Engine block aluminum vs compacted graphite iron CGI

[Honda Porsche fan]

I am comparing CGI to aluminum because that’s what NASCAR and Pro Stock have been using for nearly twenty years.

Do you have stock in CGI foundries? You keep bringing up tensile strength, but clearly none of the examples I have listed need that. If the bore can hold roundness at 250+ bar and is still lightweight,I don’t know what else you need. Cleary what they are using works.

Best of luck to you convincing the motorsports they’re wrong.

I will also add those NASCAR blocks aren’t stressed at all. They’re 1000hp+ designs making nearly half that due to rules.

My point is about engine life and how long can aluminum race engine blocks go before rebuilds vs CGI blocks. If a CGI block can last a whole season I think that saves the teams a lot of money in the long run.

I'm not disagreeing with you on the performance of aluminum for one or two races, I'm focusing on the longevity of the aluminum.

I'd rather have a CGI block that can last a whole season, have more power if that means it has to be slightly heavier than a aluminum block. CGI is much lighter than grey cast iron.

[Hoffman900]

I am comparing CGI to aluminum because that’s what NASCAR and Pro Stock have been using for nearly twenty years.

Do you have stock in CGI foundries? You keep bringing up tensile strength, but clearly none of the examples I have listed need that. If the bore can hold roundness at 250+ bar and is still lightweight,I don’t know what else you need. Cleary what they are using works.

Best of luck to you convincing the motorsports they’re wrong.

I will also add those NASCAR blocks aren’t stressed at all. They’re 1000hp+ designs making nearly half that due to rules.

My point is about engine life and how long can aluminum race engine blocks go before rebuilds vs CGI blocks. If a CGI block can last a whole season I think that saves the teams a lot of money in the long run.

I'm not disagreeing with you on the performance of aluminum for one or two races, I'm focusing on the longevity of the aluminum.

Your bearings, pistons, connecting rods, and piston rings are the weak point in all these engines. An iron block won’t save rebuild costs, and they would likely be coated bores anyway, and the longevity of that would be the same.

The one thing you can do with an aluminum block is repair it. This is why NHRA Top Fuel / Funny Car runs aluminum blocks. Those things are repaired constantly.

You are also missing one critical factor in that aluminum does provide some cushioning. This is why ProMod and nitro drag engines use aluminum rods. The lean burn F1, DTm, and LMP diesel engines run in a borderline knock state and even exceed it. With their rapid combustion concepts, it is incredibly hard on the bottom end, and to some extent, is the actual physical limit to these engines. Aluminum helps that.

And cooling is no contest.

[Honda Porsche fan]

I will also add those NASCAR blocks aren’t stressed at all. They’re 1000hp+ designs making nearly half that due to rules (induction / tapered spacer, compression, gear rule, etc)

I would really like to see Nascar go back to what they were doing in the 1990's with engine rules that allowed engine builders to aggressively invest in new valve spring design/construction and push the rev limits.

In the late 1990's and early 2000's before the rev limit, the iron blocks were fine, it was the valve springs and valves that were not capable enough.

I've often wondered what a "Desmodromic" Ducati type valve actuation would be like in a Nascar engine that did not have to worry about valve spring limitations.

[MadMax]

The Ford RY45 (large displacement, aluminum block developed by Roush Yates from the NASCAR FR9 for Late Model and off road trucks)

That engine would be stronger, lighter and smaller if it had a CGI block. It also does not last as long as a Nascar block made out of CGI.

These engines are designed to go 4000 miles between rebuilds, This is a linerless, A356Cu alloy block.

If that engine was made out of CGI it would last over 15,000 miles between rebuilds.

Do they rebuild because of the block or because of the bits in the block that whizz up and down and round and round at high speeds? Clue: it's not the block.

F1 engines are quite fragile. They've come a long way since the 1980's and 1990's but still fragile. F1 engines are not even producing 19,000 rpm like they use to. If current F1 engines were reving much higher they would last maybe two races like they did back in 2004-05.

So what? The current rules do not allow for 19k rpm so the longevity of a current engine at those speeds is irrelevant.

The Audi LMP Diesel program also had an alloy block, with no liner, steel pistons, also a structural component of the chassis, and were also well north of 200 bar with rapid combustion (which is hard on parts).

