FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: 65er on February 01, 2013, 10:42:52 AM
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Tell me a bit about supercharging please guys. I've been searching for some info but haven't really found answers to my questions.
The idea I have is to get a use Eaton M112 supercharger off Ebay such as this one for example... http://www.ebay.com/itm/03-04-Mustang-Cobra-Eaton-M112-supercharger-4-6-dohc-Mach1-99-01-Cobra-4V-GT-/271147023917?pt=Motors_Car_Truck_Parts_Accessories&hash=item3f219f3e2d&vxp=mtr
and build an intake manifold to install the think on an FE engine. Particularly a 435" FE with 4.035" bore and 4.25 stoke, based on my original 352 block. I think, especially with a supercharger, that I would like to keep the cylinder walls as thick as possible and just hone them out from the current 4.030" to accept new pistons. I realize that this would be a major project involving the fuel and ignition systems as well as the straight up mechanicals, but I'm wanting to learn about the basic mechanical aspects. Over on the 332-428 FE forum Joe D Craine mentioned a formula for horsepower increase of ((PSI/14.92)+1)*NA Horsepower. If that holds true and I were to build a mild 400 HP 430" engine with a blower set up for only 4 PSI of boost, I should net just over the magic 500 HP number.
Questions:
Do the figures sound accurate?
Would the volume of that particular blower be too small, requiring a ridiculously high blower RPM to even boost 435 CI?
Would it be ok at 4 PSI without an intercooler?
Would the heads be less sensitive to porting work because of the boost?
Would the low RPM torque curve be much fatter than a normally aspirated 435" 500 HP engine and at about what RPM should the torque start coming on strong?
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If the blower is to small for a 4.6 (thus why the customer and all the other mustang guys upgrade to a Kenne bell) then I doubt it will be up to the task of a 7.1 The cost of the cheap blower would be offset by the cost of adapting some sort of EFI system to make it work. If your looking for boost look at a 8-71 from BDS, TBS, Hampton to name a few. If you want to keep it under the hood look at doing a blow through setup like Jay had on the Mach1.
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Get this book:
http://www.amazon.com/Do-It-Yourself-Guide-To-Street-Supercharging/dp/0931472172
JDC's formula is correct and it, in various forms, is used by Hampton, Bowers (out of business now methinks) BDS, Kinsler, Paxton, and other F.I./blower suppliers. Wouldn't hurt to hit their websites either as much info can be gleaned from them.
That blower is way too small for a 400+ cid engine.
Many run up to 7-9 lbs. of boost w/o any intercooler. Still, that also to some extent depends on how it's done...boost level, fuel quality, belt-driven centrifucal, GMC 6-71, draw-thru carb, pressurized carb (old Paxton set-up) or a modern EFI system.
Heads are less sensitive to porting work because of the boost but hey, why add a blower and not try to maximize total flow?
The low RPM torque curve would be much better than a normally aspirated 435" 500 HP engine in most cases, more so with say a 6-71 top-mounted blower or a small impeller-sized belt driven centrifucal blower (Novi/Paxton, et al).
RPM is hard to judge (cam, boost level, intake and exhaust efficiency) as many variables affect when the torque starts coming on strong).
I'll shut up here as it's been years sine I've done blower motors and most were 8-71 or 10-71 GMC alky Donovan or K-B Hemi's in TAD or TAFC.....which has hardly any bearing on your questions today!
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Ok I'll stop looking at those cheap little blowers.
Think a 6-71 or 8-71 unit with a couple carbs on top would fit under a fiberglass teardrop hood?
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I would give Gary Dyer a call from Dyes blowers. He forgot more than I will ever know about supercharging. He has complete kits for anything you want to mount to an FE ford that has enough volume to work. As far as boost a bone stock engine with 7-9 to compression works well with 7 to 10 pounds of boost.
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T
Questions:
Do the figures sound accurate?
Would the volume of that particular blower be too small, requiring a ridiculously high blower RPM to even boost 435 CI?
Would it be ok at 4 PSI without an intercooler?
Would the heads be less sensitive to porting work because of the boost?
Would the low RPM torque curve be much fatter than a normally aspirated 435" 500 HP engine and at about what RPM should the torque start coming on strong?
