PowerShift408

iTrader: (44)

That is a horrible misguided attempt at a post. If they hate more lift so much, why do people put cams in these cars with stock heads?

bww3588

iTrader: (49)

how is this misguided? the LS3 heads have more volume and are more than capable of flowing a greater amount of air with the same duration. incase you didnt know, when you put a cam in an LS1 with stock heads, not only do you change the lift, but you change the duration as well. 1.8 rockers do nothing for duration.

maybe if you search you will find im not the only one that thinks 1.8 rockers are a waste on an GenIII motor.

PowerShift408

iTrader: (44)

https://ls1tech.com/forums/dynamomet...5-rockers.html

There, I searched. 8 rwhp, 17 lb. ft. of torque.

Blk_Ws6

iTrader: (4)

That's right fellas keep it going I taking notes on everything.

Blk_Ws6

iTrader: (4)

Who"s next?

SweetS10V8

iTrader: (4)

Not true, it will change the running durations.

bww3588

iTrader: (49)

whats your point?

8RWHP for what almost 300 bucks? thats stupid. you can pick that up from free mods. again, not worth it. period.

bww3588

iTrader: (49)

how do you figure? the lifter on the lobe determines the duration. the rocker is only going to change the lift at a certian point in duration. the valve will still open at the same time and close at the same time as long as the spring is doing its job.

KCS

iTrader: (20)

It will change the duration, but only at higher lift points and only very slightly. If you degree the cam, and plot the duration out at different lift points, it makes a bell curve. Going with a higher ratio rocker basically makes the curve taller, and fatter, like this:



I personally think it's not worth it, not even remotely. Like mentioned, it's a lever, so while the valve events from the cam are "amplified" to the valve, the spring force is amplified back to the pushrod as well. Same concept as a longer breaker bar, or pry bar. Not only that, but if you do go with a cam swap, you need one designed for a 1.8 rocker ratio. Some of those camshaft designs out there now are already aggressive for a 1.7 RR, so a 1.8 would be a catastrophe.

bww3588

iTrader: (49)

i honestly dont see any duration change there. the distance between 2 different sides of the cam lobe (duration) is very very close. all physical characterisitics do not allow for the valve to stay off its seat any longer with a 1.8 ratio over a 1.7 ratio. the lifter still hits the point where it lifts the vavle off the seat and hits the same point on the other side of the lobe where it lands back on its seat.

PowerShift408

iTrader: (44)

You don't see a duration change? It's not a drastic change, but duration is measured at different levels of lift. Higher ratio rockers open the valve faster, thus slightly increasing duration.

I never said this was the most cost-effective mod. However, for someone who wants to maximize what they have without swapping cams, it's a good mod. And when properly setup, roller rockers get rid of a lot of the dreaded "sewing machine" noise that LS1s are known for.

bww3588

iTrader: (49)

im not debating roller rockers arent good for valvetrain stability, im debating 1.8 rockers increase HP by any amount worth the 200+ dollars. and the valvetrain stability gained by roller rockers is ruined by the increased valve speed.

there is no two ways about it, this mod is pointless. thats why you only see a handfull of people doing it and the ones that are doing it have no clue what it does to the vavletrain in terms of valve events. all they see is SLP claims XX amount of HP and thats good, even tho it doenst happen.

bww3588

iTrader: (49)

i see what you are saying now about the valve being open longer at a given lift, but that only directly reflects vavle speed. this doesnt change anything but takes peak lift and moves it to a mid lift range. however, that doesnt change the fact that the cam is only going to let the valve be off the seat for whatever amount of duration the cam has.

lets use my cam for example. 239 degrees of crank rotation .649 peak lift w/1.7 rockers.

with 1.8 rockers peak lift is .687

now, yes, the valve will be open longer at .649 but...now the valve has to go to peak lift (.687) in the same 239 degrees of crank rotation. so total duration does not change. its a give take relationship, it adds duration here, but takes it from there.