Their iron engine block was stronger than the aluminum one. Audi wanted a engine to last one race, not over 15,000 miles.

If the engine lasted as long as it was required to, what's the problem? You design something for a given purpose and with given parameters and then choose materials, etc., to suit those parameters. If aluminium works and is easier to make, why choose something else?


Again: what is your purpose in pushing the idea that F1 should use CGI in the engines?

[Honda Porsche fan]

....

[MadMax]

An F1 engine block and heads made out of CGI would be more powerful, more compact and last longer.

You say that but with nothing to back it up.

The current engines' power output isn't limited by the block material - it's limited by fuel flow limits and engine speed limits written in the rules. The aluminium blocks don't limit the power.

F1 engines have layouts controlled by the rules. Losing a fraction of a millimetre here and there won't make any difference to the performance of the cars.

As for lasting longer, it's not the block that limits the lifespan of racing engines. It's the moving bits or their wearing surfaces that limit longevity.

Which has better thermal conductivity between aluminium and iron? What is one thing you want to avoid in a racing engine (or any engine really)? If you can deal with heat more easily, that might be a defining characteristic that leads your choice of material, especially if both materials can easily deal with the structural loads being presented to them.

[Hoffman900]

Do they rebuild because of the block or because of the bits in the block that whizz up and down and round and round at high speeds? Clue: it's not the block.

F1 engines are quite fragile. They've come a long way since the 1980's and 1990's but still fragile. F1 engines are not even producing 19,000 rpm like they use to. If current F1 engines were reving much higher they would last maybe two races like they did back in 2004-05.

So what? The current rules do not allow for 19k rpm so the longevity of a current engine at those speeds is irrelevant.

If the engine lasted as long as it was required to, what's the problem? You design something for a given purpose and with given parameters and then choose materials, etc., to suit those parameters. If aluminium works and is easier to make, why choose something else?


Again: what is your purpose in pushing the idea that F1 should use CGI in the engines?

An F1 engine block and heads made out of CGI would be more powerful, more compact and last longer.

No it wouldn't. CGI is not a new technology, it's been around for half a century. It's only used where the rules require it. You have nothing to back this up with and keep bringing up tensile strength as if they need more. Clearly they don't and you're ignoring about a dozen other considerations for material choice.

I would really like to see Nascar go back to what they were doing in the 1990's with engine rules that allowed engine builders to aggressively invest in new valve spring design/construction and push the rev limits.

In the late 1990's and early 2000's before the rev limit, the iron blocks were fine, it was the valve springs and valves that were not capable enough.

I always wondered what a "Desmodromic" Ducati type valve actuation would be like in a Nascar engine that did not have to worry about valve spring limitations.

PVRS is a better solution than a Desmo type valvetrain. The Desmo valvetrain came about before PVRS. Del West proposed to NHRA a PVRS system for NHRA Pro Stock in the 1990s but NHRA rejected it despite builders being onboard. They didn't even bother asking NASCAR because they already knew the answer.

NASCAR engines were at about the limit and would be at the limit of what the pistons could withstand with no limit. They already had higher peak piston speeds than the 19,000rpm+ F1 engines. It would require allowing MMC pistons with no weight limit, and even then, it would eventually require less stroke. The biggest change they could do if they wanted to keep the architecture and rpm limit, but make the engines more powerful is get rid of that silly EFI system that was spec'ed, let me them go with a bespoke manifold actually designed for fuel injection, allow them to run MUCH higher fuel rail pressures (I think they're like 5.5bar, a blank sheet port injection design would be north of 200 bar these days) and put the injectors where they want. Both NASCAR and NHRA Pro Stock spec'ed fuel injection systems that are 1990s sophistication wise, but everyone has to run the same stuff, so it doesn't really change the show, but that's all a sidebar.

[Honda Porsche fan]

Do they rebuild because of the block or because of the bits in the block that whizz up and down and round and round at high speeds? Clue: it's not the block.


So what? The current rules do not allow for 19k rpm so the longevity of a current engine at those speeds is irrelevant.




If the engine lasted as long as it was required to, what's the problem? You design something for a given purpose and with given parameters and then choose materials, etc., to suit those parameters. If aluminium works and is easier to make, why choose something else?


