4.3 Supercharged Chevy

[Qingdao]

Originally Posted by Homeoboxter

Pretty cool! Can we request a video of how it runs when you have the chance?

Can't figure out how to upload here. I mean I am a cave man running a carburetor LOL


I just noticed I hadn't made any update since the little detonation party I had in cylinder 3.

To fix that issue I got some deeeeeeeep dish pistons and some forged eagle con rods. Compression should be on the high side of 9.4:1. Before the compression was about 11.1:1; thats kind of a lot for 93 octane and 8psi of boost. There is a weee bit of detonation now; only after a good heat soaking on the highway. I might be able to dial the ignition timing back a hair and fix that. I might be investing in an ignition box to control timing a little better, but for now its good enough.


Fuel ratios are a little fat. 8:1 at wot... I'd like 10:1 but I wanna get the ignition sorted before I start pulling fuel out. This is my first roots blower, and from my experience so far the heat soak is real LOL. You do a few pulls and everything is super, then the intake gets warmer and warmer....

[Homeoboxter]

Just create a youtube account and upload your videos there, very straightforward.

[Qingdao]

Originally Posted by Homeoboxter

Just create a youtube account and upload your videos there, very straightforward.

I know; to be honest its a lot of work for the 8 people interested. LOL

PM me your email I'll send you a video or two, but I'm gonna warn you my wife and I are TERRIBLE camera operators.


EDIT: oh and I think I'm just gonna live with the glowing headers at idle... I mean they don't seem to mind being that hot at idle, and if thats the ignition timing required to keep this thing from pinging then thats what it takes.

[Homeoboxter]

Haha, yeah, I hear you, PM sent.

[piper6909]

Originally Posted by Qingdao

EDIT: oh and I think I'm just gonna live with the glowing headers at idle... I mean they don't seem to mind being that hot at idle, and if thats the ignition timing required to keep this thing from pinging then thats what it takes.

Wouldn't too lean of a fuel mixture cause the headers to glow?

[Qingdao]

Originally Posted by piper6909

Wouldn't too lean of a fuel mixture cause the headers to glow?

Yes, but in this case its timing related. I was trying to run a locked distributer using vacuum advance at idle retard enough to correct for the timing needed at WOT.

As of last night I've given up with that idea. I ordered an MSD boost retard control box. Supposedly it takes out 1, 2, or 3 degrees of timing per pound of boost made at the turn of a dial. It cost a pretty penny so I hope its worth it.

I was almost about to take the heads off and check which cylinders are pinging the hardest. I was under the impression that 1 & 3 were/are running harder than the rest due to the supercharger's location. I also wanted to maybe lower the compression some more. BUT I took a syringe and actually measured the dish of my new pistons. They are 18ml of dish; with a 4.120" X 0.040" HG, 64ml of head volume, and nominal deck to piston I should have about 9:1. Thats a lot lower than I was guessing at. Actually measuring things helps LOL

^^^ after that revelation I decided to buy a better ignition system; regardless of its astronomical cost.


Cost aside it is a really nice unit. It records boost pressures and timing maps. I might be able to get it to communicate with my LM-2 wide band system.

[Qingdao]

Oh yes, this is the ignition I shoulda been running from the get go. Totally tunable, I can adjust ignition on the fly with the retard nob. It lets me go full retard or just a little retarded.

I was full retard with the locked distributor; and we all know "you never go full retard". LOL





The MSD does provide LOADS of spark too. Doesn't really help much power wise, but starting is like 1 000 000 times faster.






I also gave my little box 'o' small blocks a nice hair cut.

[paulofto]

Love the Tropic Thunder reference!!