On a tangent, but Offy's are so cool! The design was so robust, really hope to see one in person someday.
This is a great read, I have a copy if anyone wants to loan it from me. GRM Library! You pay shipping...
https://www.amazon.com/Offenhauser-Legendary-Racing-Engine-Built/dp/1626540411
bluej (Forum Supporter) said:TheV8Kid said:In reply to frenchyd :
We have a pair of these on the Nova. It has a 6.0L. they work great. Makes about 900whp. From the time you foot hits the floor to 18 psi is like half a second
How do you pick one out of the seemingly identical 8 or so gt3582's?
It was the cheapest.
In reply to engiekev :
Peak power of a 159 inch OFFY was 1200 horespower using a T9 turbo at 85 psi
The first turbo's at Indy were in the Cummins diesels in 1952. By 1968 Offy was beating the 4 cam Foyt V8's 15 races to Fords 9. ( in spite of each Ford costing $16,000 more than they sold for. In 1969 USAC went to 172 cu in but that only slowed OFFY by 1 mph. Then they cut it to 159 cu in.
On the Dyno one of those (AAR) made 1400 horsepower And ran at peak RPM for a minute and a half before shut down.
frenchyd said:In reply to engiekev :
Peak power of a 159 inch OFFY was 1200 horespower using a T9 turbo at 85 psi
It's crazy to think that regular street car based engines (stroked k24) can make this hp now at that same displacement.
In reply to frenchyd :
1400 hp net or....?
Paul_VR6 (Forum Supporter) said:frenchyd said:In reply to engiekev :
Peak power of a 159 inch OFFY was 1200 horespower using a T9 turbo at 85 psi
It's crazy to think that regular street car based engines (stroked k24) can make this hp now at that same displacement.
Will they run at peak RPM for 1000 miles?
frenchyd said:Paul_VR6 (Forum Supporter) said:frenchyd said:In reply to engiekev :
Peak power of a 159 inch OFFY was 1200 horespower using a T9 turbo at 85 psi
It's crazy to think that regular street car based engines (stroked k24) can make this hp now at that same displacement.
Will they run at peak RPM for 1000 miles?
Doubtful, 1400HP modern 4-cylinder engines (KA24, 4G63, etc.) are drag race applications that see peak power for 10s or less and are rebuilt every 50miles at most.
The Offy engine essentially had no head to block interface. The "head" contained the cylinder liners and bolted to the crankcase. Genius design, at high power levels head to block sealing can be the largest design problem due to extreme cylinder pressure. You can't have head gasket sealing issues if there IS no head gasket. This is the same method a lot of high cylinder pressure applications (tractor pull diesels, etc.) try to use, but this was integrated into the base engine design!
https://www.hotrod.com/articles/assembling-270ci-offenhauser-indycar-engine-step/
frenchyd said:Will they run at peak RPM for 1000 miles?
No, not sure anyone has tried. These engines only make peak for a few seconds in a pass as they run in cars that are traction limited. Still, production based blocks, heads, etc. they would make more on methanol as well.
Also, isn't indy only half that, or can they not get into the motor after qualifying?
In reply to Paul_VR6 (Forum Supporter) :
Indy racers tend to do the whole month of of May on one motor. I'm sure some of the high dollar teams have back ups. But once qualified there are penalties assigned for motor swapping.
Considering those horsepower numbers were done in the Late 60's early 70's when 300- 400 gross horsepower cars were a really big limited availability deal.
In reply to engiekev :
They also did not have "main caps"... the crank bearings sat in a kind of full diameter shell, that was slipped endwise into the crankcase.
The engine looks like it was engineered around 1930s machining difficulties, that turned out to make it monstrously strong for forced induction.
Those bearing saddles and how it all went together is definitely quite interesting.
In reply to Paul_VR6 (Forum Supporter) :
Designed by Miller who made some of the most advanced engines of the teens and 20's. He designed that engine to help stave off bankruptcy but the Great Depression ruined that. Fred Offenhauser bought the design and patterns along with some machinery and went on to make it famous.
Paul_VR6 (Forum Supporter) said:Those bearing saddles and how it all went together is definitely quite interesting.
The early ones allowed the webs to be preassembled but by the time the turbo's were coming on song to keep the engine together they had to be assembled through the side windows.
Fred had to come up with a whole new method of casting to get blocks without the normal porosity and voids that's still in use today.
Pete. (l33t FS) said:In reply to engiekev :
They also did not have "main caps"... the crank bearings sat in a kind of full diameter shell, that was slipped endwise into the crankcase.
The engine looks like it was engineered around 1930s machining difficulties, that turned out to make it monstrously strong for forced induction.
