Centrifugal supercharger question

[My427stang]

So I am starting on an engine for myself, it will be a side project alongside the others that will pay for it

The game plan is a 510-ish cid FE, SEFI, street engine, with a centrifugal blower and air/air intercooler of some kind. Aftermarket block, all good internals, etc. Of course, too much power for the street likely, but consider it art and a learning experience, as well as a bit of a community interest piece.

My question is, do centrifugal superchargers have different boost curves or is it a pulley function and total CFM is key for the compressor?

I don't think I want something that comes on too hard off idle for street behavior. In fact, a turbo or pair of turbos may be more what I am trying to mirror, but the car doesn't have room for turbos and I don't want to do any of the funky turbos out back as I don't have room there either. as well as wanting to ensure heat stays away from a tight engine compartment and passenger floor/cowl

Thoughts? admittedly I haven't dug into the supercharger companies, but if you can throw some experience, names of good thinkers or thought my way, I am starting to dig in a bit into exploring centrifugal superchargers

If I had to describe what I am ultimately looking for, I would say 850-ish HP, the number is less important but that's about the min goal at full song, but happy in traffic with A/C and boost to build proportional with RPM (I think). That's 1.68 per cid, which seems reasonable to me with street levels of boost and a computer helping me, but this is first I have delved into supercharging (other than Detroit diesels LOL)

I know I can get to the numbers other ways, but the car is a healthy street car that I can jump in and drive cross country now (SEFI 489 inch FE) and not interested in engine swaps, other families, etc, just want to try to meet some goals and learn some new stuff with a little unnatural aspiration

Thanks in advance

[thedynoguy]

my years of dyno experience have told me that the centrifugal superchargers are softer on the bottom, regardless of the drive ratio. I've run a bunch of marine stuff that the customer's like because the lack of bottom end torque won't blow the drives up

[PackardV8]

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?

[F-BIRD'88]

Twin TorqStorm 's.

[dfarr67]

Isn't there Rotrex too?

[frnkeore]

A turbo and mechanical driven centrifugal compressor, operate on the same principle and as I remember, produce boost based on the square of the rpm.

The mechanical driven compressor, has a smoother curve, as it's boost is rpm and throttle position related. Off idle, depending on compressor gearing, low/no boost until revs increase. They also take less hp to drive them than any of the roots types.

That's a pretty big engine for the common centrifugal compressors to keep up with but, 10 lb should get you to your goal.

In application, they will come on very hard at a certain rpm.

Also, when gearing them, you need to know the compressor wheel diameter and final drive rpm, to keep the compressor wheel subsonic.

[My427stang]

my years of dyno experience have told me that the centrifugal superchargers are softer on the bottom, regardless of the drive ratio. I've run a bunch of marine stuff that the customer's like because the lack of bottom end torque won't blow the drives up

Thanks, looking forward to this one, it's overkill on the street, but as long as I can make it behave it should be fun

Twin TorqStorm 's.

Certainly would be cool, but I don't have the real estate with a/c and PS in a 70 Mustang

A turbo and mechanical driven centrifugal compressor, operate on the same principle and as I remember, produce boost based on the square of the rpm.

The mechanical driven compressor, has a smoother curve, as it's boost is rpm and throttle position related. Off idle, depending on compressor gearing, low/no boost until revs increase. They also take less hp to drive them than any of the roots types.

That's a pretty big engine for the common centrifugal compressors to keep up with but, 10 lb should get you to your goal.

In application, they will come on very hard at a certain rpm.

Also, when gearing them, you need to know the compressor wheel diameter and final drive rpm, to keep the compressor wheel subsonic.

Thanks Frank, looks like I am going to have to talk to the supercharger companies, research so far said similar, RPM limits are certainly valid as are CFM requirements. That's really the question, if I know top and bottom rpm of the engine, is it a linear curve or otherwise, and what are my choices to make it do what I want. If it is linear, it certainly makes the job easier

An additional issue is finding a head that will feed it. Jay is building heads, but not the path I want to take. Options better than ever, but still not a lot of them in the range I want for FEs

[F-BIRD'88]

Check with TorqStorm for install kits for your FE Mustang.
They are always developing new kits too.
I believe there is a 68 427 FE Cougar featured. w/twins
Contact them directly

[F-BIRD'88]

The other supercharger I like for this is the Eaton/Magnuson TVS style blower with EFI and intercooler.

