Motor for MP122
02-04-2009, 07:57 PM
#1
Motor for MP122
Let's say you have an MP122 blower and you want to build a motor to go under it. It's a front drive. The motor under it now is in my signature. It's getting a little tired.
What would you replace it with? I'll upgrad with forged pistons and better rods. I'll leave the heads alone because I don't think there's much power to be had on a HP per $ basis by spending a bunch of money on the heads.
The setup in my sig is a 6.0L and makes 9.5psi with a 2.8" pulley. Can you spin the blower any faster without just making more heat? I'm guessing it's around 500rwhp as is. Would going with a 408 make any more power or would power be similar with just less boost? What about going down it cubic inches (5.3 or 5.7)? I know the bottom end power would be less, but would the motor be more effecient? Maybe a little more MPG and similar power due to more boost. What would you build and why?
What would you replace it with? I'll upgrad with forged pistons and better rods. I'll leave the heads alone because I don't think there's much power to be had on a HP per $ basis by spending a bunch of money on the heads.
The setup in my sig is a 6.0L and makes 9.5psi with a 2.8" pulley. Can you spin the blower any faster without just making more heat? I'm guessing it's around 500rwhp as is. Would going with a 408 make any more power or would power be similar with just less boost? What about going down it cubic inches (5.3 or 5.7)? I know the bottom end power would be less, but would the motor be more effecient? Maybe a little more MPG and similar power due to more boost. What would you build and why?
02-04-2009, 09:23 PM
#2
TECH Junkie
I wonder if a 383 would like it?
02-05-2009, 07:08 PM
#5
I'm also guessing that a bigger engine (408) won't necessarily mean more power. I guess you're saying the 122 is a good match for 370 cubes? MOre cubes won't mean more power is the blower is maxed?
02-05-2009, 09:17 PM
#6
I was hoping a bump in C/R would also be a bump in MPG and power too. On the vette forums, I notice LS2's ( I think they're 10 or 10.5 c/r) with Maggies tend to be up in HP and down in TQ compared to lower compression LQ4's. I guess part of that increase is due to more effecient drivetrains. Instead of 20% drivetrain loss, the vettes are maybe closer to 12 to 15%. 112's on the LS2's run over 500 rwhp without a lot of boost. A 122 running 10 psi with 10.5 c/r ought to paste a permanent **** eatin' grin on my face.
I'm also guessing that a bigger engine (408) won't necessarily mean more power. I guess you're saying the 122 is a good match for 370 cubes? MOre cubes won't mean more power is the blower is maxed?
I'm also guessing that a bigger engine (408) won't necessarily mean more power. I guess you're saying the 122 is a good match for 370 cubes? MOre cubes won't mean more power is the blower is maxed?
You will make more power with more boost, less cubic inch and a higher compression ratio.
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02-05-2009, 11:50 PM
#8
TECH Veteran
A 408 will make more power, but at less boost. It is also very pricey to build a 408 over the cost of a 370. For the cost I'd say just build a 370 with stock crank and rods with forged pistons. I agree with Joe in keeping the compression to 10:1 or higher. Keep the cam under 230 duration and the LSA 114 or higher. If you do heads go for the most flow with the smallest port. Rather than use 317's, keep the cylinder efficient and go with a smaller chamber and flat tops. Make as much power below 6000rpm as possible. It will help keep the heat down.
02-06-2009, 06:50 AM
#10
A while back I threaded on compression ratio and Maggies...and it was pretty inconclusive. I'm running the low range @ 9.3:1, and argueably I'm lite on power. I didn't arrive at that arbitrarily tho as thats what Mag told me to do. Anyways...IAT's are ur worst enemy (and JOE @ L/C is the expert). I'd suggest the CTSV heat exchanger for a start. At some point I'll pull my heads and at least port them, but more likely up my compression to hi 9's or 10 and that'll be definative. IMHO, put serious thot into valvetrain, head and cam choice - I've been doing lots of research on this and convinced that small changes and proper choices here yield the best results for the lowest price.