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Old 08-24-2006, 03:45 PM   #1
ElPiloto
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Default Is There A Chart That Shows Cam Duration, Overlap, etc.?

All of the cams I have seen seem to be less than "all out full race". I did a search and came up with about 10,000 posts about camshafts.

I am thinking about building a full race red block. I need a high lift cam with about 280 degrees of duration, a fair amount of overlap and high lift.

I am thinking of a dual fuel setup using propane and E85 with a very high compression ratio. 12 1/2 to 1 sounds about right.

I would most likely weld up the rod journals on a forged crank and offset grind it to shorten the stroke about 1/4" and use long Chevy powder rods.

Is there a chart that shows the timing and lift of the most common camshafts?
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Old 08-24-2006, 03:57 PM   #2
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in the faq, k would do it
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Old 08-24-2006, 04:56 PM   #3
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http://www.turbobricks.com/resources...ontent=camspec
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Old 08-24-2006, 06:45 PM   #4
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Default full race

Full race Volvo cams are available from enem. They have a wide range of cams from mild to totally wild. Check out Fred's chart for some examples. The enem catalog has even more of them listed. SPM and KGtrimning also have full race cams available. Personally, I've only bought from enem. Jan was very nice to talk to. He speaks English very well.
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Old 08-24-2006, 06:50 PM   #5
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I am assuming this is for a NA motor?
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Old 08-24-2006, 06:58 PM   #6
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Thanks for the chart. It was exactly what I was looking for.

Enem does have some full race cams. I now know how an non-English speaker feels when he comes to the USA.

I'm starting to get bit by the redblock bug. I just love the idea of blowing the doors off of some V8 powered factory hot rods.
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Old 08-24-2006, 07:35 PM   #7
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Default Some tips

Its been discussed before...

If you are going to stay NA there is no need to really destroke it. You should probably go bigger. Even with the cams that are out there , go bigger on displacement . Take the lead from the fast NA cars in Sweden. It is easier to make compression when you make the stroke bigger anyway. More of whats called "swept volume".
There is a group buy on billet cranks in progress. By the time you offset grind, then balance , for a few bucks more you have a real crank.

Its spelled Pauter by the way to help with your search. Go smaller on the rod journal size too. Dont do a 2.100 or 2.00 size-- go smaller. Less bearing speed. Longer rods are going to be better 9 times out of 10 too.

Take it from an old hot rodder , by the way. 12 1/2 to 1 on the street sucks. Bad

but as they say, go big or go home.
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Old 08-24-2006, 08:01 PM   #8
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Not NA. 20+ psi boost. Destroke is to move the power band up. Long rods keep the pistons near TDC longer and reduce the rod to crank journal angle.

12.5 to 1 on the street with alcohol makes a lot of power. All turbo engines are NA until the turbo starts making power. A lot of overlap on the cam bleeds off a lot of the compression pressure at low speed.

I ran 12.5 to 1 on a radical Chevy small block in the 60s when we had Custom Supreme.

This wouldn't be a daily driver. It would be a Saturday night racer.
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Old 08-24-2006, 10:45 PM   #9
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I think with 12.5:1 you simply wouldn't be able to run more than 10psi on any gasoline at all. Boost on top of that? It would diesel!
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Old 08-24-2006, 11:15 PM   #10
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Quote:
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I think with 12.5:1 you simply wouldn't be able to run more than 10psi on any gasoline at all. Boost on top of that? It would diesel!
that all depends on camshaft design. I could run 18:1 compression and 20lbs of boost with the right set-up and CAMSHAFT.

I know a guy with a 11.5:1 21psi supercharged honda making 450 at the front wheels and get 29 mpg and has done so for the last 75k miles.....

www.theoldone.com

he is the one making my pistons that we will be offering.

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Old 08-24-2006, 11:20 PM   #11
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The big question here which everyone is hinting at but no one is saying is

which ratio, your dynamic compression ratio or your static compression ratio?
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Old 08-24-2006, 11:28 PM   #12
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sorry I was super hungry and was drawing a blank....but Ben hits it on the head....
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Old 08-24-2006, 11:31 PM   #13
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Quote:
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the head....

