Updates over the past year:
Cut the windshield down, add some attitude.
Made a new set of pipes from another set of coyote 5.0 long tubes, this time using an absorption muffler instead of an auger style baffle. I tried 3 different absorption mufflers (glasspacks) and landed on Pypes M80's, they had the deepest & boomiest sound, attenuated alot of the higher frequency noise and just all around sounded best to my ear.
Had a local fab shop bend me a three point rollbar, I was going for a Lakewood style bar. Not quite true to the actual vintage piece but close enough to allow me to mount stuff too it.
Swapped the tank out for an SS version of the same kind, flipped it around so the filler is on the backside which meant making new fuel lines for the fuel pump outlet being on the other side of the tank
Changed out the Cheater Slicks for some Drag Radials in order to maintain being put in the Hot Rod class instead of the Pro-Street class for a drag race event coming up at the end of Oct. I'll put the Cheater Slicks on again after the race.
I was having some issues with my ignition system, kept frying ignition modules and hurt two MSD boxes. So I opt'd to go back to COP, using self igniting VAG A8/R8 ignition coils (cheapo aftermarkets). When they act up I'll fork up the coin for better versions of the same design.
Last monday I drove it out of the shop, moving under it's own power for the first time (video of first drive below). On Tuesday I drove it to my work (half a block away from the shop space).
https://youtu.be/UFYE4nfWz4c
Still alot more work to do to reliably move for any distance, let alone be ready for the Kingman Az Route 66 Street Drags at the end of Oct '21. But I'm getting there, we're getting there.
thats pretty. Nice work!
Dang that sounds good!
In reply to Mykk :
Cool.
I bet it was a handful going down the strip.
What are your thoughts and impressions, & what did it run?
Been driving the car regularly. Taking it to events, cruises, hangs & shows. Addressing some of the minor mechanical glitches that come up along the way.
The Eaton M112 hasn't had very much output, the highest boost pressure logged has been in the 4-6psi range at very high RPM's, Usually the engine just lives and runs in vacuum/atmosphere 98% the time. I first thought I was battling belt slip, so added a tensioner to the slack side of the belt at the supercharger pulley. It helped, but not much.
Started looking at pulley ratios. In the original application the relationship between the crank pulley and SC pulley diameters is a 1.98:1 pulley ratio. Using the OE 3" SC pulley and the BMW crank pulley, it landed at a 1.7:1 pulley ratio, spinning the SC 16% slower then original application. Had a new SC pulley made to 2.5" diameter for a 2.05:1 pulley ratio, +20% from where it was and +4% from OE application. Leaving the Supercharger max RPM at 14,200rpm at 7k engine rpm, just beyond the superchargers rated max rpm. We'll start here and can go as low as 2.2" for a 2.3:1 pulley ratio, that would be way beyond the superchargers max rpm. Also, the smaller the pulley the more chance for the belt to slip with less contact area.
Decided it was time to address the Race Stripe boat seats I originally installed. Despite being comfy enough I was just never in love with them.
Ordered a set of less flashy boat seats and "Bomber" style seat frames:
Now to figure out some interior panels to cover up that fiberglass
I love that your "starting point" was described as "just beyond the limits of the supercharger." Badass rod.
Just stumbled upon a neat formula for figuring out potential supercharger boost on any given application:
Supercharger Displacement in liters x the pulley ratio = A
A divided by half of the engine displacement in liters = B
B x 14.7 = C
C- 14.7 = Boost PSI, then round down.
ex: My M112 has 1.835L of displacement, my V8 is 4.4L so 1/2 is 2.2.
With a 3" pulley the pulley ratio is 1.7, 2.5" = 2.05 pulley ratio, 2.2" = 2.3 pulley ratio
1.835 x 1.7 = 3.12
3.12 / 2.2 = 1.42
1.42 x14.7= 20.87
20.87-14.7 = 6.17 Round down to 6psi boost
So a 2.5" pulley on my set up has a 10psi potential, and a 2.2" pulley has a 13psi potential. Kinda cool!
Really like how the car sounds, didn't remember seeing that video before. Like how this is shaking out. Very cool.
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