Ultra-High RPM Dual Valve Spring / Titanium Retainer Set
Dec 7, 2009, 02:19 PM
#16
Been using Supertech Duals on our cars without any issues.. Remember RPM is not the only contributing factor to Valve float.. BOOST IS also.. I have sene valves float well before 9000 at certain boost levels where the car would hold well over 9000 at lower boost levels.. We use a particular Supertech setup that hasnt let us down yet.. Many float valves and dont even know they are losing power on top..
Mike
Mike
Dec 7, 2009, 02:25 PM
#17
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Been using Supertech Duals on our cars without any issues.. Remember RPM is not the only contributing factor to Valve float.. BOOST IS also.. I have sene valves float well before 9000 at certain boost levels where the car would hold well over 9000 at lower boost levels.. We use a particular Supertech setup that hasnt let us down yet.. Many float valves and dont even know they are losing power on top..
Mike
Mike
Dec 7, 2009, 03:04 PM
#19
I love these threads. I am firm believer in not over springing the motor. I run 37 psi on stock evo 8 springs 280 cams to 8300rpm with no valve float. stock 8 springs only have 52lbs seat pressure. I will let you guys figure out if you need 97lb seat pressure.
Oh and valve float in no way causes loss of power. valve float just increases valve lift.
Oh and valve float in no way causes loss of power. valve float just increases valve lift.
Dec 7, 2009, 03:09 PM
#20
I love these threads. I am firm believer in not over springing the motor. I run 37 psi on stock evo 8 springs 280 cams to 8300rpm with no valve float. stock 8 springs only have 52lbs seat pressure. I will let you guys figure out if you need 97lb seat pressure.
Oh and valve float in no way causes loss of power. valve float just increases valve lift.
Oh and valve float in no way causes loss of power. valve float just increases valve lift.
Dec 7, 2009, 03:28 PM
#21
floating valves is not same thing as valve bounce. valve bounce hurts power. valve float does not. valve bounce is more related to poor quality spring or improperly designed one that suffers from harmonics that allow the valve to bounce on the seat. its not as simple as being not enough seat pressure. a good designed 52lb spring can work better than a poorly designed 75lb spring.
I also am not much a believer in duals. there just insnt the room to do it correctly. springs do vibrate and move around. keeping dual springs from hitting each other is no easy task. Cosworth design looks awesome to me in that respect. they use a seat riser to keep the spring shorter. less likely to move around so much.
I also am not much a believer in duals. there just insnt the room to do it correctly. springs do vibrate and move around. keeping dual springs from hitting each other is no easy task. Cosworth design looks awesome to me in that respect. they use a seat riser to keep the spring shorter. less likely to move around so much.
Last edited by 94AWDcoupe; Dec 7, 2009 at 03:33 PM.
Dec 7, 2009, 03:43 PM
#22
floating valves is not same thing as valve bounce. valve bounce hurts power. valve float does not. valve bounce is more related to poor quality spring or improperly designed one that suffers from harmonics that allow the valve to bounce on the seat. its not as simple as being not enough seat pressure. a good designed 52lb spring can work better than a poorly designed 75lb spring.
I also am not much a believer in duals. there just insnt the room to do it correctly. springs do vibrate and move around. keeping dual springs from hitting each other is no easy task. Cosworth design looks awesome to me in that respect. they use a seat riser to keep the spring shorter. less likely to move around so much.
I also am not much a believer in duals. there just insnt the room to do it correctly. springs do vibrate and move around. keeping dual springs from hitting each other is no easy task. Cosworth design looks awesome to me in that respect. they use a seat riser to keep the spring shorter. less likely to move around so much.
Mike
Dec 7, 2009, 03:51 PM
#23
"edited based on new info"GSC now rates at 9k, maybe further testing made them decide to up the limit.
94AWD, valvefloat (though I see since I started this you also use the term "bounce") does this to power:
I am pretty sure that if that was all the higher you want to rev it I guess it would be okay. I am pretty sure seat pressure is 65 when I measured them but I can doublecheck.
Stock springs are fine to 8300 on smaller cams (think S1s) but at some point you are going to want to think about stiffer springs. I dont think Kiggly's are for everybody. Typically I only recommend them (or a Ti retainer based spring) above 9k. We havent been vary impressed with Supertech however since they do eat valvestem seals. The reason is there isnt much clearance between the inner spring and the seal and they seem to "walk".
Last edited by JohnBradley; Dec 8, 2009 at 08:47 AM.
Dec 7, 2009, 03:54 PM
#24
FP doesnt recommend revving higher than 8600, I didnt say they couldnt
GSC now rates at 9k, maybe further testing made them decide to up the limit.
94AWD, valvefloat does this to power:
I am pretty sure that if that was all the higher you want to rev it I guess it would be okay. I am pretty sure seat pressure is 65 when I measured them but I can doublecheck.
