ZROSSA Posted September 30, 2001 Share Posted September 30, 2001 I have been pondering this one for a couple of years. Turbos make more power than superchargers but have lag. Superchargers have instant throttle responce but dont make as much power. Also the more efficient centrafugal (spelling?) can be prown to breaking shafts do to load reversals when getting off the throttle.(a old can am mechanic told me this, it may not be true anymore) So the idea is to hydrolicly drive the centrafugal supercharger. This would solve a lot of the problems of instalation. You could put the blower anywhere, mabye even in front of the bumper sraight into a intercooler. I would gear it so that full boost came in around 2000 rpm and just use a hydrolic valve to bleed of pressure to maintain this boost. A blow off valve could be used to stop surge when backing off and the fact that it is fluids driveing the blower it would cushion the shock loads to the drive mechanisim. I havent really thought out what you would use to drive it. Mabye a power steering pump or tap into the cooling system. I saw an ww2 vintage plane engine that had one driven buy oil pressure but this never went past testing. I could go on a bit more but lets see what you guys come up with. Buy the way this could all be done without complicated electrical controls. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted September 30, 2001 Share Posted September 30, 2001 Not a bad idea, depends on how much HP the pump will cost and if you can turn the RPM you want for a turbine to be effective. Just some thoughts... Regards, Lone Quote Link to comment Share on other sites More sharing options...
ZROSSA Posted October 3, 2001 Author Share Posted October 3, 2001 That, lone, is the million dollas question. I have had a bit of a search around and there is lots of pumps and motors for heaps of different flow rates, But i have know idea what would be required. Anyone out there knowlegable on hydraulic's or perhaps point me in the right direction? Douglas Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted October 3, 2001 Share Posted October 3, 2001 Shaft breakage - if you run a centrifigul supercharger with a cog belt than you can indeed have problems. I've never heard of a shaft breaking but the bearings will wear and the impeller will contact the volute - whoops! Not using a cog belt is the easy solution as the belt will simply slip a bit when you get off the gas (shrug). Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 3, 2001 Share Posted October 3, 2001 I've read that this is just not practical. Too many losses involved, too many headaches. Turbos don't HAVE to have lag. I think a big cube motor with 8.5:1 or 9:1 compression and low to medium boost ought to give you the best of both worlds. It's tough to beat the efficency of turbos. You just have to design the system to work well in the application and usage you want. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted October 3, 2001 Share Posted October 3, 2001 Turbo book has the results of what occured when a turbo V8 was first built and dynoed. At around 10PSI it simply went to pieces! Made so muh torque that the "pink" rods couldn't handle it and the crank broke too. We're talking some serious power. I'm wondering how we'd hook that power in a Z. However if you're only going to go for 10PSI or less I'd look at centrifigul superchargers. Turbos are fun to play with but for that little boost they'e not really needed. Personally I'm torn - I'd LOVE to have a turbo to play with other than my $RX7$ but a supercharger is pretty easy to do. "Cheap" too compared to a turbo unless you're a whiz at fabb'ing. We'll see but if I go turbo I'd want 15PSI or so Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 3, 2001 Share Posted October 3, 2001 Jim, I hear ya on the centrifugal supercharger, but that article that the Mustang guy wrote on the HotRod site rings true here - you have to size the drive to not overrev at high rpm as an upper bound, and you have to size the drive so it gives decent low/mid range boost as a lower bound. In other words, you can't have more than minimal boost at low rpm if you want it to live at higher rpms. The turbo doesn't have this problem, if wastegate, turbo, etc. are sized correctly. Plus I've heard too much about the expensive centrifugal blowers having problems for me to take the plunge with my $3k. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted October 3, 2001 Share Posted October 3, 2001 Sizing isn't too bad actually. The RPM ranges on these things are known as are the CFMs. You can figure this stuff up much liek you can with a turbo - they have compressor maps of sorts. Talking to the manufacturer is a good way to do this. IF I do it I'll simply buy a used head unit and an NPR intercooler. The rest will probably be custom except pulleys. Yeah, turbos have excess boost so you can have a flatter curve but overall the centrifigul units are pretty responsive. In a car with traction problems anyway it works to our advantage. Supercharger bearings CAN be an issue. Mine had been run on a race car with a cog belt. Sure enough the shaft deflected too much and needed bearings. This cost me a hundred or two and a little time but it's right as rain now. I figure turbos have this problem some too with oil seals and whatnot going bad occasionally. Advantages and disadvantages to both methods. I really think turbos are the better unit for max power and flexability but I'm not chasing peak performance in this case. The biggest downside to a supercharger is the NVH - darn things ruin any surprise! Quote Link to comment Share on other sites More sharing options...
