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I am the law.
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There was some text under the picture, but I couldn't link it in.


http://www.sae.org/automag/technewsletter/070402Powertrain/04.htm





The 2007 Dodge Viper SRT-10 is attracting headlines for its new V10 engine, which is rated at 600 hp (450 kW) at 6100 rpm, a huge increase from the previous 510 hp (380 kW) at 5600 rpm. Yes, the engine now has twin throttle bodies, a new deep-breathing intake system with larger intake valves, and more aggressive cam lobe profiles.

More significant, however, is that it is also the first production pushrod-valve engine with truly variable valve timing (VVT)—on the exhaust valves. Using a phaser on a camshaft-within-a-camshaft design (Mahle's CamInCam), the V10 can change exhaust valve timing up to 45° vs. intake valve timing, although only 36° actually are used.

This compares with General Motors' simpler VCT (variable cam timing) on 3.5- and 3.9-L V6 engines, in which a phaser on a single solid shaft changes timing equally on both intake and exhaust lobes.

The Viper design, developed with Mechadyne International, provides the advantage of VVT while retaining the compact size of a pushrod-type, cam-in-block engine. Chrysler Group did look at a dual overhead-cam arrangement to advance the Viper V10 performance, but it simply would not fit.

Exhaust-valve control was chosen over intake to provide the valve timing variability needed to improve the idle and part-throttle combustion stability, normally an issue with engines whose camshafts are tailored for high-end power. The performance camshafts produce high exhaust-gas dilution of the intake charge at low rpm/light loads. This results in unstable combustion, which can affect idle quality, emissions, and the ability of the engine computer to detect misfire, which is a federal emissions requirement.

Intake valve control was not chosen because its prime benefit would be improved low-end torque, something the 8.4-L V10 has plenty of, although the 560-lb·ft (760-N·m) peak is at 5000 rpm. Intake control would simply "translate to more tire smoke on a Viper," explained Chrysler SRT engineer Kraig Courtney.

Although technology exists for both intake and exhaust VVT with the pushrod cam-in-block, it would require new designs both for the camshaft and phaser, deemed an unnecessary complexity and cost at this time. The exhaust-only VVT design enables use of a modified Mahle hollow camshaft and a reworked off-the-shelf cam phaser by INA.

The cam-within-a-cam consists of a solid intake camshaft within a hollow exhaust camshaft. The solid shaft has holes for cylindrical pins, located at five points that align with axial slots in the hollow outer shaft.

The intake valve cam lobe assemblies are slid onto the hollow exhaust camshaft and positioned above the slots, in a build sequence that permits exhaust lobes to be pressed into position on the hollow shaft. Locking pins are driven through the intake cam lobe assemblies. They pass through the slots in the hollow shaft and are pressed into the pin holes in the solid shaft, locking the intake lobes to the solid shaft. When the solid shaft is turned, the phaser can move the hollow exhaust camshaft between advance and retard positions vs. the solid camshaft, within the range allowed by the slots and the solid pins that go through them.

The 500-rpm increase for peak power was enabled by a number of changes that reduce valvetrain weight, including new valvetrain geometry. Although the intake valves are larger in diameter for improved breathing, the stems are hollow and shorter. The exhaust valve stems also are shorter.

Although the Viper engine displacement was increased from 8.3 to 8.4 L and the bore was increased from 102.3 to 103 mm (4.03 to 4.06 in), the objective was not the tiny increase in swept volume. The higher engine performance called for stronger reciprocating parts, particularly the connecting rod. With just the small bore change, the SRT V10 could take the already-available rod and piston assembly (with a floating wrist pin) from the 6.1-L SRT Hemi V8.

The V10 cooling system was upgraded with reshaped chambers for better flow, and two new two-speed electric fans that provide more airflow replaced the hydraulic fan.

Although the Viper SRT V10 VVT valvetrain now is the technology leader for cam-in-block engines, it's known that GM has a small-block V8 in development with variable intake- and exhaust-valve timing in a three-valve configuration. We may not see a four-valve pushrod gasoline engine, despite use of that valvetrain in diesel V8s. However, cam-in-block pushrod gasoline engines have a high-tech, high-performance future, and both Chrysler Group and GM keep engineering teams on the job of developing it.

Paul Weissler
 

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Hennessey is famous for taking peoples money and doing nothing to their cars in return....
I've seen their twin turbo Viper in action first hand. You think they don't do anything but take your money? I'd disagree. Do you think a stock Viper can smoke the tires at 100 mph? I saw the Hennessey one do it. I was very impressed with their work on it.
 

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Fuck talk, Duck walk!
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Sex on the outside, neon on the inside. Worst "supercar" interior out there. Id still like to have one though.
 

