billet s480 vs cast GT5088 on 370
09-13-2013, 12:46 PM
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billet s480 vs cast GT5088 on 370 A few questions I have regarding the mid frame GT5088 is if it has the same exterior dimensions as the s400 due to my turbo kit being built off a s400 turbo.
I had considered a GT55 unit but there is no way that thing will fitwith my kit.
Billet s480 has a 96mm turbine and 1.32AR rated at 1350hp
Cast GT5088 has 100mm turbine and AR option as big as 1.39AR rated at 1550hp
Spool characteristics dont worry me to much since its a street car I just wanted to see if anyone is running one or if its worth the $2,000 price tag!
Goal is 1k to the tire with the least amount of boost possible (20psi and under)
I had considered a GT55 unit but there is no way that thing will fitwith my kit.
Billet s480 has a 96mm turbine and 1.32AR rated at 1350hp
Cast GT5088 has 100mm turbine and AR option as big as 1.39AR rated at 1550hp
Spool characteristics dont worry me to much since its a street car I just wanted to see if anyone is running one or if its worth the $2,000 price tag!
Goal is 1k to the tire with the least amount of boost possible (20psi and under)
09-13-2013, 01:15 PM
#2
I haven't seen compressor maps for either of those wheels so is hard to say. The BW units tend to breathe better at relatively lower boost levels. Most of the garrets I've seen work better at higher boost levels compared to BW. Its a toss up though since ultimately the GT50 will net you lower exhaust backpressure. If it were me I'd run the billet 80 
09-13-2013, 01:20 PM
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I haven't seen compressor maps for either of those wheels so is hard to say. The BW units tend to breathe better at relatively lower boost levels. Most of the garrets I've seen work better at higher boost levels compared to BW. Its a toss up though since ultimately the GT50 will net you lower exhaust backpressure. If it were me I'd run the billet 80
09-13-2013, 01:29 PM
#4
You don't have to worry about back pressure as much if you run less lobe overlap on the cam. Too much and the bigger turbine will just be a crutch for the problem while sacrificing spool time and having to rev higher. Why are you trying to keep the boost under 20psi?
Last edited by smokeshow; 12-05-2013 at 09:45 PM.
09-13-2013, 03:33 PM
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09-13-2013, 07:50 PM
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09-13-2013, 09:50 PM
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Yea I think im just gonna go with the ETR 84mm since it is the same price as the 80mm ajd gonna do the 1.58AR as well. Later the bigger turbine will be available and I will send it in. Should be 1400whp capable.
09-14-2013, 11:07 PM
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True but I am planning as far ahead as I can. I cant keep my **** alone, I will probably build another shortblock with more cubes before Tx2k. GT5088 would be a happy medium between the 96 and 111 turbine. I might be able to score one from a member since he is upgrading.
09-15-2013, 12:15 AM
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Funny you mention that, a few turbo/can gurus said they woukd like to see my camshaft paired with the bigger GT55 turbine due to the large amount of duration im running. Opposite of what your saying.
09-15-2013, 12:35 AM
#18
Well, what are the specs of your cam? My point is you don't need a lot of cam once you feed it with a turbo... Of course if you already have a giant cam, then it makes sense to go with the largest turbine possible. But why let a $400 part determine which $2000 part you buy? Especially when the bigger turbine will just contribute to lag and you the same or less power in the end.
A good example as usual is stock48 with the smaller cams he runs. There are countless people trying to keep up with him that swear by their giant cams. And I don't see too many people outrunning him lol. Perhaps it is time to redefine 'guru'...
A good example as usual is stock48 with the smaller cams he runs. There are countless people trying to keep up with him that swear by their giant cams. And I don't see too many people outrunning him lol. Perhaps it is time to redefine 'guru'...
09-15-2013, 02:54 AM
#20
Exhaust duration by itself has nothing to do with backpressure.
Overlap does and plays a much larger role in managing drive pressure.
Where you open the exhaust valve will also play a huge role in when/where reversion starts and how you evacuate the cylinder before it happens, which in a turbo motor reversion will inevitably occur. It also plays a huge role in how you manage drive pressure and evacuating the cylinder with that pressure present.
I've tried to get SlowLSX into a smaller cam for months now. So it isn't me that's telling him this.
I've been grinding camshafts with less intake duration a lot lately. Makes more torque, better E.T. and contributes less to excessive drive pressure by keeping overlap lower.
Overlap does and plays a much larger role in managing drive pressure.
Where you open the exhaust valve will also play a huge role in when/where reversion starts and how you evacuate the cylinder before it happens, which in a turbo motor reversion will inevitably occur. It also plays a huge role in how you manage drive pressure and evacuating the cylinder with that pressure present.
I've tried to get SlowLSX into a smaller cam for months now. So it isn't me that's telling him this.
I've been grinding camshafts with less intake duration a lot lately. Makes more torque, better E.T. and contributes less to excessive drive pressure by keeping overlap lower.