Centrifugal Supercharger
Senior Member
Joined: Nov 2003
Posts: 480
I would think that even at ~2600, 14.0 should be attainable (probably
not easy). Street port (maybe a 4 port would be better than a 6?),
free flowing exhaust... no idea what the power potential of the
factory intake parts would be, even with the AFM removed. S4 doesn't
look too bad. S5 looks like 4 snakes tied in a knot.
Anyway my 12A was street ported (RB tamplate) on the intake, and mildy
opened up on the exhaust. RB header+presilencer (single pipe), 2.5"
behind the presilencer, straight through muffler at the back. Holley
carb, RB intake, 4.44 rear. Looking back it could have been improved
on. Trap speeds were around 97 mph, give or take a little. Best 60'
was 2.12. Given that info, I would think that the larger 13B could lug
a couple hundred extra pounds along.
not easy). Street port (maybe a 4 port would be better than a 6?),
free flowing exhaust... no idea what the power potential of the
factory intake parts would be, even with the AFM removed. S4 doesn't
look too bad. S5 looks like 4 snakes tied in a knot.
Anyway my 12A was street ported (RB tamplate) on the intake, and mildy
opened up on the exhaust. RB header+presilencer (single pipe), 2.5"
behind the presilencer, straight through muffler at the back. Holley
carb, RB intake, 4.44 rear. Looking back it could have been improved
on. Trap speeds were around 97 mph, give or take a little. Best 60'
was 2.12. Given that info, I would think that the larger 13B could lug
a couple hundred extra pounds along.
Senior Member
Joined: Nov 2003
Posts: 480
Originally Posted by Fluid Dynamics' date='Jun 13 2004, 01:28 PM
The car weighs 2400 lbs with half a tank of gas. It is an FC NA that runs 15.5 @ 97 with stock exhaust.
torquier (ie width of useful powerband) than your 6 port 13B. I took the car
apart years ago, so I don't remember really well but it seemed to have a
decently wide power band. All intake ports were identical (25* ATDC open,
60* ABDC close), as is normal with old carbed engines. I haven't played with
a 6 port myself, but always saw the small primaries/late secondary closing as
a complication.
Did you see the Drag Sport article where Jim Mederer was tuning a street ported
6 port? Lots of good info there. Anyway he said that a 4 port would have made
maybe 20 more HP or so. No mention was made as to how any of the intake systems
would drive, as all the work was done on an engine dyno.
Thread Starter
Senior Member
Joined: Dec 2003
Posts: 419
From: Corvallis, Oregon
I have to feather my clutch at 3k on launch. If I actually dumped it at that rpm there would be a total burnout. The street tires can't take any kind of torque. I might get some slicks and 14" wheels eventually, and be able to dump the clutch at 5-6k like the serious drag racers who break their drivelines a lot. There is probably another second to lose for that MPH.
The car drives quite nice even being NA on stock exhaust, and is a bit faster than a stock TII I drove, and much easier to drive because the throttle response is instant and the torque curve is very flat. The G readings I get on the Gtech hold from about 2.5k to 6k rpm, then drop a tad above that, but it will pull to 8k. Right now it does .5 in first, .34 in second and .22 in third.
Light weight allows the car to be tossed around like a first gen, but with that stable independent rear suspension and longer wheelbase. Yay for stripped and modded FC's.
The car drives quite nice even being NA on stock exhaust, and is a bit faster than a stock TII I drove, and much easier to drive because the throttle response is instant and the torque curve is very flat. The G readings I get on the Gtech hold from about 2.5k to 6k rpm, then drop a tad above that, but it will pull to 8k. Right now it does .5 in first, .34 in second and .22 in third.
Light weight allows the car to be tossed around like a first gen, but with that stable independent rear suspension and longer wheelbase. Yay for stripped and modded FC's.
Senior Member
Joined: May 2002
Posts: 22,465
From: California
Originally Posted by Fluid Dynamics' date='Jun 13 2004, 08:35 PM
ILight weight allows the car to be tossed around like a first gen, but with that stable independent rear suspension and longer wheelbase. Yay for stripped and modded FC's.
Senior Member
Joined: Nov 2003
Posts: 480
Originally Posted by Fluid Dynamics' date='Jun 13 2004, 08:35 PM
I have to feather my clutch at 3k on launch. If I actually dumped it at that rpm there would be a total burnout. The street tires can't take any kind of torque. I might get some slicks and 14" wheels eventually, and be able to dump the clutch at 5-6k like the serious drag racers who break their drivelines a lot. There is probably another second to lose for that MPH.
Senior Member
Joined: Jul 2002
Posts: 2,483
From: Fayetteville, Georgia
Originally Posted by 83turbo' date='May 20 2004, 09:16 AM
Well sort of the first thing you learn in "Forced Induction 101" is "thou shalt not blow through with a roots blower".
He seems to think he's got the obvious problem licked by adding a bypass valve. Well, it takes vacuum to open the thing, so as soon as the vacuum level drops too low, the valve closes and the system goes into "stupid mode", wherein it makes a gazillion psi upstream of the throttle. Even with a super huge blow off, it's still making too much psi. Gotta do wonders for throttle response too. It would take a book to explain all the flaws, but the problem is that anyone who needs them explained probably wouldn't understand anyway - until they try it and find out it doesn't work right.
Yeah, they were all proud for having "proven the experts wrong". Turns out the experts aren't so dumb after all.
Whipple supercharger - I believe this is a Lysholm type. I got to check out a Mazda Millennia S supercharger a while ago. The rotors are geared up and spin at a much higher rate than a roots. I read it was 21,000 and 35,000 for each rotor respectively at max engine RPM.
He seems to think he's got the obvious problem licked by adding a bypass valve. Well, it takes vacuum to open the thing, so as soon as the vacuum level drops too low, the valve closes and the system goes into "stupid mode", wherein it makes a gazillion psi upstream of the throttle. Even with a super huge blow off, it's still making too much psi. Gotta do wonders for throttle response too. It would take a book to explain all the flaws, but the problem is that anyone who needs them explained probably wouldn't understand anyway - until they try it and find out it doesn't work right.
Yeah, they were all proud for having "proven the experts wrong". Turns out the experts aren't so dumb after all.
Whipple supercharger - I believe this is a Lysholm type. I got to check out a Mazda Millennia S supercharger a while ago. The rotors are geared up and spin at a much higher rate than a roots. I read it was 21,000 and 35,000 for each rotor respectively at max engine RPM.
Senior Member
Joined: Nov 2003
Posts: 480
Originally Posted by Dysfnctnl85' date='Jun 14 2004, 08:55 AM
I could be wrong, but the guys on HorsePower TV use roots blowers and carbs on their big blocks all day long...
