Hi there,

Got two recommendations on turbo sizing for my international harvester 392 motor build.

Stroke has been increased, bore upsized, to displace 451 cubic inches. Maximum boost, no more than 10 psi. Cruising speed and overdrive around 2,200 RPM. This is a weekend toy, not a daily driver. The motor will never see more than 5200 RPM max. Shift points will be around 3200 RPM.

Precision turbo recommended the quantity of two, pn 11102010229. .96AR, 62mm inducer compressor wheel
Compressor cover:"E" compressor cover 3.0" inlet/2.0" outlet, 66mm, 76 trim turbine wheel
Turbine housing: T4 Tangential .96 Area Radius (A/R) with 3 5/8" OD (outer diameter) V-Band discharge.

VS Racing offered a similar model, .96AR, their 6466 model. I don't have specs for this, other than the model number, and the AR ratio.

Does this seem accurate for my description?

Not looking for a barnstormer, just a fun, unique build, that's not cranky.

I'm not looking for more than 10 PSI boost, nor am I looking for more than 700 horsepower.

Thank you!

 

S475 from whatever manufacturer would do it. Rpm are your friend.

 

Low rpm motor. It will never see more than 5200rpm.

Your recommendation looks pretty big. Is thos for a single turbo or for twins?

I'm considering twin turbo because of packaging and lower rpm use.

 

That would be a single. Why the low rpm?

 

Street rig.

OEM motor isn't designed for more than 4200 governed rpm. Dump truck motors.

Bumping up the band a bit to 5500rpm.

 

Then go supercharger, it will be better almost all the way around than turbos at that low of boost.

If you absolutely want to stay with turbos, then your 10psi and 5200rpms gives you ~735hp. So you'll need to stay below 10, and that's why I recommended a s/c. There isn't alot of exhaust energy for turbos below 10psi, so they're kind of more in the way than anything.

Your turbo recommendations look pretty good according to my numbers, id go with precision over vsracing.

 

Good feedback.

I considered a supercharger of some sort.

I focused on turbos because of packaging and seemingly less effort for installation.

A belt driven supercharger of most any kind, except a centrifugal, would have to be a side mount because of hood clearance.

To use a roots I would have to fab an intake. If I could find a side mount Eaton, this is not much of an issue.

For either centrifugal or roots belt driven, i'm looking at having to adapt, or fabricate from scratch, a kit.

Suppose it could be a wash between turbo or supercharger.

I'd like to get my hands on a B&M 250.

If centrifugal, what size am I looking at?

Historically, is belt slippage really only a problem with the roots, and no others?

Thank you!

 

Roots style sc create boost by physically ramming the air into the engine.

Whipple, Magnuson, and the eaton tvs create boost by compressing it within the rotors.

Centrifugal is a belt driven turbo basically.

Of the 3, the "whipple" style would be the one I would choose. They're more efficient than roots, and less "bs" than centrifugal. Centrifugal has to spin that compressor pretty fast to make boost. So there's a bit of hp lost in just stepping up the rpms, plus you have high speed bearings etc to deal with.

I'll run some more numbers tonight for ya.

 

Sweet!

Thanks man

 

For your unique build, turbos make the most sense imo. The supercharger is gonna add a whole lot of complexity to the build, and for what you're doing those turbos will be plenty efficient. I agree with needing as much rpm as will be reliable... it'll actually be easier on the engine. It wasn't designed for rpm, but it surely wasn't designed for boost either. Low rpm boost is tough on parts.

 

So, did some digging and found a compressor map for the eaton tvs2300, and I'll be honest was impressed. It moves 2.3L's of air per revolution, your 451 moves 225cu/in of air per rev, or 3.7L. That's at 100% efficiency, I doubt that old motor moves air at 100% efficiency, so I assumed 85%, which means it's really moving 575cfm at 5,200rpms.

7psi of boost (1.5ish pressure ratio) going through an intercooler increases the airflow pre-sc to 810cfm, or 22,936 liters per min. Divide that by the superchargers 2.3L per rev and we get 9,972rpms. Looking at the map, that's at an impressive 70% efficiency!

They also plot the power consumption and its at a measly 18kw, or (18,000 ÷ 745=) 24hp. Assuming the belt drive is 98% efficient (stretch, friction etc) we'll call it 25hp.

So there ya go you need a 1.9:1 drive ratio to power an eaton tvs2300 blower. Side mount it and pipe it through an intercooler and you'll be better than any turbo system on that engine. #ad

 

What compression? And what's the stroke?

Sounds like a fun build.

 

Thanks!

Bore at 4.28"
Stroke 3.92"
Compression... Before forced induction, was wanting 10:1. The motor will have full computer control, so 10:1 may still be possible with careful tuning, but may go lower to 9:1. Factory is 8.02:1.

Been researching tvs2300 side mount installs.

Trying to figure out an intake.

I have a CAD file for intake manifold flanges, ordered up some 6061 t6 1/2" thick for those. Maybe a top mount is possible? Can't seem to find a whole lot of pictures of tvs2300 companion motor intakes. Need to see what they look like before deciding on a side mount, or the traditional top of motor/ intake.