TSP Texas Giant to EPS custom spec Cam Swap Results
08-23-2010, 09:57 AM
#1
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TSP Texas Giant to EPS custom spec Cam Swap Results Sorry, this was a bit vague earlier today. This is not a bash post, geoff from EPS is awesome people, Yes i expected more.. But I dont think the cam is to blame. What Is I dont know.
Gain from 516.7 rwhp to 522.x with the eps cam
Lost torque, 488 to 483 with the eps cam.
Peak seems low. But it doesn't nose over.. pulls flat to 7k
These HS rockers keep on coming up, But ECS has had no trouble with them to 7k..
Mentioned was flow balance the fast 42lbs.. might have a weak one or two..
Dyno was the same, tuner the same, weather was 20 degrees cooler today.
NEW CAM
OLD CAM
Setup-
Its a 402 forged ls2 stroker
Callies crank, Rods
Manley pistons
11.8:1 comp
Steel top rings
Arp everything
TEA TFS 225cc heads
Harland sharp RR
Texas giant cam - SWAPPED FOR EPS CUSTOM SPEC
Lsxr 102mm
Ls2 Tb
1 7/8 kooks Lts
This is in an 01 Z
Build by me, Tuned by ECS
Gain from 516.7 rwhp to 522.x with the eps cam
Lost torque, 488 to 483 with the eps cam.
Peak seems low. But it doesn't nose over.. pulls flat to 7k
These HS rockers keep on coming up, But ECS has had no trouble with them to 7k..
Mentioned was flow balance the fast 42lbs.. might have a weak one or two..
Dyno was the same, tuner the same, weather was 20 degrees cooler today.
NEW CAM
OLD CAM
Setup-
Its a 402 forged ls2 stroker
Callies crank, Rods
Manley pistons
11.8:1 comp
Steel top rings
Arp everything
TEA TFS 225cc heads
Harland sharp RR
Texas giant cam - SWAPPED FOR EPS CUSTOM SPEC
Lsxr 102mm
Ls2 Tb
1 7/8 kooks Lts
This is in an 01 Z
Build by me, Tuned by ECS
Last edited by nysbadmk8; 08-23-2010 at 03:30 PM.
08-23-2010, 10:09 AM
#2
Your post is far too vague for anybody to give you any kind of advice. Dyno graph? Cam specs? What month was the 516 made vs the 507? I've seen cars lose 25HP in the summer compared to what they dyno'd in the fall/winter, even with correction factors.
Less griping, more info. Then you'll get help.
Less griping, more info. Then you'll get help.
08-23-2010, 10:14 AM
#3
Part of it was richening the tune from 14 to 13.2 (at the tailpipe) and a heavier driveshaft...but I also added a pulley.
Both pulls were with the same stall unlocked and both on drag radials
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08-23-2010, 03:31 PM
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08-23-2010, 03:32 PM
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08-23-2010, 03:47 PM
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08-23-2010, 03:48 PM
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08-23-2010, 04:15 PM
#17
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Both cams are peaking lower than they should. I see valve float in both graphs. I know people keep saying HS rockers... I am seeing the same thing. I've had no luck with them with cams that aggressive. Those cams should peak somewhere between 6150 and 6400. Some dynos smooth things out so much on the graph its hard to spot. The power peak and the way it falls just after 5800 are the tell-tale signs.
I'd go to stock rockers. Just my .02...
Shane
I'd go to stock rockers. Just my .02...
Shane
08-23-2010, 04:29 PM
#18
Well in doing that lies the problem as Trick Flow warns against using stock rockers due to the incorrect geometry that they can produce and possibly cause increased valve guide wear. Or so they say. So that is one reason actually why people prefer the other heads to trick flows. They are advertised to use stock rockers.
I have no problem with using stock rockers as they are less expensive and lighter and I have seen no problems with them on higher HP applications.
Could be worth a quick valve cover removal/rocker install to quench a problem.
I have no problem with using stock rockers as they are less expensive and lighter and I have seen no problems with them on higher HP applications.
Could be worth a quick valve cover removal/rocker install to quench a problem.
08-23-2010, 04:56 PM
#19
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I should have clarified, I have a kit which allows the use of stock rockers with proper geometry on the TFS heads. I basically did what ET/PI did and figured out the proper stand height and pushrod length to get proper geometry with the shallower valve angle. I definitely see valvetrain instability in both graphs. those cams should peak higher and the curves have bad dips just past peak then seem to recover slightly. This is a classic sign of valve bounce on a dyno graph.
Shane
Shane
08-23-2010, 05:25 PM
#20
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I should have clarified, I have a kit which allows the use of stock rockers with proper geometry on the TFS heads. I basically did what ET/PI did and figured out the proper stand height and pushrod length to get proper geometry with the shallower valve angle. I definitely see valvetrain instability in both graphs. those cams should peak higher and the curves have bad dips just past peak then seem to recover slightly. This is a classic sign of valve bounce on a dyno graph.
Shane
Shane
How much is your kit, I dont own any stock rockers either.. It might be cheaper for me to run YT's