What kinda rpms can the hemi turn before it starts slinging parts? Got a bully dog programmer and got the shift points sat at 6000 rpms. Everyone says that i need to be careful and not push the motor to hard but i am under the impression that this motor is built and being as it is computer controlled doesn't it have safety limits built in. So if anyone could help me out here to put everyones concerns to rest around my parts. Thanks

 

Superchips' techs certify that the engine can do 6300 easily with no adverse effects, so you should be fine.........

 

If you're going to live in the higher rpms i'd lighten up the valvetrain if I were you. Pushrod engines don't like high rpms...and they don't need them. I dunno what you consider a "built" engine but it doesn't have forged internals and it's an mass produced engine put together by machines. Now an 03-04 cobra engine is "built" from the factory..

 

With the stock valve train I would not rev it past 6200. With my Predator my shift points are at 6k and 5950 with the rev limiter at 6200. Once you upgrade the valve train you can get away with 6500. But once you start doing that your gonna want to start looking at upgrading your pistons

 

Kinda pointless to go past the 5600 shift points. The engine doesn't make any more power that high and it will actually slow you down.

 

EXACTLY!

Lots of people have this big misconception that the higher the rpms, the more hp you will make. Wrong!

 

does anyone know who has had dyno time no where it really starts to fall off at?? I would think a good bit before 6000 rpm's

 

Im gonna have to disagree on that. Back when I first got my superchips I ran at the track with performance 91 tune and stock shift points and ran a 15.3. Changed to 6k shift points and ran a 15.2. Truck pulled hard all the way to 6k on the 1-2 and of course fell on its face on the 2-3 shift cause of the gearing which just about every ram does, it did the same thing with stock shift points. Other people may have different results but those were mine.

 

Disagree with what?

Here's the only graphs I could find. One was from JBA's website with their headers installed. Hemi motor clearly falls off after 5300rpms http://products.jbaheaders.com/dyno.asp

And another from Edge Evolutions website for their programmer. Notice there's no graph after 5k rpms!!! http://www.edgeproducts.com/product_...no_pdf-241.pdf

 

You guys are both right in this situation. Yes, the engine does start to drop off in power as you go past about 5500 rpm's or so. There are lots of dyno sheets around that back this fact up. And at the same time, yes the trucks do run faster times with the shift points raised higher. There are plety of people who have experimented with shift points and had the same results. The thing that needs to be considered is that when the truck is at say 6000 rpm's, the amount of horsepower the engine is producing is still greater than what it produces at the rpm it will be at when the truck shifts to the next gear. This is why the truck runs faster when you raise the shift points to higher levels.