Joe's answer on power is roughly correct, although the blower takes power to run too, and that will subtract from the gains. On my 489" supercharged engine, at 17 psi of boost the blower took over 100 HP to run.
I think that blower is too small to work on your setup. You have to start thinking of horsepower in terms of air volume per unit of time. The more air in terms of cfm that you can put through the engine, the more horsepower you will make, blower or not. The blower in the ebay ad may not provide the airflow to even get you back to your existing, unblown horsepower level. In that case it will make zero boost and potentially cost horsepower. If you could find some data on the blower you could figure that out for sure.
I don't think that an intercooler is ever really required, it will just add horsepower if you use one. The more boost you run the more the intake charge is heated, and this leads to less combustion efficiency. Having said that, running higher boost levels (and heat levels in the intake charge) can lead to detonation if you are not careful, so limiting the boost to 7 psi will minimize this problem. You can also look into a Boost Cooler setup, which sprays a methanol/water mix into the intake tract before the fuel, to cool down the intake charge.
Anything you do in terms of porting, big valves, big cam, etc. will give you a directly proportional benefit with supercharging. You can look at this one of two ways; build your engine with standard ports and valves and a small cam, and use the boost to increase your horsepower by some percentage, and you have subtracted the cost of the normal performance tricks from the build. Or, you can build your engine with ported heads, big valves, and a big cam, and use the blower to increase that power by the same percentage. In other words, if you build a 400 HP engine and add 8 psi of boost, you will have a 600 HP engine. If you build a 500 HP engine and add 8 psi of boost, you will have a 750 horsepower engine.
Boost will always fatten the torque curve, but using a supercharger it will not come on immediately; it will be engine speed dependent. So, at 1500 RPM you may not get a big boost in torque over a naturally aspirated engine. At 4000 RPM you certainly will.
For what it's worth, I was very happy with the Vortech centrifugal blower that was installed on my Mach 1, and I was able to get over 1000 HP out of the 489" engine, running 17 psi of boost. It would be pretty easy, to get 700 out of a 390 stroker engine using the same setup and a reduced boost number. You will be spending a pretty fair chunk of change setting up your engine with a blower, so why not go for a little more power? Once you've got the blower adding boost is just changing pulley ratios. And if there is too much power, you can always throttle back ;D
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If you went roots a 6-71 would be very happy with 350 to 450 cubes. Thing about a roots is they are limited to 6500 RPM a centrifugal will go higher but all superchargers loose efficiency at higher than rated RPM. They will become a restriction and overheat the the charge and engine so if you plan on spinning big RPM go with a turbo like Ray Jay or something comparable with pressure lube and a waist gate.
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No, it won't but it'll look cool!
I forgot Gary Dyer (we used to race him long ago!) and he's got great stuff too as noted. You should spend a lot of time learning about all the variants of supercharging one can literally bolt-on today in kit form. As Jay noted below, he made tons of hp but.....one really can't run 15 psi of boost on a regular daily-driver basis and expect a base 390 engine to live long.
What's neat is one can easily (in most cases) change pulleys for the track but keep a lesser pulley on the motor for 90% of your driving. And, a well set-up blower motor will defintely scare the hell out of you at times!
Ok I'll stop looking at those cheap little blowers.
Think a 6-71 or 8-71 unit with a couple carbs on top would fit under a fiberglass teardrop hood?
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The 6-71 is rather low profile it fits under the hood of a camaro with no scoop.
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Yes, the blower itself may well fit under a teardrop hood but, with carbs and some kinda' aircleaner setup, methinks it will be iffy.
BDS has a nice panel of 'advice' btw:
http://www.blowerdriveservice.com/recommend.php
I would disgaree with the steel crank rec as a well-prepped cast unit would work fine...at least will lower boost levels (like under 10 psi or so).
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You could even go hyperutectic pistons to save cash at 7 psi. Anything above that is just extra insurance.
