Advice on Superchaegers

Jay Hamby · #1 (**permalink**) 04-07-2002, 08:42 PM

I purchased a Superformance Cobra over the winter and I'm just starting to get a feeling of comfort in the car's characteristics. It has been everything I imagined. What an attention getter!

I have a Ford Racing 351 W crate motor stroked to 392 CID. I've got an MSD Ignition System, Barry Grant Speed Demon Carb and a K&N Air Filter. Yesterday I took the car to be chassis dyno tested and it registered 357 HP with a max torque rating of 432. The numbers are respectable but now I'm kicking around ideas of increasing these numbers by adding a Supercharger.

It there anyone out there that could offer some advise on whether or not this is a sound idea. And if it is sound, is there a specific model/brand Supercharger I should consider.

I appreciate the input.

Quote:

I feel the need for speed

750hp · #2 (**permalink**) 04-08-2002, 07:24 AM

If you want to retain the carb, I'd look at http://www.holley.com/HiOctn/ProdLin...-174_FSBP.html This blower is good for 20+lb boost, but with the compression ratio that I'd expect your currently running, I'd suggest no more than 6 or 7 lb boost.

Hood clearance may be an issue, and you'll have to search around to find who is still making the adaptor plates to mount a 302 manifold on a 351. I think a few companies still make them.

A respectful word of warning : don't ever become complacent about the performance potential of your car..... these things CAN BITE

BLACKJACK · #3 (**permalink**) 04-08-2002, 01:07 PM

HELLO, JAY,

I HAVE BEEN DOING A LOT OF RESEARCH ON SUPERCHARGERS.(CERTAINLY NOT ENOUGH TO BE CONSIDERED AN EXPERT). I WANT TO INSTALL ONE IN MY EXCALIBUR COBRA WHICH HAS A NEAR STOCK 302.

GIVEN THE FACT THAT THIS IS MY "CRUISER" (AS OPPOSED TO THE "BRUISER") AND IT HAS FAIRLY "TALL" REAR AXLE GEARING AND I WANT TO IMPROVE THE PERFORMANCE SIGNIFICANTLY ACROSS THE ENTIRE RPM SPECTRUM, I HAVE BEEN LOOKING SERIOUSLY AT KENNE-BELL. THE TWIN SPOOL, WHIPPLE DESIGN, PROVIDES SUBSTANTIAL BOOST RIGHT OFF OF IDLE AND FULL BOOST BY 1700 TO 2000 RPM. IT IS ALSO REASONABLY SMALL AND COMPACT AND "VERY" QUIET. (THIS ALLOWS YOU TO "SNEAK-UP" ON THE BIG BLOCK GUYS). IT IS VERY VERSATILE BECAUSE YOU CHANGE THE BOOST PRESSURE RANGE JUST BY CHANGING A PULLEY.

IF YOU CALL THEM AT 909-941-6646 THEY WILL SEND YOU A COMPLETE CATALOG, PRICE LISTS AND A BUNCH OF GREAT TECHNICAL INFORMATION. THEY HAVE AN E-MAIL AND A WEB SITE AND A FAX MACHINE BUT THEY DON'T RESPOND VERY WELL TO THOSE. I CALLED AND HAD THE INFO IN THE MAIL TWO DAYS LATER.

I HOPE YOU GET SOME RESPONSES FROM MORE EXPERIENCED GUYS. I'LL BE WATCHING.

Y'ALL HAVE A REALLY GREAT DAY,

BLACKJACK

BLACKJACK · #4 (**permalink**) 04-08-2002, 01:34 PM

JAY,

750HP IS ABSOLUTELY CORRECT (AS USUAL) REGARDING HIS WARNING.

NEVER, EVER, EVER, GET COMPLACENT WITH A COBRA. THESE SUCKERS WILL SNAP AT YOU IN A HEARTBEAT.

DRIVING A COBRA IS A WHOLE LOT LIKE FOOLING AROUND WITH MARRIED WOMEN - - - ABOUT THE TIME YOU THINK YOU'RE GETTING GOOD AT IT - - - YOU GET KILLED.

Y'ALL HAVE A REALLY SAFE DAY,

BLACKJACK

Dave Samson · #5 (**permalink**) 04-08-2002, 03:45 PM

Jay,
This is a huge subject and a lot could be written on it in this thread. I suggest however , that you go out and buy a book titled "Street Supercharging" by Pat Ganahl. It will discuss and answer many questions that you have probably not thought about yet.
I and I'm sure others with supercharger experience would be happy to help you out with advice along the way to an a$$-kicking blown engine and drivetrain.

Bill Wells · #6 (**permalink**) 04-08-2002, 04:02 PM

Jay, I am currently having a 60's era Paxton supercharger (upgraded to VR-4 specs by Paradise Wheels ) installed on my SPF with 351 SVO crate motor and Holley 750 double pumper . I am following instructions and lessons learned from another SPF owner who already did the same thing to his 351 SVO . So far this has only been done to one SPF , according to SPF owner records from the SPF Registry. My engine is not a stroker so it is not apples and oranges to yours. Space limitations under the hood have very close tolerances, espcially from the s/c air intake over the valve covers on my car, valuable space needed for the air inlet plumbing ., I suspect it would be tighter on your stroker. Paxton has 'bolt on kits' for 289/302 engines , but alas, none for the 351. Hence there are many attachment and misc pieces that need to be fabricated, which is where I am now. Project should be completed within 2-3 weeks once some custom aluminum fab pieces are constructed . We are planning on keeping boost to a 7-9 pound level for hoped for engine longevity, final number not decided yet, but will most likely be conservative as ya can't drive em when they are broken down...and our summers in Michigan are so short I don't want to lose any drive time due to 'unit down' condition. Contact me offlline if you would like for additional information. Bill Wells

Jay Hamby · #7 (**permalink**) 04-08-2002, 07:35 PM

Bill,

Thanks for the input and guidance. I don't quite know why I'm kicking this thing around, but if I decide to go ahead with it I want it to be an informed decision.

