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| 300WHP Supernatural 3.XX Coming Soon! (Page 4/54) |
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FieroWannaBe
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JAN 09, 08:13 PM
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| quote | Originally posted by pmbrunelle:
I think that these compromises explain the high rocker arm ratios in GM V8s lately. |
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The cylinder head design has everything to do with the rocker arm ratio and overall lift on the latest V8s. Early GM cylinder heads just dont have the head flow to make high use of higher valve lifts.
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La fiera
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JAN 13, 09:38 PM
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| quote | Originally posted by Steel:
I'd be more impressed to see you actually drive the car for a few thousand miles without it failing in multiple areas.
** This isn't an insult at all either, please don't take it that way. I was hoping for some performance numbers (times etc) on your 250whp venture.. that's why I'm baffled to see you going for yet more power but haven't actually made the car functional to handle 250whp yet?
Very interesting thread, not many are willing to spend time and money on the 60* platform these days.
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I understand you very clear Steel. The 3XX is on the works but the 250WHP Supernatural has some unfinished business. I'm not into 1/4 mile racing but my goal is for low 12's or high 11's to prove that power to weight ratio is the key. People go to great lengths to install LS engines and trans upgrades to boost performance and keep reliability and here I am with my little V6 matching or surpassing them. Of course drivability will suffer on a 60*V6 NA to match or surpass LS power but to each their own, I respect and admire those who go for the LS or other swap because that is what they want.
You are right on the monetary part also Steel. No one from this forum is giving me one penny to help me get there, this is on my own. So just sit tight and wait and you won't be disappointed, be patient my friend!
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Will
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JAN 13, 10:15 PM
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| quote | Originally posted by La fiera:
Thanks for the complement Will but they are brand new and each of them is designed for a specific purpose and as a matter of fact each of my cams I give it a personal name based on their characteristics. For example, the cam that Blacktree has I named it "Le Mans" and he'll see why when he installs it.
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I wasn't being facetious... You have to be adventurous enough to get outside the box to try new things. Trying new things means, at least some of the time, trying things that don't work. You're obviously an adventurous builder, so it's no surprise you'll have a list of things, and maybe even corresponding parts, that you'd like to try.
| quote | Originally posted by La fiera:
Everyone talks about roller cams like they are invulnerable to wear, that flat tappets are the only ones prone to failure due to their design.
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I don't know of anyone who talks like that.
Out of tens of millions of LS engines built, thousands of failures is hardly noteworthy.
Every NASCAR engine is an example of a "flat" tappet cam living under extreme conditions. Of course they literally flood the cam tunnel with oil; as in... floor to ceiling, no air volume left. Offies also have rounded flat tappets that work in pretty extreme conditions. Superbike engines run flat tappets and steel springs.
Not all roller lifters are created equal either. The Cadillac CTS-V race cars used hydraulic roller lifters... Yes, a professional race engine using hydraulic lifters. They're good for over 7500 RPM... and moving LS7 sized valves too.
There are also REALLY awesome roller lifters that eliminate the needle bearings at the roller axle in favor of turning the roller against a cushion of oil just like a main or rod bearing. This completely eliminates the roller lifter problem of pounding the needle bearings flat with extreme ramp rates accelerating enormous valves at ridiculous RPM.
| quote | Originally posted by La fiera:
Use some common sense for once and let your intelligence aside and try this exercise Will:
Get a Volley ball, bounce it up and down to the floor and back striking it with your hand at hip level as fast as you can. Time yourself for 15 seconds and write down the number of bounces.
Do the same test but this time with a Basket ball and write the number of bounces and tell me:
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Lol...
Yes, it takes less force to reciprocate a lighter component.
However, this translates to less FRICTION on the cam and does not reduce the engine's moment of inertia.
But like I said, though heavier, roller lifters still have less friction against the cam lobe than flat lifters. The switch to roller lifters was worth 0.5 mpg in the L98. The difference is probably bigger now since the rest of the engine's internal friction has been significantly reduces since then.
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La fiera
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JAN 15, 08:58 PM
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| quote | Originally posted by Will:
Lol...
Yes, it takes less force to reciprocate a lighter component.
However, this translates to less FRICTION on the cam and does not reduce the engine's moment of inertia.
