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Is the .4 second gain that showed at their test track also garbage to you?
It was not evident on the engine dyno as the HP numbers were the same. 421hp The revealing test was on my chassis dyno, when we put the engine back in the car with everything exactly the same the car made 37ft/# better and 21HP and was 0.4 seconds faster at Lanier National Speedway where the car had thousands of laps.
Hard to trust veracity of internet data, I tend to agree but seemed like that particular tester/data collector was in a good position with appropriate research and resources to provide a quality data point.
I don’t know about this one…I’ve got thousands of laps at Lanier myself in a Late Model. I can tell you that nothing short of nitrous is going to give you .4 seconds per lap there. Impossible. I was in great equipment and also in not-so-great equipment through the years I ran there, and .4 seconds would give you a track championship hands down. You’d also get torn down to the crank every Saturday night for those numbers and take your engine home in a box. And knowing that place…you’d be in a fist fight for it also. Rough crowd.
All the talk about light rockers and valves is good and all and those do help to rev the motor faster but when it's all said and done it is really the valve springs job to keep the valve from floating and once that happens whether it be by an ineffective spring or insufficient guide clearance the end result can lead to a valve kissing a piston followed by a snapped valve and then more carnage. I don't care if they're hollow stems, solid stainless or even titanium valves because they all can all float and eventually snap off. It's just the price we pay when building racing engines.
I forgot the springs I used in my C5 but I had double springs thank God and number 7 exhaust let go and I was running original LS6 valves. Sodium filled exhaust valves very light. It tapped the piston because it was under load but no damage to the valve. The outer broke and the inner spring had to do all the work but what you stated is correct. The valve spring plays the biggest roll in YOUR valve train. You can spend money on light solid titanium valves but if your springs are **** those valves will end up like any other.
Great point. 👍🏼
Kill any Questions is the Quest of facts or data of Any Question asked. 👍 It's always about Who your talking to and What Experience they may have in a given subject or field.
I feel your statement,"Guys have been running SS Valves for Decades with out any problems." is in error. It all depends on what you call a problem. The problems I see are increased spring wear, fatigue and valve train fatigue caused by valve train float. racers have no idea how bad the valve train is out of control past 7000rpm. You install Ti valves in any engine that exceeds 7000rpm and you will get a 30 to 45hp gain all the way to 8000rpm. Ti valves make the valve train smooth and increase power by decreasing valve bounce and float. This will decrease your valve train problems TEN FOLD! How much money is spend ( wasted) by having to replace springs, lifters and rockers and other valve train components. Point in case, I just receive in a set of Dart 355 Pro1 heads from a racer that put hundreds and hundreds of runs (he said 580 runs) on them over ten years. I will do a valve job on these heads, replace the Ti valves and send him on his way. He might go for another ten years. That cant happen with steal valves that bounce and hammer the seats, lifters, rockers and push rods.
Its false economy to believe that steal valves are the answer in an engine that routinely exceeds 7000rpm.
Just an opinion from a guy who sees valve train destruction on a daily basis.
The usual motivation for installing titanium valves is to increase maximum rpm. More than 30 years ago, when we put a set of titanium valves in a 287-cubic-inch Modified Production small-block, the elapsed time immediately dropped two tenths of a second. It was a revelation then, and the same technology still works today. Swap the steel valves in one of our Reher-Morrison Super Series sportsman big-blocks to titanium and the peak engine speed will increase instantly by 400-500 rpm with no other changes.
I haven't seen the factory LS6/LS3 cams compared to anything on a spintron, but I do know some of the solid roller stuff is super mild. Outside of the LS world we live in, guys have been spinning 3/8" valve big blocks over 8k with a solid roller. Knock 50g off the valvetrain by going to a 8mm hollow stem and now you don't need as much spring, so now you can use 1.3" diameter dual springs that's another 30-50g lighter than the triple springs you were using and it just snowballs from there.
This young mans 2 post give the best general idea of the theory... I don't know it personally but I do know what is Said is on Point 😉
Kill any Questions is the Quest of facts or data of Any Question asked. 👍 It's always about Who your talking to and What Experience they may have in a given subject or field.
I like to listen to all inputs for sure. I find it interesting when opinions differ on technical topics, especially when it's vendors that disagree on theory. Similar to cam theory threads from years ago when 2 big cam "spec'ers" would disagree. Usually became a highly technical discussion and you would glean bits from both sides. I still haven't heard anything to sway me to a hollow stem valve on anything other than max effort/class racing, but posts like psicko quantifying weight vs. extended rpm range are fantastic.
....Swap the steel valves in one of our Reher-Morrison Super Series sportsman big-blocks to titanium and the peak engine speed will increase instantly by 400-500 rpm with no other changes.
I like to listen to all inputs for sure. I find it interesting when opinions differ on technical topics, especially when it's vendors that disagree on theory. Similar to cam theory threads from years ago when 2 big cam "spec'ers" would disagree. Usually became a highly technical discussion and you would glean bits from both sides. I still haven't heard anything to sway me to a hollow stem valve on anything other than max effort/class racing, but posts like psicko quantifying weight vs. extended rpm range are fantastic.