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rack tap re-rack click
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I've seen their twin turbo Viper in action first hand. You think they don't do anything but take your money? I'd disagree. Do you think a stock Viper can smoke the tires at 100 mph? I saw the Hennessey one do it. I was very impressed with their work on it.
Sure he has built a few good cars...but talk to anyone with the venom 550...matter of fact talk to a few Viper owners and see what they think... google his name and see what you come up with....plenty of other tuners out there to choose from and they do the work they are promised...you should do some research with people that own these cars not what you read in magizines...me being a former owner I think I know what I'm talking about
 

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81 inches of fun
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Sure he has built a few good cars...but talk to anyone with the venom 550...matter of fact talk to a few Viper owners and see what they think... google his name and see what you come up with....plenty of other tuners out there to choose from and they do the work they are promised...you should do some research with people that own these cars not what you read in magizines...me being a former owner I think I know what I'm talking about
Most of the guys I have met that have them, buy them and they sit in their garage and cruise it to the local show-n-shine. All they know about the car is 'that it's fast and ladies like it.' The one guy has a 94 with ~5000 original miles tops.... it's "too unfriendly to drive a lot" he said :sonicjay:

Being a former owner wouldn't mean anything more then you were an owner :sonicjay:

Post up some track times with stats and pics and that would show you know what your talking about. :thumb:
 

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Blowd up
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Most of the guys I have met that have them, buy them and they sit in their garage and cruise it to the local show-n-shine. All they know about the car is 'that it's fast and ladies like it.' The one guy has a 94 with ~5000 original miles tops.... it's "too unfriendly to drive a lot" he said :sonicjay:

Being a former owner wouldn't mean anything more then you were an owner :sonicjay:

Post up some track times with stats and pics and that would show you know what your talking about. :thumb:
I think being a former owner probably means he spent time doing some reading and probably has a good idea of the market/industry even if he doesn't have the personal experience.
 

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Sure he has built a few good cars...but talk to anyone with the venom 550...matter of fact talk to a few Viper owners and see what they think... google his name and see what you come up with....plenty of other tuners out there to choose from and they do the work they are promised...you should do some research with people that own these cars not what you read in magizines...me being a former owner I think I know what I'm talking about
So Hennessey doesn't do what they say they will do? Why did you buy one? I didn't read about it in a magazine, I watched it first hand doing full speed laps.
 

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I bought a "venom 550" off a friend who had all the paper work and such...then the more I dove into my car the more I realized it had nothing but a few cosmetic changes and that was it...I didn't pay the extra $18,000 and some change for the package, he did...and part of that $18,000 package was a special race exhaust, which turned out to be nothing more than turbo tubes welded on after the cats...needless to say that was one of the first things I change when I took over ownership…the only good thing that came with that package was the hardtop and windows, which I still have so if you know anyone with a Viper looking for a hardtop I have that stuff for sale. I have nothing to prove do some research of your own. If you think the guy is good, that’s your choice.
 

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I bought a "venom 550" off a friend who had all the paper work and such...then the more I dove into my car the more I realized it had nothing but a few cosmetic changes and that was it...I didn't pay the extra $18,000 and some change for the package, he did...and part of that $18,000 package was a special race exhaust, which turned out to be nothing more than turbo tubes welded on after the cats...needless to say that was one of the first things I change when I took over ownership…the only good thing that came with that package was the hardtop and windows, which I still have so if you know anyone with a Viper looking for a hardtop I have that stuff for sale. I have nothing to prove do some research of your own. If you think the guy is good, that’s your choice.

Not sure how your friend overpaying for a chromed up viper make the henessey venom 1000 anything less than what it is? Saleen S281 anyone? Who gives a shit anyhow?
 

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Not sure how your friend overpaying for a chromed up viper make the henessey venom 1000 anything less than what it is? Saleen S281 anyone? Who gives a shit anyhow?
true..but I'm not sure you understand what the 550 package is supposed to come with...but you are right who gives a shit..I sure don't anymore...and on a side note that Viper was cool but I'd never buy another one again...ever.
 

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The N3rd
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I bought a "venom 550" off a friend who had all the paper work and such...then the more I dove into my car the more I realized it had nothing but a few cosmetic changes and that was it...I didn't pay the extra $18,000 and some change for the package, he did...and part of that $18,000 package was a special race exhaust, which turned out to be nothing more than turbo tubes welded on after the cats...needless to say that was one of the first things I change when I took over ownership…the only good thing that came with that package was the hardtop and windows, which I still have so if you know anyone with a Viper looking for a hardtop I have that stuff for sale. I have nothing to prove do some research of your own. If you think the guy is good, that’s your choice.
It sounds like this "friend" of yours scammed you, and you didn't check it out for yourself first, not Hennessey.
 

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More boost than yours:)
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I saw the cam back in a spring edition of SAE International . . . I think.

I'm sure someone thought of it a long time ago, but I thought about that about 4 years ago when I first heard of variable cam timing. . . dammitt!
 

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rack tap re-rack click
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It sounds like this "friend" of yours scammed you, and you didn't check it out for yourself first, not Hennessey.

I'm sure he did...he even went as far as sending the car away for a month a back when he first got it and then made some fake receipts...I knew that asshole was lying to me!!!
 
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