Stock 6.0L + XER281HR + TV81 W/12PSI Boost = ?HP
08-11-2006, 11:39 PM
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Stock 6.0L + XER281HR + TV81 W/12PSI Boost = ?HP I just bought a cam off eBay, it's a XER281HR-12 232/234 112LSA .595 .598 lift @ 0.050. What do you think the HP numbers would be with this cam in a stock perfectly tuned 9.5:1 6.0L Vortec w/317 heads & LS6 manifold buzzed to 7000RPM force fed by a TV81 turbo @ 12PSI W/5" exhaust, No Cats or Mufflers???
Is this cam worth Dyno Time, any thoughts...
Is this cam worth Dyno Time, any thoughts...
08-12-2006, 02:06 AM
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that's the cam i'm running and i'm ditching it for a ZO6 cam in my winter turbo build
like those guys said, it's way too inefficient to fully utilize your system
like those guys said, it's way too inefficient to fully utilize your system
08-12-2006, 05:52 AM
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Originally Posted by Wnts2Go10O
not enough lsa
Here are my thoughts... The TV8117 and its large turbine ar housing of 1.39 would give a low exhaust to boost back pressure allowing me to utilize a more conventional grind cam. A friend of mine ran a 242/244 115LSA with an 18deg 374ci high winding Gen I twisting twin t72's and made over 1000HP on the Dyno with only 11PSI boost. That cam had a larger overlap of 13degs vs. the 281's 9deg overlap. I also thought during the tuning stage on the Dyno I could use a smaller rocker ratio on the exhaust if needed, any other thoughts?...
Originally Posted by iamsickofitall
that's the cam i'm running and i'm ditching it for a ZO6 cam in my winter turbo build
Last edited by StingrayCrazy; 08-12-2006 at 06:05 AM.
08-12-2006, 07:56 AM
#7
StingrayCrazy, I think your logic is right on track. I can't believe people still get so hung up on LSA, when overlap is really what's allegedly important. The stock Buick GN cam is on a 106 LSA and they work great with turbo's, as proven for decades. Since the duration is <200, the overlap is minimal.
Also, with the low backpressure offered by a T6-framed TV81 series turbo, I think the overlap will actually be benficial. There's a guy on the turbomustangs forum that's made 1625 hp at 15 psi with twin turbo's on a 572 and 28 deg overlap at .050". I guess we should let him know that his cam is all wrong. . .
Another example is the single turbo 370 LSx that Speed Inc. built. Their cam was 236/242-112, but it still managed to make 994 rwhp at 22 psi through a TH400 and loose converter. Once again, I guess we need to let them know that their cam should be on a 114 and it has too much overlap. . .
The next turbo buildup that I'm attacking is similar to yours also. It's a 406 SBC, AFR 210's, solid roller (257/269-112). The owner wants a low-buck blow-through turbo setup. I'd like to install a TV8101 equivalent turbo on it and try it with the cam he has. Not sure if it will work, but for the reasons you listed (low backpressure), I think it will really rev and make power at low boost levels.
I'll be VERY interested to see the results of your cam testing. All of the evidence that I've seen actually indicates that overlap, even on a turbo motor, is a good thing.
Mike
Also, with the low backpressure offered by a T6-framed TV81 series turbo, I think the overlap will actually be benficial. There's a guy on the turbomustangs forum that's made 1625 hp at 15 psi with twin turbo's on a 572 and 28 deg overlap at .050". I guess we should let him know that his cam is all wrong. . .
Another example is the single turbo 370 LSx that Speed Inc. built. Their cam was 236/242-112, but it still managed to make 994 rwhp at 22 psi through a TH400 and loose converter. Once again, I guess we need to let them know that their cam should be on a 114 and it has too much overlap. . .
The next turbo buildup that I'm attacking is similar to yours also. It's a 406 SBC, AFR 210's, solid roller (257/269-112). The owner wants a low-buck blow-through turbo setup. I'd like to install a TV8101 equivalent turbo on it and try it with the cam he has. Not sure if it will work, but for the reasons you listed (low backpressure), I think it will really rev and make power at low boost levels.
I'll be VERY interested to see the results of your cam testing. All of the evidence that I've seen actually indicates that overlap, even on a turbo motor, is a good thing.
Mike
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08-12-2006, 10:59 AM
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Originally Posted by DrTurbo
Which size TV81 though?? They range from 72 all the way to 85mm.
Specs are: TV8117
Compressor housing A/R .95 (5" inlet 3.5" outlet)
Compressor wheel 56 trim (108mm / 4.270" major) (81mm / 3.177 inducer)
Turbine housing A/R 1.39 (5" V-band outlet and T6 inlet)
Turbine wheel 75 trim (111mm / 4.360" major) (96mm / 3.785" inducer)
Originally Posted by engineermike
The next turbo buildup that I'm attacking is similar to yours also. It's a 406 SBC, AFR 210's, solid roller (257/269-112). The owner wants a low-buck blow-through turbo setup. I'd like to install a TV8101 equivalent turbo on it and try it with the cam he has. Not sure if it will work, but for the reasons you listed (low backpressure), I think it will really rev and make power at low boost levels.
Last edited by StingrayCrazy; 08-12-2006 at 11:43 AM.
02-29-2012, 11:43 AM
#12
I cant believe how long it takes to get rid of those old school myths. Today's turbos impeller designs and light weight parts are different from the turbos in the old days- it used to be exhaust pressures were double or more than the intake side and tight lobe separation were needed to work good. Nowadays with properly matched turbo(s) that spool up so much faster the pressure differential is a lot lower sometimes close to equal and so what makes power in n/a set-ups makes power in turbo set ups to a certain extent.
Wide lobe separations also allow people to use incorrect turbos like from earth movers and tractors. I've also seen some guys making tons of power with turbos with 10 deg less exhaust duration split ground into their camshafts. Yes you read that right 10 deg less duration in the exhaust lobe. People need to talk to racing engine builders or do thier own r&d and stop listening to old school myths and people only interested in selling parts.
Wide lobe separations also allow people to use incorrect turbos like from earth movers and tractors. I've also seen some guys making tons of power with turbos with 10 deg less exhaust duration split ground into their camshafts. Yes you read that right 10 deg less duration in the exhaust lobe. People need to talk to racing engine builders or do thier own r&d and stop listening to old school myths and people only interested in selling parts.
02-29-2012, 02:52 PM
#13
Been looking at similar cams for my 5.3 s480 with 96mm turbine. With the large turbine, my thought process is that I might be able to get away with a more traditional "NA" style split rather than a reverse split "turbo cam" due to the lower backpressure. Thoughts?
02-29-2012, 03:03 PM
#14
Holy myth revival. When I posted in this thread I just started dating a woman who is now my wife. My car also had three different setups since then.
I will agree. I don't buy into the whole lsa deal. People make it a bigger deal than it is. My setup runs great and spools fast on a 232/236 112 cam from back in the day.
I will agree. I don't buy into the whole lsa deal. People make it a bigger deal than it is. My setup runs great and spools fast on a 232/236 112 cam from back in the day.
