Nytmare

What's the deal on these rockers? Aren't they designed to combat valve float passed 6500 rpm ? On a freshly but motor, why would you not use YT rockers ? Do you agree that the stockers are better? Why? Are stock sized YT rockers a good upgrade from stock ? Why are they harder on springs than the stock rockers if they're supposed to be better ? What is the best rocker for our motors / DAMN the price !

Ryan02SS

iTrader: (3)

I've been running the 1.7 YT's since I put in my TR224 cam about 5K miles ago. The addition of the YTs noticeably quieted down the sewing machine engine sound of fast ramp rates and stiff valvesprings. Revs to 6800 with no valvefloat. They are also a very nice well made part. IMO people that have seen valvefloat while using these rockers comes from the fact that the YT's don't flex at high rpms and you will see the full extent of your cam's lift. That effect combined with valvesprings that are very close to thier max lift capacity then starts floating the valves. So far I love my YT's.

Phil99vette

iTrader: (11)

I am running YT's and roll to 7200 with ease. I did have valve float issues with XER + 987s + YTs but I think thats more of a spring issue.
Phillip

Neumonic2002

good question Nytmare,I am also considering the YT-I just put a TR227/224 cam in my 02 Z06 and have that sewing machine valve train noise. Ryan02SS you said that helped quite your V/T, could you elaborate on that a little more?
I am deff interested in a full roller rocker and what a + if it helps with the V/T noise as well..There wouldn't/shouldn't be any HP loss in that upgrade could there? They do seem a lot larger than the stock rockers.

ROGERSPERF.

Info on valve train http://www.carcraft.com/techarticles...402_spring/ins.




mike

Pro Stock John

iTrader: (34)

Ryan nailed it. Float is some of the springs that are out there not holding up.

Ryan02SS

iTrader: (3)

Neumonic.... Fast aggressive ramp rates and heavy valvesprings = sewing machine sound. With the addition of the YT's it seemed the sound was muffled somewhat. I can best describe it being not as high pitched as with the stock rockers. If I remember correctly someone did some back to back testing on the YT's and picked up about 5 rwhp over the stockers.

Nytmare

Thankx all ! Whewwwwww!!!

Neumonic2002

thanks Mike @ ROGERSPERF for the link, I will read through that this afternoon.Also thanks for the reply Ryan02SS, I want to make my cam upgrade as efficiant as possible and have been toying with the YT idea since December when I bought the kit, from all the threads I have read it seems the 918 comp springs I am running with my new cam and hardened push rods are a quality spring and after I changed to NGK TR-55 plugs w/.50 gap the car is finally feeling noticeably stronger than with my stock cam/setup..the next thing is going to KC to have RGMS do the LS1 edit on the 20th to dial in the tune.. am I leaving anything out? Thanks again

mods are:
FLP's w/out cats, Halltech cai,msd wires,NGK TR-55,ASP Pulley, 178 stat
TR 227/224cam kit, stock Z06 mufflers

Ryan02SS

iTrader: (3)

Neumonic, Sounds like you have a very strong setup there on your Z! Congrats! I hope I never run into you on the street. You should be making 420+ rwhp with your setup and combined with your weight advantage, makes for a quick *** Z06. The C918s are a great spring with their beehive design and have proven to really control the valve at high rpms but thier only drawback is they are still a single spring and springs do break. When I need to replace springs I might go with a dual spring just for peace of mind. I bought my YT's when Thunder had their special on them. If your looking for performance from them they are definately not worth the money but If you are looking for a shaft mounted roller rocker that won't puke out needle bearings and fit under the stock LS1 valve covers they are hard to beat for the price.

Neumonic2002

Thanks Ryan!! trying to be somewhat stealth with the stock mufflers but hope they do not kill to many ponies on the dyno, will find out soon enough.
no suprise to anyone out here that I am still trying to find a few more ponies before I have to spend big bucks(like better flowing heads)..I am still on the fence on the rockers even though I never shift past 6500 rpms..I think when I am able to figure out the best head setup to go with I will bump the cam to a 230 or something and will deff go with the daul spring setup..I am not sure I would want to pull up next to you either, with all the diff time slips with compareable HP #'s it still has a lot to do with the driver.