Roller cam and turbo charging

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RJK3

RJK3

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Reading through the "turbo bible", it says flat tappet is better for lower boost levels.
I'm planning 6-15 psi with my build. My machinist is pretty convinced I should go roller, I'm not against it, but it is contrary to what I've read. What's the consensus? He says "I put a roller in everything I can". Lol
This will be a street driven set up, with the occasional track day.
 
I have no experience with turbos.
But, Im reasonably well read in stuff.
The reason for the flat tappet statement I think is no longer valid.Camshaft technology has moved forward.
It used to be that flat tappet designs would whack the valves open a little faster in the low lift area.Higher boost requires more spring pressure. Ergo lower boost doesnt require as much spring pressure. Flat tappet cams do not tolerate high spring pressures as well as rollers. Rollers are expensive.
That book was trying to make the point that at lower boost levels, rollers may not be required(not so much that FTs were better,period) because the spring pressures are survivable by flat tappets and the tiny bit of fast rate advantage goes to them, and theyre less money
However, if you take money out of the equation, the advantage goes to the rollers.Especially now that rollers are being built for Mopar lifter bores, and roller ramp rates are increasing, and the lowZDDP hit us. That one reason alone spells -advantage rollers-
And they are transferable to subsequent cams.
Theres no downside to rollers except there initial cost. After losing just one cam, it wouldda bin cheaper for me to have gone roller,to start with.
My vote is roller. Your cam problems will be history.
 
Makes sense to me, thank you for your explanation. I kinda felt that it might have been a little outdated info. The mechanical advantage seemed clear to me.
 
You may wanna call a cam company and get a custom grind. With the larger stroke, a 4" crank tends to "soak up" more duration than if it were installed in a 318. So you'll need a little more duration, maybe In the 220-230 @ .050 range. And a higher LSA is always desired In a turbo setup.
 
i'm thinking about putting a turbo set up on my 1970 dodge dart slant 6 is there a proven kit i can get and how much
 
T56MaxTorq said:
You may wanna call a cam company and get a custom grind. With the larger stroke, a 4" crank tends to "soak up" more duration than if it were installed in a 318. So you'll need a little more duration, maybe In the 220-230 @ .050 range. And a higher LSA is always desired In a turbo setup.
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That's the plan, would you have a good recommendation?
 
Brian at IMM does turbo grinds also. Friend got cam specd by Bullet and Brian, basically same price and specs. Roller is good suggestion.
 
Howards Cams! Custom grind flat tappet cams for under $150 shipped. Call howards Cams ( 920.233.5228 ), tell them what you have and what you want. The will give you a core # and a grind # call up summit racing give them the info( http://www.summitracing.com/parts/hrs-719991/overview/ ). Mine was $149.97 shipped. I will be running a 360 and the specs for the howard turbo cam is 226 at .050 int and exht. .560 lift 114 lobe seperation on a 110 ic. A stroker will be capable of handling more duration. I havnt looked up prices on howards roller cams though. Roller cams are usually the way to go if you can afford it!
 
Check out, Crower's grind number 34116. Ground on a 114 lobe center,[email protected]/284 advertised/.484 lift with a 1.6 rocker ratio. Idled like glass ,in a stock carbed Magnum 5.9 (21" of vacuum) . Something like those specs,ground on an LA cam core ,would be close.
 
hey rjk3, how high u plan on revving it, I would think of a hyd. roller, crane, comp, isky, whatever, custom if needed, up to 6500 for around $490 for just the cam. how much better is an $840 stick
 
Marcohotrod said:
hey rjk3, how high u plan on revving it, I would think of a hyd. roller, crane, comp, isky, whatever, custom if needed, up to 6500 for around $490 for just the cam. how much better is an $840 stick
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Custom roller comp cam from a shop with their specs if 800-1k. Brians is 1k with lifters for a turbo cam.
 
I'm not planning on taking it past 6500...not on purpose anyway. I too was thinking hyd. Roller as well. Hughes has a hyd/roller lifter set for a pretty good price, like $360 or so. Anybody have any experience with them? @Bomber: I'll check into the Crower piece. Thanks for the input guys!
 
like I said, call / shop around, learn the numbers so u don't need to spend $800 for a turbo cam, a turbo cam is a single pattern cam - equal intake and exhaust duration, and around 113* lobe seperation. for a more specific cam rec. we need tons more info about the combo
 
^^ Mine is not a single pattern.. mine is split and my lob seperation is more.. the reason mine was so expensive is no one made a core on a 115 lobe sep. my car is a max effort setup so i wanted all the power i could get so i left the spec'ing to the professionals
 
rgreule said:
id go roller..

bullet/lil jon spec'd my solid roller turbo cam.. be ready to spend some coin.
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Not a better guy today than liljohn motorsports for turbo cams. He is the man right now.

Fwiw i have ran rollers in all of my turbo cars. Dont have a clue how an old school rattle tappet cam would work compared to todays tech. Probably not very well.
 
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