boosting that thing up and I am wondering how far could I go with this supercharger head unit, as that would allow me to determine how low of a compression I could run.
I know that Andy has done 12PSIg @ 10.4:1 compression, but my aim is 9.5:1 and about 14PSIg, does anyone have any idea if this is doable with this head unit, I am spending money on forging the internals and have no budget on replacing the head unit.
boosting that thing up and I am wondering how far could I go with this supercharger head unit, as that would allow me to determine how low of a compression I could run.
I know that Andy has done 12PSIg @ 10.4:1 compression, but my aim is 9.5:1 and about 14PSIg, does anyone have any idea if this is doable with this head unit, I am spending money on forging the internals and have no budget on replacing the head unit.
Any help would be appreciated.
Forget about it. In order to get 14 psi out of a T Trim in a 427 engine you will have to spin it too fast, past its maximun recomendable. And this is with the stock cam, if you change it the engine will demand even more air.
If you stay at 11:1 you can up the boost more. In the example you mentioned above, Andy did a Dynamic compression ratio of 19:1. If you run 8psi on 11:1 cr, you will be at 17:1 Dynamic cr which is safe.
If you run 14psi with 9.5:1 your dynamic cr would be 18.5:1 (less safe.)
Forget about it. In order to get 14 psi out of a T Trim in a 427 engine you will have to spin it too fast, past its maximun recomendable. And this is with the stock cam, if you change it the engine will demand even more air.
If you stay at 11:1 you can up the boost more. In the example you mentioned above, Andy did a Dynamic compression ratio of 19:1. If you run 8psi on 11:1 cr, you will be at 17:1 Dynamic cr which is safe.
If you run 14psi with 9.5:1 your dynamic cr would be 18.5:1 (less safe.)
Can you give me that comp ratio formula again. There is a max impeller speed calculator for the V2 superchargers on Vortech's website, but I need the crank pulley diameter to use this, whats the crank pulley diameter
The crank pulley dia. is the damper dia. in the LS7 is 7.5". Watch for the CFM of the T-Trim at max impeller speed it could not be enough for the big LS7. The power and torque could go down as rpm goes very high
The formula for the dynamic compression ratio is:
((boost/14.7)+1)xCR
If you drop the comp to 9:1 and keep the stock cam, you can get away with spinning your little Vortech to about 10 PSI (MAYBE 11... MAYBE) before you will generate more heat and negate the added boost.
If you are going the forged route and want to put a better blower cam in, then it's time to come off the wallet and upgrade that head unit!!
Good luck and let us know how it turns out!
Oh, and when you do it.... Let me give you a little tip....
You are going to be VERY traction-limited.
Hoosier R6 345's on the rear (and 285's on the front if you still take those highspeed turns!! ). They all fit on the stock wheels and don't rub.
The crank pulley dia. is the damper dia. in the LS7 is 7.5". Watch for the CFM of the T-Trim at max impeller speed it could not be enough for the big LS7. The power and torque could go down as rpm goes very high
The formula for the dynamic compression ratio is:
((boost/14.7)+1)xCR
This is the max impeller speed calculator, I know that the impeller speed isnt going to be the bottle neck, but the max CFM flow of the supercharger why? Because other than the fact that I got catless headers and boost, ill also port/polish the heads and intake, which should lower the boost pressure required to generate the same power, don't forget the blower cam as well.
Also, given two scenarios:
11:1 comp and 10PSI of boost
VS.
9:1 comp and 15PSI of boost
Both scenarios lead to a dynamic compression ratio of 18.3. Which is safer to run?? The first one will make more low-end power, but the latter would obviously have the top-end advantages, I don't know how big the difference is going to be though.
What is a safe dynamic comp ratio for a street driven vehicle on 93 octane fuel, and a good tune
This is the max impeller speed calculator, I know that the impeller speed isnt going to be the bottle neck, but the max CFM flow of the supercharger why? Because other than the fact that I got catless headers and boost, ill also port/polish the heads and intake, which should lower the boost pressure required to generate the same power, don't forget the blower cam as well.
Also, given two scenarios:
11:1 comp and 10PSI of boost
VS.
9:1 comp and 15PSI of boost
Both scenarios lead to a dynamic compression ratio of 18.3. Which is safer to run?? The first one will make more low-end power, but the latter would obviously have the top-end advantages, I don't know how big the difference is going to be though.
What is a safe dynamic comp ratio for a street driven vehicle on 93 octane fuel, and a good tune
The second situation will make more power because to generate more boost, the SC has to blow more air (+CFM=+HP)
You might get 10psi with the T-Trim (at mid rpm, not 6500 or 7000), but to get 15psi you will need a different head unit.
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V2 T-Trim max power?