By the way, that's quite an impressive collection of fine cars you have in your gallery.

Take care,

Jay

LETSRCE · #8 (**permalink**) 04-08-2002, 07:48 PM

Take a look at Powerdyne superchargers, they are quiet and reliable if you don't over spin them, and they are cheap, about $2000. Look at a kit for a mustang or they might have something for carbornated cars already.

I had one on my 93' Lightning (351w) and it made 400 RWHP & 426 RWTQ with a stock short block and 7 lbs of boost.

-Joe

Excaliber · #9 (**permalink**) 08-05-2002, 01:13 AM

I'm following Blackjacks ideas on the super charger, but with a twist. The 5.0 in the Excalibur is underpowered (stock Ford), but strangely, my gear ratio is very LOW, excellent for the road course I run. VORTECH for me! About 2K for the "base" kit, botl on in a few hours, 5 pounds of boost. For me, 5 pounds will be enough and provide good reliabilitly. I road race more than I drive street.

Dave Samson · #10 (**permalink**) 08-05-2002, 01:30 AM

Excaliber,
Watch out for the 5 p.s.i. boost with a Vortech driven by the crank. You'll probably lose half of the boosted benefit in additional crankshaft load and hotter intake charge temperature. Though I'm not familiar with your set up, I think you'll need around 9 p.s.i gross boost, less a couple p.s.i. lost to the crank, less 2 p.s.i. lost to an intercooler which is necessary when boosting 9 p.s.i. because your intake charge temperature will be around 160 deg. F. when boosting 9 p.s.i.
Good luck anyway.
Dave

Jerry Chabino · #11 (**permalink**) 08-05-2002, 06:05 AM

Poat this on cobraforum.com. Those folks know the subject too.

Mr.Fixit · #12 (**permalink**) 08-06-2002, 02:49 PM

Superchargers can be a real pain on cars that get driven much. I would rather put that money into cyl heads and a rotating assembly that makes more power. An 8000 rpm 13.5:1 motor is a bunch of fun, if you don't mind the price of race gas. Putting boost on a motor, without low comp pistons or knock sensor, you should be using the good gas anyway. If you are not a fabricator, you will spend lots of money having all those little custom goodies made for the blower install.

xlr8or · #13 (**permalink**) 08-06-2002, 03:50 PM

Just get a big block. Plenty of low end horses and all the torque you'll need.

Chaplin · #14 (**permalink**) 08-06-2002, 05:51 PM

xlr8or-
That is exactly what I was thinking. I just can't believe that it took so long for someone to post that, but I guess it was only a matter of time . . . .

Mike

427sharpe · #15 (**permalink**) 08-06-2002, 06:24 PM

I have a Paxton on my 66 GT350. Been rock solid for 36 years (was a dealer installed option). Still available, and ot uses a pressure bonnet that encloses the carb, only adds about a half inch to height. I can give you a source of interested.

Great Asp · #16 (**permalink**) 08-06-2002, 08:54 PM

Howdy Jay!,

I did quite a bit of review of Superchargers on my old car 992. My spin on the long and short of it.

If Supercharging is the ticket for you, build an engine to support it. Sell your old motor as is. Second, go EFI, do NOT try to use a carb based system, as Mr Wells will point out, carbs have limitations. The main one being the ability to regulate fuel efficiently for high demand. Use a Forged crank, forged low compression pistons, you will need to install a return line for fuel to the tank, and a different cam from the one you have now. Fixit is correct, heads are a key to any build. If you still want a Super on your Super (lol), I can recommend AFR heads, either the 185 intake, or 205 intake runner heads with the thick bases (think massive compression here) use an intercooler, I like a 3 core ATI unit, and it can be mounted flat in front of the oil pan under the car.

Now yer ready for 16 lbs of boost, and a case of hair coloring for all the grey hair you are about to get.

Say hi to "T" for me!

Eric Brown ak Great Asp! SPF 1380

mickmate · #17 (**permalink**) 08-07-2002, 08:07 AM

I agree with previous post wholeheartedly. If you're gonna huff it then build a motor for it so you can actually use it. We have been putting Vortech blowers on some tight space applications (beemers) and their compact design makes for a flexible installation package BUT alot of fiddly little bracketry and fab problems to address. Main thing is to keep em plenty rich so injection technology is definetely worth utilising. The torque they produce is more impressive than the power.
Plenty of blown 302's in FFR's running around, check some of them out.

got snake? · #18 (**permalink**) 08-07-2002, 09:33 AM

Eric,

How many miles have you got on your 418? I wish I stayed longer at DVSF to hear that motor rumble!

GS

Great Asp · #19 (**permalink**) 08-07-2002, 07:53 PM

GS,

1250 miles so far. Had a bad needle and seat that stuck at 1000 miles, causing lots of gas to get into the oil, fouled the plugs, no biggy, I wanted to change the oil at 1000 miles anyway, but changed the plugs too, rebuilt the carb. Race Demons are easy to work on.

Went racing last weekend, but rain, and a bad alternator diode place a damper on fast passes, not to mention a "jacked up" driver stomping on 2nd gear and getting out of the ruts. Still turned mid 13's with the most horrible runs, and too much tire pressure. I will go back, I should be able to get into the 11's for sure.

This motor is fantastic! I made a good decision on the motor and the builder (thanx Eric H. at Performance Engineering!)!

I'll let ya know what I turn in the 1/4, once I get my head out of my b*tt when racing

Eric

got snake? · #20 (**permalink**) 08-07-2002, 11:12 PM

cool