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VVT/VVL for pushrod engines.

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Kubboz

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Post Thu Aug 09, 2012 5:55 am

Re: VVT/VVL for pushrod engines.

I'm not taking either side, because I know nothing about Viper engine, but i believe that power to capacity ratio is overrated way of rating the engine performance. I'd check power to weight ratio instead. Or power to engine dimensions.
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Killrob

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Post Thu Aug 09, 2012 5:57 am

Re: VVT/VVL for pushrod engines.

Well, you can produce 6500hp from a pushrod 8L V8 too if you want... and that IS pretty awesome. But yeah, you'd probably be able to make some more from a DOHC engine, being much larger though.
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T-5 Killer

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Post Fri Aug 10, 2012 6:54 am

Re: VVT/VVL for pushrod engines.

autofrank wrote:
loady740 wrote:have you looked at the horsepower and torque numbers for it ........ read all the facts before you judge dude :P


Yes, because 640bhp from 8400cc is awesome :roll:


Horray for Ricer math where HP per Liter really matters.

Check up on what happens when smaller motors make lots of HP.
No area under the curve so it ends up being peaky and lacking mid and low range power. For Example Look at a dyno graph of any high HP 2JZ MK4 Supra and you will see a shit ton of lag and huge spike in power before redline. Now compare that to a Large displacement engine making the same HP.
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thereddaikon

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Post Fri Aug 10, 2012 4:11 pm

Re: VVT/VVL for pushrod engines.

It's not great, but it's not horrible either. It makes a higher specific power than any of the NA LS engines. It's also worth pointing out that intentionally making a larger displacement engine allows you to run lower octane for the same power and also detune it to increase life. Just because you can have 100hp/l doesn't mean you should. The engine builder should make it clear that a high specific output motor will have a shorter life unless you over build it and then costs go up quite a bit. You can get away with this in Ferraris because of their cost, or in the Honda S2000 because it's an I4 and will always be cheap due to size. The Viper and Corvette are far cheaper than Euro exotics but are expected to have comparable power. The only way to retain reliability and keep the costs in check is to use a big ass motor. I don't want to think how much a Ferrari V8 costs to make or maintain. An LS is cheap to build and is stupid cheap to keep going, even the supercharged models. Mercedes does a very similar policy on their motors, but they aren't quite as detuned. It's actually hilarious how much extra power an AMG motor will make with just an ecu retune.

http://www.renntechmercedes.com/www/node/754

This was all intentional. When you build a car you have certain goals you wish to achieve and certain constraints you have to sit within. If you have a cost is no option approach and your engineers get to go wild then you get a ferrari. There are very few companies that get to do this though, even Porsche doesn't get to go that wild and it shows in how bulletproof their flat-6 motors are.
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