Lt1Powerz

iTrader: (1)

Who has a set that is fairly inexpensive and will work well! I am trying to hit 450+whp on my daily so anything will help just nothing too crazy...

Thanks in advance!

02*C5

iTrader: (1)

Roller rockers are not going to help u in gaining any hp first off. Second the stock rockers are the lightest rockers specially when you do the trunnion upgrade they are hard to beat. You can run a .615 lift safely because that is what I am running in my present configuration with stock rockers and trunnion upgrade. Now unless you have aftermarket heads that call for aftermarket rockers you are wasting money. Most "off the shelve" cams are made to run with a 1.7 rocker ratio and if your trying to get higher lift numbers you have to build your valve train from ground up to run with a higher rocker ratio specially if you have stock heads.

What are your mods is it an A4 or M6 and maybe we can guide you in the right direction.

Lt1Powerz

iTrader: (1)

Im using my stock ones for another project...

I have tsp 5.3 2.5 heads, ms3 cam, ls6 ported intake, 3600 stall, lt's full exhaust, yaddah yaddah yaddah... Its gonna be a ten second daily after some vigorous tuning... So the last thing i need is the roller rockers...

02*C5

iTrader: (1)

Yella Terra but i still say stockers are the best way to go. again though they do not and will not add any hp.

good luck

SweetS10V8

iTrader: (4)

The stockers are still your best option!! Just buy some more stock rockers for cheap and swap the trunions. The OEM rockers are an exceptionally nice piece especially after you upgrade the trunion. I just got mine back from having Comps trunion upgrade installed.

Im running .620 lift with them, without issue.

soundengineer

iTrader: (16)

thats the biggest crock of **** I've ever heard...
they may not gain you anything substancial...but when you have less friction, and more stability with less flex, you get more power...

if you are going to get roller rockers just be sure to get a high quality shaft mount rocker.. I prefer the Jesel

if you do keep the stock rockers... just be sure to order a trunion upgrade...it is an engine saver...

LS12Fast4U

iTrader: (1)

And the battle between which is better begins

bww3588

iTrader: (49)

this is the biggest crock of **** ive ever heard....

if in your mind, valvetrain stability = power, then yes. the amount of power you gain with roller rockers is about that of sneezing out your window backwards while your going down the road....

sounds to me you swallow everything your fed. comp cams says you gain x amount of power doesnt make it true. what they tell you is, "while installing the roller rockers, we installed this vortech S trim as a supporting mod, the gain we saw from our roller rockers was 120hp at the wheels." and you beleive it.

98PurpleT/A

iTrader: (16)

02*C5

iTrader: (1)

I guess I didn't make my self clear. What we seem to be missing when comparing rockers which is the most important part of the whole thing is mass and moment of inertia. We'll get back to that in a second.

Most of your flex does not occur in rocker but the push rod. This flex comes up and snaps on the rocker and affects the valve/valve profile. That is why you see so many people when they change cams they go to the hardened push rods to diminish the push rod flex. Hence you have less flex of the push rod and less effect of the valve/valve profile. So really is your push rod which causes most flex not so much the rocker as you stated. Also the less lift (<.600) and less aggressive lobes will lessen flex and snap.

Now getting back to to moment of inertia, that is how the affect of how close the weight is to the center of the rocker's rotation. Now thew stock rockers are the best rockers when you compare the two things that matter mass and moment of inertia. Are they less rigid than after market rockers yes but a good hardened push rod will take care of most of the flex. again not all but most of it. More rigidity more transference of power. Like you stated.

rockers do not make any substantially measurable HP gains PERIOD.

I hope i made myself clear.


ROFL

soundengineer

iTrader: (16)

wow...I cant believe you tried to go there....

I'm not a newb to racing...I've gone 6.5@200mph and flipped a car end over end on ESPN at the end of the 1/4 mile in Late 2000.....

stability does improve power...
with rockers its not a huge amount...1-2hp at the most if you had some valvetrain issues to begin with...
I never said its gonna gain you 30hp or something retarded like that

and it can increase your valvetrain reliability and life, which leads to retaining more power when others valvetrains are wearing out and going south.

you get even a little deflection on a valve and you get friction, which creates heat and stress that robs power...