ZROSSA Posted October 3, 2001 Author Share Posted October 3, 2001 Guys, the idea really was to get a super flat tourque curve. Use tthe hydraulic drive to spin up the centrafugal supercharger to peak boost early and then bleed of hydraulic pressure to maitain that boost. It would also be much easyer to package. you could put the supercharger any where. Quote Link to comment Share on other sites More sharing options...
PaulR Posted October 3, 2001 Share Posted October 3, 2001 Interesting V8 Turbo information here: toohighpsi I like the "Budget TT 351" article! Quote Link to comment Share on other sites More sharing options...
DavyZ Posted October 4, 2001 Share Posted October 4, 2001 Pete, I'm with you on the 500-600 easy horses! Man, that would be livin'! I'm afraid that if I do this and go higher in boost I'll seriously brake something since my bottom end is mostly stock. I can live with 450 hp on 5 lbs of boost Davy Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted October 4, 2001 Share Posted October 4, 2001 Yup, turbo V8 baby, that would rock. Actually with some sort of in-the-car boost control, you could hook up on lower hp, then lay into it on the back side of the track. Regards, Lone Quote Link to comment Share on other sites More sharing options...
DavyZ Posted October 4, 2001 Share Posted October 4, 2001 quote: Originally posted by pparaska: I think a big cube motor with 8.5:1 or 9:1 compression and low to medium boost ought to give you the best of both worlds... And 350 cubic inches is HUGE for a turbo motor--besides diesels, what manufacturer is putting turbos on engines of this size? I ran some calculations, and getting into the mid 400 hp range is simple, while running an insanely low amount of boost like 6 to 8 pounds! What happens if we run 17 pounds like some of the I6 guys are, but we do it on a V8? Davy Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 4, 2001 Share Posted October 4, 2001 Davy, the reason I like the 350-ish c.i. medium compression low/medium boost turbo motor ideas is that 400 hp is so easy to get, if not high 400s. Heck, 10psi should put you near/at 500 or 600hp. I ran this through the web page that Lone mentioned the other day, and 10psi on a turboed 350 was ROCKIN'. Plus you get lots of low end torque, and if you sized things right, lag on the street should not be a concern. Keep the revs below 6000rpm and you could size two small or one medium turbo on such a setup, maybe even without an intercooler and have a nice fat and high torque curve. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted October 4, 2001 Share Posted October 4, 2001 Yup, you could use any number of boost controllers to do this. The HKS unit I had used three different boost buttons and included a "scramble boost" option where you could hit a button to allow it to "overboost" for a period of time. Launch with about 2PSI, hook it, and then hit the button for 8 or 9 down track. Turbos have a giant top end rush anyway so I can only imagine what that would feel like. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted October 6, 2001 Share Posted October 6, 2001 in regards to what it would feel like...probably like the hand of God reached down from the heavens, and flicked your car like you and I would a gnat.... Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted October 6, 2001 Share Posted October 6, 2001 i have a l28 turbo in my car-but since i work at a ford dealer i have been kicking around idea of a turbo 5.0.i like the smoothness of turbo engine-you dont need a big rough cam.a well thought out turbo car will easily handle commuting to work but the power is always there if you push the pedal a little more.another turbos like is pulling a taller rear gear-the boost build better if motor is pulling hard.my car with stock l28et passes 4 cars in a row on a 2 lane highway great now-55mph to 100 mph is no problem.its hard to imagine what a good v8 with intercooler and 10 psi boost would be like.easy to build-they sell forged 8 to 1 pistons in summit catalog.i would spend the money for a good custom for your appplication turbonetics ball bearing turbo though-those dont have much lag. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted October 6, 2001 Share Posted October 6, 2001 Ballbearing turbos are awesome. Only downside is they're too expensive for most folks. I've driven cars with regular turbos and ones with bb ones. BIG DIFFERENCE. Lag is cut down and throttle response is more crisp. Imagine twin ball-bearing turbos Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted October 7, 2001 Share Posted October 7, 2001 Randy - you can run stock 9.25:1 compression on a 302 w/turbos. I've got a set of manifolds in the garage for this now if you'd like to see some pics to get ideas. They came out of my FOX Mustang and worked well. They were T25 turbos - little things. Fast boost though! Only ran about 10PSI. Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted October 7, 2001 Share Posted October 7, 2001 idea i have in my mind is to run shorty headers backwards.stuff motor as far back as possable and put turbo in front of motor.would use 97 v8 explorer serpintine belt drive -it makes engine 3" shorter.it should work on a 3" exhaust-i have 3" mandrel bent exhaust now.not planning on using crossmember for motor mount-i will build another crossmember for motor.only question in my mind is how much cylinder head flow is needed-are those $1100 heads needed for turbo engine.the late v8 explorer have good heads and camshaft.when we do warrenty work the parts are held for 90 days and then thrown into scrap bin. Quote Link to comment Share on other sites More sharing options...
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