FAST High Rpm runners results/thoughts
03-21-2019, 09:20 AM
#1
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FAST High Rpm runners results/thoughts Hi Everyone.
I am wanting to know some definitive answers as to whether these FAST high rpm runners work well with stroker engines.
I cannot find any info anywhere on the internet where there are tests done on stroker engines with wild cam timing and 400 CID+ displacements.
There is only test I have seen done on an LS3 with a BTR 229/244 113LSA camshaft.
It showed the gains were only above 6500rpm while the torque curve was lower everywhere including peak compared to the FAST long runners.
My engine combination as follows:
LS2 408
CNC LS3 Heads
Fast 102mm Intake with standard runners
Nick Williams 102mm throttle body
12:8.1 compression
242/257 .660 .655 113 LSA +3 camshaft
1:8.1 Yella Terra Roller rockers
PAC 1209X springs
3:91 rear gears
3200 rpm stall converter
Morel Tie Bar lifters
Does anyone know if my engine would benefit at all with those High Hp runners or should I stick to the long runners?
I certainly do not want the engine to lose torque in the low and mid range and feel like a turd for the sake of a few hp in the upper rpm range.
Engine is currently at the tuners getting that camshaft fitted along with the rest of those modifications.
If I am to use those runners the best time for me to get them is now while the top part of the engine is apart.
I would appreciate any advice or recommendations.
I am wanting to know some definitive answers as to whether these FAST high rpm runners work well with stroker engines.
I cannot find any info anywhere on the internet where there are tests done on stroker engines with wild cam timing and 400 CID+ displacements.
There is only test I have seen done on an LS3 with a BTR 229/244 113LSA camshaft.
It showed the gains were only above 6500rpm while the torque curve was lower everywhere including peak compared to the FAST long runners.
My engine combination as follows:
LS2 408
CNC LS3 Heads
Fast 102mm Intake with standard runners
Nick Williams 102mm throttle body
12:8.1 compression
242/257 .660 .655 113 LSA +3 camshaft
1:8.1 Yella Terra Roller rockers
PAC 1209X springs
3:91 rear gears
3200 rpm stall converter
Morel Tie Bar lifters
Does anyone know if my engine would benefit at all with those High Hp runners or should I stick to the long runners?
I certainly do not want the engine to lose torque in the low and mid range and feel like a turd for the sake of a few hp in the upper rpm range.
Engine is currently at the tuners getting that camshaft fitted along with the rest of those modifications.
If I am to use those runners the best time for me to get them is now while the top part of the engine is apart.
I would appreciate any advice or recommendations.
03-21-2019, 09:54 AM
#2
I'm gonna run the mid-length runners in my 398" build (3.90 stroke, 14:1 compression, and a .750ish cam) so, I'm gonna spin it up pretty good. Mine is a strip only car so it is either idling or WFO. What is the purpose of your build?
The mid's were recommended by Hammer and NavyBlue to name a few...
The mid's were recommended by Hammer and NavyBlue to name a few...
Last edited by ragtopz28; 03-26-2019 at 03:01 PM.
03-21-2019, 10:11 AM
#3
TECH Addict
Thread Starter
I'm gonna run the mid-length runners in my 398" build (3.90 stroke, 14:1 compression, and a .750ish cam) so, I'm gonna spin it up pretty good. Mine is a strip only car so it is either idling or WFO. What is the purpose of your build?
The mid's were recommended by Hammer and BlueNavy to name a few...
The mid's were recommended by Hammer and BlueNavy to name a few...
My stroker engine can be revved to 7000-7500 if I am still making power that high..
I have not been able to find any more info on these runners other than what I posted in my OP.
Could you send me some links if you have any?
Cheers
03-21-2019, 10:49 AM
#4
http://www.superchevy.com/how-to/eng...runner-system/
https://ls1tech.com/forums/generatio...r-results.html
For a street car, I don't think they are worth the expense. Max effort strip car, Yes.
https://ls1tech.com/forums/generatio...r-results.html
For a street car, I don't think they are worth the expense. Max effort strip car, Yes.
03-22-2019, 02:35 AM
#7
TECH Addict
Thread Starter
Pushrods are being replaced with the 3/8 thickness versions.
