High Altitude Boosters Please Help
10-26-2015, 11:47 AM
#1
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High Altitude Boosters Please Help I am at 4200 feet of elevation regularly the track is 6k-7k DA.
I am in the process of piecing together a turbo kit for my TBSS.
I am going to be staying with a stock bottom end for a couple years so boost will only be 8-12 lbs.
I have picked a front mount S475/83 t4 I just cant figure out what size a/r to go with. My tuner is saying .86-.94 because of elevation forced inductions is saying 1.10-1.25. Bullseye is saying 1.0-1.10
I know the turbo has to spin faster at higher elevation to make the same boost. Which would me more possibility for lag if the a/r is too big right?
What are other high elevation guys running for a/r ? I am going to have a cam specced for my build so I have to figure everything out so I can pass it along.
I will have a 3200 FTI stall also not sure if that matters
I am in the process of piecing together a turbo kit for my TBSS.
I am going to be staying with a stock bottom end for a couple years so boost will only be 8-12 lbs.
I have picked a front mount S475/83 t4 I just cant figure out what size a/r to go with. My tuner is saying .86-.94 because of elevation forced inductions is saying 1.10-1.25. Bullseye is saying 1.0-1.10
I know the turbo has to spin faster at higher elevation to make the same boost. Which would me more possibility for lag if the a/r is too big right?
What are other high elevation guys running for a/r ? I am going to have a cam specced for my build so I have to figure everything out so I can pass it along.
I will have a 3200 FTI stall also not sure if that matters
10-26-2015, 01:45 PM
#2
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If you're not going after every bit of air the turbo will put out, get the smaller A/R, although I feel I'm wrong when contradicting FI's advice, specially given the smaller turbine wheel.
10-28-2015, 04:09 PM
#5
I am at 4200 feet of elevation regularly the track is 6k-7k DA.
I am in the process of piecing together a turbo kit for my TBSS.
I am going to be staying with a stock bottom end for a couple years so boost will only be 8-12 lbs.
I have picked a front mount S475/83 t4 I just cant figure out what size a/r to go with. My tuner is saying .86-.94 because of elevation forced inductions is saying 1.10-1.25. Bullseye is saying 1.0-1.10
I know the turbo has to spin faster at higher elevation to make the same boost. Which would me more possibility for lag if the a/r is too big right?
What are other high elevation guys running for a/r ? I am going to have a cam specced for my build so I have to figure everything out so I can pass it along.
I will have a 3200 FTI stall also not sure if that matters
I am in the process of piecing together a turbo kit for my TBSS.
I am going to be staying with a stock bottom end for a couple years so boost will only be 8-12 lbs.
I have picked a front mount S475/83 t4 I just cant figure out what size a/r to go with. My tuner is saying .86-.94 because of elevation forced inductions is saying 1.10-1.25. Bullseye is saying 1.0-1.10
I know the turbo has to spin faster at higher elevation to make the same boost. Which would me more possibility for lag if the a/r is too big right?
What are other high elevation guys running for a/r ? I am going to have a cam specced for my build so I have to figure everything out so I can pass it along.
I will have a 3200 FTI stall also not sure if that matters
10-29-2015, 01:42 AM
#6
That S475/83 will work really well in altitude. 4200' is not too bad. I race in denver a lot and it's 5900' and 9000+ DA. Like John said need to keep the cam conservative and a 1.15~1.25 AR will be fine on the T4. I have a S475/83 1.25 T4 on my lq4 with My triple 12 cam and it's been bottom 10's in Colorado @4850 lbs, spooled well. Have ran mid 8's in the nova with a similar combo with the billet S476/92 1.25 T4, and my 218 cam and it worked really well in the high DA. My new combo with the Billet 76/96, and ported 1.25 T4, with mid 220's cam is really laggy up there with a 3400 converter. FTI has a few pretty good conveters but you will definitely want it to be a turbo converter. The Na converter will be a bit tight down low and loose once turbo comes in.
10-29-2015, 01:51 PM
#7
That S475/83 will work really well in altitude. 4200' is not too bad. I race in denver a lot and it's 5900' and 9000+ DA. Like John said need to keep the cam conservative and a 1.15~1.25 AR will be fine on the T4. I have a S475/83 1.25 T4 on my lq4 with My triple 12 cam and it's been bottom 10's in Colorado @4850 lbs, spooled well. Have ran mid 8's in the nova with a similar combo with the billet S476/92 1.25 T4, and my 218 cam and it worked really well in the high DA. My new combo with the Billet 76/96, and ported 1.25 T4, with mid 220's cam is really laggy up there with a 3400 converter. FTI has a few pretty good conveters but you will definitely want it to be a turbo converter. The Na converter will be a bit tight down low and loose once turbo comes in.
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10-30-2015, 11:21 AM
#8
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I live at 8600 and race/drive in the Denver area a lot. I have an L33 with ljms 218/223 cam, s480 with 96 turbine and 1.10 ar, 2.25 divided hotside, 3200 PTC converter and 3.23 gear, spool surprised me, works well.