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If im right informed so a eaton 112 have a displacement (spellin might be wrong)
of 112 cuin per revolution and if so you have to spin it pretty fast to feed a 435 with
boost. A roots 6-71 8-71 looks impressiv but take much power to drive pretty in-
effectiv i think Paxton /Vortex is the best allternativ or if there is bigger eatons
My son is building a Volvo 16 valve B230,2,3 liter about130 cuin with a eaton 112
that will be interesting to see the result of that
150 stock hp, with 1 bar bost 300 hp teoretical but i dont think
he is going that high in boost
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Dayum! I don't think I've ever had such helpful responses from a forum before. I guess I finally asked just the right questions of just the right people, lol. This sounds to me like this might actually be worth digging deeper. I think I'll go ahead and order the supercharging book and also check out the BDS link as well as Dyer's and any others I can find. I'm not too interested in the centrifugal style even though they do work. I just can't get past the looks of the darn thing and a big part of the appeal of a supercharger is the look. 6-71 or 8-71 would be even that much better than that little Eaton unit too. I'll have to check into my options on carburation/EFI and hood clearance.
I actually have a set of rods and a brand new set of hypers and rings under the bed for std bore 390 and a good 390 crank in the closet. Not saying I'd want to do all that with hypers, but shoot, I could put a fresh 390 shortblock together for next to nothing and spend the whole budget on blower parts, lol. With about 9:1 SCR and 6 PSI of boost wouldn't it be pushing close to 500 HP? I think that really would satisfy me. According to Werby's Gonkulator I've got around 375 horse right now and I'm really pretty happy with that. Say 85 percent satisfied at the moment, lol. An extra 125 hp ought to really take care of my wants here. But what Jay says makes a ton of sense too. If going for a 50% increase, why not start with more? Porting, valves, cam are still all part of the equation, I guess even more so if you consider a 50 hp valve job could be worth 75 hp under boost...
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Really the only point as far as port work you would see gains is on the exhaust side, intake wise you won't see much. You just want to open up your most restrictive spot so there is less bottleneck.
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Really the only point as far as port work you would see gains is on the exhaust side, intake wise you won't see much. You just want to open up your most restrictive spot so there is less bottleneck.
Not true, John, improvements in the intake port will be directly reflected in improvements in supercharging, provided the blower can keep up with the airflow requirements of the better ports. Trust me on this, I've done the tests ;)
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Care to toss out a guess on HP and torque output for this combo? Point out any serious issues such as the pistons or rods not being up to the job?
390, std bore, std stroke. Flat top hypers, moly rings
mill piston tops to dished shape for 8.5:1 CR. (enlarge valve reliefs to a single larger area basically)
Stock 390 rods, upgraded rod bolts. Notch cylinder walls at exhaust valve locations.
C4AE-G heads, smooth and blend ports, no hogging. Polished combustion chambers, unshroud exhaust valves. Good valve job, stock valve sizes.
Hydraulic roller cam approx 230 @ .050 (custom grind to suit)
6-71 blower geared for 7psi (at what RPM? I have a lot of reading to do...)
Port fuel injection, Megasquirt controller
Throttle body unknown, open to suggestions...
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I would say 500 or in that neighborhood based on a 375 HP stock 390 running 7 lbs of boost but there a lot of variables such as ignition , exhaust and induction?
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I would also say about 500, but a minor cam upgrade and boost upgrade would easily get you to 575. Go to 9 psi and maybe a 242@.050" cam. That will be plenty safe and drivable. Much more power than that and you will have to start thinking about crossbolting the block for longevity, and all that...
By the way, think WIDE lobe separation on the cam for best efficiency with a supercharger, like 114-116 degrees.
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Just to help fill in the blanks...
Exhaust - Crites headers with 2" primaries, 3" dual exhaust to mufflers, H-pipe, 2-1/2" tailpipes over the axle
Ignition - crank trigger/coil packs, megasquirt controller
Induction - A supercharger! heh... what's ahead of the supercharger is TBD. Probably either a 4V throttle body or maybe a pair of throttle bodies similar to the one in the linked Ebay auction. I think the pair of 2's could be set up with 4 holes in a row and I would have to fab some sort of air cleaner. Maybe something like a ram's horn shaped thing with a cone-shaped filter aimed toward each of the headlights.
