Vipers and higher RPM

[Nine Ball]

What is the general consensus on spinning a stock '06 SRT-10 engine beyond 6,000 rpm? This may not help on an all-motor setup, but my Paxton setup sure could use 6,500-7,000 rpm to see its full potential. The engine is pulling extremely hard at 6,000 rpm and would probably carry out to 7K no problem with the blower.

Anyone know if the Viper rotating assy, valve springs, and oiling system can keep up beyond 6K?

What is needed to move that rev limiter up? Can the factory PCM be retuned for that? Does the SCT handheld adjust RPM limits?

Tony

 

[Steve-Indy]

"Anyone know if the Viper rotating assy, valve springs, and oiling system can keep up beyond 6K? "

I would say...NOT FOR LONG...unless you have a total rebuild aimed at your stated purpose.

As much as I love Vipers...and have experienced & LOVED some high reving engines...the stock setups are not Ferrari's.

 

[01ACR/VIPER]

Mine started floating valves at 6100rpm.New springs would be the first MUST DO.

 

[Alexarz]

"Anyone know if the Viper rotating assy, valve springs, and oiling system can keep up beyond 6K? "

I would say...NOT FOR LONG...unless you have a total rebuild aimed at your stated purpose.

As much as I love Vipers...and have experienced & LOVED some high reving engines...the stock setups are not Ferrari's.

............and Ferraris don't have any torque. The Viper engine is a short stroke motor so I am wondering if a valvetrain upgrade along with some other mods might allow higher revs. Any Viper engine builders in the house?

 

[Tiago]

Need to call UGR and discuss with them, from what I have read its a oiling problem.

 

[Grant]

...my Paxton setup sure could use 6,500-7,000 rpm to see its full potential...

Why not just put a slightly smaller pulley on the blower then?

 

[TexasSnake]

Why not just put a slightly smaller pulley on the blower then?

I think he previously stated in another thread that he had stock internals. I would think twice about going with a smaller pulley without forged internals.

 

[Nine Ball]

7K rpm is not huge. The Z06 is a 427ci and the factory redline is 7K.

LS7 = 4.00" stroke and 4.125" bore.
SRT = 3.96" stroke and 4.03" bore

Both are oversquare engines, with similar stroke and bore. It should be able to rev to 7K if the oiling system and valvesprings can handle it. The Viper has a shorter stroke and a smaller piston, why couldn't it rev like the LS7?

Why not just put a slightly smaller pulley on the blower then?

Sure, I could do that to increase power. I specifically want to know the limitations of the SRT-10 engine and how to increase rpm though. If the engine is capable of more rpm, I'd like to use it.

 

[Frankster]

In my younger (and dumber days) I built a Chevy 283 to rev. I used forged internals (crank, rods, pistons), fluid damper and then selected a camshaft, valve, valve spring and an intake combination for 9000 RPM. I used a Melling high volume and high pressure oil pump.

Make sure to blueprint then professionaly balance the internals.

Most engines can take more RPM than stock but what limits them most is valve float due to weak valve springs (unless you're electronically rev limited).

Rev limiting on the 283 was set for 9000RPM. The motor ran great at the higher revs but it sounded like it was going to explode at any minute.

If you're going to live at higher revs just know that engine life is shortened accordingly.

 

[steponz]

I would talk to Jeff Morys... The make of Stryker heads.....

To get up there I would say rebuild your bottom end because everything is apart... new cam.. probably go solid... all valve train.. Honestly ask Jeff....

Joe

 

[vipeuup]

What is the general consensus on spinning a stock '06 SRT-10 engine beyond 6,000 rpm? This may not help on an all-motor setup, but my Paxton setup sure could use 6,500-7,000 rpm to see its full potential. The engine is pulling extremely hard at 6,000 rpm and would probably carry out to 7K no problem with the blower.

Anyone know if the Viper rotating assy, valve springs, and oiling system can keep up beyond 6K?

What is needed to move that rev limiter up? Can the factory PCM be retuned for that? Does the SCT handheld adjust RPM limits?

Tony

What kind of headers do you have?

 

[Grant]

Both are oversquare engines, with similar stroke and bore. It should be able to rev to 7K if the oiling system and valvesprings can handle it. The Viper has a shorter stroke and a smaller piston, why couldn't it rev like the LS7?

There is the weight and strength of the piston and rod to consider, as well as the size of the rod bearings. The strength of the rod bolts (a common upgrade for early LS1s wanting to rev higher) can be an issue too. Then there is crankshaft and block stiffness, and probably a ton of other factors I know nothing about.

LS7 (titanium) rods are 464 grams, while their pistons are 482. Any idea what the Viper's weigh?

EDIT: Looks like SRT8 / Gen 4 pistons weigh 435 grams, but I can't find anything on the rods.

Valve springs are a pretty easy thing to change out, at least when compared to rods and crankshafts.

 

[Paul Hawker]

Increasing revs on a stock engine with Paxton is just asking for it.

You would need to change tons of things to make the engine last reasonably long.

I would think a 10% increase in RPM would result in greater than 80% reduction in engine life.