Again: what is your purpose in pushing the idea that F1 should use CGI in the engines?

An F1 engine block and heads made out of CGI would be more powerful, more compact and last longer.

No it wouldn't. CGI is not a new technology, it's been around for half a century. It's only used where the rules require it. You have nothing to back this up with and keep bringing up tensile strength as if they need more. Clearly they don't and you're ignoring about a dozen other considerations for material choice.

I would really like to see Nascar go back to what they were doing in the 1990's with engine rules that allowed engine builders to aggressively invest in new valve spring design/construction and push the rev limits.

In the late 1990's and early 2000's before the rev limit, the iron blocks were fine, it was the valve springs and valves that were not capable enough.

I always wondered what a "Desmodromic" Ducati type valve actuation would be like in a Nascar engine that did not have to worry about valve spring limitations.

PVRS is a better solution than a Desmo type valvetrain. The Desmo valvetrain came about before PVRS. Del West proposed to NHRA a PVRS system for NHRA Pro Stock in the 1990s but NHRA rejected it despite builders being onboard. They didn't even bother asking NASCAR because they already knew the answer.

NASCAR engines were at about the limit and would be at the limit of what the pistons could withstand with no limit. They already had higher peak piston speeds than the 19,000rpm+ F1 engines. It would require allowing MMC pistons with no weight limit, and even then, it would eventually require less stroke. The biggest change they could do if they wanted to keep the architecture and rpm limit, but make the engines more powerful is get rid of that silly EFI system that was spec'ed, let me them go with a bespoke manifold actually designed for fuel injection, allow them to run MUCH higher fuel rail pressures (I think they're like 5.5bar, a blank sheet port injection design would be north of 200 bar these days) and put the injectors where they want. Both NASCAR and NHRA Pro Stock spec'ed fuel injection systems that are 1990s sophistication wise, but everyone has to run the same stuff, so it doesn't really change the show, but that's all a sidebar.

What do you think of 180 degree crank, 4 valves per cylinder, dual overhead cams, gear driven cams, finger follower rocker arms and dual injection for Nascar engines ?

Maybe adopt a combo of Ford Coyote and Corvette C8R tech ?

[Hoffman900]

An F1 engine block and heads made out of CGI would be more powerful, more compact and last longer.

No it wouldn't. CGI is not a new technology, it's been around for half a century. It's only used where the rules require it. You have nothing to back this up with and keep bringing up tensile strength as if they need more. Clearly they don't and you're ignoring about a dozen other considerations for material choice.

I would really like to see Nascar go back to what they were doing in the 1990's with engine rules that allowed engine builders to aggressively invest in new valve spring design/construction and push the rev limits.

In the late 1990's and early 2000's before the rev limit, the iron blocks were fine, it was the valve springs and valves that were not capable enough.

I always wondered what a "Desmodromic" Ducati type valve actuation would be like in a Nascar engine that did not have to worry about valve spring limitations.

PVRS is a better solution than a Desmo type valvetrain. The Desmo valvetrain came about before PVRS. Del West proposed to NHRA a PVRS system for NHRA Pro Stock in the 1990s but NHRA rejected it despite builders being onboard. They didn't even bother asking NASCAR because they already knew the answer.

NASCAR engines were at about the limit and would be at the limit of what the pistons could withstand with no limit. They already had higher peak piston speeds than the 19,000rpm+ F1 engines. It would require allowing MMC pistons with no weight limit, and even then, it would eventually require less stroke. The biggest change they could do if they wanted to keep the architecture and rpm limit, but make the engines more powerful is get rid of that silly EFI system that was spec'ed, let me them go with a bespoke manifold actually designed for fuel injection, allow them to run MUCH higher fuel rail pressures (I think they're like 5.5bar, a blank sheet port injection design would be north of 200 bar these days) and put the injectors where they want. Both NASCAR and NHRA Pro Stock spec'ed fuel injection systems that are 1990s sophistication wise, but everyone has to run the same stuff, so it doesn't really change the show, but that's all a sidebar.

Would a 180 degree crank, dual overhead cams, gear drive cams, finger follower rocker arms and dual injection also help Nascar engines build more power ?

Maybe adopt a combo of Ford Coyote and Corvette C8R tech ?

