LB/Min CFM Question

terbow

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03.5 MSP
ok i need a little help for my secret project ;)

ok so i want to eventually go gt28rs. Which puts out more cfm or lb/min than my stock t25r (msp). So i will base my question on the gt28 since it will be figuring high and im looking for a flow requirement. here goes:

The GT 28 rs, based on cheapturbo puts out 35 lb/min or 500 cfm (based on calculations for 80 degrees @ sea level). Now where does this figure lie? Is it on the very edge of its limit or where it normally operates?

I ask this because the IC im getting (what type is irrelevent i think) flows 390cfm. So since im only going for 250whp which is below the efficiency of the gt28rs (its good for 350 hp i hear, so im guessing id need less than 15 psi to get there), would the 390cfm be plenty of flow since i wont be near the 500cfm threshold, or is that 500cfm/35lb/min figure somewhere in the middle and my IC would create a bottleneck. Thanks!!

heres some flow charts if it helps to explain it to me better. Im not that good at reading compressor maps. but fomr the chart it looks like the 35/lb a min would be way past what im shooting for. am i correct?
 

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do you understand what "pressure ratio" is?

its (atmospheric pressure + boost pressure) / atmospheric pressure

so 10psi would be (14.7 + 10) / (14.7) = 1.68... which has a pretty good range in the top efficiency range
 
Accordining to that formula, and MPNick, the "sweet spot" of that turbo would be 15-18psi. Nick likes to be in the 2.0 to 2.2 range. So at those numbers you would be around the 350hp number. I would think 10psi would be fine with that intercooler, but I'm just guessing.
 
after i posted this i found all those terms and such. so i do understand a bit. I think it will be fine too. thanks guys.
 
terbow said:
ok i need a little help for my secret project ;)

ok so i want to eventually go gt28rs. Which puts out more cfm or lb/min than my stock t25r (msp). So i will base my question on the gt28 since it will be figuring high and im looking for a flow requirement. here goes:

The GT 28 rs, based on cheapturbo puts out 35 lb/min or 500 cfm (based on calculations for 80 degrees @ sea level). Now where does this figure lie? Is it on the very edge of its limit or where it normally operates?

I ask this because the IC im getting (what type is irrelevent i think) flows 390cfm. So since im only going for 250whp which is below the efficiency of the gt28rs (its good for 350 hp i hear, so im guessing id need less than 15 psi to get there), would the 390cfm be plenty of flow since i wont be near the 500cfm threshold, or is that 500cfm/35lb/min figure somewhere in the middle and my IC would create a bottleneck. Thanks!!

heres some flow charts if it helps to explain it to me better. Im not that good at reading compressor maps. but fomr the chart it looks like the 35/lb a min would be way past what im shooting for. am i correct?
On a good day that core is only good for 230whp. Plus keep in mind what everyone seem to forget. The core is only rated before the tanks are installed. When you had the tanks your pressure drop will go up. Then you have to look at the tubing size and the feet of tubing. If you are a little small or undersized with you system you will not only make less power whp you will also have more lag.
 
ok so they have one that flows 920cfm, which is way more than the other, and i can only imagine i would be able to hit the 250whp number with that. so would that one be a better choice? or is it to big? my i can get one inbetween those but its a different manufacturer but whatever u recommend for cfm i can find it. its bigger but i can make it fit. im good a putting 10 lbs of s*** in a 5lb bag ;) thanks for all the help.
 
terbow said:
ok so they have one that flows 920cfm, which is way more than the other, and i can only imagine i would be able to hit the 250whp number with that. so would that one be a better choice? or is it to big? my i can get one inbetween those but its a different manufacturer but whatever u recommend for cfm i can find it. its bigger but i can make it fit. im good a putting 10 lbs of s*** in a 5lb bag ;) thanks for all the help.
Are you looking at cores or full systems?
 
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