How the Viper Engine got its Horsepower

[NT-ACR]

This is a great little article that lays out the unique evolution of the Viper engine for each generation. In addition, the quotes from the article are all from someone who we all respect quite a bit. Enjoy.

http://www.hotrod.com/cars/featured/how-the-viper-engine-got-its-horsepower/

[Space Truckin]

Good read, always enjoy what Mr. Winkles has to say about our beloved V10....:United_States:

[J TNT]

Thanks for sharing ! I had always been a Big Fan of the Early Ramcharger Engineers and hearing the current SRT /Dodge engineers work there magic is always insightful !

[7TH_SIGN]

“It’s an aluminum block based loosely off the small-block Chrysler V8,” says Winkles. “It’s not the truck engine. If you went through it, we shared, like, one part. A bolt or something. It was much more like the A-engine.”

That had me laughing out loud.

[C.J]

"Ring of fire..." Great description of the Gen III crossover exhaust!

Really good read, thanks for posting!

[Vprbite]

Good read, always enjoy what Mr. Winkles has to say about our beloved V10....:United_States:

That guy knows the Viper engine to such amazing detail. imside and out and every way in between. Always good to hear what he has to say.

[lochnessmonster]

So here's a question. My Honda S2000 has the F20C engine in it, which produces 240hp out of a 2 litre 4 cylinder engine. Essentially, 120hp per litre. I have wondered why the Viper engine is so far off the mark in terms of hp per litre? Does it have something to do with engine mass? That is, making a massive piston like the one in the Viper's engine, by comparison, change direction will result in a loss of overall power, so as displacement increases, you simply can squeeze as much power per litre out of an engine? I know Dick mentioned emissions, and if it wasn't for those constraints, the Viper engine would produce 800hp, but that's still 200+ hp below the F20C's output. Or, is the F20C just a far superior engine design? I know it held tge record for several years back in the day for most powerful naturally asperated production engine on the plant until Ferrari took the crown back.

[Malu59RT]

So here's a question. My Honda S2000 has the F20C engine in it, which produces 240hp out of a 2 litre 4 cylinder engine. Essentially, 120hp per litre. I have wondered why the Viper engine is so far off the mark in terms of hp per litre? Does it have something to do with engine mass? That is, making a massive piston like the one in the Viper's engine, by comparison, change direction will result in a loss of overall power, so as displacement increases, you simply can squeeze as much power per litre out of an engine? I know Dick mentioned emissions, and if it wasn't for those constraints, the Viper engine would produce 800hp, but that's still 200+ hp below the F20C's output. Or, is the F20C just a far superior engine design? I know it held tge record for several years back in the day for most powerful naturally asperated production engine on the plant until Ferrari took the crown back.

I guess the question also could be raised, when the AP2 came out with the 2.2L engine, why was Honda unable to match the 120hp/L of the F20C. I just don't think you can assume a linear trend based on displacement.

[lochnessmonster]

But I want to know why? Also, the objectives were different for Honda with the F22C. They were looking for more mid range power and torque. Which they achieved. I don't recall the disparity between the two, but as I recall it's in the neighborhood of 3 hp. Very minor really.

[IndyRon]

Could 800hp have been made with our current displacement naturally aspirated? Absolutely! Would we want that motor in the Viper? Debatable. Could we afford a Viper with that powerplant? Most of us couldn't.

Remember HP is a function of RPM, carry a torque output over a higher and higher RPM range and voila! You have horsepower. If the 8.4L Viper engine was built such that it turned 9000+rpm also, 800hp could be doable. Major changes would have to take place though. Most likely we would have needed a significantly shorter stroke and super lightweight reciprocating parts and valvetrain. To keep airflow decent at that RPM, definitely 4 valve heads like the Honda and high high compression like the Honda as well. Of course to maintain the 8.4L you'd have to add cylinders or increase bore. The first option would disqualify it from being a "Viper" engine. The second would probably be counterproductive as the smaller displacement engine would be able to spin higher and make more higher RPM HP all else equal due to mass in the moving parts.

It's a complex question to answer but the reality is that the Viper engine, while amazingly engineered is very low tech in its approach to making HP. Its the age old hotrodder approach, add more cylinders and displacement. The Honda is a totally different paradigm. On top of all that, I think you'd be amazed at the amount of engineering $$$ that went into the Honda plant vs the Viper. That isn't meant do disparage the Viper in any way, its just that to build those types of engines, the R&D is ridiculously expensive.