575 HP potential with parts from under the bed? WOOF! This one looks like it's going to be more than a daydream, I could actually do this without too much trouble. First off I need to figure out how to make it fit. Anyone have a height measurement available? Need to know from the top of the china walls to the carb mounting flange I guess...
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The vendors have blueprints they will gladly email or fax to you with your desired setup.
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65er,
Don't forget Jerry Magnuson @ Magnacharger. http://www.magnacharger.com/. He uses the roots type blower in his applications. He builds nice hot rods, too! Back in the 70s I bought a Weber carb conversion for my Harley Sportster from him... He was doing superchargers for Harley's back then too.
Btw, how about a quick update on how that new tranny is performing? Curious Galaxie owners would like to know! (http://)
Bruce
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The TKO is a champ as expected Bruce :)
With the old cruisomatic misbehavin' as it was I never could put the hammer down for fear of blowing the tranny out. Now I've been burning a bit of rubber here and there with no worries and am ready for a few more horses under the hood :D
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Guessford does a 6-71 FE 427. Nice pics and a very complete BOM with prices. Just ignore that burned rod journal.....LOL!
http://www.gessford.com/cobra/images/KeithSmith427.htm
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Keep in mind torque levels also rise with a supercharger, even more than HP in many cases so drive train upgrades are necessary in most cases. The TKO is good for 5 or 6 hundred pounds. You for sure will need 35 spline axles also, 28 spline will snap like a pretzel rod.
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If you want drop me your phone number at TotalPerEntofPa@aol.com , will gladly discuss Roots 671 FE combo's been running it since 1987 , lots of good advice posted , BUT there are a few that are NOT so good
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Thanks Faron and thanks to all of you guys.
I saturated myself this weekend with info on supercharging and between all the fab work, expense of doing it right, and the prospect of having to cut a hole in my hood, which I don't want to do, I think I'm going to be best off with plan "A" which was to build a nice stroker FE with some good head work. As I had mentioned, I'm currently not far from being satisfied with what I've got. If I get the stroker together with something like 450 HP and really nice stout bottom end torque output then I'll be ready to move on to restoring the interior and other non-drivetrain aspects of the car. If sometime later on down the road I itch for more then I can build it onto the stroker motor instead of starting over again.
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A normally aspirated 445 cid FE set up properly will easy put out 600. But heads are going to be a necessary upgrade.
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If you want drop me your phone number at TotalPerEntofPa@aol.com , will gladly discuss Roots 671 FE combo's been running it since 1987 , lots of good advice posted , BUT there are a few that are NOT so good
Isn't the purpose of this board to share knowledge and have an available repository, not direct traffic away? If you have information that contradicts the good advice already shared, why not post it here?
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If you want drop me your phone number at TotalPerEntofPa@aol.com , will gladly discuss Roots 671 FE combo's been running it since 1987 , lots of good advice posted , BUT there are a few that are NOT so good
Isn't the purpose of this board to share knowledge and have an available repository, not direct traffic away? If you have information that contradicts the good advice already shared, why not post it here?
+1 on that. Come on Faron, let's hear it! :D
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I never said I know it all. If I did I would be.in a very lucrative business making all the aftermarket parts and would be engineering all new vehicles too.