The standard Paxton just about is all you can get without upgrading parts. The Paxton should not be spun much higher either.

 

[waltershu]

the viper engine would need a cam and valvetrain design to peak at 7k and beyond.

 

[Viper X]

Interesting question. Has been discussed many times before.

Bottom line, don't even think about spinning your stock engine any higher without changing most everything. Grant's post is pretty good on this subject.

My current engine build (blew up two others trying to spin them higher without the proper build and tuning) allows me a red line of 6600 rpm and yes, the engine continues to make power till red line; but this cost some $$$$'s to accomplish.

Best contact on this is Kevin Singleton of Exotic Engine. He and Jeff (JM Cyliner Heads) work together on high hp Viper engine projects.

Good luck,

Dan

 

[Nine Ball]

Grant, even a now outdated LS1 can spin up to 6800 rpm on the stock shortblock. That is the typical shift point when we port the stock heads and do a cam/spring swap. The bottom end with stock steel rods and hypereutectic pistons can rev no problem. The valve float rpm is typically the ceiling.

Maybe it is the harmonics of spinning a 10-cyl crank, maybe it is just too much weight. Some of you mentioned needing a different cam, but that would only be for an all-motor build. The stock cam is just fine when using forced induction. The stock cam would also be easier on the valvetrain at higher rpm.

 

[Viper X]

On the higher RPM Viper engines, like those found in the LeMans GTSR Vipers, the engine builders cut down the main journals (among many other changes).

Street Viper engines are not designed or built to spin past 6000.

 

[Camfab]

On the higher RPM Viper engines, like those found in the LeMans GTSR Vipers, the engine builders cut down the main journals (among many other changes).

Street Viper engines are not designed or built to spin past 6000.

Dan you hit the nail on the head! The crank is really stout, and that strength comes from huge main journals. Large journals do not like rpm and in the Vipers case you will have problems. A proper cam and cylinder head will increase your power output exponentially without a large increase in rpm.

 

[Nine Ball]

What is the current redline in the 2008+ model? Did they change the main journals on that crank, or just give it better flowing heads and bump the limit up?

 

[Malu59RT]

What is the current redline in the 2008+ model? Did they change the main journals on that crank, or just give it better flowing heads and bump the limit up?

Looks to be 6250rpm

You must be registered for see images attach

 

[aries]

Looks to be 6250rpm

You must be registered for see images attach

And from the looks of that picture, YOU'RE SPEEDING!!!!

 

[Malu59RT]

And from the looks of that picture, YOU'RE SPEEDING!!!!

Speeding? I'm being passed on the Autobahn as I slowed down to take that pic

 

[Grant]

Grant, even a now outdated LS1 can spin up to 6800 rpm on the stock shortblock. That is the typical shift point when we port the stock heads and do a cam/spring swap. The bottom end with stock steel rods and hypereutectic pistons can rev no problem. The valve float rpm is typically the ceiling.

LS1 owners are also typically less worried about the longevity of their stock motors. I rev my AFR-headed Katech-bolted stock LS1 to 6500 (6800 limiter), but then it sees road course duty. I've always believed that raising RPM significantly is a terrible performance-to-reliability tradeoff on most engines.

The '08s could definitely benefit from more revs, even with stock power. The new Mopar ECU seems to raise the rev limit to 6500. Of course, the '08s also have a revised oiling system.

 

[LiquoRT/10]

08 video courtousy of mark in the tuning 08 thread.

http://www.youtube.com/swf/l.swf?sw...QY2JsMnUC&use_get_video_info=1&load_modules=1

 

[GuitarSteve]

What I found interesting is how the tach needle was hesitating to move further.

 

[HOLLYWOOD1]

That was an excellent video however its ramp up seemed to slow quite at bit once it hit 6K. One thing, it pulled to 170 faster than any Z06 I have seen. The show seemed over at 6K though even though it still pulled pretty ******* the speedo. These are vastly different motors both trying to achieve the same goal....GO FAST and GET THERE RIGHT NOW! No complaints on this show.

 

[Joseph Dell]

As stated previously, the problem is two-fold. 1 - oiling. 2 components. The rod/stroke ratio of a SB chevy is also far more conducive to higher reving than the viper motor.

 

[RTTTTed]

V8 Viper is about 370ci? with an extra 2 cylinders. Not similar to a 427.

The Viper heads have the same sized intake and exhuast valves as the old 360 engines.

Head ports really need enlarging for higher rpm and bigger valves'

Engine isn't designed for high rpm.

Higherblower rpm (with or without engine) makes higher boost. Smaller pulley and forged pistons would be cheapest way to go

Ted

 

[RTTTTed]

What is the current redline in the 2008+ model? Did they change the main journals on that crank, or just give it better flowing heads and bump the limit up?

The 09s have SRT pistons and rods in the engines. stronger parts and since they're shared with another engine they're cheaper.

Powder metal rods

Ted

 

[Malu59RT]

The 09s have SRT pistons and rods in the engines. stronger parts and since they're shared with another engine they're cheaper.

Powder metal rods

Ted

Err..08/09 Viper's have SRT-8 pistons and rods?