Hi all. I actually have a C3, but need some blower advice. I have a '76 with a stock hood and an L88 hood needing paint that I'll put on it eventually. My current motor is a 10.4:1 cr 427 sb with a long duration solid roller cam, 6" rods and forged Mahle pistons, crank, rods,Dart little M block with a custom efi setup, that I really want to keep because I have a lot of money tied up into it, ported Motown, FAST TB, FAST xfi computer, crank sensor, MSD 6A box and coil. I already have a set of 55 lb low impedance Delphi injectors that I would like to use and already have an aeromotive A1000 fuel pump and adjustable fpr.

I'm thinking I could get a Vortech blow through setup for a regular sbc carb motor and make my current setup work with lower compression pistons? Would I also need 3.85" rods? How low compression ratio do I want, or could I even get? Special head gaskets too? What about the cam? I currently have a .671/.671; 250/258 duration, 111* LS cam (after the 1.6 ratio rockers).

I would like to get some serious hp, 800+, so what amount of boost should I shoot for? Is methanol injection as good as an intercooler? How about both? This is going to be a well planned project that is at least a year away, but I want to really think this through.

I added a few motor pics so you can see what I'm working with. I also have a stock radiator with dual spal 11" fans.

Thanks for any help.

 

You need bigger injectors and a smaller cam. The compression ratio you want is based on the fuel you want. 10.4 with race gas is ok . 9.5 or less with pump. The 55's will be stressed at 800 crank. Get a Vortech YSI or Procharger F series.

 

I would suggest getting a universal kit from vortech or procharger, or one of their big distributors with a carb hat. Start with a pulley setup that will give you 10psi or less(WITH INTERCOOLER). That should give you a 50%+ increase in power.

Once you have run that system for a while then swap out the pistons to get a lower compression ratio. For moderate boost 9:1 is good with SBC heads, for big boost shoot for 8:1. Monty's old 427 made 1200hp on 22(?) psi. But that was with a turbo setup, so figure a 100 or so less on the same boost level.

As far as the cam I can't comment since the solid rollers seem to run differently than the hydrolic rollers do, but it seems big to me. You will want to go with more exhaust than intake duration, but limit the amount of valve overlap. If you are planning on redoing the engine it might be an option to just leave your current cam in there until you redo things. But if there is too much overlap you will be blowing boost out the exhaust, which is good if you are trying to keep the boost down but bad if you are trying to tune it perfectly. You will be blowing unburned O2 into the exhaust.

Another good way of controlling the boost with a big blower is to place a turbo wastegate on the intake pipe. This will allow you to bleed off extra pressure above the setpoint. This setpoint is also adjustable on the fly.

I would suggest getting a larger pair of injectors. Since you have the FAST you should have no issues running any of the injectors you would choose. I would say atleast 72# if not higher.

As for the blower, I would shoot for bigger, probably an F series from procharger. I would also suggest a cog setup. Do it right once and be done with it. There is a post a little further down about sprag cogged pullies, you should read it.

Good luck.

 

I'm running around 6psi on 10:1 motor, 93 octane. No knock.

The larger the motor the more duration you want on the cam. It will bleed off some cyl pressure and loose a little boost, but won't explode. I'm on 112* lsa..

114* lsa's, low compression, and big blowers are turds below 4,000rpm..

-- Joe

 

turbocharged.

blower is much cheaper though, lower compression pistons for 800+ horsepower on pump gas should be a pretty easy to meet goal with your cubes if you out some 9:1 pistons in the motor, the rest looks good. the blower on your motor with that cam will be fine, may not make as much low end torque as a smaller cam but you'll make a better looking less peaky torque curve and have a wonderful horsepower band up top!

Procharger will be a wise choice, I like there head units better then the vortech. D1SC minimum but I would look closer at an F1A. F1A will fit anywhere a P1SC will, just try and find someone who has done a C3 bracket and find out if they had any belt slip issues with it, alot of time belt slip will cause you to spend money twice. I would be curious to see if a C4 kit would fit on the front of your motor.. I would imagine the accessory drive would be easily swapped over.... something to check out!

Chris

 

Thanks for all the input guys.
ICvette: Yeah, I'm not too interested in turbos as I really like my Hooker/header/4" pipes with spiral baffles. Sounds great. As to the head unit itself, yeah I would prefer to get the right size and did read some of the cog pulley info, so that seems like the way to go. I do have some aftermarket pulleys on the motor now with a crank sensor and short waterpump, not sure if a C4 set would work or not.

Anesthes: how much before and after power did you have with your 6psi, 10:1 motor? What fuel were u running? I don't have a knock sensor and not sure it would work with the solid roller cam anyway would it?

MN vette: So do you think I could run 6 psi with this motor? It would be nice not to have to pull the motor as it is running great. I thought I read somewhere that 6" rods result in some weak pistons, but maybe 6psi isn't a big deal? They are forged Mahle pistons, pretty pricey. As to the injectors, I'm kind of disappointed the 55's won't work as they cost almost $600. I was having problems leaning this motor out at low rpm and idle, so went with the 48's again and got it running great at around 14:5-15:1 afr (idle) Could have been all fuel pressure though as it was running at 50 psi, I turned it down to about 43 psi, then did some retuning. How clean could I get t his motor to idle with 72 lb injectors? I really don't want to go back to the eye burning fumes, especially with the sidepipe setup.

 

HI !! people I came from the old school !!!! If you want the Max out of a supercharger keep the com. @ 9.5 max & put the boost to it....I ran 28 lbs.Of boost on pump gas.....

 

I'm thinking about going with a standard 8 lbs of boost and using a different pulley with a higher octane fuel for more boost (with a different tune). This with my current motor.

1. Any recommendations for the above idea?
2. Would a standard Vortech or similar carb blow through kit put about 8 lbs of boost out with my setup?
3. Any head gasket recommendations to possibly decrease the compression a bit? How much boost could these gaskets handle without cylinder head studs? With studs?
4. I don't have a 'knock' sensor, do I have to get one? Don't solid lifter cams cause problems with these sensors?

Thanks for any help guys.