Disappointing results with TFS Heads
Originally Posted by 99C5JA
Overlap refers to the time when both valve's are open. The lobe separation angle and duration determine overlap. Smaller LSA's will increase overlap which can be bad or good depending on your setup.
Not to be rude, but can you please continue this discussion via pm's or with a different thread? It's hard enough trying to get a handle on what the heck is wrong with my car without two different conversations going on.
Not to be rude, but can you please continue this discussion via pm's or with a different thread? It's hard enough trying to get a handle on what the heck is wrong with my car without two different conversations going on.
My Apologys. Just trying to understand why you had such bad luck with the same heads I am going to use. I don't want to make the same mistake. This is your thread. But it is a Public Forum.
He said overlap could be your problem & thus why i asked what it means & to prevent this problem on your car & others people setups
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From: ohio
Originally Posted by Brian Tooley
I have seen 2 poor results with TFS heads, yours and a guy with a C6 Vette LS2 and TFS 225 heads, the only thing in common is both combinations had YT roller rockers...
I would take the advice of Mike above...
I would take the advice of Mike above...
Correction Brian, The other guy has PP- adjustable rockers.
https://ls1tech.com/forums/dynamometer-results-comparisons/681283-dyno-issues-tfs-headed-ls2-vette.html
I have heard the YT's need to be shimmed up about .050" to get nice geometry and use a 7.550" pushrod.
Originally Posted by JakeFusion™
Isn't the "stock" pushrod length 7.700" for use with the TFS heads? If so, why would you go to a 7.500" which is .200" shorter? Even if you mill the heads .18" ~ 61cc, you'd still need 7.675" pushrods. Do the YTs require a different length pushrod?
The 7.500" is now the correct length. The 7.700" was used on some of the early heads but they made a revision.
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usually a valvetrian issue will be fiarly dramatic. this just looks like low power production. thats why i brought up overlap.
Originally Posted by Mike@TEA
Correction Brian, The other guy has PP- adjustable rockers.
https://ls1tech.com/forums/showthread.php?t=681283
I have heard the YT's need to be shimmed up about .050" to get nice geometry and use a 7.550" pushrod.
The 7.500" is now the correct length. The 7.700" was used on some of the early heads but they made a revision.
https://ls1tech.com/forums/showthread.php?t=681283
I have heard the YT's need to be shimmed up about .050" to get nice geometry and use a 7.550" pushrod.
The 7.500" is now the correct length. The 7.700" was used on some of the early heads but they made a revision.
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From: Ankeny, IA
Originally Posted by SEBLS1
My Apologys. Just trying to understand why you had such bad luck with the same heads I am going to use. I don't want to make the same mistake. This is your thread. But it is a Public Forum.
He said overlap could be your problem & thus why i asked what it means & to prevent this problem on your car & others people setups
He said overlap could be your problem & thus why i asked what it means & to prevent this problem on your car & others people setups
Originally Posted by 99C5JA
I believe he was referring to your 110 LSA cam choice. I certainly value any input. I was just trying to keep the thread from going off on in a different direction. If it turns out that he was trying to address my issues, then I apologize for the remark.
If anyone is wrong. It was me. please continue. I will post a new thread. Sorry.
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i was specifically adressing your issue. You have to much overlap in that camshaft.
Originally Posted by 99C5JA
I believe he was referring to your 110 LSA cam choice. I certainly value any input. I was just trying to keep the thread from going off on in a different direction. If it turns out that he was trying to address my issues, then I apologize for the remark.
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From: Ankeny, IA
Originally Posted by LS1curious
i was specifically adressing your issue. You have to much overlap in that camshaft.
Something else to add. Look at the cam used in the other thread:
https://ls1tech.com/forums/showthrea...3&page=1&pp=20
Seems like a very similar cam.
Last edited by 99C5JA; Jun 14, 2007 at 12:43 PM.
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From: Ankeny, IA
Also the YT rockers when installed on the milled 241 heads used the supplied shims (I did this to restore the geometry with the hardened pushrods I had). I did not shim them when installing the TFS heads. Mike/Brian would I be better off at this point to shim the YT rockers and purchase the appropriate pushrods or get some Harland Sharp rockers?
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I wouldn't be willing to put my name on it or anything but i would be willing to bet it a 114 would be a fiarly large improvment. Overlap can cuase the intake runners to back up with exhuast at moderate RPM if the exhuast is to restrictive.
Originally Posted by 99C5JA
Interesting. So do you think a 114 LSA cam solve the power problem here?
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From: Ankeny, IA
Originally Posted by LS1curious
I wouldn't be willing to put my name on it or anything but i would be willing to bet it a 114 would be a fiarly large improvment. Overlap can cuase the intake runners to back up with exhuast at moderate RPM if the exhuast is to restrictive.
Last edited by 99C5JA; Jun 14, 2007 at 01:42 PM.
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From: Ankeny, IA
Originally Posted by Slowhawk
I'd think valvetrain.Too much preload will do that.
Or shim the current setup to reduce preload a bit?
Last edited by 99C5JA; Jun 14, 2007 at 02:22 PM.
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You would have to run a open header with a tunned primary and collector to make an overlap cycle that long work.
Originally Posted by 99C5JA
The exhaust on this car doesn't seem to be restrictive. But I did edit my previous post to point out that the LS2 car dyno'ing low was using a cam very similar to this one. It seems a suspicious coincidence if nothing else.
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From: Ankeny, IA
Originally Posted by LS1curious
You would have to run a open header with a tunned primary and collector to make an overlap cycle that long work.
OK so the exhaust is restrictive then on this setup. So it's sounding like swap the cam and replace the rockers would go along with the 2 main trains of thought here. 
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ls6 intake and stock TB arnt doing you any favours. What does your MAP log under WOT? If its less than atmospheric then you have an intake problem.
What exhaust are you running? long tube 1.75" or better?
What exhaust are you running? long tube 1.75" or better?
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Originally Posted by 99C5JA
Yup, 1 3/4" longtubes, no cats. I don't have a log of the runs. I can always throw the laptop in the car and make a few though.
I would suggest some log runs so you can give us some figures. My first though was to say the intake, but with your old heads and the Ls6 intake you should have been up near the 450s. Now if you had those rockers on with the previous heads it is possible something is up with the geometry. I was also looking at the exhaust and cannot find FLP headers for a C5. Do they come with a X or Y pipe? What is the pipe size back to the catback? I do not think the stock air bridge is holding you back that bad. I know Allan has done a car or two with the F14 slightly larger cam, and had no problems making over 480 rwhp with the TFS heads. I would look for some simplier solutions before you take the cam out.
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From: Ankeny, IA
FLP headers have an X-pipe and reduce to 2.5" after the cats/no cats pipe. They aren't quite up to the Kooks/LG headers but are solid headers. A friend with a supercharged '99 C5 made 620/520 with them.
Do you recall if he make that kind of power with a 112 or 114 LSA cam? Rockers were on for both runs.
Do you recall if he make that kind of power with a 112 or 114 LSA cam? Rockers were on for both runs.
Last edited by 99C5JA; Jun 14, 2007 at 04:22 PM.
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I don' think that the cam is the problem. All of Futural's cams have been proven to make power. The overlap on that cam isn't anywhere near what I've seen on many people's cams in here. It's actually pretty mild.
Question: Would the fact that he has no advance on a 112LSA cam have anything to do with this?
Question: Would the fact that he has no advance on a 112LSA cam have anything to do with this?