[SSGNRDZ_28]

But I want to know why? Also, the objectives were different for Honda with the F22C. They were looking for more mid range power and torque. Which they achieved. I don't recall the disparity between the two, but as I recall it's in the neighborhood of 3 hp. Very minor really.

“I feel the Viper engine is at the zenith of a naturally aspirated cam-in-block two-valve engine. There aren’t any large stones unturned. You could make over 800 hp if you didn’t have to pass emissions, but we do. Emissions will force the downsizing of engines, so that will mean more power adders in the future.”

The S2000 engine is DOHC. That, and a combination of emissions would be my guess. Pushrod engines have their advantages (weight, CofG, etc.); this isn't one of them.

[lochnessmonster]

Could 800hp have been made with our current displacement naturally aspirated? Absolutely! Would we want that motor in the Viper? Debatable. Could we afford a Viper with that powerplant? Most of us couldn't.

Remember HP is a function of RPM, carry a torque output over a higher and higher RPM range and voila! You have horsepower. If the 8.4L Viper engine was built such that it turned 9000+rpm also, 800hp could be doable. Major changes would have to take place though. Most likely we would have needed a significantly shorter stroke and super lightweight reciprocating parts and valvetrain. To keep airflow decent at that RPM, definitely 4 valve heads like the Honda and high high compression like the Honda as well. Of course to maintain the 8.4L you'd have to add cylinders or increase bore. The first option would disqualify it from being a "Viper" engine. The second would probably be counterproductive as the smaller displacement engine would be able to spin higher and make more higher RPM HP all else equal due to mass in the moving parts.

It's a complex question to answer but the reality is that the Viper engine, while amazingly engineered is very low tech in its approach to making HP. Its the age old hotrodder approach, add more cylinders and displacement. The Honda is a totally different paradigm. On top of all that, I think you'd be amazed at the amount of engineering $$$ that went into the Honda plant vs the Viper. That isn't meant do disparage the Viper in any way, its just that to build those types of engines, the R&D is ridiculously expensive.

Wow, awesome answer!!! That makes total sense. Thanx!!

[J TNT]

How much Torque does the Honda produce ? Something that gets overlooked . fwiw .

[IndyRon]

How much Torque does the Honda produce ? Something that gets overlooked . fwiw .

Torque, I'm not sure it makes torque.....
:lol2:

[viper_eddie]

Engines that are high revving usually have a short stroke and wide bore. There are a variety of reasons for why different companies use different approaches but I think a significant portion has to do with taxation in their respective countries. The Europeans tax a lot on engine size so running an 8.4L engine is extremely expensive.

American companies have usually used displacement as a way to increase power since it's cheap from an engineering and taxation point of view. Keep in mind though that American engines have a ton of low end torque due to their longer strokes.

[City]

“I feel the Viper engine is at the zenith of a naturally aspirated cam-in-block two-valve engine. There aren’t any large stones unturned. You could make over 800 hp if you didn’t have to pass emissions, but we do. Emissions will force the downsizing of engines, so that will mean more power adders in the future.”
.

Thanks for the link and article. Great read!

All should note that is article is 2 years old. Not that any of the history has changed, but in the two years since, it's not impossible that newer technology MIGHT impact some of his future observations and predictions (as quoted above).

[lochnessmonster]

How much Torque does the Honda produce ? Something that gets overlooked . fwiw .

It makes 167 ft lbs. So 83.5 per liter. At 8.4 liters that is 701.4 ft lbs. We are at 600 ft lbs. So, yes, it does make torque.

[J TNT]

Look up Viper 543 on YouTube , you can see the V 10's potential.

It makes 167 ft lbs. So 83.5 per liter. At 8.4 liters that is 701.4 ft lbs. We are at 600 ft lbs. So, yes, it does make torque.

[lochnessmonster]

Look up Viper 543 on YouTube , you can see the V 10's potential.

Cool. I'll check it out.

[ViperPete]

Great article!

Thanks for posting.

[Snakebit10]

Nice read thanks.

How about the Porsche's GT3 RS 4 liter flat 6 at 500hp and 460lb torque all NA. That is pretty incredible feat considering the Gen 3 Viper had 510hp and 535lb torque at 8.3 liters. Two different approaches to going fast. I like both the lower tech and the newer tech approach. If it works it works. I don't think either one invalidates the other.

