I'm going to be removing my Air Gap/QFT 850/MSD Pro Billet, and installing a 671 blower/two QFT 650 blower referenced carbs, and a duraspark distributor. I figure I'm going to have to run colder plugs, but is there anything else I should know?
Depends on how hard you're going to run the engine I've had 671's & 871's on SB Chev 377 stroker, 392 & 426 Hemis all running nitro, you may want to put a pulley combination that lowers the boost down to around 7-8 lbs for street use. What compression pistons are you running, are they stock rods? The lower your compression the more boost you can give it with pulley changes but with stock pistons & rods I wouldn't put much boost on it you wont gain much unless you're racing it.
Just my opinion someone may have some other advice.
Sounds like some good equipment with 10.5 compression I'd suggest no more than 5-6 lbs using at least 105 octane non ethanol gas, after running it for awhile 1-2 hours of street driving I'd check the plugs for any signs of detonation and keep a close eye on it it's better to run rich than lean. Not 100% sure on a street motor but you might look into some thicker head gaskets to lower the compression if you feel it's a problem.
We don't have a local source for 105 octane that I'm aware of, so it's gonna have to live with 93. Dyers recommended 3-4 pounds of boost, but my engine guy said 5 would be okay.
Bob & Sue, why recommend fuel with no ethanol on a blower engine ? It would seem that ethanol in the fuel, for a blower or a turbo car, is exactly what you want. The more the better. We have turbo'd and super'd customers who have switched out to E85and they love it. Can you explain ? LSG
Bob & Sue, why recommend fuel with no ethanol on a blower engine ? It would seem that ethanol in the fuel, for a blower or a turbo car, is exactly what you want. The more the better. We have turbo'd and super'd customers who have switched out to E85and they love it. Can you explain ? LSG
The only reason not to run an ethanol blend from a gas station is you don't know how old the gas is ethanol has a short life at most about 90 days the gas your buying may have been in the stations tank for months and has already separated and absorbed moisture. A 93 octane blend is only about 84 octane with the ethanol raising it to 93 if it's already started to separate you may only be burning 84 to 93 octane you don't what your burning. I'd only burn ethanol blends if I tested it and ran it out of the tank within a couple weeks.
Just my opinion from burnt pistons.
I run E85 on several cars from a 12.5:1 sbf to a 15:1 BBF and a TT 5.4. BUT a 93 octane gas with ethanol mix is just that. Its a fuel that just makes 93 octane after the addition of the alcohol, not a 93 premium fuel + alcohol. So its not true premium gasoline. An additional problem with these added blended fuels (and I do run these pump fuels myself on drivers) is that they aren't consistent on blend and therefore not consistent on AFR's either. If your getting near the limits, then this can make you lean and burn a ring or lift a head.
I'm not suggesting a mixed fuel is junk. It's just hard to know what you have with a mixed blend and sadly in areas of the country that is just about all there is at a pump station.
YES alcohol and E85 is loved......LOVED.......by boosted engines. 10.5:1 boosted is full steam ahead and "game on" with E85 if available. Just don't let it gel up over winter.
On another subject - I've read from blower kit suppliers than you're not supposed to run a PCV valve. I'm planning on a pair of fabricated valve covers, each with a welded-in AN-12 fitting running a line to two separate catch cans (mostly because I like symmetry).
3lbs of boost hardly seems worth it (from a performance standpoint)...but it will look really cool.
Wonder if you could run a bit more but use a timing controller to pull out some timing for every pound of boost. MSD used to sell a timing controller for boosted cars.
3lbs of boost hardly seems worth it (from a performance standpoint)...but it will look really cool.
Wonder if you could run a bit more but use a timing controller to pull out some timing for every pound of boost. MSD used to sell a timing controller for boosted cars.
Agreed on 3psi. I run a supercharger on the 351 in my Bronco and am running 10 psi at max rpm. The engine's CR is 9:1. It has an Eaton SC from an '04 Lightning grafted onto a 351 manifold including the intercooler. It is fuel injected and also runs EDIS through a Megajolt controller which allows you to pull timing under boost. https://www.autosportlabs.com/product/megajolte/
Granted, the Eaton does not look nearly a bad *** as a 671 with a pair of carbs on top, but if I was going to go to all that trouble, I would make sure I got the kick in the pants to go with the good looks.
I'd say use a thick set of Cometic head gaskets to get the CR down, run electronic ignition that will allow you to pull timing under boost, and get that psi number up there. I would think 8 psi is easily achievable and will make your car scream. Although maybe without an intercooler you can't get there on pump gas.
My compression is 10.5 - Since tearing the top end apart just to replace gaskets that will realistically net me only about -0.2 in compression, I'll wait until I can afford to replace the pistons. This whole thing is more for eye-candy anyway (this car is just a show car). It's the only street-driven 2012 Mustang with a carbureted Windsor stroker (that I know of) within a 5-state radius, and soon, it will be one of two S197 Mustangs with a 671 blower. You gotta take care of the unicorns so people can stare open-mouthed as you drive by.
Sounds awesome. I'm sure I'd be one of those starring!
FWIW, if you go from a standard thickness gasket of say .020" compressed thickness to a much thicker one like .080" you can drop the compression on a 351 from 10.5 to about 9.2. Cometic makes some really great stacked stainless steel head gaskets that come in varying widths (up to .120") which allows you to fine tune CR.
I had a friend that ran 105 in his race boat for awhile. He had to get it from a small airport nearby. He took some 55s and filled up.
any small airports around?
On Wednesday evening, I took it to the shop that's gonna install the blower. As of yesterday, we have the blower installed, the cooling system reconnected, the fuel system reconfigured and connected, the new electric fans mounted, and the linkage setup started. Still need to connect the fans, clean up the electrical (because of changes in sensor placement and removal of A/C), and mount/connect the breather tank to the valve covers.
We hope to fire it up sometime today, and if that happens, there will be videos. (It's gonna whine like an ex-wife looking for more alimony.)
Gonna have to be a lift off style hood or split down the middle with the size of that intake. Even a lift off style would be a pain, would require an assistant lifting the hood eye level to clear everything.
It's gonna be hinged, and just have a hole for the blower. According to my cursory Mk-1 Eyeball measurements, I'm going to have about 5 inches of hood behind the blower, and almost two feet in front of it. The sides are a inconsequential because the hole will only be 13 to 13-1/2 inches wide.
I am confident the hood will open without a problem. I think my biggest problem will be finding a way to edge the hole. The hood is a double-layer design, so door edge guard may not be possible. I'm thinking probably ABS sheet cut into strips and glued together to create a frame, and then maybe riveted to the hood.
Are the layers close enough together maybe a caulk/seam sealer would fill the gap? Then something around the edge to protect the edge of the fiberglass and give it a more finished look.
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