SuperSport01

Hi folks I need help choosing valve springs. The cam will be a Comp LXL lobed unit going into a stock 2002 LS1 shortblock. I will be using new LS7 lifters, LS2 trays, Trend 3/8" pushrods, Comp trunions, and stock 2.00" 1.55" valves in professionally ported 241 heads. The engine will at times be subjected to 6000+rpm for extended periods.

I would prefer to use .625" max lift beehive springs such as PSI 1511ML (130lbs@1.800") or PAC 1219X (145lbs@1.800") but I'm wondering if either will be enough.
I know many people recommend the Brian Tooley .660" Platinum double spring kit (155lbs@1.78") but I feel it may be a bit overkill for me.

The LXL lobed cam I have chosen has a relatively gentle ramp rate of 52 and should make all of its power below 6700rpm. With 7000 being the most the engine will ever see.
LXL Intake lobe #13159.. 230@.05" .609" with 1.7
LXL Exhaust lobe # 13175.. 236@.05" .614 with 1.7
112 lsa with 108 icl.

Thanks in advance.

brobinson216

iTrader: (11)

I would never turn one of these motors >6400 on a single spring period. I've broken singles on a low mile Z06 and that taught me a valuable lesson.

The BTR springs will not be overkill.....call Brian himself and get his opinion. He will explain that it's more about seat pressure than anything else.

Think about some link bar short travels as well.

The CM lobes are less violent on the valve train so why not look at one of their cams.

Man I can spend people's money like it's going out style around this joint.

JakeFusion

iTrader: (7)

LS7 lifters aren't designed for aftermarket spring pressures. Step up to some Johnson or Morel lifters.

Also, talk to Kip @ Cam Motion about what he recommends as far as a cam. He sells the BTR springs and likes them too.

Exidous

iTrader: (11)

I run the LSL with Johnson 2110's, Manton 11/32" series 4 .120", YT Ultralite's, Manley hollow intake, and Mamo chosen duals with titanium retainers. Not sure which ones he used.

The LXL is certainly more mild than the LSL but I would still never run a beehive on anything but a slightly modified stock motor. Even with the LXL I'd run good lifters and springs. Especially at 6700-7000.

vettenuts

iTrader: (4)

Even if you want to use the PSI springs, they won't work on your setup. You need to look at required seat force of the spring and the amount of shimming that will be needed to get the PSI spring to that seat value. Once you figure that out, you will find there isn't enough travel left to support your lift.

Not sure on the PAC's, but you may find the same thing there as well.

Brian Tooley Racing

iTrader: (13)

You would be shocked at how much pressure is required to properly control a LXL lobe camshaft.

Us old guys remember when .500" lift on a SBC street car was a lot, now everyone thinks over .600" lift on a LS is nothing.

Inadequate spring pressure manifests itself in broken parts. Most of the cam core damage, broken lifters and spit out rocker bearings are a direct result of a valve train that's out of control. We saw upwards of .700" lift from a .600" lift Comp cam on the Spintron, think about the damage that can occur to the cam core and lifters with that type of valve train component loft.

Martin Smallwood

iTrader: (2)

Brian is 100% correct. It's amazing what you find on the Spintron.

Valve bounce was extremely eye opening to me, especially seeing it with lobe profiles I was commonly using and with spring pressures I was also recommending at the time.

I have since moved away from those lobes, and now have my own proprietary lobe designs that Kip grinds for me. I know Brian uses a lot of softer smoother lobes as well.

Darth_V8r

iTrader: (4)

It's amazing how different recommendations are. Read PatG torque coming out of my ears thread, and he is actively recommending LSK loves with 47 degree ramp rates. Now, we are finding gentler lobes making more power

JakeFusion

iTrader: (7)

That thread is old too.

Brian Tooley Racing

iTrader: (13)

I think as cylinder heads have gotten better, at least in terms of mid lift airflow, that lifting the intake valve fast just isn't needed.

The first time I back to back tested two cams that were almost identical except for ramp rate was 2001, and the slower lobe made more power everywhere, and carried out 800 rpm more before valve float. That was a real wake up call, but the intake airflow was awesome from .300"-.500" lift for a .500" lift class engine.

In the years since, I've tested many cams back to back that were almost identical other than ramp speed, and more times than not the slower ramps made more power.

In other back to back testing, less exhaust lift made more power everywhere, so there's a lot more going on than what most think.

Never forget that adding lift and ramp rate increases parasitic losses, so the power GAINED from lifting a valve faster or further has to EXCEED the parasitic loss from doing so, otherwise the change is a net LOSS.

thunderstruck507

iTrader: (18)

Kip has told me this same information. A lot of lobes have the extra lift because it comes with the duration of the lobe...since he can grind them how he wants it's no longer necessary.

Tuskyz28

Less exhaust lift means means better valvetrain stability. Such a awesome deal

Darth_V8r

iTrader: (4)

yes. That was my point. How starkly different cam lobes are being cut on the same engine ten years ish later

Brian, thanks for the very through reply. I've read posts where people have said by focusing more on low lift flow - even at the expense of peak flow - power increased. I'm thinking that is due to the amount of time spent at .2-.5 vs the amount of time spent at .6.

Also, I appreciate your note at the end about NET power increase. Higher lift means more spring compression, which requires more force, which adds to the work required just to spin the engine. I had always thought of valve springs as regenerative - while the valve is closing, the spring pushed on the lobe, reducing resistance (?). Sounds like that isn't the case.

JakeFusion

iTrader: (7)

I am now advocating solid rollers. No need to run hydraulics. With the low lash solid rollers now available, you have a lot more reliability out of the solid rollers nowadays, especially with good lifters and good rocker arm systems.

brobinson216

iTrader: (11)

Absolutely for those who have the ability/money to do so.

Guaranteed the vast majority of traffic on this site will never see ROI.

DavidBoren

The btr platinum duals. That should be everyone's first choice with any .6xx" lift aftermarket cams... Especially after reading the daily driver year after year thread that is active in this section.

93Polo

iTrader: (5)

Are they lofting the valves? Interesting and scary on the .700" lift. I would assume proper spring pressure would tame the lift.

I have thought about using the LXL 230/236 lobes mentioned in a HPDE buld or maybe a HUC/LXL cam. I will using a LS6 shortblock, Edelbrock/WCCH 215s, YTs, FAST92 etc

Brian Tooley Racing

iTrader: (13)

For a street car that's going to be driven, this isn't the best choice in my opinion.
The LLSR cams have very long seat duration and therefore low vacuum at idle which makes tuning difficult.
The solid roller lifters tend to push too much oil into the valve cover area.
Some of these setups make no more power than a good hydraulic roller setup.

If the application is more track oriented with a high flowing intake then the solid roller stuff is great.

DavidBoren

Yeah, I've always imagined llsr cams and single plane intakes going together like peanut butter and jelly.

For a street car, stay hydraulic roller. You can still have a damn nice hr cam and valvetrain.

JakeFusion

iTrader: (7)

Brian, every solid roller I've ever seen is significantly faster seat-to-seat than any hydraulic roller. Is what you're seeing specific to the LLSR stuff? Is that a byproduct of the lower lash?