[NT-ACR]

So here's a question. My Honda S2000 has the F20C engine in it, which produces 240hp out of a 2 litre 4 cylinder engine. Essentially, 120hp per litre. I have wondered why the Viper engine is so far off the mark in terms of hp per litre? Does it have something to do with engine mass? That is, making a massive piston like the one in the Viper's engine, by comparison, change direction will result in a loss of overall power, so as displacement increases, you simply can squeeze as much power per litre out of an engine? I know Dick mentioned emissions, and if it wasn't for those constraints, the Viper engine would produce 800hp, but that's still 200+ hp below the F20C's output. Or, is the F20C just a far superior engine design? I know it held tge record for several years back in the day for most powerful naturally asperated production engine on the plant until Ferrari took the crown back.

Terrific question and something I've been wondering as well. One of my favorite examples of a relatively large engine making great power and torque is the SLS AMG's M159.

SLS AMG Black Series- 6.2L (378.8 cu in) V8, 622 hp@7,400, 468 lb·ft@5,500, 8,000rpm redline, 11.3:1 compression ratio, 102.2 x 94.6 mm bore and stroke, 452 pounds dry engine weight
SLS AMG GT- 6.2L (378.8 cu in) V8, 583 hp@6,800, 479 lb·ft@4,750, 7,200rpm redline, 11.3:1 compression ratio, 102.2 x 94.6 mm bore and stroke
Viper (Gen V)- 8.4L (512.6 cu in) V10, 645 hp@6,200, 600 lb·ft@5,000, 6,400rpm redline, 10.2:1 compression ratio, 103 x 100.6mm bore and stroke

SLS Black Series dyno chart:
http://weistec.com/media/catalog/product/cache/1/thumbnail/9df78eab33525d08d6e5fb8d27136e95/s/l/slsbsna.jpg

SLS GT dyno chart:
http://lghttp.40715.nexcesscdn.net/8014F63/magento/media/catalog/product/cache/1/thumbnail/9df78eab33525d08d6e5fb8d27136e95/s/l/slsnagraph.jpg

Viper dyno chart:
http://services.edmunds-media.com/image-service/media-ed/ximm/?quality=85&image=/srt/viper/2013/fe/2013_srt_viper_ill_fe_1211122_600.jpg

However, I think the best comparison is the Lamborghini Huracan's engine due to it being a V10 and relatively large at 5.2L.

Lamborghini Huracan- 5.2L (317.6 cu in) V10, 602 hp@8,250, 413 lb·ft@6,500, 8,400rpm redline, 12.7:1 compression ratio, 84.5 x 92.8mm bore and stroke
Viper (Gen V)- 8.4L (512.6 cu in) V10, 645 hp@6,200, 600 lb·ft@5,000, 6,400rpm redline, 10.2:1 compression ratio, 103 x 100.6mm bore and stroke

Concerning the Huracan's engine:
"The new engine is both port- and direct-injected to optimize fuel delivery at every single firing. It also has variable cam timing on all four cams. This comes with a wealth of benefits. The peak power and torque increases nearly 50 hp and 15 lb-ft are just one. Seventy-five percent of that torque (310 lb-ft) is available from 1000 rpm, an impressive achievement for a naturally aspirated engine." -Motor Trend

Lamborghini Huracan dyno chart:
http://www.fabspeed.com/content/hosted_images/forums/Lamborghini%20Huracan%20Supersport%20-%20Dyno.jpg

Viper dyno chart:
http://services.edmunds-media.com/image-service/media-ed/ximm/?quality=85&image=/srt/viper/2013/fe/2013_srt_viper_ill_fe_1211122_600.jpg

This one is just a fun comparison, not very relevant:
Porsche Carrera GT- 5.7L (349.8 cu in) V10, 612 hp@8,000, 435 lb·ft@5,750, 8,400rpm redline, 12.0:1 compression ratio, 98.04 x 75.95mm bore and stroke
Viper (Gen V)- 8.4L (512.6 cu in) V10, 645 hp@6,200, 600 lb·ft@5,000, 6,400rpm redline, 10.2:1 compression ratio, 103 x 100.6mm bore and stroke

Carrera GT dyno chart:
http://www.dragtimes.com/images_dyno/22161-2008-Porsche-Carrera-GT-Dyno.jpg

Viper dyno chart:
http://services.edmunds-media.com/image-service/media-ed/ximm/?quality=85&image=/srt/viper/2013/fe/2013_srt_viper_ill_fe_1211122_600.jpg

So, after looking at these dyno charts and comparing engine specifications, it seems to me that the if the Viper's engine were to be upgraded to DOHC, port- and direct-fuel injection, a redline of around 7,500rpm, and variable cam timing on all four cams, that the displacement could be reduced to somewhere in the 7.0-7.5L range while still seeing an increase in power and at least keeping torque the same as it is now. Something like 750hp@7,300rpm and 600lb·ft@5,500rpm while increasing fuel economy sounds pretty terrific to me. In addition, if this engine were to receive a cylinder deactivation feature like the Corvettes utilize, then fuel economy could be even better. (I know most of you don't care about fuel economy but it is a legitimate concern for the viability of an engine of this nature's future.)