Stock springs are fine to 8300 on smaller cams (think S1s) but at some point you are going to want to think about stiffer springs. I dont think Kiggly's are for everybody. Typically I only recommend them (or a Ti retainer based spring) above 9k. We havent been vary impressed with Supertech however since they do eat valvestem seals. The reason is there isnt much clearance between the inner spring and the seal and they seem to "walk".
GSC now rates at 9k, maybe further testing made them decide to up the limit.
94AWD, valvefloat does this to power:
I am pretty sure that if that was all the higher you want to rev it I guess it would be okay. I am pretty sure seat pressure is 65 when I measured them but I can doublecheck.
Stock springs are fine to 8300 on smaller cams (think S1s) but at some point you are going to want to think about stiffer springs. I dont think Kiggly's are for everybody. Typically I only recommend them (or a Ti retainer based spring) above 9k. We havent been vary impressed with Supertech however since they do eat valvestem seals. The reason is there isnt much clearance between the inner spring and the seal and they seem to "walk".
Somehow after that my car ran 8.7 & 167mph.. so i guess I made the right decision on the Spring change..
Mike
Dec 7, 2009, 04:02 PM
#26
The Sound is pretty distinctive once you know what it is.. Then you can confirm with your graph.. SOmetimes its just starting to float and the graph doesnt drop huge but it looks like litle misfires on top.. Then you go up with the boost and youll get the drop that we call valve float others call Bounce i guess... LOL
Mike
Mike
Dec 7, 2009, 04:11 PM
#27
Valve float is when the cam follower leaves the top of lobe. as stated earlier this would not hurt power. you just get more lift. valve bounce is when the valve bounces off the seat. very different from valve float and it does hurt power. changing the material of the valves can also cause valve bounce. I hear titanium valves need special seats as they have a very high tendancy to bounce. its a broad subject guys. tear away at if you like. in the end its all about trial and error. I also love the stock valves. they are very well designed and no need to change them IMHO. I use them in the above results on the stock springs. here a good video on how much movement there is.
http://www.youtube.com/watch?v=_REQ1...eature=related
http://www.youtube.com/watch?v=_REQ1...eature=related
Last edited by 94AWDcoupe; Dec 7, 2009 at 04:21 PM.
Dec 7, 2009, 04:18 PM
#28
I doubt very seriously you would here valves floating or bouncing. Valve float is when the cam follower leaves the top of lobe. as stated earlier this would not hurt power. you just get more lift. valve bounce is when the valve bounces off the seat. very different from valve float and it does hurt power. changing the material of the valves can also cause valve bounce. I hear titanium valves need special seats as they have a very high tendancy to bounce. its a broad subject guys. tear away at if you like. in the end its all about trial and error. here a good video on how much movement there is.
http://www.youtube.com/watch?v=_REQ1...eature=related
http://www.youtube.com/watch?v=_REQ1...eature=related
Now i know what your thinking.. how can mike hear them floating in the head?? LOL From experience once again its not the float you hear its the tone of the motor when it happens in high RPM..
So I am going to stick to what i believe is termed VALVE FLOAT and i believe from my experience it causes power loss..
Btw.. I have seen that video and that, anyway you word it, will cause a loss in power.. Just look at the reply from 1 person.. He said he can see POWER LOSS & HEAR IT.. AMAZING!! LOL
"You can tell. I have an inline six in a pickup, notorious for weak springs that has no RPM. I can feel valve float as low as 4,000RPM.
Typically, on my engine, it manifests as a loss of power and a tone/pitch change in the exhaust note"
Mike
Last edited by AWD Motorsports; Dec 7, 2009 at 04:27 PM.
Dec 7, 2009, 04:28 PM
#30
Pulled from Wiki but good definitions. Point is there is no doubt that with high rpm and higher lift cams there is a time when a stiffer spring is needed then the stockies.
"Valve float is an adverse condition which occurs when the poppet valves on an internal combustion engine valvetrain do not remain in contact with the camshaft lobe during the valve closure phase of the cam lobe profile. This reduces engine efficiency and performance and potentially increases engine emissions."
"Valve bounce is a related condition where the valve does not stay seated, due to the combined effects of the valve's inertia and resonance effects of metallic valve springs that effectively reduce the closing force, and allow the valve to re-open partially."
"Valve float is an adverse condition which occurs when the poppet valves on an internal combustion engine valvetrain do not remain in contact with the camshaft lobe during the valve closure phase of the cam lobe profile. This reduces engine efficiency and performance and potentially increases engine emissions."
"Valve bounce is a related condition where the valve does not stay seated, due to the combined effects of the valve's inertia and resonance effects of metallic valve springs that effectively reduce the closing force, and allow the valve to re-open partially."