180 crank won't hold together at those speeds at that displacement. Been tried many a time. The C8R does because RPM is capped.

DOHC, finger followers, 4 valves, absolutely, but why not just spec an Indy Car engine at that point?

The production Ford Coyotes and C8R are production based engines. Even with good tech features a bespoke purpose built 2 valve is going to make more power and last longer. Either one of those engines won't live 3000 miles spinning at 9000rpm. They weren't designed to do that. The GM, Toyota, and Ford blocks / heads were designed to be 1000bhp platforms and spin 10,000rpm and do so for over 500 miles. They're bullet proof now because they're making half that power.

There is nothing magical about naturally aspirated race engines. A Cosworth CA looks just like a whittled down DFV, a I4 Sportbike engine, a Honda I4, etc. all are pretty much the same. Some are just designed to survive longer at higher rpm (and that's the hard part), but it's extremely formulaic.

[Honda Porsche fan]

No it wouldn't. CGI is not a new technology, it's been around for half a century. It's only used where the rules require it. You have nothing to back this up with and keep bringing up tensile strength as if they need more. Clearly they don't and you're ignoring about a dozen other considerations for material choice.



PVRS is a better solution than a Desmo type valvetrain. The Desmo valvetrain came about before PVRS. Del West proposed to NHRA a PVRS system for NHRA Pro Stock in the 1990s but NHRA rejected it despite builders being onboard. They didn't even bother asking NASCAR because they already knew the answer.

NASCAR engines were at about the limit and would be at the limit of what the pistons could withstand with no limit. They already had higher peak piston speeds than the 19,000rpm+ F1 engines. It would require allowing MMC pistons with no weight limit, and even then, it would eventually require less stroke. The biggest change they could do if they wanted to keep the architecture and rpm limit, but make the engines more powerful is get rid of that silly EFI system that was spec'ed, let me them go with a bespoke manifold actually designed for fuel injection, allow them to run MUCH higher fuel rail pressures (I think they're like 5.5bar, a blank sheet port injection design would be north of 200 bar these days) and put the injectors where they want. Both NASCAR and NHRA Pro Stock spec'ed fuel injection systems that are 1990s sophistication wise, but everyone has to run the same stuff, so it doesn't really change the show, but that's all a sidebar.

Would a 180 degree crank, dual overhead cams, gear drive cams, finger follower rocker arms and dual injection also help Nascar engines build more power ?

Maybe adopt a combo of Ford Coyote and Corvette C8R tech ?

180 crank won't hold together at those speeds at that displacement. Been tried many a time. The C8R does because RPM is capped.

DOHC, finger followers, 4 valves, absolutely, but why not just spec an Indy Car engine at that point?

The production Ford Coyotes and C8R are production based engines. Even with good tech features a bespoke purpose built 2 valve is going to make more power and last longer. Either one of those engines won't live 3000 miles spinning at 9000rpm. They weren't designed to do that. The GM, Toyota, and Ford blocks / heads were designed to be 1000bhp platforms and spin 10,000rpm. They're bullet proof now because they're making half that.

Was the reason why the CART/Champ Car V8 turbo methanol engines from 1994-2002 did not blow up was because they were only 2.65 liter ? I believe Toyota was able to get their engines up to 18,000 rpm by 2002, that's with valve springs.

At what liter does a 180 degree crank become a liability? 5.0 liter? 5.5 liter ? 6 liter ?

[Hoffman900]

The CART engines only were seeing 16,500rpm in qualifying in 2002. 18,000rpm is urban legend.

It’s a stroke issue, but you can only go so big on the bore. 97-100mm is about the sweet spot for good combustion efficiency. Beyond that, at rpm’s beyond 10,000rpm, and you struggle with stable combustion.

Production based MotoAmerica / WSBK engines can be built to go to 15,500rpm with valve springs if allowed by rules.

[Honda Porsche fan]

The CART engines only were seeing 16,500rpm in qualifying in 2002. 18,000rpm is urban legend.

It’s a stroke issue, but you can only go so big on the bore. 97-100mm is about the sweet spot for good combustion efficiency. Beyond that, at rpm’s beyond 10,000rpm, and you struggle with stable combustion.

The Corvette C8R raced in IMSA and raced at the 24 Hours of Le Mans and Rolex Daytona, are those production based engines and if so how do they get them to last ?

