What rpm to run 7.3

[littleredstroker]

My rig tachs out at 3400... For sled tugging I wonder if running to 3800-4000rpm would be too much ?
I pull at the rev limiter almost the entire way down the track in second, but it bogs in 3rd... Was wondering if higher revs would help, or if the issue of pulse width being too short would limit power that high.
sent while staring at a windowed block

 

[Jarrod B]

doesnt valve floating happens past 3500?

 

[littleredstroker]

doesnt valve floating happens past 3500?

Wouldn't valve springs eliminate that ?

sent while staring at a windowed block

 

[dealwithit]

The big power rigs sing pretty high, so I dont see how it couldnt help, assuming you built the valve train abit, springs, pushrods, etc.

 

[Jarrod B]

Wouldn't valve springs eliminate that ?

sent while staring at a windowed block

yeah i heard 910 springs help that. but you need push rods too or you will be binding the stocks right and left.

 

[Southmike]

there are a few guys turning much higher rpm's
I suggest talking to hot rod.. etc.

 

[Groomzybanshee]

Just because your turning 4500 that doesn't mean your making any power there. What size tires/ gears you have

 

[Jarrod B]

http://powerstrokearmy.com/forums/showthread.php?t=39214

 

[superstroker99]

:whs: when mine was in stockish form i had same issue. would have been nice to carry just 4-500 more rpms would have helped alot. I know there is a point were power just falls off. Then i was falling off at 3100

 

[JD3020]

My old tunes maxed out at 3500, and it'd hit that plenty of times when i pulled. Only decent pull my truck ever made it locked in 2nd then hit 3rd and RPM's started falling quick. Which there were mulitple issues that caused it, but i think RPM's would've helped it.

My goal for a good pulling tune will be for it to start in 2nd, then shift into 3rd around 4k, maybe higher. Or if i have to stick to 2nd gear for whatever reason i can spin it a little higher and get a hair more wheel speed.

 

[Binder man]

Don't be afraid to run them to 4K plus if needed and you have springs/pushrods. Your not making as much power up there but your keeping wheel speed up until the sled pulls you down into your sweet spot for RPM's.

 

[Tim @ P.I.S.]

Just because your turning 4500 that doesn't mean your making any power there. What size tires/ gears you have

Exactly.

We have run injectors at 10,000 RPM on our bench. There isn't really any fuel there, but they will fire.

I have yet to see any dyno graphs show any increase in power past 3500 RPM's. There are still a few hurdles left to overcome.

 

[PDT1081]

The big power rigs sing pretty high, so I dont see how it couldnt help, assuming you built the valve train abit, springs, pushrods, etc.

I stood next to a Pro Stock Semi one night when he took off from the line. Last I could see, his tach was right around 6,000.

 

[littleredstroker]

Even if it kept the same power, my idea behind it isn't to gain power, but to gain wheel speed

sent while staring at a windowed block

 

[Binder man]

Even if it kept the same power, my idea behind it isn't to gain power, but to gain wheel speed

sent while staring at a windowed block

I ran gas motors way above there peak RPM power to gain wheelspeed and let the sled pull me down to peak.

 

[Blowby]

Exactly.

We have run injectors at 10,000 RPM on our bench. There isn't really any fuel there, but they will fire.

I have yet to see any dyno graphs show any increase in power past 3500 RPM's. There are still a few hurdles left to overcome.

Let off a little early but it would have climbed more on the HP graph up to 4k rpm.

 

[Tim @ P.I.S.]

I can now see I worded this poorly.

I too have a graph here that holds a table top all the way to just past 4000rpm. But it just doesn't make the big numbers that combo is capable of. So far you could have the BIG #'s or the RPM. I personally think a better compromise is possible.

I think some more fine TUNING could help out some more.

And also nice graph. I do like the ratio of trq to hp.

 

[Blowby]

Thanks for the comment on the Tq relation. I'm working on low Tq high HP tuning and have come a long way over the last 11 months. The only drawback to this is with higher RPM's you get a shrinking window for fuel delivery.
The advantage is the ability to create HP from 2700-3500 at over 750 (peaking at 1000) with a flat Tq curve of 1600 ft lbs during this RPM range. This is a good programing direction to go for drag racing but not a winning run for a Dyno racer. The engine components will thank you as well.

So back to the OP, high RPM's are a favorable option to shoot for.

 

[littleredstroker]

Is this doable on stock pushrods?

910s were shimmed to 1.750 +-.005 , is that enough ?

I had asked a couple times in 3 different threads about correct shim height and nobody really responded...

sent while staring at a windowed block

 

[Magnum PD]

Pushing the limits on stock pushrods with added power is a big gamble. Would not recommend it. Plus it's an easy mod.

Don't have shim data in front of me.