GT4088R or GT4508R
06-19-2008, 05:42 PM
#1
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GT4088R or GT4508R Hi Ls1Tech
I have been reading through a lot of new and old threads over the last few week’s trying to find out as much information as I can, to help me chose a turbo combination for my Holden Ute.
Few things about my project:
Engine: Ls1 346 CI “compression will be lowered for FI”
A Turbo Cam will be fitted
Fuel system will be upgraded with 60 lb injectors and fuel pumps Fuel will be 98 octane
Twin 3” Exhaust “high flow cats, we got to have them
”
But hear is my dilemma, what turbo?
I am 99% sure that I am going for a single turbo setup, but I have two option in the kits which I can have for my ute.
Garrett GT4088R
Or
Garrett GT4508R
I have attached both graphs if this helps.
My power goal is around 650 Hp at the engine, without having to go higher then about 5750 rpm, and full spool by about 3500 - 4000 rpm, also I don’t really want to go more then 10 psi with out having forged internals.
So what are your thoughts on which turbo to get?
Thanks
Lee
I have been reading through a lot of new and old threads over the last few week’s trying to find out as much information as I can, to help me chose a turbo combination for my Holden Ute.
Few things about my project:
Engine: Ls1 346 CI “compression will be lowered for FI”
A Turbo Cam will be fitted
Fuel system will be upgraded with 60 lb injectors and fuel pumps Fuel will be 98 octane
Twin 3” Exhaust “high flow cats, we got to have them
”But hear is my dilemma, what turbo?
I am 99% sure that I am going for a single turbo setup, but I have two option in the kits which I can have for my ute.
Garrett GT4088R
Or
Garrett GT4508R
I have attached both graphs if this helps.
My power goal is around 650 Hp at the engine, without having to go higher then about 5750 rpm, and full spool by about 3500 - 4000 rpm, also I don’t really want to go more then 10 psi with out having forged internals.
So what are your thoughts on which turbo to get?
Thanks
Lee
Last edited by lee ls1; 06-19-2008 at 05:57 PM.
06-19-2008, 06:51 PM
#2
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you do realize boost pressure is the LAST thing you should consider when selecting a turbo, right? you need to plot your engine on the graph and see where your surge lines run with your air flow.
and...10psi means NOTHING in the real world other than how far the needle on the gauge moves. you need to limit yourself by power, not boost. 10psi on a gt28rs is not the same cfm as 10psi with a 106mm turbo. just don't even THINK about a psi limit when planning your build.
but for just 650whp...i'd go with a GT4202 you've got a pretty big difference with the 4088 and the 4502...4088 is a street turbo for honda's now, haha
and...10psi means NOTHING in the real world other than how far the needle on the gauge moves. you need to limit yourself by power, not boost. 10psi on a gt28rs is not the same cfm as 10psi with a 106mm turbo. just don't even THINK about a psi limit when planning your build.
but for just 650whp...i'd go with a GT4202 you've got a pretty big difference with the 4088 and the 4502...4088 is a street turbo for honda's now, haha
06-19-2008, 07:00 PM
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you do realize boost pressure is the LAST thing you should consider when selecting a turbo, right? you need to plot your engine on the graph and see where your surge lines run with your air flow.
and...10psi means NOTHING in the real world other than how far the needle on the gauge moves. you need to limit yourself by power, not boost. 10psi on a gt28rs is not the same cfm as 10psi with a 106mm turbo. just don't even THINK about a psi limit when planning your build.
but for just 650whp...i'd go with a GT4202 you've got a pretty big difference with the 4088 and the 4502...4088 is a street turbo for honda's now, haha
and...10psi means NOTHING in the real world other than how far the needle on the gauge moves. you need to limit yourself by power, not boost. 10psi on a gt28rs is not the same cfm as 10psi with a 106mm turbo. just don't even THINK about a psi limit when planning your build.
but for just 650whp...i'd go with a GT4202 you've got a pretty big difference with the 4088 and the 4502...4088 is a street turbo for honda's now, haha
thanks for that rhd, these where the two choose which came with the kit, but could look into have a GT42 fitted, will have a look at the maps.
I had a go at plotting on the graph where i would be, and came out about:
1.7 and 70 ib/min but was not 100% on my calc's.
But thanks for your help
06-19-2008, 07:17 PM
#4
For the numbers your trying to make a TC series unit would be best suited...plain and simple. Compact, powerful and not near the price of a GT4508R....geez those suckers are pricey.
06-19-2008, 10:14 PM
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I found some tools http://www.turbofast.com.au/javacalc.html to work out what turbo spec's would work well, just thought i would share if it helps with anyone