Valve seats etc are being re machined to fit stronger solid stainless steel valves too.
And with those rockers we are using the optional 10mm studs from yella terra vs the factory 8mm so we have extra clamping force and to ensure reliability. Threads will be machined suit,
Valve train will be very stable once completed
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03-23-2019, 11:30 AM
#9
TECH Addict
Thread Starter
I am not using the standard ultra light . These are rated up to 400 LB and the ultra light pro at 480 LB
I am using the Pro Street version which are rated up to 600LB of open spring pressure.
The PAC 1209X have 510LB open spring pressure so I am well within spec.
These certainly won't be noisy.
The ones I have now are super smooth and quiet and they are pro street but the standard 1:71 ratio.
It depends on how they are set up etc
03-24-2019, 04:22 AM
#11
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Thread Starter
Yella Terra are regarded as the best and strongest aluminium rocker in the world.
Obviously steel is stronger but also way more costly. Steel rockers would be more resistant to breakage with higher spring pressures but I doubt would run as quiet.
Yella Terra are run all the time here on the V8 super cars using the platinum series which are rated to 900LB of open spring pressure.
No one at yella terra has seen them break yet.
There is only one customer I know of, who managed to split the factory 8mm stud because he was racing the vehicle while using standard yella terra rockers with too heavy a spring.
If you are within spec and under the limit of the max capability you will not have any issues.
Out of curiousity, send me a link the rockers you approve of so I can compare
03-24-2019, 08:12 AM
#13
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Thread Starter
They have been used with huge success.
Those other branded rockers you mentioned are obviously stronger but they are more for racing and endurance.
They would also be very noisy.
The Yella Terra has an emphasis on being smooth and quiet too.
They are more than strong enough for my application and will handle strip work no problem
03-24-2019, 03:46 PM
#14
A lot of people.
They have been used with huge success.
Those other branded rockers you mentioned are obviously stronger but they are more for racing and endurance.
They would also be very noisy.
The Yella Terra has an emphasis on being smooth and quiet too.
They are more than strong enough for my application and will handle strip work no problem
They have been used with huge success.
Those other branded rockers you mentioned are obviously stronger but they are more for racing and endurance.
They would also be very noisy.
The Yella Terra has an emphasis on being smooth and quiet too.
They are more than strong enough for my application and will handle strip work no problem
03-24-2019, 04:46 PM
#15
He is also from Australia i believe so his sample ratio of anything else is likely limited. The extrusions are far less strong than any steel rocker, whether they are made with extra csa or not. I have seen months and months of yella terras of all styles breaking due to bad batches of extrusions. All documented on here. A search will show that.
Alum has quite a bit less fatigue life vs steel also in most instances including rocker arms ie repetitive motion. Thats not abuse or overload, thats from doing their job. Then add in even more load on them? If you were using 5/16 pr before then likely they were flexing and taking the load off the rockers also. They are also more noisy. And alot heavier over the nose especially these badass version yella terra has. Youre soaking up ALOT of hp you could have as well for the sake of....? In the higher rpms it matters ALOT. Overbuilding can be an issue as well.
You have quite a bit more to attend to it seems before even worrying about the losses from the intake runners but you refuse to see it or take direction, so build it how you want regardless.
Alum has quite a bit less fatigue life vs steel also in most instances including rocker arms ie repetitive motion. Thats not abuse or overload, thats from doing their job. Then add in even more load on them? If you were using 5/16 pr before then likely they were flexing and taking the load off the rockers also. They are also more noisy. And alot heavier over the nose especially these badass version yella terra has. Youre soaking up ALOT of hp you could have as well for the sake of....? In the higher rpms it matters ALOT. Overbuilding can be an issue as well.
You have quite a bit more to attend to it seems before even worrying about the losses from the intake runners but you refuse to see it or take direction, so build it how you want regardless.
03-24-2019, 07:20 PM
#16
Seriously my friend, listen to these people that are trying to help you. They know a lot. I will just cut to the chase here also.………...those rockers are nothing but trouble. You are introducing so many issues to a build where it's not needed. Don't over think this. 