[PackardV8]

The other supercharger I like for this is the Eaton/Magnuson TVS style blower with EFI and intercooler.

The Whipple also fits compactly.

[My427stang]

Check with TorqStorm for install kits for your FE Mustang.
They are always developing new kits too.
I believe there is a 68 427 FE Cougar featured. w/twins
Contact them directly

They haven't answered an email yet in 3 weeks, but who knows. I'll work with all the suppliers to see who works best, but typically the Torqstorm look small displacement, likely why they go twins

I don't need a kit, but I do need to predict the best I can that I am buying parts that match my planned use.

The other supercharger I like for this is the Eaton/Magnuson TVS style blower with EFI and intercooler.

The Whipple also fits compactly.

I doubt I can go up with that style, FE with Pentroof v/c and a low hoodline would likely require some hood surgery.

I intend to move the radiator forward a bit and maybe reshape the front of the radiator support to make a path for intercooler air, but really want to keep it looking like a stock Boss 9 externally

Plus I think the benefits of the positive displacement styles are immediate boost, I sort of think I need to delay it

I appreciate the input though

[F-BIRD'88]

Yes each Torqstorm blower can produce up to 700 hp so yes for 800+ hp you'd want twins.. Probabily need a custom built intercooler or 2 custom intercoolers.
Yes the Eaton TVS will need a hood bulge or a cowl induction hood or maybe a Eleanor style hood.

[emsvitil]

Are there any centrifugal superchargers that use a what would be the equivalent of a constant speed transmission?

Lots of gear multiplication at low rpm, then taper off as the rpm's increase.

[panic]

Yes, the original Paxton and McCullough had systems that changed compressor speed as engine speed increased. I suspect something like that could be made from a snow mobile or junior dragster variable clutch drive.
Read my brief comments on my site here: http://victorylibrary.com/mopar/blower/ ... McCullough

[rustbucket79]

So I am starting on an engine for myself, it will be a side project alongside the others that will pay for it

The game plan is a 510-ish cid FE, SEFI, street engine, with a centrifugal blower and air/air intercooler of some kind. Aftermarket block, all good internals, etc. Of course, too much power for the street likely, but consider it art and a learning experience, as well as a bit of a community interest piece.

My question is, do centrifugal superchargers have different boost curves or is it a pulley function and total CFM is key for the compressor?

I don't think I want something that comes on too hard off idle for street behavior. In fact, a turbo or pair of turbos may be more what I am trying to mirror, but the car doesn't have room for turbos and I don't want to do any of the funky turbos out back as I don't have room there either. as well as wanting to ensure heat stays away from a tight engine compartment and passenger floor/cowl

Thoughts? admittedly I haven't dug into the supercharger companies, but if you can throw some experience, names of good thinkers or thought my way, I am starting to dig in a bit into exploring centrifugal superchargers

If I had to describe what I am ultimately looking for, I would say 850-ish HP, the number is less important but that's about the min goal at full song, but happy in traffic with A/C and boost to build proportional with RPM (I think). That's 1.68 per cid, which seems reasonable to me with street levels of boost and a computer helping me, but this is first I have delved into supercharging (other than Detroit diesels LOL)

I know I can get to the numbers other ways, but the car is a healthy street car that I can jump in and drive cross country now (SEFI 489 inch FE) and not interested in engine swaps, other families, etc, just want to try to meet some goals and learn some new stuff with a little unnatural aspiration

Thanks in advance

I would call the companies you are considering, an email to a large company, you are one of dozens of tire kickers each day whereas a phone call, you are spending money to talk to them, you are at least somewhat serious.

Centrifugal is the right call here, any manifold mounted supercharger setup is a colossal pain in the ass with a front mount distributor, we did a 427 Windsor with a 8/71 and even with a spacer it was tight and we were fighting mixture distribution issues.

Big thumbs up for incorporating an intercooler in your program.