8v, 16v, or 20v
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Old 08-24-2006, 11:57 PM   #14
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Quote:
Originally Posted by ElPiloto View Post
Not NA. 20+ psi boost. Destroke is to move the power band up. Long rods keep the pistons near TDC longer and reduce the rod to crank journal angle.

12.5 to 1 on the street with alcohol makes a lot of power. All turbo engines are NA until the turbo starts making power. A lot of overlap on the cam bleeds off a lot of the compression pressure at low speed.

I ran 12.5 to 1 on a radical Chevy small block in the 60s when we had Custom Supreme.

This wouldn't be a daily driver. It would be a Saturday night racer.
yes but...

Back in the day ,gas had lead in it and this helped inhibit detonation. We all know that.

A "radical" camshaft from the 60s was far from radical by todays standards but I get what you're saying.

Running on alcohol the street is not running on E85 on the street.

For what you are trying to do , an off the shelf camshaft for a NA 2.5 litre rally car isnt going to get you where you want to be so I would just get one ground for what you want.

Good luck with it !
George
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Old 08-25-2006, 12:00 AM   #15
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Quote:
Originally Posted by blkaplan View Post
The big question here which everyone is hinting at but no one is saying is

which ratio, your dynamic compression ratio or your static compression ratio?
Quote:
Originally Posted by blkaplan View Post
8v, 16v, or 20v


isn't he asking about a single cam(so 8v) and didn't he say 12.5:1 CR ... so that would be static CR .... which if he said he'd like to run 20+ psi on it give him an effctive CR of ~30:1
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Old 08-25-2006, 12:02 AM   #16
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you can have a 7.5:1 car witha T cam and then take an A cam and advance the hell out of it and have an amazing increase in Dynamic compression.

Static compression can be somewhat of a useless number. Dynamic compression is what really matters.

BTW Mike, I really like your new sig...
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Old 08-25-2006, 12:04 AM   #17
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thx its an old picture(like 2 days old tho it makes it look likes its and old old pic)

so sorry to wander OT but what is dynamic compression? i know static is the base or set engine CR .. and effective is when booooost is added(some crazy ass math) but what is dynamic?
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Old 08-25-2006, 12:09 AM   #18
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this is a quick little read that explains it better than i can in my exhausted state of being.

http://www.kennedysdynotune.com/Dyna...ion%20Tech.htm
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Old 08-25-2006, 01:16 PM   #19
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E85 is 85% alcohol and about 106 octane. Propane is 110 octane. Custom Supreme used to be 104 octane. All can handle 12.5 to 1 CR.

You WILL need a lower compression ration if you use a supercharger because you are getting boost from idle to max RPM.

With a turbo charged engine, you have 2 kinds of engines in one. From idle to the point that the turbo starts making boost, you have a normally aspirated engine. When the turbo starts making boost to max RPM you have a pressure fed engine.

An SOHC engine like the redblock should go to 8500 rpm. The weak points on the redblock are the rods and main bearing caps and the cams. The rods are available and the main caps could be milled flat and reinforcing bars could be made easily. Using studs with the bars would prevent dancing crankshafts. Using smaller rod journals is a great idea, but I want to use off the shelf Chevy powder rods. The long duration cams are available from Sweden.

Cams in the 60s were just a radical as the cams of today. There are no more camshaft secrets. High overlap means that both valves are open at the same time. At high RPM high overlap overlap doesn't make much difference because of the inertia of the fast moving air/fuel mixture. At lower RPMs the high overlap bleeds off some of the compression pressure.

I would like to use a 16v head, but the expense is the problem. I intend to use a B21 block because of the thicker cylinder walls. I'm not too impressed by the redblocks oiling system, so I might dry sump it.

All of this is speculation. I want a high RPM engine because there is a lot of horsepower up there.

I don't do things like everybody else does. I may grenade a few engines before I get it right, but that's how you find weaknesses and flaws in your theory and in the engine parts.

I want enough horsepower to blow off the factory hot rods and those pesky Japanese 2 wheeled crotch rockets too.
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