Note- I only included the dyno charts to show how each engine makes its power throughout the rev range, I understand that the actual numbers are useless for comparison purposes as they would all have to be done on the same dyno, on the same day, in roughly the same conditions for accurate comparisons to be made.

[NT-ACR]

Nice read thanks.

How about the Porsche's GT3 RS 4 liter flat 6 at 500hp and 460lb torque all NA. That is pretty incredible feat considering the Gen 3 Viper had 510hp and 535lb torque at 8.3 liters. Two different approaches to going fast. I like both the lower tech and the newer tech approach. If it works it works. I don't think either one invalidates the other.

I would be thrilled if the 991 GT3 RS's engine made 460 lb-ft but unfortunately it only makes 338 lb-ft. Still a great figure considering its displacement and cylinder count.

[Steve M]

HP/L is good on paper, and that's about it. You are also comparing peak output, not average.

Since we're talking about an S2000, why not throw up a dyno graph of one of those?

http://i305.photobucket.com/albums/nn227/meentss02/S2000%20dyno_zpscumjvxyl.jpg

Better grab the duct tape and make sure your socks are securely fastened, because they're about to be blown off by a massive 100 ft-lbs of torque at 2,500 RPMs. If we use the graph above for the Viper's output, it's putting out what? 425-ish at the same point? Where the S2000 shines is 6,000-9,000 RPMs, but that is a pretty narrow window for optimal performance, and it comes at the expense of durability. Know what kills engines? Sustained high RPM operation. You could make a Viper rev to 9,000 RPMs, but you'd need to shorten the stroke to keep the piston speeds down to an acceptable level, redesign the entire valvetrain, etc. Want a DOHC V-10? You'd better be prepared to redesign the entire car to fit the larger physical volume that engine would have to occupy. Cam-in-block motors, while seemingly archaic in design, actually aren't that bad - they generate lots of torque, and fit in a very small package with a low CG, and those very desirable traits in an engine that's going in a small car.

The only way you could scale up an S2000 motor to make an apples to apples comparison (that is 8.4L to 8.4L) is to do it on paper. It just wouldn't work in reality...you'd end up with trash cans for pistons, and I have a feeling that they wouldn't be seeing 9,000+ RPMs much, if at all. Okay, maybe once. HP/L math is a nice and convenient mental exercise, but it just doesn't work out in the real world.

[lochnessmonster]

Some awesome observations and insights into how modern engines make power. Of course the point of my question wasn't to detract from the Viper engine at all. It was just something I had been wondering about. At the end of the day, I just returned from a 1000 km road trip in my Viper, and if I had to choose between the two cars, well, it isn't really a choice is it? I met a young punk in his Mustang on the hwy between Regina and Saskatoon and we had some fun. I showed him how slow his car was..... He was actually pretty cool about it, and his buddy was totally loving it. 4th gear at 4000 rpm and pinning the foot to the floor, over and over again. What a blast. I absolutely love the Viper!!!!

[7TH_SIGN]

The Viper motor is old school engineering technology and there in nothing wrong with that. I've had critics tell me how disappointed they are that its a V10 8.4L yet only makes 640hp.

My little inline 6 183 cubic inch Supra motor made 1400whp and everyone is shocked and impressed by these motors yet completely pass up the amount of psi and high octane fuel is needed in order to accomplish this. Not to mention the strain the motor has to go through.

One of the most appealing things about the Viper to me was its huge engine and its simplicity. These cars do just fine with boltons, but throw some snails on them and thats when you see what they're really capable of.

