Centrifugal supercharger question

[My427stang]

Thanks I certainly will, too many questions and options not to. I was just surprised that a new company didn't answer one of many from a builder when their website sort of drives you to that.

Regardless, I'll start digging in this week, can't really start the bottom end without know what's going on top

[plovett]

I am looking into centrifugal blowers also. It seems that a lot of turbo setups control boost via a controller and wastegate. They can have a flat boost curve once it gets blowing, usually from pretty low rpm. The belt driven centrifugal blower setups seem to have a linear boost curve more or less directly related to rpm and pulley ratio. I think this is good for your situation as a more progressive increase in boost will make getting that power to the ground on street tires less of an abstract idea.

It seems to me that one bigger blower would be better than two small ones (like two Torqstorms) in terms of space management in your tight engine bay. I would try The Supercharger Store. They have kits for your application and can supply different sized blower head units for your needs.

paulie

[PackardV8]

It seems that a lot of turbo setups control boost via a controller and wastegate. They can have a flat boost curve once it gets blowing, . . . The belt driven centrifugal blower setups seem to have a linear boost curve more or less directly related to rpm and pulley ratio. paulie

Not really, unless the centrifugal has the same waste gate system as the turbo. A turbocharger and a centrifugal supercharger are the same type impeller, subject to the same laws of physics, just with differing drive systems. Both generate boost as a function of the square of RPM; boost rises sharply and definitely non-linearly. But yes, both can theoretically be made to deliver a flat boost curve if equipped with engineered wastegates and intercoolers.

While these are rough approximations and results will vary as to how well the compressors are matched to the engine, it does illustrate the sorts of raw curves each produces.

[plovett]

It seems that a lot of turbo setups control boost via a controller and wastegate. They can have a flat boost curve once it gets blowing, . . . The belt driven centrifugal blower setups seem to have a linear boost curve more or less directly related to rpm and pulley ratio. paulie

Not really, unless the centrifugal has the same waste gate system as the turbo. A turbocharger and a centrifugal supercharger are the same type impeller, subject to the same laws of physics, just with differing drive systems. Both generate boost as a function of the square of RPM; boost rises sharply and definitely non-linearly. But yes, both can theoretically be made to deliver a flat boost curve if equipped with engineered wastegates and intercoolers.

While these are rough approximations and results will vary as to how well the compressors are matched to the engine, it does illustrate the sorts of raw curves each produces.

Yeah, I thought of that too. But to use engine power to make excess boost that is then bled off doesn't make much sense with a belt driven centrifugal blower. At least it seems that way to me.

[chimpvalet]

One dead simple approach to boost limiting is to restrict airflow at the compressor inlet, either turbo'd or belt driven. I believe WRC rally cars of a few years back were HP limited in this manner, gave NASCAR levels of torque from their 4 bangers before choked airflow put a cap on top end. I expect the drive power demands for a belt driven blower would be flattened in similar terms as the impeller churned through thinning air.

[Ron E]

We have some experience with the old McCulloch and Paxton centrifugals; back before synthetic oils and better filters, they weren't really durable for street use. Today, they're too small for most applications.

Those who've used Vortec, Procharger, et al; how do they last in high miles/hours applications?

Jack, about 20 years I put 100K on a procharger that I had bought used. It was not the self contained lube type. It used engine oil for lubrication.
On the curve. mine was dead until a bit past 3000 RPM. Then it came on hard. Nailing it in 2nd gear from about 1700-2000 it would accelerate no different than stock until it reached around 3K RPM then the tires would start slipping and before 4K it just blew them off. (90Mustang 5.0,5sp, 3.55 gears, otherwise stock)

[F-BIRD'88]

I am looking into centrifugal blowers also. It seems that a lot of turbo setups control boost via a controller and wastegate. They can have a flat boost curve once it gets blowing, usually from pretty low rpm. The belt driven centrifugal blower setups seem to have a linear boost curve more or less directly related to rpm and pulley ratio. I think this is good for your situation as a more progressive increase in boost will make getting that power to the ground on street tires less of an abstract idea.

It seems to me that one bigger blower would be better than two small ones (like two Torqstorms) in terms of space management in your tight engine bay. I would try The Supercharger Store. They have kits for your application and can supply different sized blower head units for your needs.

paulie

The 2small Torqstorms has many advantages including fit and smaller unit physical size compared to a big single supercharger of equal horsepower capability..
The big race single blowers are known to be hard on the front of the crankshaft. Often requiring a crank support brace.

[turbo camino]

The 2small Torqstorms has many advantages including fit and smaller unit physical size compared to a big single supercharger of equal horsepower capability..
The big race single blowers are known to be hard on the front of the crankshaft. Often requiring a crank support brace.

