Well, last time on the dyno, we were making decent power, but I had some big problems with the belt flying off at 4800 rpms. I sat down and redesigned the cog drive setup. Since my crank was a little messed up in the key area from when the Whipple started to shear the key off, I was having some issues with the balancer staying true on the crank. I decided to try to use the factory cage setup as a band aid fix for my wounded crank/balancer, so it wouldn't come flying off the truck at half track . I basically took the lower cog pulley, turned it around, and attached it to the stock Lightning lower pulley. I machined the hub on the stocker flat, and tapped 6 holes into it and bolted the cog on. The cog is so big, the stock lower fits completely inside it . I made a bunch of idler and blower brace changes as well.

So today I strapped it back on the dyno and made the first pull. Well the first pull was the only pull. Once again, the motor pulled like a **** to about 5kish, then I felt a huge power loss. I thought it threw the belt again. I hopped out and took a look. The belt was till there and looked to be riding perfectly on track. We that's one issue fixed. I spun the blower by hand and the lower pulley turned with it. Looked closer at it under the truck, and the balancer is not spinning with it (which is a good thing). So either I snapped the shaft that connects the balancer to the pulley hub, or I ripped the threads off the hub itself. I won't know for sure until I take it apart.

On a good note, the truck made 653rwhp (SAE, 669 STD). The torque cruve just amazes me. The truck is making 500 ftlbs at 3500 rpm. I didn't expect anywhere near that, or for the truck to still make higher torque than hp like the postive disp blowers do. Of course. I'm not complaining. This is with only 18 degrees timing, which is nothing for a cent with an air to air intercooler.

Below is the graph from the run...

 

HOLY SHINKEYS BATMAN!

Damn Impressive Sal! You said that Centrifigal SC were the way to go, but that is a TON of torque down low on the RPM/s. I always thought Cents were for High RPM High Horsepower. Guess I'm wrong.

 

sal if you ever need me to do any street testing look no farther

 

Ok, the problem has been diagnosed. For those of you who aren't familiar with the stock Lightning pulley setup, there is a shaft that connects the balancer and the pulley hub. The shaft screws into the hub center, in a reverse thread, so that it's being tightened when the motor is spinning. When it's tightened all the way, it bottoms out on a lip on the shaft. Well what has happened is the hub had so much force on it, that it actually started to continue to tighten down, pull the hub back farther, and the wider lip acted like a wedge and started to split the threads on the hub till it cracked. Looks like I may need to look into an aftermarket cage setup, depending on if the hub is stronger.

 

That is impressive torque numbers with a Centrifigal.

 

I wonder how much power it takes to bust up that drive mechanism like that

What I find really impressive is that the damper only registers on about 3/4" of crankshaft and it "only" has a 12mm bolt to hold the whole mess on there and that doesn't seem to have any problems at all.

Sal....if your thinking of going to an aftermarket damper....I already tried that and the steel damper tried to weld itself to the steel crankshaft and it did so in short order. I had to go back to the stock cast damper on the stock crankshaft and I think it should be okay now.
Dale

 

Dale, thanks for the advice. I guess I wasn't too clear on what I was explaining though. It wasn't the damper end of the shaft, it was the pulley end. The damper side is fine, it was the hub of the factory lower pulley that cracked on the threads of the FRONT of the shaft.

 

Okay got it now.....I was thinking backwards

 

i think i might be selling the magnum

 

Saweeeet Sal

Iam sure once you get thru the little problems, it will once again kick some major league ***

 

Awsome Sal can't wait to see ya back at the NMRA events again.

 

Man you couldn't do that on Saturday while I was there

Great numbers , you have to start that thing up for me next time I am out there.

 

What's the matter Tom, you didn't like the 427 Cobras I was dynoing when you were there .

 

True , True, True...
If anyone is in the area and you want to see some cool cars there is always plenty at PSP.
So far in my 3 or so times there. I have seen about 5 427 cobras, a few 03 cobras, a saleen mustang, Z06 w/ spray, The red beast of coarse, and there is always an SRT 10 parked on his corner
We want to see the RED beast at the Track Sal!!!!

 

Sounds good Sal ! Yes their are alot of 427 cobras running around here too. One came into BMW dealershiop last week with a 514 crate motor running a M-3 series rear-end in it she was sounding good, guy wants to sell it though nice paint Red like firengine many coats. hey I almost got all my stuff on just have to hang exaust and maybe front drop! See you soon.