Nitroused383

iTrader: (10)

Those trickflow heads have farily heavy valves. A popular mod is to use turned down LS3 hollow stem valves. TEA does this and Chris1313 has a post on here with back to back results on a N/A setup. Helped out quite a bit above 6500 rpm. There is not much out there that is a light as the stock rockers on the tip. Those rollers on the tip of aftermarket rockers are heavy.

TracyRR

iTrader: (8)

Hey nitroused, Chris1313 has a bunch of interesting posts.... If the rockers made that big of a difference, i wonder if i should shim the springs a bit more for more seat pressure?

stevieturbo

If you have 170lb seat pressure, IMO there isnt a chance in hell it's valve float.

Fbodyjunkie06

iTrader: (10)

So if it isn't the coils which you pointed out wasn't the problem, and it isn't valve float then what is it?

Don't take this as me being smart, I just would like to know what you think is wrong?

Slowhawk

iTrader: (12)

Little late but I would of pointed at the rockers first. Had that problem many times running aftermarket rockers.

TracyRR

iTrader: (8)

Thanks for any assistance you offered but you must have missed my post where i said it was the rockers.

Pretty amazing that a little weight over the valve can make that kind of difference!! Thanks

Phil99vette

iTrader: (11)

Interesting that it was the rockers. Its not like that has happened a ton of times in the past.

TracyRR

iTrader: (8)

lol....phil (or well respected racer, ha ha), would i benefit with anymore seat pressure? In other words, do i just want enough seat pressure to not have float or do i need to build a little insurance in seat pressure? Thanks phil

blackmagicturbo

iTrader: (2)

What was your preload on the yella terras (how many turns ) vs. the stock rockers ? Thanks and congrats on finding the problem ..

Phil99vette

iTrader: (11)

I've seen and experienced it a dozen times with the yella terra.

TracyRR

iTrader: (8)

Thanks black, it was about 1/2 turn for both the YT and the stockers.

Thanks phil!

stevieturbo

I was referring to the more seat pressure query. Although I picked it up that he/she was still experiencing problems which is why they wanted to know if more seat pressure would be needed.

It seems now that all problems are solved, so certainly no extra spring pressure is needed.


Although I'd like to know which YT's were used, and why some experience problems and others dont ?

I'm using the YT Ultralights, 1.7 ratio, and mine spins freely to 7k no problem at all.

So is the problem only a rocker problem, or a combination of parts problem ?

Fbodyjunkie06

iTrader: (10)

I tend tend to agree with your statement of 170 pounds of seat pressure being enough for a cam the size of his and the rpm range given. Valves and rockers do play their part in that equation too though as do the pushrods.

Given that the XER lobes were never really meant for an LS anything and their ramp rates and it being in the high 23's low 24's in duration I can see how a heavy rocker especially one heavy on the tip where all the force of the wipe pattern is concentrated being the breaking point in this situation. Combined with the heavy trick flow valves it sealed the deal for valve float. Nitroused was having valve float in his ride not too long ago so I'm sure he exhausted all the options this route leads to before he got his diagnosed right.

Tracy what springs do you have in now?

TracyRR

iTrader: (8)

Hey stevie, definately a he. No issues, i'm used to it by now, lol. I was using the YT ultralite's. I bought them about a year ago so it should be their newest version i would imagine.

hey junkie, i'm using the k800 k-motion springs w/titanium retainers. They are slightly larger at 1.46 OD so i'm sure that added a bit of weight as well. I think you're both correct.....it had to be a combo of parts to cause the float. I don't plan on using an aggressive lobe again for a street car!! Thanks guys, tracy

Fbodyjunkie06

iTrader: (10)

Those springs should be fine for this app, as long as the other parts are selected right as you found out!

I see why so many people use the stock rockers with the comp trunion upgrade. I think I know what else to add to my list while the motor is out!

stevieturbo

But it does beg the question as to why some people have no issues with aftermarket rockers. And others have no luck at all.

It just doesnt make sense ?

Nitroused383

iTrader: (10)

It all has to with the weight of the valvetrain. LS6 and LS3 heads have some of the lightest valves available. If you do some searching you will find quite a few people with trickflow heads and aftermarket rockers who are down on power in the higher revs N/A. Here is a good thread from thunder racing https://ls1tech.com/forums/dynamomet...ts-inside.html

stevieturbo

I'm also using Trickflow heads with no issues.

I was led to believe the stock rocker setup would not work with their heads. Although Ive never had a stock setup to try anyway

Beaflag VonRathburg

iTrader: (176)

Fueling wise could you not turn the base fuel pressure up and get a little more out of the injectors. Your pumps should be able to keep up.

TracyRR

iTrader: (8)

Hey beaflag, yes, i've already raised it a total of 10 pounds....68 base pressure. Since the new valve springs and more tuning, i have an injector duty cycle in the upper 80's with only 15.5 pounds of boost. If i want to crank up the boost another 5 - 10 pounds at the track, i think i'm going to have to go to a larger injector. I just don't know what size to get.....i don't want idle issues so i'm taking my time to get the right one. Any suggestions? Thanks