pls help with converter recomendation

sheldonw

Weekend Racer
Apr 13, 2008
62
0
0
hey guys im gonna be upgrading converters just wanna see what u guys think would be optimal
my new setup
82 cutlass 3600#
355 sbc
afr 195's
weiand 142 at 2.3:1 ratio should see about 8.5psi
custom solid flat tappet cam 238/244 @.050 .486 and .505 int/ex 114 lobe sep
8.33 compresion
with snow water meth
th350
3.73 rear w/28" tall tire
drag shocks all the way around and a sphon arb

last year i ran a best of 11.85 with a 1.71 60f @ 113.23 mph
with a tamer set up
blower was run at 2.17 ratio 6psi
nx268h cam 224/[email protected] .483/.497 113lobe sep
no water meth, no arb
and a 10" holeshot 2400 (im sure it was killing my et)
the rest was the same
it was dynoed at 459whp at 6200rpm which really doen't match my et so either that dyno was extremly optimistic or my setup was way off

Thanks!!
 

Damon

Pro Stocker
Feb 7, 2005
1,655
1
38
Philly Area
I've got some experience with that blower..... 495 at the rear wheels is definitely not reality. I have a milder setup than you using that blower, but sitting on a 383ci bottom end. I'm putting 390 to the rear wheels at 6000 RPMs and my MPH tells me that's about right (113-114 on street tires). I'm running a 2.28:1 pulley ratio (7" bottom, 3.07" top), a teeny-tiny 214/224* 112 LSA cam, AFR heads, 8:1 compression and I'm getting barely over 5 PSI.

Here's the sad truth that you're not gonna want to hear.... you may pick up some ET with the new setup overall, but don't expect much more peak power. You might even go backwards. And you DEFINITELY won't see increased boost. The blower is just too damned small to feed a big cammed motor. You can't pulley it up high enough to build serious boost against a big cam. There's just isn't enough headroom, unlike a big 'ol X-71 class blower.

I started with bigger cams and found that it worked better the SMALLER I went. I tried, believe me, but the little blower's efficiency falls off a cliff as you pulley it up. Keep the engine the same, pulley it up, you get more boost, a little more midrange torque but precious little additional peak horsepower. Add a big cam to the mix and it gets worse- you give up torque down low but the peak HP doesn't improve or gets worse.

500HP at the flywheel seems to be about the lid. The little mini blower just doesn't have the lungs for much more. You start heating up the air tremedously, building more boost but moving very little additional air. You can trade torque vs. RPMs but the HP lid seems to net out somewhere around 500 regardless.

Honest opinion? Your current combo is a lot closer to optimum than what you plan to build. Your current 2400 stall isn't hurting you much, if it's a good quality converter. My combo makes brutal torque practically above idle- I ran it against a stock converter and my current 2700 stall unit. Either way the tires are gone before the pedal hits the carpet. At the strip, running on slicks, I'm sure the higher stall will work better but it's not like you need a very high stall to get a max-effort lauch out of it. My peak torque is probably right around 3000, if that. Impossible to say becuase I can't lug the engine low enough on a chassis dyno to find the peak.

Fastest I ever heard anyone run with this little blower in a street-weight car was a low 11 @ 120. And that's just internet jibber-jabber, not verified fact. The ones I've personally seen run don't go hardly any faster or quicker than you are now. I run mid 12s @ 113-114 on true street radials, zero traction, 2700 stall and 2.73 rear gears, BTW. With sticky rubber I'm sure I could be in the low 12s, but after that it would quickly become a game of compromises.
 

sheldonw

Weekend Racer
Thread starter
Apr 13, 2008
62
0
0
thanks for reply
the cam is already in there so no turnin back ... at least hopfully
 

Damon

Pro Stocker
Feb 7, 2005
1,655
1
38
Philly Area
Let us know how it goes. Nothing would make my happier than to be proven horribly wrong on this!
 

Goob

Top Fueler
Jun 6, 2003
3,641
0
0
Indianapolis
Call Art Reed at Coan....he'll hook ya up.
 

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