons..... so take that for what its worth.... you'll never change the piston to valve or piston to head clearances inside a motor and if they are tight from the factory... yep you have contact..... if they are loose from the factory and you upgrade springs and keep the RPMs moderate... then you don't have contact....

My favorite picture to show in times like this is:

How close did that piston need to be that head so you could read the engraved marking on the top of the piston? It sounded smooth while running at idle.... it was disassembled because it popped a head gasket. This was a "built" motor assembled by a "racing" shop...... I'd have to go see if I still have the notes on this, but IIRC this clearance was right at the tight edge of factory, perhaps just a TOUCH tighter.....

Piston out of the same motor:

This motor had beehives in it with a well known camshaft.

 

[under pressure]

Hey look, those pistons are pre marked and ready for the machine shop.....

 

[85_305]

^Ouch, thats crazy....What kinda rpm's was he spinning?

 

[01PSD]

I see a fair number of upgraded motors get disassembled after failure have valve imprints on the pistons..... so take that for what its worth.... you'll never change the piston to valve or piston to head clearances inside a motor and if they are tight from the factory... yep you have contact..... if they are loose from the factory and you upgrade springs and keep the RPMs moderate... then you don't have contact....

My favorite picture to show in times like this is:

At least it looks happy.. LOL

 

[neverkickn]

So what would you reccommend for a max piston protrusion to keep the risk of contact down in a high rpm application. I am guessing you would still need to flycut the pistons.

 

[under pressure]

And does a properly setup 7.3 shifting @ 4100 rpms produce more useable power than say, using stock 7.3 shifting points @ 2800-3100rpms?

Explain, we still talking stock injectors with spring and p rods..... Then no.

 

[Hotrodtractor]

^Ouch, thats crazy....What kinda rpm's was he spinning?

Considering I think there was 10 miles on that motor when I got it... it doesn't really matter - but I would assume 4K. Perhaps the owner will be along to elaborate if he wants to.

 

[85_305]

So what would you reccommend for a max piston protrusion to keep the risk of contact down in a high rpm application. I am guessing you would still need to flycut the pistons.

Interested in this also

Explain, we still talking stock injectors with spring and p rods..... Then no.

No, I'm talking mods but not redoing pistons, rods, head work etc... Injectors, turbos, hpop etc is all fine.

 

[85_305]

Considering I think there was 10 miles on that motor when I got it... it doesn't really matter - but I would assume 4K. Perhaps the owner will be along to elaborate if he wants to.

Whoaaaaaaaaa 10miles?! Wtf did he have going on w/ that motor to create so much interference?

 

[Hotrodtractor]

Whoaaaaaaaaa 10miles?! Wtf did he have going on w/ that motor to create so much interference?

Simply RPMs - tight clearances - high boost. There is a thread somewhere in the bowls of PSN - but I have zero desire to go find it.

 

[85_305]

Simply RPMs - tight clearances - high boost. There is a thread somewhere in the bowls of PSN - but I have zero desire to go find it.

So high rpm's and high boost crashed that guys motor in less than 10miles? I'm impressed, in a sadistic way....