Why only two, why not one per cylinder and 16 carbs?? That'd be awesome!

[rustbucket79]

The 2small Torqstorms has many advantages including fit and smaller unit physical size compared to a big single supercharger of equal horsepower capability..
The big race single blowers are known to be hard on the front of the crankshaft. Often requiring a crank support brace.

Why only two, why not one per cylinder and 16 carbs?? That'd be awesome!

I see what you did there

[turbo camino]

I see what you did there

Well I mean it's not as if two 500-hp superchargers cost twice what a single 1000-hp supercharger does, so no reason not to use as many as you want. I suppose you could mount them on a trailer and rig up something like a tractor's PTO to drive them. Seems easy enough, just do it.

Never mind that the OP is specifically looking for something that is the opposite of a PD blower's power delivery. Why let that get in the way of being a broken record?

[frnkeore]

A single, larger diameter compressor has advantages and disadvantages.

Keep in mind, that you need to run the compressor, just under sonic and it takes less gear, to do so. The capacity is increased by widening the compressor wheel and that takes less space and fewer bearings, than multiple compressors.

My dad worked for Meyer and Welch, from '45 - '52, Louis Meyer (3 time Indy winner) owned the Novi and dynoed it there, in those years. The Novi used a large diameter (about 12-14") compressor wheel. One of the drivers, Duke Nolan, told my dad that he could break the tires loose, any place on the track, at Indy. You had to have a very light foot, to drive it. As a matter of fact, a new driver, had to put a block under the accelerator, to stay on the track for qualifying.

The BAD thing about that supercharger, was that it also took skill to know when to back off, because the compressor wheel had a flywheel effect and it wouldn't slow for the corner, like other cars. It took a very skillful driver, to drive it.

The engine, ran 8K, I don't know the gearing for it but, the compressor wheel ran supersonic and that made it have a very unique sound but, didn't seem to effect power to much, at that time.

Because of the above, I would recommend using a sprag clutch (one way clutch) for a large compressor wheel or at least, keep that in mind when on it.

[My427stang]

I would consider twins if I had the real estate, but it's going to be tough to fit a single

Early pic, but this is where it has to fit....battery will go out back, some elctronics that are hidden will move, radiator and a/c may go forward, but not a lot of room

[plovett]

I would consider twins if I had the real estate, but it's going to be tough to fit a single

Early pic, but this is where it has to fit....battery will go out back, some elctronics that are hidden will move, radiator and a/c may go forward, but not a lot of room

I have the same engine bay, but I have cut back shock towers. That gives me a little, but not that much really. I don't have power steering or power brakes, or AC and I am not looking at intercoolers, battery is already in the trunk, and mine is still tight. So you are definitely packing a lot in there. I don't doubt you will get it done and done well.

My question is, what about air supply to the inlet of your blower? Unless you get a reverse rotation blower the inlet will be facing the shock tower. There is little room there for a decent sized filter, and the filter will be right by the engine and headers. Maybe since yours will be intercooled the inlet temperature will not be a significant factor? Or are you thinking of punching a hole in the fender and routing some tubing to a filter in there? Or make a heat shield in the engine bay between the engine/header and the blower inlet? Or route an air supply up to your scoop? That seems like it would be difficult and it would likely get heat from being so close the top of the engine.

I think I remember reading a test where just one 90 degree bend in the inlet tubing hurt power a lot on a centrifugally blown engine. So getting cool inlet air might not be worth it. I dunno.

pl

edit: http://fepower.net/Dyno%20Results/dyno_results_10.html

[My427stang]

I don't know yet Paulie, I am still stuck on boost map and forecasting.

I called Procharger and they can't get off pushing me to the supercharger store and a kit, which no kit will meet my needs unless I can get some data, and Torqstorm guy I talked to yesterday didn't know anything but what the web site said, frustrating. I'll try the supercharger store today and see what they have to say, but I really want to know a little more depth than "will it bolt on"

I will say though, my initial thought is come off the TB high and gentle curve with the big Boss 9 scoop. The intercooler of course will cool things, as far as where the air feeds the blower, it will have to have some distance between it and the MAF to make sure air is smooth and stable, so who knows, but I sort of think a U-shape bend coming forward and a big filter up front, or maybe across the manifold and back into the scoop, although I doubt I can fit enough filter under the hood and scoop area. The car gets a vote though. No intention to go into the fenderwell unless I have to.

[jake197000]

I've got an old ball drive on my 331 sbf for over 30 years cnc ported twisted wedge heads Anderson stage 2 blower cam studs on heads and mains stud girdle drive it hard.stock rods never any trouble.10 pounds boost.its an 87 mustang get convertible.love this car.bought it in 89 and built the engine soon after.