Swamplizard

Foreword - I have asked questions on a number of sites - answers are all over the map. I might get flamed for asking stupid questions but I have to get back to basic reliable answers.

Existing Set Up:

Twin 502s - holley 850 cfm carbed motors, rollers, high torque CAM supposedly recommended by Chief. One motor is counter rotating. Connected to BorgWarner 71 transmissions with 1.5:1 reduction. Supposedly the motors are 415-425 HP.

Goal: Bump the torque numbers higher to handle heavy boat without removing the motors or even pulling the boat out of the water....bolt on. Looking to put more meat into the power curve not race it or rev any higher than 4800 rpm.

Drives are ASD8s so not concerned about breaking them with too much torque.

Questions:
Do blowers increase torque accross the entire RPM range?
Can weiand 144 do the job or must I go 177 or 250?
Can a weiand blower be reversed?
If I keep it below 4.5 pounds of boost can I avoid intercooler and avoid detonation? (I have limited space above motors.
Thanks for your patience with newby

Biggus

iTrader: (1)

If you put blowers on you will eat those little 71C trannies.

Swamplizard

really - first I heard of that being a weak link. I'll look into it and talk to bam guys or something - thanks Biggus
Even if I go mild and just add 100 hp via blower?

badluck

I would use a 250 blower for 502's provided you have good internals. Limit your boost to 4-5psi they will be a turn key. I don't think you can spin the blower backwards, so the counter rotating engine has to be converted.

Another route to take would be a stroker kit, you would be able to keep the counter rotating cam etc.

bl

cuda

What's your compression ratio?

bcarpman

I've seen people use a gear drive to keep the blower going in the right direction. I don't remember where I saw it, so sorry, i'm no help for finding a source. I guess I'd also be surprised if someone doesn't make a reverse rotation blower???

bcarpman

Depends what type of blower:
Roots type like you refer to will give low end torque increase.
Whipple type - Less so.
Paxton type - Almost no increase until 3000-3500rpm.

Still, if you really want low end torque, no blower will do it like added displacement will.

t500hps

That's the value of free advice!!!

I ask questions here too but remember, take that info with a grain of salt and research that info for yourself. None of these guys have to live with the decision after they hit the "submit reply" button. (Since the answer vary widely obviously some are correct and some are not.)

czy40p

I found this helpful, I know it is bias towards weiand, but I thought it was worth a read.

handfulz28

Swamplizard, I don't see any stupid questions here. For all of us that actually post there's at least 10 lurkers that are appreciative of the info.
Whipple seems to advertise that their systems make power down low (below 2k rpm). I like what I've read about Whipples, all except the cost.
A 144 is mostly a small block blower. 177 probably too small. The Blower Shop offers a 192 that would probably be perfect.
You need to know your exact compression ratio and cam spec to determine if they're low-boost friendly.
Good luck. I'm near LHP if you ever need a local helping hand.