who here has messed with tuning VES springs?
- Thread starter Lorduss
- Start date
I was having a lot of chatter from the valves last season. Put in green/white springs and we'll see how that goes. 14.1 DI, slp pipe and can, PCV riding 8k+.
Yep... the green/white .
I've heard of corrosion issues with the Pink springs though... pre-mature breaking.
Worth a try though.
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Worth a try though.
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G
geo
Well-known member
Theory question. For info-discussion reasons only.
I installed the green whites (thanx TRS) and like the consistency they created even at my relatively low 5 to 6 thousand ft.
Many seem to be popping these in so why?
Poo has them in stock but spec the sled with very stiff springs. Cylinder pressure is required to open the valves. Increases in elevation, worn rings, low rpm, all lower cylinder pressure.
Is there always enough pressure to overcome any spring?
Theoretically if a valve hangs closed too long it increases air flow there and may create a lean or even det condition. Worse case scenario is the valve does not open at all. We all know that would mean less power at high rpm.
In reverse if too soft a spring is selected (doesn't close maybe because of carbon build up) the worse case scenario is lost mid range or rich bog.
Why, theoretically, does Poo spec these springs? They know this stuff too and must realize the sled is headed for elevation. Doo has spec'ed stiff springs but on carbed models so there was some built in correction for air velocity (carbs work on intake velocity). No air correction factor in the Poo injection system.
If the valve opens when the solenoid dictates (theoretically) what does a spring change do? This valve opening is timed with some important engine management adjustments by the 'putor too.
What do you think is happening when you install a softer exhaust spring? What have you "felt"?
I installed the green whites (thanx TRS) and like the consistency they created even at my relatively low 5 to 6 thousand ft.
Many seem to be popping these in so why?
Poo has them in stock but spec the sled with very stiff springs. Cylinder pressure is required to open the valves. Increases in elevation, worn rings, low rpm, all lower cylinder pressure.
Is there always enough pressure to overcome any spring?
Theoretically if a valve hangs closed too long it increases air flow there and may create a lean or even det condition. Worse case scenario is the valve does not open at all. We all know that would mean less power at high rpm.
In reverse if too soft a spring is selected (doesn't close maybe because of carbon build up) the worse case scenario is lost mid range or rich bog.
Why, theoretically, does Poo spec these springs? They know this stuff too and must realize the sled is headed for elevation. Doo has spec'ed stiff springs but on carbed models so there was some built in correction for air velocity (carbs work on intake velocity). No air correction factor in the Poo injection system.
If the valve opens when the solenoid dictates (theoretically) what does a spring change do? This valve opening is timed with some important engine management adjustments by the 'putor too.
What do you think is happening when you install a softer exhaust spring? What have you "felt"?
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I know on my 03 rmk i could feel, hear and see it on my egt's with too soft of a spring (pinks at 2200'). I never played with it at higher altitudes.
I could cruise along at a steady throttle position/speed and at a certain point i would see the egt's lean out a little and feel a surge of power. I tested this a few times, change to a heavier spring and could not get it to repeat itself.
I always switched springs in my 03 as i rode it at different altitudes alot. I havent bothered changing with the '11 as i dont ride it as much down low since i bought my 04 proxr.
I could cruise along at a steady throttle position/speed and at a certain point i would see the egt's lean out a little and feel a surge of power. I tested this a few times, change to a heavier spring and could not get it to repeat itself.
I always switched springs in my 03 as i rode it at different altitudes alot. I havent bothered changing with the '11 as i dont ride it as much down low since i bought my 04 proxr.
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C
crashnbash
Well-known member
Just because the solenoid closes does not mean there is enough cylinder pressure to open the valves. The ecm maps the fuel with the soleniod operation. If the valves don't open, or stay open, with the solenoid the fuel mapping is off until the valves do open. At high elevation this happens quite often.
I have a 2013 pro 870 BB , i was having this same thing happen , if i hold the RPM,s at 6800-7000 it sounded like the exhaust valve were chattering , put the pink springs in and also lower the valve opening point to 5000 RPM,s ( i am running the ViPec ECU ) In doing this i had to remap ( more fuel ) from 5000-7000 RPM,s and re-clutch , it pulls really hard , also the pipe temp. and pressure effects the exhaust valve operation , ran into this valve chatter again in the spring , pipe temp. got high , added timing and fuel correction to deal with this ( i hope )
G
gman086
Well-known member
The valves open sooner and stay open longer. If you run an aftermarket exhaust, you darn well better be running softer springs to prevent heat build around the exhaust ports! Just read your egt's and that's all you'll need to know. Porting requires more air flow and softer springs too. Something I learned real fast with funky noises coming from my Union Bay motor (sounds like someone shuffling cards if your exhaust valves are not opening soon enough). Also the higher the altitude, the lower the spring pressure. UBR didn't run any springs in a lot of their hillclimb sleds.
Have FUN!
G MAN
Have a pipe coming for my new '15. Riding elevations from 2200-7000'. Would there be a benefit from swapping out springs? If so, to the pink? Or the green/white?
G
gman086
Well-known member
https://startinglineproducts.com/catalog.cfm?pageID=detail&catalogID=3&catID=18&productID=155
Start with pink and go lighter as needed. Guys running trees and boondocking lower elevations want stiffer; guys running WOT hill climbs and pulls all day want lightest. Restrictive/aftermarket exhausts need lighter (most cans are actually more restrictive than stock).
Have FUN!
G MAN
Start with pink and go lighter as needed. Guys running trees and boondocking lower elevations want stiffer; guys running WOT hill climbs and pulls all day want lightest. Restrictive/aftermarket exhausts need lighter (most cans are actually more restrictive than stock).
Have FUN!
G MAN
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I recommend the Green/White for the 800 CFI2
Blue for the 800 CFI4
I have tested a majority of the springs available from PI from 5000-11,000'.