7th Darkness

iTrader: (15)

This diagram shows how the rocker ratio works to multiply cam lift and how changing the distances between the pushrod cup and roller tip, relative to the fulcrum pivot centerline, alters the ratio.

02*C5

iTrader: (1)

I think that if this was such a good idea for hp gains then everyone would be doing it. The people who actually do this is a for a short cut and do not want to do the cam change. Will you see any gains yeah are they significant no. Every car that i have seen do this at most its a 2 to 5 hp gain and for 200 to 400 dollars to be with in margin of error of a dyno to me is not worth the instability and unnecessary abuse your valve train is going to experience when there is no need for it. Get a cam with the lift you want, and you will see true gains (20hp-30hp).

kinglt-1

iTrader: (26)

Could you guys dig up some info proving these rockers only gain 2-5hp on a gen3 motor?? I have seen more than 1 ls engine pick up 7-12 whp and 15-18wtq just by switching these rockers out. Dont forget these are gains at the wheels!! I don't know how you can say its not worth it... I think there are some biased opinions in this thread. I agree that running stock rockers and swapping cams is the better way, but adding 1.85 rockers to the stock cam is a decent option for some. as stated earlier just set your valvetrain up correclty and it will be fine. A stock cam with 1.85 rockers is not going to beat up the valvetrain any harder than all these new agressive lobe cams out there running 1.7's lmao. The stock rockers have been proven to be one of the most reliable rockers, so thats why I think you see people stick with them. the slp 1.85's are modified stock style and are proven very reliable too, not many peple use them because of price and they usually just go with a new bumpstick and call it good. You have to remember that some(especially the older folks) think its a cardinal sin to change any internals of an engine for a daily/weekend driver... Thats why the 50yr old previous owner of my car did not change cam and went with the 1100.00 slp 1.85 rocker arm/spring package lmao... I would of never spent that much, but hey it didnt cost me anything.

Siciliano15

iTrader: (7)

i gotta agree with above^^^^. Besides that dyno result of 8hp and 17ft-lbs, the slp rockers are stock design and just as light and reliable so of course the extra lift is going to make more power. Its going to be similar to going from an ls1 cam to a ls6 cam. Now for $400 or whatever they cost its a great deal. Yea you can pick up the 8-10hp in some of the free mods but what happens when those are done????? for people that dont want or need to do a cam swap then why not do this mod its 10hp more than you had before. higher ratio rockers always works out great on stock cams. did that on my dakota 5.9 r/t when it was stock and picked up 15hp at the wheels going from 1.6 to 1.7 rockers.

This is what i plan on doing in 2 months on the t/a. I already have all the boltons and gonna install some ls6 243 heads along with the slp rockers and keep the stock cam. bet everyone its gonna make a huge difference in power output.

bww3588

iTrader: (49)

you just said it yourself. not only that but you contridicted yourself.

when you switch the rockers, you also have to change the springs and pushrods. (to do it right). thats the cost of a cam swap right there.

thats how i can say its not worth it.

people are spending 200+ dollars on the rocker arms, then around 200 on the springs and pushrods maybe more. for around 4-500 bucks, you can have a good cam swap.

its all fine and good if you consider spending 500 bucks for 6-10 hp and 10 -15 ftlbs, but i dont know what world your living on, but thats not worth it.

bww3588

iTrader: (49)

https://ls1tech.com/forums/5520537-post8.html

ill go with Tony Mamo on this subject. now he doesnt touch on gains or anything here, but obviously by his post, its neccessary to change springs and pushrods with these rockers. meaning its not just a 200 dollar bolt on and go.

bww3588

iTrader: (49)

again, your living in a fantasy world if you think 400 bucks is worth 8 or so hp. its not....

and no, its not similar to switching to an LS6 cam. switching to an LS6 cam increases duration lift and a whole lot more varaiables that make it more reliable and easier on the valvetrain.