Yes, some crazy overbuilt engineering going on due to manufacturing limitations. Similar to how 80s and early 90s engine designs were overbuilt due to CAD and Simulation limitations. Now, everything is optimized within 5%, huge Safety Factors don't exist anymore, and tuners wonder why the latest and greatest modern engine can't handle additional 25psi of boost?
In reply to engiekev :
Gawd, look at the width of the rod journals!! That looks normal... for a V engine!
Also observe the counterweight thickness, and massive fillet radius on the journals. You don't see that on ANY 4-cylinder crankshaft, even off the shelf aftermarket. That crank can probably hold 2000HP.
The only 4 cylinders that come close to this design are bespoke billet designs, nothing based off any OEM designed block. OEM blocks just don't have the structural rigidity to handle extremely high specific output and massive cylinder pressures, you're working well past the design limit. Something like this time attack 4.0L (yes, 4L) 4 cylinder making 1500HP at 8000RPM:
https://www.youtube.com/watch?v=J87SVqG18sY
https://www.thedrive.com/article/15015/thor-is-a-4-0-liter-four-cylinder-that-can-make-over-1500-hp
In reply to engiekev :
VWAG fours and fives, at least the forced-induction ones I am familiar with (G60 1.8l, Audi turbo 2.2l fives) didn't have huge rod radiuses, but they did all have rolled fillets.
Not sure which ends up being stronger (the rolled is smaller, but adds strength due to the mechanical process) but it's nice that they cared.
I've never heard of an Audi five cylinder crank failing in anything.
Pete. (l33t FS) said:In reply to engiekev :
VWAG fours and fives, at least the forced-induction ones I am familiar with (G60 1.8l, Audi turbo 2.2l fives) didn't have huge rod radiuses, but they did all have rolled fillets.
Not sure which ends up being stronger (the rolled is smaller, but adds strength due to the mechanical process) but it's nice that they cared.
I've never heard of an Audi five cylinder crank failing in anything.
True, I guess I meant more of a blanket statement with the size of the rod journal radius, filleting, counterweighting. The whole package.
In reply to engiekev :
Well, yeah, different priorities.
One of the old farts on speed-talk.com was railing about modern garbage POS engines with open decks and who all knows what else (yelling at cloud like typing detected), a real good engine design was a top fuel engine that could make 8000hp.
I pointed out that a street engine's priorities are to warm up quickly, and run from idle to 30hp smoothly, efficiently, and with minimal emissions. A Top Fuel engine is bad at all of those things and it would be a horrible engineer who used any of its primary features for a Corolla engine.
In reply to Pete. (l33t FS) :
Well said. Most cars are transportation modules. We racers and wanna be racers probably account for . 002 of the market.
Face it less than 2% of new cars sold have manual transmissions anymore. And really how much longer will we rely on the Piston going up stopping and coming back down with one stroke out of 4 making power?
EV's are wicked fast And while steam engines are interesting. Who really wants that obsolete technology? Are ICE's that much further behind?
Here's what you do, get two t3 from eBay and get some steam pipe fittings and make two long log manifolds to mount the turbos on.
Then you take the pressurized air and put it in the motor.
"What if it's the wrong sized T3?"
It won't be. It will be the correct size because no one else is doing this set up so no one will correct you.
Start at low boost and work your way up. You'll learn when you break stuff.
1SlowVW said:Here's what you do, get two t3 from eBay and get some steam pipe fittings and make two long log manifolds to mount the turbos on.
Then you take the pressurized air and put it in the motor.
"What if it's the wrong sized T3?"
It won't be. It will be the correct size because no one else is doing this set up so no one will correct you.
Start at low boost and work your way up. You'll learn when you break stuff.
That's my advantage. I'll throw a pair of T3's on it and see what I've got. If it goes bang I've got other motors and other parts. By using E85 it will be as gentle as it can get and a lot less likely to go bang.
Run 4 t25's or 4 mitsubishi td05 turbos.
It looks like it might be possible to flip the exhaust manifolds left to right on the V12 Jag and run them facing up. That puts the turbos up high and easier to fabricate an adapter for. They might foul the factory fuel injected motor intake though.
Edit: if you are running non intercooled it might let you just run a small intake pipe straight from the turbo outlet to the throttle body.
frenchyd said:That's my advantage. I'll throw a pair of T3's on it and see what I've got. If it goes bang I've got other motors and other parts. By using E85 it will be as gentle as it can get and a lot less likely to go bang.
I'm really liking that plan! Excited to see the results. BTW, I'm sure you mentioned, but I don't remember what car this is for? Thanks
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