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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 11-20-2006, 01:47 AM   #11
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1.92 modded stockers have been around for quite some time. Modded and stock rockers deflect - they have been known to deflect over 2.0. 1.95 will be fine... If you are going to do springs then I'd do 1.95 to try to make up for the HP the springs are going to eat up.
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Old 11-20-2006, 01:58 AM   #12
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Quote:
Originally Posted by PURENVY
1.92 modded stockers have been around for quite some time. Modded and stock rockers deflect - they have been known to deflect over 2.0. 1.95 will be fine... If you are going to do springs then I'd do 1.95 to try to make up for the HP the springs are going to eat up.
Couple questions - who makes these 1.95 rockers? What is the hp difference between these and 1.9'*? Back on the topic of springs - a local GP racer told me to run 105 springs and not the 90 lb. ones. Some kooky story that the seat pressure is actually higher on the 90'* and they will wear down your timing chain and tensioner quickly. The guy seems fairly knowledgeable, but occasionally misses on something here or there. The numbers I have seen published (I think maybe either SLP website or Intense) show that the 105'* have a higher seat pressure at every lift. Is there some kind of difference not published because you have to use a different retainer or did this GP guy cross his numbers?
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Old 11-20-2006, 02:09 AM   #13
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The rocker are made by the well known company Yella Terra. The 1.95 ratio are specifially made for ZZPerformance that has worked with Yella Terra on these rockers.

As far as the springs go I'd do comp cam 105'* with comp cam retainers. ZZP has an artical on this: http://www.zzperformance.com/grand_p...les1.php?id=53

Taken from the artical... "Spring rate determines how much pressure the spring will have when the valve is open. This is very important because the spring pressure when the valve is opening determines the force needed to open the valve. The more force needed, the higher the stress on the timing chain system. In our case, the stock timing chain dampener. This means that the higher the spring pressure during valve opening the more wear on the stock timing dampener.

The LS6 spring increases in pressure faster than the Comp 105 or the Comp 130 (which has the same spring rate as the 105). By the time you get to .300 lift, the yellow LS6 spring has passed the Comp105 in pressure. At valve lifts of .500 (close to what a 1.9 rocker gives) the LS6 spring is up to 275#, while the Comp105 is only 250# and the Comp130 280#."
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Old 11-20-2006, 02:46 AM   #14
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Quote:
Originally Posted by PURENVY
The rocker are made by the well known company Yella Terra. The 1.95 ratio are specifially made for ZZPerformance that has worked with Yella Terra on these rockers.

As far as the springs go I'd do comp cam 105'* with comp cam retainers. ZZP has an artical on this: http://www.zzperformance.com/grand_p...les1.php?id=53

Taken from the artical... "Spring rate determines how much pressure the spring will have when the valve is open. This is very important because the spring pressure when the valve is opening determines the force needed to open the valve. The more force needed, the higher the stress on the timing chain system. In our case, the stock timing chain dampener. This means that the higher the spring pressure during valve opening the more wear on the stock timing dampener.

The LS6 spring increases in pressure faster than the Comp 105 or the Comp 130 (which has the same spring rate as the 105). By the time you get to .300 lift, the yellow LS6 spring has passed the Comp105 in pressure. At valve lifts of .500 (close to what a 1.9 rocker gives) the LS6 spring is up to 275#, while the Comp105 is only 250# and the Comp130 280#."
Hmm, food for thought, but what the article does not explain is why a roller rocker vs. stamped rocker will produce valve float with stock springs - my guess is that the rollers have a "true" ratio due to the roller tip and the standard one loses some lift sliding on the valve. This would put me back to square one - 1.84'* with stock springs? I don't see any dyno numbers to justify 1.95'* or 1.9'* for that matter. If say 10 hp. can be had for the extra cost of the Comp 105 springs with 1.9 or 1.95'*, might be worth it. The only dyno comparison I've seen though is 1.9'* vs. stock. Thanks for the info. Also - how long have the 1.95'* been around?
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Old 11-20-2006, 02:19 PM   #15
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I'm thinking that you are starting to see what I'm saying. You are looking at most 5 WHP from 1.84'* with stock springs then 1.95'* with 105 springs - It is actually more like 2-3 WHP. Is 2-5 WHP worth $150-$190 for the cost of springs and retainers? I don't think so.

Here is another artical on rocker ratio'* and RPM.

"We spent a lot of time optimizing ratios and studying the market for rockers. Most people are in one of two categories. Those that don't want to change valve springs and those that do. We did extensive research to determine optimal ratios. We researched where valve float occurs with each ratio, what the difference there is between a used set of stock valve springs and a new set, and what RPM is optimal to spin your engine to vs. what rpm are people commonly running.

What we found is that even with stock shift points and the super light weight of our rockers, most people running higher mileage valve springs will still get valve float with our 1.9 ratio rockers. What we also discovered is that we could run very close to 1.9 if we kept the shift points stock (1.8. The problem is that there are gains to be had shifting higher. The second problem is that most people running rockers have an aftermarket PCM with raised shift points already. So to explain in basic terms: You are better off performance wise, running a 1.8 ratio with 6k shift points than you are running a 1.9 ratio with 5700rpm shift points.

Once we settled on an optimal shift point, we set out to pinpoint the optimum ratio roller rocker for use with stock valve springs. A ratio that would give the highest possible gains without the risk of valve float, even on higher mileage engines. We cam up with 1.84 and while this may seem a lot less than the 1.9'* you keep the benefits of the lower spring rate. That means less tensioner wear and slightly less rocker deflection. "

Down under a company has been selling 2.0 ratio rockers for quite some time. Yella Terra cam out with 1.95 ratio rockers because that is what is safest without worring about the pushrod hitting the cast of the head. The 1.95 have been out since spring but ZZP has been testing them and different ratio'* for close to a year.
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Old 11-22-2006, 03:04 PM   #16
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So I was thinking about keeping stock springs - but saw this:

http://www.bonnevilleclub.com/forum/...ic.php?t=66676

Makes me wonder how much the stock springs can withstand. Sounds like possibly poor quality product out of the GM factory? Maybe I'll go with the Comp 105'* after all.
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Old 11-22-2006, 03:20 PM   #17
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A cam is going to be allot harder on a spring then rockers because of duration. Also that spring broke because he was shifting above 6200 RPM. If you are running a stock or aftermarket PCM you are at most going to be shifting at 6000 RPM.

But if you still don't feel safe and want to do springs def. do ZZP 1.95 roller rockers.
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