But like I said, though heavier, roller lifters still have less friction against the cam lobe than flat lifters. The switch to roller lifters was worth 0.5 mpg in the L98. The difference is probably bigger now since the rest of the engine's internal friction has been significantly reduces since then. |
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Will I admire your intelligence and I see you are well informed about about specific racing teams using specific items. Literally down my street there are a lot of teams of different brands and I know personnel that works there and I get info on things that is insane! I have Riley & Scoot, Acura IMSA team, the majority of NASCAR teams, the place were NASCAR developments take place and the list is long, this town is know as "Racing City USA". I've seen some wicked prototype stuff on shelves and the money they spend on R&D is insane! That's why I said screw that, I'll just work with what I have and what I can get on my budget.
Some of my customers have lots of money and I can use that advantage to build their engines spending their money, I don't have that luxury.
I know the advantages of a roller lifter over a flat tappet but the advantage vs cost on a good custom set of roller lifters for my engine from Crower is not feasible. The set costs over $500. If I had money to throw away then I'd get 5 sets. With that kind of money I can get more things for the build. And with today's oil technology rollers are not the norm.
Yes, it is the intelligent way to go with roller lifters to make more power but most of the time the intelligent choice isn't always the smart one.
Cheers mate! [This message has been edited by La fiera (edited 01-15-2018).]
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FieroWannaBe
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JAN 16, 08:38 AM
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| quote | Originally posted by La fiera:
And with today's oil technology rollers are not the norm.
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 Show me a modern push rod engine using modern oils that doesn't incorporate a roller on the cam lobe...
Even most OHC engines are using roller followers.
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but most of the time the intelligent choice isn't always the smart one. |
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La fiera
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JAN 16, 03:53 PM
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| quote | Originally posted by FieroWannaBe:
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The only engines with rollers are the american units, that I'm aware of. As far as the European and Asian OHC engines the y all use a bucket type lifter and have no roller units in them.
My Abarth has a roller rocker on the intake cam lobe. The exhaust valve lobe rides on a bucket type lifter.[This message has been edited by La fiera (edited 01-16-2018).]
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FieroWannaBe
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JAN 16, 04:07 PM
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| quote | Originally posted by La fiera:
The only engines with rollers are the american units. As far as the European and Asian OHC engines the y all use a bucket type lifter and have no roller units in
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American engines are also the only ones using cam-in-block construction, and 2 valve heads over large bores. And even then, there are only 2 families left in automotive use. NASCAR finally allowed roller lifters in 2016, and If you where to ask any top American engine builder, they will tell you that a roller lifter is the better route to go for a performance build.
| quote | In my experience, the people who tend to favor flat tappets are either newcomers to racing who are trying to save money or veterans who had a bad experience with roller lifters in the distant past. I think that both groups are making a grave mistake by not using a roller cam unless they compete in a class that specifically requires flat tappets. Yes, a roller cam and kit does cost more than a flat tappet cam and a set of lifters, but the cost of fixing an engine after flattening a cam or dropping a valve is much more expensive. It’s true that a roller lifter may fail occasionally – usually as the result of a broken valve spring or incorrect valve lash adjustment – but the likelihood of trouble is much less than with flat tappets.
-David Reher of Reher/Morrison |
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Will
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JAN 17, 08:39 PM
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| quote | Originally posted by La fiera:
The only engines with rollers are the american units, that I'm aware of. As far as the European and Asian OHC engines the y all use a bucket type lifter and have no roller units in them.
My Abarth has a roller rocker on the intake cam lobe. The exhaust valve lobe rides on a bucket type lifter.
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The because of the lower spring loads, the MPG gain wasn't worth pursuing in OHC engines until many years later.
GM OHC engines use roller finger followers with hydraulic lash adjusters in the cylinder heads. The Ecotec 4's, Atlas 4, 5 & 6 cylinder mills and the Northstar all used the same roller follower. Jessel even makes (or made) high performance versions for the Ecotec racing program.
BMW went to similar followers on their Valvetronic engines in the early/mid 2000's. In fact relatively few *modern* OHC engines still use buckets.
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La fiera
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JAN 27, 09:26 PM
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Will
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JAN 28, 09:08 AM
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If you're pulling those bolts to greater than stock torque, it's a good idea to have the rods resized.
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