not to mention the extra strength you get from some of the aftermarket rockers...
jesel is one of the strongest out there...and you dont have to worry about the tips breaking off like you do on an agressive high lift cam with the stock rockers

also..its not about how light the rockers are in total mass... its about how that mass is centered over the pivot point.
you get a rocker that has perfect weight geometry and its going to outperform the stockers every time(the stockers arent bad... but there are some that are better)

again...I'm not talking about tons of power... but the technical side of it is that you can gain power over the stockers with an aftermarket rocker

soundengineer

iTrader: (16)

and atleast we both posted about moment of inertia things at the same time...

bww3588

iTrader: (49)

so has John Force, but i bet he doesnt know an oil filter from a crankshaft...

back to my sneezing analogy. if you had valvetrain issues to begin with and you gain 1-2 hp, that = less than 1 hp on a car with no valvetrain issues

never said you did...

and? ill sneeze out my window before i go spending 400+ dollars on rockers that i dont need. on a heads/cam car, your not going to see any power increase over a properly functioning stock rocker setup.

show me one instance where the tips break off. all ive seen is the needle bearings going on a stroll to the bottom end of the motor.

your talking about the same amount of power increase i am. power that is not worth it. people who upgrade their rocker arms (like you judging from your posts) thinking they are going to pick up power are delerious. the only time roller rockers should be used is when your running insane RPM levels or a huge cam (read .700+ lift) where it is very hard to get a decent wipe pattern on the valve tip with a non roller, where valvetrain harmonics far exceed the limits of the stock components ability to dampen them, and the H/C/I setup the OP has is not in any way near in need of wasting money on roller rockers. period. period. period.


i agree that better units do a better job, but.....it is not needed on this application and will not see any power increase outside of that of changing your oil.

joecar

A roller tipped rocker has a higher moment of inertia just by virtue of the roller being at the furthest point, there's no getting away from this.

Also, steel rockers are stronger (flex less) than aluminum rockers, so the aluminum rockers are made thicker to limit flexing, and this distributes the mass away from the pivot, so again increasing MoI.

(Also, aluminum is more easily susceptible to fatigue (due to flexing) than steel, but I don't know if there have been failures specifically due to this... but this is why the aluminum rockers are so "thick", to limit flexing which reduces fatigue)

The tip on the OEM rocker is designed to make contact with the tip of the valve in a "rolling" motion [if the wipe pattern is correct]...(very similar to involute gear tooth design)... there is very little friction.


LOL, I like the sneezing analogy.

98PurpleT/A

iTrader: (16)

This guy FTW



Keep stockers = save $400= money for better things

vettenuts

iTrader: (4)

Hardened pushrods do not decrease flex per se, but since they have a slightly thicker wall they will help some. Here is some information that compares various pushrods and their lateral stiffness: http://forums.corvetteforum.com/c5-t...stiffness.html

vettenuts

iTrader: (4)

There are a few dyno's that have shown 5 hp from Yella Terra's. However, on a cost per hp basis it is not a good mod. There are other reasons to go to a properly setup roller rocker, but hp is not one of them. The problem is most guys bolt parts in without correctly setting them up. This alone would overshadow any potential gain. When you tell them that you need tools such as valve spring micrometers, or adjustable pushrods to correctly measure and set up the valve train they don't want to spend the money. So the question I would ask is if the OP has a correct setup with his current parts or is there other things that can be done with the same parts properly set up and adjusted.

The other thing mentioned in this thread is pushrod flex. There are documented gains of 10 hp with stiffer pushrods, especially if your valve spring seat/over the nose values are high. I saw this in my dyno after installed double tapered pushrods, which flattened the hp curve up top as there was better valve control which is what I was after when I did the swap. The OP's cam is pretty aggressive so this may be an area for further investigation.

chrs1313

iTrader: (24)

i really believe anything over 5/16" pushrods is overkill for our engines...I have swapped between both 5/16 .080 to 11/32 .120 ~50% heavier, the graph was identical to what it was before, no added stability or power to be gained...now i want to note that i also did not lose any power either...alot of heads out there run into clearance problems using thicker pushrods, i think for a hydraulic roller ls1/2 the 5/16" .080 wall is plently...

mine was also pulled to 7K, with yella terra rockers...spring are pretty heavy duty too 160# seat, 460# open

vettenuts

iTrader: (4)

Interesting. Erik contacted me about the same write-up curious as to my results and said they have seen up to 10hp depending on the application with hydraulic roller setups. The extra weight is less relevant on the lifter side.

02*C5

iTrader: (1)

What push rod would you recommend specially with aggressive lobes like XE-R and lifts above .600