TR230/224 + Comp 987 Springs = valve float????
10-17-2003, 01:21 AM
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TR230/224 + Comp 987 Springs = valve float???? After seing a TR230 dyno graph of someone without comp 987 springs I noticed that they keep making power up until 7000rpms.
Off Axis mentioned he's getting valve float with Comp 987 springs.
My car hits peak power at 6400rpm and drops off steadily after that, and really slows down at 6800rpms.
I have titanium retainers, and Ferrea/UDI intake/exhaust valves. I just added YT rockers which should eliminate some valve float, but could I very well be getting valve float with 987's?
What's the best way to tell?
Off Axis mentioned he's getting valve float with Comp 987 springs.
My car hits peak power at 6400rpm and drops off steadily after that, and really slows down at 6800rpms.
I have titanium retainers, and Ferrea/UDI intake/exhaust valves. I just added YT rockers which should eliminate some valve float, but could I very well be getting valve float with 987's?
What's the best way to tell?
10-17-2003, 05:39 AM
#2
Re: TR230/224 + Comp 987 Springs = valve float???? No valve float for me. I made peak power with the 230/224 @ 64-6500 rpm. 427 to the wheels on a conservative dyno. No dyno tricks, SS 10 spokes, 12 bolt 430 gears. Was still making 420 @ 6800 rpm and the curve was nice and smooth. 
Bruce
Bruce
10-17-2003, 09:28 AM
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Re: TR230/224 + Comp 987 Springs = valve float???? I have the 987's and the tr230 cam and I have no valve float. My dyno curve stays nice and straight till the 7k rpm limiter.
10-17-2003, 11:24 AM
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Re: TR230/224 + Comp 987 Springs = valve float???? glhs, I have the same springs and hes you do, and wonder why my graph drops off a bit from 6400rpms? I don't think I'm alone.
10-17-2003, 11:30 AM
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Re: TR230/224 + Comp 987 Springs = valve float???? I think 987's and the TR230 cam are on the hairy edge of floating valves, that's why thunder recomends the 918's, because they were experiencing valve float themselves with the 987's.
Anyway, what would be the best valvespring out there to replace them with?
Dan
Anyway, what would be the best valvespring out there to replace them with?
Dan
10-17-2003, 02:00 PM
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Re: TR230/224 + Comp 987 Springs = valve float???? Here is an old dyno from when I first got the heads/cam package last year. Does this look like valve float? I shut the car down at 7000rpms. The bottom got cut off of the dyno sheet.
The reason I got the 987's was because I thought for high revving applications they'd be better than the 918's? That is what everyone was telling me at the time.
The reason I got the 987's was because I thought for high revving applications they'd be better than the 918's? That is what everyone was telling me at the time.
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10-17-2003, 02:08 PM
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Re: TR230/224 + Comp 987 Springs = valve float???? I see the downward curve you are talking about verbs.
I wish I had a scanner and I would scan my sheet in.
Mine goes above 400 wheel around 5800rpm or so and goes straught across untill my limiter kicks in a 7k. It doesn't ever get the downward curve towds the limiter, mine is more like a cliff. It drops off strainght down when the limiter kicks in. Kind of make me think mine would still keep going making power if I raise the limiter?
I wish I had a scanner and I would scan my sheet in.
Mine goes above 400 wheel around 5800rpm or so and goes straught across untill my limiter kicks in a 7k. It doesn't ever get the downward curve towds the limiter, mine is more like a cliff. It drops off strainght down when the limiter kicks in. Kind of make me think mine would still keep going making power if I raise the limiter?
10-17-2003, 02:14 PM
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Re: TR230/224 + Comp 987 Springs = valve float???? I got the double springs when I ordered the heads becasue of all the 918 problems at the time. Also, like you verbs, I though they would be better at handling the lift and rpm than a single spring would. I called comp and they told me the way my 987's were set up by TEA that the were only good to 580 lift. Not saying a 987 can't handle more lift, but comp said they were set up in my heads to only handle 580. I was thinking of selling the 230 at the time and getting a g5x2, but since I heard that from comp, I will stay with what I have.
10-17-2003, 05:55 PM
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Re: TR230/224 + Comp 987 Springs = valve float???? Verbs: You could be floating. I'm not sure what the lift is on that cam, but it depends on how the springs were installed - what the installed height is. The 987 is stiffer than the 918, but can't handle as much lift. In order of stiffness, the 918 is 313 lb/in, the 987 is 344, the 978 is 403, and the 977 is 441. The Crane stock size is in between at 369 lb/in. Thing about the 987 is that it only has a recmmended lift of 0.500" at 1.800" installed height. If you install it longer, so you don't bind, the seat pressure drops. You could then get into bounce which would hurt power. You can't get more than about 325 lbs over the nose with that spring shimmed to near coil bind. If the TR has gentle lobes, that should be enough. An XE-R lobe wants about 135 lbs seat and 345 lbs over the nose. I guess after entering this that I doubt you have float unless the springs are tired or installed height is too long. I think seat bounce might be more likely. I don't think you want a 918 since it will have less over the nose pressure at the same install height as a 987. The Crane or 978 would be a better choice.
10-17-2003, 06:12 PM
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Re: TR230/224 + Comp 987 Springs = valve float????
Verbs: You could be floating. I'm not sure what the lift is on that cam, but it depends on how the springs were installed - what the installed height is. The 987 is stiffer than the 918, but can't handle as much lift. In order of stiffness, the 918 is 313 lb/in, the 987 is 344, the 978 is 403, and the 977 is 441. The Crane stock size is in between at 369 lb/in. Thing about the 987 is that it only has a recmmended lift of 0.500" at 1.800" installed height. If you install it longer, so you don't bind, the seat pressure drops. You could then get into bounce which would hurt power. You can't get more than about 325 lbs over the nose with that spring shimmed to near coil bind. If the TR has gentle lobes, that should be enough. An XE-R lobe wants about 135 lbs seat and 345 lbs over the nose. I guess after entering this that I doubt you have float unless the springs are tired or installed height is too long. I think seat bounce might be more likely. I don't think you want a 918 since it will have less over the nose pressure at the same install height as a 987. The Crane or 978 would be a better choice.
It just boggles me when seeing other people with the same springs not having their dyno's dip after 6400rpms.
10-17-2003, 07:20 PM
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Re: TR230/224 + Comp 987 Springs = valve float???? My cam goes 579 on the intake, 569 on the exhaust.
Verbs how many miles were on the springs when you dynoed it?
Too many 7k+ rpm blasts.
Verbs how many miles were on the springs when you dynoed it?
Too many 7k+ rpm blasts.
10-17-2003, 07:42 PM
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Re: TR230/224 + Comp 987 Springs = valve float????
My cam goes 579 on the intake, 569 on the exhaust.
Verbs how many miles were on the springs when you dynoed it?
Too many 7k+ rpm blasts.
Verbs how many miles were on the springs when you dynoed it?
Too many 7k+ rpm blasts.
You can never have enough 7000rpm blasts
10-17-2003, 09:22 PM
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Re: TR230/224 + Comp 987 Springs = valve float????
I was planning on doing a TR236 with 918's here in a week or so.. Looks like this is not a good idea? 236/.599 on the intake.
10-18-2003, 12:17 PM
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Re: TR230/224 + Comp 987 Springs = valve float????
If you don't mind me stepping in, what is valve float mean?