I truly understand as I like a good fight or fact based conversation with Differing opinions.
But the Key to Any question is who one is talking to and there data.
3v Performance does spin-tron testing on Many apps.
Billy Godbold needs no introduction of who and what he does.
What you posted with 99 Black TA and the young man I referenced are 100% on Point. Never asked this particular question but when I purchased hollow stems what was said by Either above was Basically what I was told and Sold on...
I'll control that MF'ing Valve.
But 💩 does happen with a high Usage part in Springs and valves, it's just part of the game. Buy the best available and Pray for the Best outcome.
I'm using a Pac endurance spring myself with enough spring pressure for a S/R with .750 lift and I'm @ .738 lift.
Pac 1238x ...again 💩 happens but speaking with someone Who does this Daily with Data gives one a better idea of a parts Usage, from experience.
That valve kissed a piston because the one cylinder valve wasn't in control = a bad spring or valve for one particular cylinder.
Between me and you DD it's a Common Sense answer to a problem seen before.
Guys rock Solid or Hollow stem valves to 8000 in various classes or builds... But it's in control!!! 👉 with the lighter valve being able to Rpm or accelerate faster because of Less mass...Although one is lighter the valve must still be in control not Dependant on Valve material...
I feel your statement,"Guys have been running SS Valves for Decades with out any problems." is in error. It all depends on what you call a problem. The problems I see are increased spring wear, fatigue and valve train fatigue caused by valve train float. racers have no idea how bad the valve train is out of control past 7000rpm. You install Ti valves in any engine that exceeds 7000rpm and you will get a 30 to 45hp gain all the way to 8000rpm. Ti valves make the valve train smooth and increase power by decreasing valve bounce and float. This will decrease your valve train problems TEN FOLD! How much money is spend ( wasted) by having to replace springs, lifters and rockers and other valve train components. Point in case, I just receive in a set of Dart 355 Pro1 heads from a racer that put hundreds and hundreds of runs (he said 580 runs) on them over ten years. I will do a valve job on these heads, replace the Ti valves and send him on his way. He might go for another ten years. That cant happen with steal valves that bounce and hammer the seats, lifters, rockers and push rods.
Its false economy to believe that steal valves are the answer in an engine that routinely exceeds 7000rpm.
Just an opinion from a guy who sees valve train destruction on a daily basis.
The usual motivation for installing titanium valves is to increase maximum rpm. More than 30 years ago, when we put a set of titanium valves in a 287-cubic-inch Modified Production small-block, the elapsed time immediately dropped two tenths of a second. It was a revelation then, and the same technology still works today. Swap the steel valves in one of our Reher-Morrison Super Series sportsman big-blocks to titanium and the peak engine speed will increase instantly by 400-500 rpm with no other changes.
Completely agree on the points made. Lighter valves have the ability to extend the rpm range as long as valvetrain is in check. I’ve seen 700 rpm gained on a engine dyno with nothing other than Ti valves, retainers, and locks, because valve timing was controlled. The additional 700 rpm brought power with it but the gain was from 8100 to 8800 rpm, which is way out of reach for the average guy here.
My comments made about Lanier National Speedway (man I miss that place) was made from experience. Me being an engine guy and my builder at the time, we were always looking and experimenting with carbs, headers, exhaust, etc. The hard parts were already in place and put together as lightweight as possible with longevity and max power in mind. The dry sump engines were restricted by a 350 cfm carb (that would flow around 600ish, btw after cheated to death) so we had to dig for every single hp, and torque was king at Lanier. The key point I need to make here about Lanier is that a fast lap for us was 14.10 to 14.25 seconds. Here’s the thing…you spent 8 seconds in the corners and 6 seconds on the straights….so handling trumped power all day, every day at that bullring. We were out of the gas more than we were in it. Horsepower made you feel faster, but slower was faster at Lanier…which makes no sense to the average individual.
I guess the question in reverse is how much spring pressure is reduced by going titanium (say 20 gram reduction in weight) from hollow stem (my Manley LS7 2.20 inch ones weigh like 79 grams). Say a hollow stem is 100 grams. Does this mean that if the hollow stem can go say 7000 rpm with say 150/420 pounds of closed / open pressure that with the titanium being 20% lighter I can go with 120/340 pounds (80%) of pressure to get same spring control? I guess you would need to factor in everything else like retainer, keeper and spring (which probably has some fractional factor in it) itself so maybe 10% less so that would be 135/380 pounds for same control.
Dynamic systems are not first order problems so you can’t just assume linear relationship between mass and anything else. The math is actually done in an entirely different imaginary realm using Laplace transforms and then converted back to reality.
Sometimes more mass can dampen a dynamic system and shift a resonant point higher or lower too.
They made the spintron to answer these questions lol empirical testing is probably the only way to get concrete answers to most of these questions.
09-29-2021, 12:18 PM