[Hoffman900]

The CART engines only were seeing 16,500rpm in qualifying in 2002. 18,000rpm is urban legend.

It’s a stroke issue, but you can only go so big on the bore. 97-100mm is about the sweet spot for good combustion efficiency. Beyond that, at rpm’s beyond 10,000rpm, and you struggle with stable combustion.

The Corvette C8R raced in IMSA and raced at the 24 Hours of Le Mans and Rolex Daytona, are those production based engines and if so how do they get them to last ?

A short stroke for a V8 (3.15in) and a rpm limit dictated by the restrictor and rules that keep piston speeds down. Going back to the bore thing, this means the engine can’t really be any bigger than 5.5L. It would never survive at its factory delivered rpm limit for a 24hr race.

A NASCAR Cup engine has a 3.25in stroke and the rpm they run at, a 180* crank would shake the entire thing apart. I know third hand of a Pro Stock team who tried one in the late 90s and it didn’t get very far.

The Ford Voodoo 180 crank had a 3.7xin stroke and had all sorts of warranty issues from the vibrations and they stopped making it.

The 180* crank doesn’t really make more peak power, but can help with the power curve shape. It also helps with pulling on the ACO mandated restrictors easier.

[Honda Porsche fan]

The CART engines only were seeing 16,500rpm in qualifying in 2002. 18,000rpm is urban legend.

It’s a stroke issue, but you can only go so big on the bore. 97-100mm is about the sweet spot for good combustion efficiency. Beyond that, at rpm’s beyond 10,000rpm, and you struggle with stable combustion.

The Corvette C8R raced in IMSA and raced at the 24 Hours of Le Mans and Rolex Daytona, are those production based engines and if so how do they get them to last ?

A short stroke for a V8 (3.15in) and a rpm limit dictated by the restrictor and rules that keep piston speeds down. Going back to the bore thing, this means the engine can’t really be any bigger than 5.5L. It would never survive at its factory delivered rpm limit for a 24hr race.

A NASCAR Cup engine has a 3.25in stroke and the rpm they run at, a 180* crank would shake the entire thing apart. I know third hand of a Pro Stock team who tried one in the late 90s and it didn’t get very far.

The Ford Voodoo 180 crank had a 3.7xin stroke and had all sorts of warranty issues from the vibrations and they stopped making it.

The 180* crank doesn’t really make more peak power, but can help with the power curve shape. It also helps with pulling on the ACO mandated restrictors easier.

Does a large displacement V4, V6, V10, V12 with a 180 crank suffer the same vibration issues as the 90 degree V8 ?

Can a 6.0 liter V10 with a 180 crank rev higher than a 6.0 liter V8 with a 180 crank ?

[Hoffman900]

The Corvette C8R raced in IMSA and raced at the 24 Hours of Le Mans and Rolex Daytona, are those production based engines and if so how do they get them to last ?

A short stroke for a V8 (3.15in) and a rpm limit dictated by the restrictor and rules that keep piston speeds down. Going back to the bore thing, this means the engine can’t really be any bigger than 5.5L. It would never survive at its factory delivered rpm limit for a 24hr race.

A NASCAR Cup engine has a 3.25in stroke and the rpm they run at, a 180* crank would shake the entire thing apart. I know third hand of a Pro Stock team who tried one in the late 90s and it didn’t get very far.

The Ford Voodoo 180 crank had a 3.7xin stroke and had all sorts of warranty issues from the vibrations and they stopped making it.

The 180* crank doesn’t really make more peak power, but can help with the power curve shape. It also helps with pulling on the ACO mandated restrictors easier.

Does a large displacement V4, V6, V10, V12 with a 180 crank suffer the same vibration issues as the 90 degree V8 ?

Can a 6.0 liter 72 degree V10 with a 180 crank rev higher than a 6.0 liter 90 degree V8 with a 180 crank ?

I really don’t have time to write a dissertation on how to build and design a racing engine from pan to valve cover. You’re going to have to wait for someone else to respond or look this up on your own. No one builds large displacement V10s and V12s.

I will say, F1 programs had terrible vibration problems going from the V10s to V8s, and again going to the V6s. More cylinders reduce velocity fluctuations in the crank.