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Chad is right , and I do love to share , BUT , I also hate typing , LOL the info I would give to 65r would be more specific to a combo, than general , but AS for general info , I will say this, a 671 is NOT low , it can easily spin past 6500 , and if put together with the realization it will ( have yet to figure this one out ) cause the car to run about 20 degrees hotter than a comparable normally aspirated combo , so OVERKILL on the cooling system is a Must , I run a Crank tiggerd Ignition ( because Pa has a Obstruction of vision requirement in the Vehicle Code ) so My combo is as low as any FE 671 with carbs can be , but its still high enough that a big scoop or hole in the hood is needed on almost any car , for Carb's , you need to be honest and say I will race this ( full 1/4 mile bursts ) or its a fairground / street only cruiser, racing dictates Holley Double Pumpers , or 660's , Holley Vac Secondary's can be made to work , but with the right mods , Stay away from Eld's or Carters , unless you like ash trays that resemble pistons , also ALL, brands of Headers will Crack given enough time , No coating short of top fuel stuff will stay on , Stainless might last ,( just my pockets are not deep enough to try them ) unless you have a crossbolted block , stay away from strokes over 3.78 ( 390 ) use Head and Main Studs , Good machine work is critical ( as is any engine making 500+ hp ) I run stock 390 3/8 bolt rods with good bolts and have never had a falure , BUT my last combo was put together in 96 , lots of aftermarket stuff now , My engine is apart , it started pushing water ( after 8 full seasons and 3 partial seasons 0 plus 11 years of street miles between ) turns out #7 cyl wall cracked , its a garden variety 390 block .030 so no big loss , also , if you like the whine of a Blower ( who doesn't ) use the 1/2 pitch drive , the round tooth millimeter stuff is stronger , but doesn't sound as cool , if yo run 10% over or less 1/2 is fine , JUST BE SURE to use as big of pulleys ( teeth count ) as possible to get the ratio , in other words 31 crank and 31 top is 1-1 , BUT , you get poor belt wrap , and that can cause problems of belt skipping , ( rips off the belt teeth ) and at about 100.00 a pop aint cheap , I don't like under 37 for tooth count , also belt tension is critical , it needs to be almost TOO loose when cold , those pulley really expand , get it wrong and off comes the crank snout ( SBC and BBC have the most problems ) , also I run JUST a Hub , no Dampener , ok enough for now , have questions shoot away
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I'm actually surprised that no one has mentioned it, so I might be missing some new info here. But I personally wouldn't use hypereutectic pistons on anything that I was going to flog, especially a blown application. Just because they have a higher silicon content than other cast pistons doesn't mean that they are equal to forged and there are way too many off-the-shelf forged pistons for our application these days to consider a cast piston for a performance FE.
JMHO, Steve
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His proposed engine was a low boost application. Say 7 lbs or boost and no Moore than 5500 rpm. There ate advantages of the hyperutectic over forged, Wear resistance is one the other is lower expansion. They outlast a forged piston in a non race environment about twice as long. As far as breaking cranks off and such that is simply a case of harmonics, if harmonics are not controlled in any machine bearing failure will occur, shafts and gears break simple engineering fact 101. As far as belt wrap and tension this is maintained by an idler on the pull side and adjuster on the slack depending on therm an expansion is a uncontrollable factor it starts loose and once warmed ends up still loose, belts are engineered with expansion figured in regardless of the style, if it has teeth it shears, if it is v or ribbed it burns. A lot of good info on basic belt function can found on the Gates site. I an engine when breakage occurs and you started off with good parts engineered for an application then you are going beyond the expectations of the part, superchargers are no more than a pump. If you spin the pump to fast it overheats and raises the incoming air charge to the extent you are getting no volume and burning everything up making it completely inefficient, at this point a larger pump is needed to keep up with demand or part failure will occur. If pressures exceed the capacity of the vessel containing it a rupture will occur along with the excess heat of the over spun inefficient pump. In the case or a supercharger that is spun over designated modified design, over 6500 and the drive system is improperly engineered, harmonics at not controlled and boost exceeds the capacity of the block it is a ticking time Bond. A prime example of a properly or even over engineered engine would be the Buick 3800 supercharged engine, the rum for over 200,000 miles with not an issue. My beater Park Ave Has over 260,000 on it and still runs like new. The rest of the car is junk but the engine uses no oil and has cast pistons.
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John, while I claim to be no expert, I purport that an FE with a huffer and a pair of Holleys has very little to do with the tightly controlled fuel/air/spark of your high mileage Buick. The advantage of forged pistons lies in the ductility of the aluminum after the forging process. This ability to absorb damage without shattering has the potential to save an engine where a hypereutectic piston's harder makeup would shatter rather than deform. To assume that the spark and A/F ratios are going to be controlled such that there'll be no detonation in a supercharged FE would be ambitious in the least and that is the reason that I'd go with forged in any non-computer controlled performance engine.
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I myself went forged due to I needed the extra strength for high compression and higher than normal engine speeds. I I had built it to run 8-9:1 I and ran gas at 5500 red line it would have been different.
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I would NEVER suggest anything but Forged Pistons in a Boosted app , just one of the things I had eluded to before I relented and typed a bigger reply