03-25-2019, 08:38 AM
#17
TECH Addict
Thread Starter
He is also from Australia i believe so his sample ratio of anything else is likely limited. The extrusions are far less strong than any steel rocker, whether they are made with extra csa or not. I have seen months and months of yella terras of all styles breaking due to bad batches of extrusions. All documented on here. A search will show that.
Alum has quite a bit less fatigue life vs steel also in most instances including rocker arms ie repetitive motion. Thats not abuse or overload, thats from doing their job. Then add in even more load on them? If you were using 5/16 pr before then likely they were flexing and taking the load off the rockers also. They are also more noisy. And alot heavier over the nose especially these badass version yella terra has. Youre soaking up ALOT of hp you could have as well for the sake of....? In the higher rpms it matters ALOT. Overbuilding can be an issue as well.
You have quite a bit more to attend to it seems before even worrying about the losses from the intake runners but you refuse to see it or take direction, so build it how you want regardless.
Alum has quite a bit less fatigue life vs steel also in most instances including rocker arms ie repetitive motion. Thats not abuse or overload, thats from doing their job. Then add in even more load on them? If you were using 5/16 pr before then likely they were flexing and taking the load off the rockers also. They are also more noisy. And alot heavier over the nose especially these badass version yella terra has. Youre soaking up ALOT of hp you could have as well for the sake of....? In the higher rpms it matters ALOT. Overbuilding can be an issue as well.
You have quite a bit more to attend to it seems before even worrying about the losses from the intake runners but you refuse to see it or take direction, so build it how you want regardless.
And yes I am from Australia!
First of all the failure rates, were with the very early batches of rockers however these have been rectified. From what year were these failures listed in this forums? I know there was an issue years ago with these.
Secondly, my engine is not short on hp and doubt these current rockers are robbing hp. It's making 505rwhp through a 3200 stall and 3:91 rear gears with a mild camshaft. This is on a stingy pro dyne dyno that reads about 15hp less than the others.
I know the pro street are heavier over the nose and more weight is can be disadvantageous, however, spending 3 times as much money with something I will never notice or need for my application just doesn't make sense. If I was racing then yes, they would be worthwhile.
I know those shaft mounts rockers are stiffer and made of better materials.
I have had my current set of yella terra rockers for almost 9 years now and never had an issue with them.
As stated, my pushrods will be upgraded to thicker and stronger ones to support the increased spring load.
As for them being noisy, my engine is super quiet. I don't see how the noise could be less than it already is.
In order to hear anything engine noise you need to put your head close to the intake manifold.
Ever since I did the stroker, the engine has been running super quiet and smooth.
I never said I disagreed about the intake runners. I was just concerned with the low and mid range torque.
I just want to wait and see how this setup goes with the long runners first and then in the future change them out and use the mid length runners and see how it is.
I will post the results here. This hasn't been done by anyone yet.
03-25-2019, 08:40 AM
#18
TECH Addict
Thread Starter
You all seem to say this however, why in Australia are they so reliable?
They are used by most of us here for hot street, racing etc and is so rare to hear of them breaking.
Only in America. lol
03-25-2019, 10:41 AM
#19
TECH Senior Member
I think Americans bought a lot more than got sold in Oz, therefore a larger sample and a larger "pool" for failures to happen. More chance of failure with 1000 than 100.
03-25-2019, 11:15 AM
#20
No one has posted results for mid runner fast? There's tons of data out there...magazine data and people on this site.
A guy with a stroker in a drag truck picked up like 3 tenths.
Mid runner vs long is really going to come down to the person driving. If you're driving it like you should, 10 ft lb of loss in the midrange is inconsequential to the 20 hp you gain at peak, and the gobs of power you gain way after peak.
You will be down on power likely until about 5700 rpm, but will now be able to rev it out to 7500. If you set your shift points correctly it should never fall out of the powerband.
A guy with a stroker in a drag truck picked up like 3 tenths.
Mid runner vs long is really going to come down to the person driving. If you're driving it like you should, 10 ft lb of loss in the midrange is inconsequential to the 20 hp you gain at peak, and the gobs of power you gain way after peak.
You will be down on power likely until about 5700 rpm, but will now be able to rev it out to 7500. If you set your shift points correctly it should never fall out of the powerband.