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Performance, Brainstorming & Tuning Talk about modifications, or anything else associated with performance enhancements. Have a new idea for performance/reliability? Post it here. No idea is stupid! (please use Detailing and Appearance for cosmetic ideas)

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Old 07-26-2006, 01:38 AM   #11
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You’re kind of heading out into uncharted water, at least here in the US. Aussies have rockered and cammed LN3s in RWD form and IIRC they refer to this as their series 1.
When putting rockers on your really concerned with 2 things.
1. At what lift are you maxing out performance, making it pointless to go higher in ratio.
2. When are you going to see valve float, basically when the valve springs can't keep up with how rapidly the valves are opening and closing. This gets worse in the higher rpm range as you increase rocker ratio. (valves may hit pistons)
***No I have no clue when either of these things will happen in your engine.
But I'll take a stab at guessing..***
Being the low end torquester those LN3s are I would have to guess you would be maxing performance out with a lift around a 1.8 ratio.
Because of the mileage on those stock springs I wouldn't take the risk of getting valve float putting hose on.
A 1.7 ratio seems like the safest option if you don't want to swap out the springs.
But there are two things that help valve float besides stiffer springs. They are lightening up the valvetrain(i.e. lighter rockers), and roller fulcrums & tip rockers. Your stock rockers have neither roller fulcrums nor tips but an aftermarket rocker would.
This may just be enough to combat a 1.8 ratio on your springs but I still wouldn't suggest it as no one on this board has found that out.
As far as reworked stockers go, to the best of my knowledge they are not available for the LN3 or L27 but Blazin_low might have something up his sleeve?? They would not be roller though.
Hopefully that made some sense. And remember this is just my best guess.
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Old 07-29-2006, 06:09 PM   #12
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Thanks for all the great information. I see has a group buy on some series one rockers, could the one'* that blazin is working on be similar? Do you have any idea what I may gain since my car is only N/A? How hard is it to change springs? From what I've read the rockers are an easy bolt-on but the springs and other goodies can be hard and bad stuff can happen if things go wrong. I like to work on my car rather than pay someone else to do it, but I wouldn't want to attempt something that is outta my league and end up with a big mess.

Also, I checked up on the exhaust situation I have a 2.5" DP to the cat and then 2.25" from the cat back. Plus the back half is crush bent, not mandrel. Would it be worth my time to get some 2.5" mandrel bent tube from the cat back? Woud you reccomend going with stainless, aluminized, or something else?

Thanks again
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