[lochnessmonster]

All true and good points. I have to say, I cringe a bit eveytime I spin my little F20C up to its 9000 rpm redline. It loves it, and actually seems to thrive on it, but it is so counterintuitive. The comments you've heard are some of the ones that prompted my question. Although, I read them somewhere. People stating something to the effect that the Viper engine is a failure. And if you did a very simplistic uninformed analysis based on simply multiplying hp per litre, you would come to the same conclusion. But, as we can see, based on the much appreciated contributions to this thread, it's not that simple. As with so many things in life, there is a lot more to consider. Thanx so much guys!!! Your detailed, well thought out explainations, with dynograph plots to boot are a brilliant explanation of how the Viper gets its horsepower, and why it's right where it needs to be.

[dethred]

But I want to know why? Also, the objectives were different for Honda with the F22C. They were looking for more mid range power and torque. Which they achieved. I don't recall the disparity between the two, but as I recall it's in the neighborhood of 3 hp. Very minor really.

It's generally acknowledged that smaller motors are more efficient in terms of hp/liter. Just look at sport bikes. Part of that trade-off is the lack of any power below 6000rpm. I barely miss my S2000, it was so gutless unless you were wringing its neck. I'd rather have a broad torque curve and 640hp/600tq out of an 8.4 liter, than 840hp and 350tq.

[Snakebit10]

I would be thrilled if the 991 GT3 RS's engine made 460 lb-ft but unfortunately it only makes 338 lb-ft. Still a great figure considering its displacement and cylinder count.

My error on that you are correct 338-339lbs torque. Yeah pretty impressive hp/tq from such a comparably small NA motor without FI. Poster child for the small displacement high-tech approach whereas the Viper is the poster child for the tried and true approach. The results on track speak volumes to both approaches.

[lochnessmonster]

It's generally acknowledged that smaller motors are more efficient in terms of hp/liter. Just look at sport bikes. Part of that trade-off is the lack of any power below 6000rpm. I barely miss my S2000, it was so gutless unless you were wringing its neck. I'd rather have a broad torque curve and 640hp/600tq out of an 8.4 liter, than 840hp and 350tq.

Yeah, I've owned more sport bikes than I can even remember, and that makes sense. I've always wondered why you could get 170 hp out of 1000cc on a sport bike, but the same wasn't being achieved in cars. I still love my S2000 but obviously not for brute power. The car is a blast to drive, top down option, great motor, great leather interior, fantastic 6 speed manual, surprisingly big trunk, 29mpg......on and on. But perhaps the greatest thing I love about the car as of late? If you've been watching the prices on them, they are going up. There are 23 for sale in all of Canada on autotrader. Only two are red like mine, and I can easily sell it for about $8,000 more than I bought it for. Why? Because six speed manual two seat convertible roadsters are becoming hard to find. What about the Mazda MX5 you say? The S2000 has about 100bhp more than that car, and is far more advanced in almost every way. Talk about gutless. I think people are starting to view the S2000 similarly to the NSX. Anyway, the Viper is a far superior car, but I just took the recycling to the depot in the S2000, which I would never do in the Viper, and had a blast.........

[dethred]

Yeah, I've owned more sport bikes than I can even remember, and that makes sense. I've always wondered why you could get 170 hp out of 1000cc on a sport bike, but the same wasn't being achieved in cars. I still love my S2000 but obviously not for brute power. The car is a blast to drive, top down option, great motor, great leather interior, fantastic 6 speed manual, surprisingly big trunk, 29mpg......on and on. But perhaps the greatest thing I love about the car as of late? If you've been watching the prices on them, they are going up. There are 23 for sale in all of Canada on autotrader. Only two are red like mine, and I can easily sell it for about $8,000 more than I bought it for. Why? Because six speed manual two seat convertible roadsters are becoming hard to find. What about the Mazda MX5 you say? The S2000 has about 100bhp more than that car, and is far more advanced in almost every way. Talk about gutless. I think people are starting to view the S2000 similarly to the NSX. Anyway, the Viper is a far superior car, but I just took the recycling to the depot in the S2000, which I would never do in the Viper, and had a blast.........

Yep, I got out of mine a bit early, which is the story of my life with assets appreciating. I did make about 2k profit and drove it about 2,000 miles in the process. Hard to not call that a win. I still kind of regret not keeping it and boosting the crap out of it, but... then it'd lose value for not being original. Over-engineered, low mass, forged internals, etc. Just not cost-feasible with a large pushrod V10.

[lochnessmonster]

I think you did pretty well. Any car you can sell for a profit is a win. I've been looking very seriously at the S.O.S.stage II supercharger kit for the S2000. From what I gather, that little F20C is a beast in terms of the stock internals handling boost. And you're absolutely right about resale, which is why I've held off as well.