How did you fix it?

 

Switching to Lt's will make a big difference in the low and mid range and will probably bump up those torque numbers. They will also make it drive even better and smooth it out. I know when I switched from SLP to Pacesetter the difference was night and day.

As far as valve float find out the pressures of the springs you're running and see if you think they are high enough. If not then maybe go a little stiffer and see if it helps. Springs are hard to choose sometimes, you want a spring strong enough to control the weight and acceleration of the valve, but not so strong that it robs power from the valvetrain. It's a fine line.

 

I had the Comp 26918 beehives on my car with the XFI268 cam and would run into serious valve float around 6200rpm. As the springs became weaker my power strarted dropping off above 5000rpm from previous dyno runs.

I just replaced the springs with the Manley beehives with 150# on the seat. My power came right back and I can now rev the motor to at least 6500rpm with no valve float. Also the power holds on until that point and does not drop off.

 

I never did on my old setup.
I was going to put on pac1518's on but they are the same pressure as the 918's so I don't see that doing anything. Comps new 918's have a higher spring rate so that might be something to look into. Did you check the spring installed height? Mine varied from 1.8-1.75" on my LE2 heads, and Javiers were at 1.80" even though they reccomend installing them at 1.75" so yours might be off too.

 

It's not a fine line for a street car. Having an oversprung setup is ALOT better than an undersprung setup, expecially with a street driven vehicle. I would gladly give up 1-2hp to be able to miss a shift without blowing my motor, or having the springs give up a few lbs over time and start running into valve float issues.

 

Okay guys.
I am running PAC 1218's on the LE2 heads.
Specs are 130# on the seat and 318# open.

I am holding in my hands now my brand new set of Comp 921'a w/ titanium retainers.
Specs are 135# on the seat and 400# open.

Obviously the 921's are a stiffer spring which should do a better job at not floating the valves. Are these springs overkill or is there something more practical. These 1218's are not getting the job done?

 

are you sure its the springs?

i have the same heads, same springs, and a bigger cam. i have not had it on the dyno yet but i can tell you for sure when i let off at 6600 it is still pulling.

i do realize that cam uses more aggressive steeper lobes than mine, and i dont know enough about cams to know if that is what would cause that

 

Right now vlave float is the most likely suspect. Tuner did a similarly cammed car recently and it had the same problem at 5.8K RPM. I think that fellow has actually responded to this thread. Once I have the chart I will post it. We are currently checking spring height and rocker pre-load.

The power peaks at 6K RPM then falls right off the mountain. I cant imagine the headers or anything else showing this kind of exrtreme out of nowhere behavior, but I am open to suggestions. PAC says the 1218 beehive is good up to .600, I am a tad above that already.

 

Nice #'s, wonder how far behind my 357 will run.

I won't be dynoing it for a while though, I'm going to break in the motor and then get a few mods which will take a while, then tune before dyno.

 

I agree with you about rather have too much than not enough. Not going to argue with you about this, but it's a lot more than 1-2 hp and if people would actually shell out the dough for quality springs then fatigue wouldn't be an issue.

Yes, I know these are the springs that Lloyd/Bret recommend for their setups, but do you think they could offer such good prices and sell so many if they ran Isky springs which cost twice as much as Comp springs?

 

where's the graph? what rpm did the numbers peak?
if those numbers hold true you should be real close to the 12.0 range depending on gearing and such. 3.90's just may be perfect depending on your power peak. what's the race weight?

 

Actually, based on what Wrd said, we pretty much do.
His sounds identical to JoeB's LE1N20 grind.

Jerry always puts on a good show
I sure hope we get to do Jeremy's 21-car burnout salute.

 

Gorgeous car!

 

Just checked the beehives spring height. They are at 1.780" and Lloyd said to set them at 1.750". If it turns out that I need to reset the beehives then I am just going to put the Comp dual springs in and hopefully eliminate the possibility of spring pressure all together.

Still waiting on the tuner to send them to me. Race weight is going to be heavy at around 3900 pounds. Tuner stated that 3.90 is looking like the best gear for street tires or 255-50-16 ET street radials.

 

.030 isn't going to make that big a difference in spring pressure to notice. I would just drop in the dual springs and see where you are at and if it is the springs you should be good.