[Tom Vaught]

The subject of this thread will be about ALTERNATIVE belt driven superchargers, TWO Centrifugal SUPERCHARGERS on one engine.

Some background info:
The engine happened to be a 632 cid engine that was tested on John Meany's (The Big Stuff 3 EFI Guy) engine dyno in September of 1998. Meany's dyno 1n 1998 in Michigan was very accurate dyno. The dyno building some years later had a major fire and the building/dyno was destroyed.

The bracketry for the twin superchargers was designed and fabricated by John Carter and his contacts. The superchargers were normal rotation superchargers but mounted backward (inlets to the front and drive pulleys to the rear) with a innovative dual cog belt drive system. The crankshaft cog belt drove a jackshaft and the jack shaft drove both of the superchargers using two other cog belts.

Two supercharger systems were tested:
One system with the smaller J-Trim Vortech Superchargers and one system with the larger X-Trim Vortech Superchargers.

The dyno numbers for the smaller J-Trim system
No inter-cooling for either testing.
J-Trim Data: 1643 HP and 1300 lbs/ft of torque at 7500 rpm. 23 psi of boost

X-Trim Data: 2043 HP and 1450 lbs/ft of torque at 7500 rpm. 23 psi of boost

The people at the dyno were John Carter, John Meany, and myself (representing Vortech Supercharger Engineering as a on-site Technical Advisor for the dyno testing).

Points of the Thread:
1) Some innovation and you can make a larger engine generate some nice power numbers with much lower boost numbers vs the typical single turbo application.
2) 2000+ hp from a non-intercooled gas engine at 23 psi IN 1998 (TWENTY YEARS AGO) was quite a accomplishment.

Most Centrifugal Supercharger packages can fit under the hood (without a scoop) and make as much or more HP vs the alternative systems.
Most centrifugal superchargers require less HP to drive them for the same power level which means more HP to the tires.

Tom V.

[3fastgtos]

Very true Tom but I'll keep my PSI screw blower. Besides, I like stuff sticking out of the hood.
SD

[Tom Vaught]

Sorry, this thread was supposed to be posted in the Boost Forum.
For some reason it is not allowing me to delete it (probably because you replied to the thread).

Mods please move to boost forum.
Tom V.
PSI made a fine blower when Norm D was running the company.

[Dragncar]

Its OK Tom, I like reading about this stuff here too. Is it sort of like "a poor mans twin turbo but without the lag ??

[Tom Vaught]

Screw Superchargers make internal compression of the air so they are more efficient, can run 18,000 rpm vs 14,000 rpm but they still suck up a lot of HP that the Turbos don't consume because TURBOS are actually driven by exhaust (normally wasted) heat energy on the other superchargers.

Tom V.

[Half-Inch Stud]

Bold genreality
Exhaust-driven boost likely to be 100-200 HP advantage over crank driven boost. Exhausr-driven Advantage being waay higher in efficiency in ALL aspects.

I don't like hot bearings or orange-hot metal, but thats a trade from hot boost air.

How about an exhaust driven screw displacement project?

[Tom Vaught]

Centrifugal Superchargers consume about 1 hp for every 10 hp that they make so at 1100 engine hp actually generated by the engine the drive belt/supercharger would be using 110 hp to move the air so the engine dyno would report 990 HP.

Roots style superchargers and Screw superchargers would consume more hp for the same actual engine hp.

Lots of data from Vortech Engineering, Whipple Engineering, Eaton Superchargers, and Lysholm Superchargers on those numbers to generate the very basic rule of thumb numbers.

Tom V.

[Elarson]

Originally Posted by Tom Vaught

Centrifugal Superchargers consume about 1 hp for every 10 hp that they make so at 1100 engine hp actually generated by the engine the drive belt/supercharger would be using 110 hp to move the air so the engine dyno would report 990 HP.

Roots style superchargers and Screw superchargers would consume more hp for the same actual engine hp.

Lots of data from Vortech Engineering, Whipple Engineering, Eaton Superchargers, and Lysholm Superchargers on those numbers to generate the very basic rule of thumb numbers.

Tom V.

My sources tell me that the NHRA big show cars consume about 1500 hp running the blower. So that's about 1.5 hp loss per 10 engine hp.

Eric

[70 bird]

I worked for the Kalitta's for 5 years as a GSE mechanic. I was able to go into their race shop in Ypsilanti Mi. several times. They have a blower dyno cell for testing of their blowers, it uses a BBC on a fixture just to turn the blowers.

[Tom Vaught]

I can believe the 1.5 hp per 10 HP Eric.
I actually assumed it might be a bit more on the Big Show cars. Thanks for the info.
70 bird, Vortech Engineering actually has a dedicated supercharger test stand (in a test cell) that allows them to generate
a lot of good engineering data as far as impeller design vs the flow rate. I have a program that they sent me that allows getting very close with the numbers. This is for centrifugal S/C components.

Tom V.

[Half-Inch Stud]

Tom, As you well know (as i do believe it or knot) the theoretical and actual adiabatic efficiencies for these boost topologies can very well reveal (quantify) the shaft HP, and temperature of the Pounds air delivered @CFM.

Boost folks know these things.

What is the best way to disseminate working knowledge to PY folks aspiring to attain boost?

So good decisions are made. ( simple ranking chart(s) with attributes).

[Tom Vaught]

It depends, HIS, on whether the manufacturer of the boosting device is giving you real adiabatic efficiency data or if the map data has been 'optimized" maybe a bit more than it really was during the testing.

We tested some Lysholm Superchargers (screw) from a company and the supercharger maps did not match the data we were seeing on our dyno tests when the supercharger assy was installed on the engine and the engine tested on a very accurate climate controlled engine test cell.

That is once reason why we spent several million dollars installing a Turbo dyno cell system made by Kratzer. https://www.testsystems24.com/en/tes.../turbocharger/

We still had a year long corrolation program between the Turbo manufacturers and our stand to make sure that the data matched.

So very hard to explain specifics vs general info to the average forum reader, HIS. And the supercharger or Turbo is only one part of the engine equation.

Tom V.

[Half-Inch Stud]

You being retired and all, do you see a need to draw up a Tech training kit, go do specialized classes (internet school), and help dial-in up some test centers?

[Tom Vaught]

I have a friend in Wisconsin who has worked with the EPA on emissions and F.E. projects and HE does go around the country and help dyno people, colleges, and Tech Schools understand Emissions and dyno testing.

Not really enough work for two people doing that kind of work.

Tom V.

[Jack Gifford]

Originally Posted by Half-Inch Stud

... How about an exhaust driven screw displacement project?...

Anybody?