Pistons - Please

[olaosunt]

So if I skipped the more expensive predator block and settled for Gen 3 coyote /3.662 bore .
Callies 3.8 crank = 5.2 L
MMR 3.84= 5.3 L
The Callies crank would seem a better option as it’s seems made specific for boosted applications .

.... and I would already have a 5.2 in the car (3.65 stroke predator Is being built) so I won’t need to make anymore badges . Lol

Yes ,this would be a spare (a second actually- already have parts to rebuild the stock block with stock length rods and pistons ) .
I may drop the compression if I build the stroker though since other are 12:1 CR.

I cant have too many with my luck . Lol
If one goes down and I put in the spare , I will still have a spare(while one is being rebuilt )
Lol

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[engineermike]

Here’s some fun math for any other car geeks out there:

Max torque = 0.328 x CID x (17.39 - Compression Ratio)

This will yield the most flywheel torque you can make at the threshold of knock on pump gas (non-E85) at OEM reliability levels using GDI. I’ve tested it from 7.5/1 up to 13/1 and it appears to be very accurate in that range. The formula assumes that for any compression ratio, boost and timing are optimized for max torque at that compression ratio. There are dozens of things that can prevent the limit from being met, but very few (if any) have exceeded this number with stock reliability levels. You can plug in different compression ratios and see how much more torque you can make when compression is dropped.

I’ll put together an equation for port injection tomorrow.

 

[markmurfie]

LMAO the formula assumes a lot. So if you have a 17.39 compression ratio, you can't make any torque, and if you go higher than 17.39, you have negative torque, what the gasoline isn't powerful enough to turn the engine over? SMH

By this formula maybe if we left the valves open during the entire compression stroke, we would make more torque. Who needs compression, our FI is going to boost air pressure up to 13 bar before it even enters the cylinder. Think of how Jet engines do it! Oh wait.

Maybe if you used a natural logarithmic function It would be more believable, but then you would have to admit that the higher the compression ratio, the more potential the engine has of making torque. Octane is a limit, lowering an efficiency factor doesnt get you around it, it just hurts output over all. You want air flow, not pressure. Think of what the compression ratio does to the intake stroke.

 

[engineermike]

I figured someone would try and pick it apart but it is, in fact, valid. As I stated, this is an accurate limit between 7.5 and 13/1. It is simply a curve-fit based on what has been demonstrated by the oems. The oems have not produced a pump gas 17.39/1 compression engine and if they did, would it not be at the threshold of detonation?

For example....

- At 11/1 and 3.0 liters (bmw b58), the result is 383 ftlb. The engine is rated at 369 ftlb.
- At 9.3/1 and 3 liters (bmw s58), the result is 485 ftlb. The engine is rated at 443 ftlb.
- At 9/1 and 3.5 liters (ford GT), the result is 579 ftlb. The engine is rated at 550 ftlb.
- At 10.3/1 and 1.5 liters (civic SI), the result is 214 ftlb. The engine is rated at 192 ftlb.
- At 9.8/1 and 3.8 liters (911 turbo), the result is 575 ftlb. The engine is rated at 516 ftlb.

See how it works?

 

[engineermike]

Ok for port injection, the limit would be:

Max torque = 0.262 x CID x (17.24 - Compression Ratio)

Try it out for yourself, but here are some examples:

- At 9.5/1 and 6.2 liters (Demon), the result is 766 ftlb. The engine is rated at 717 ftlb.
- At 9.5/1 and 5.2 liters (predator), the result is 638 ftlb. The engine is rated at 625 ftlb.
- At 8.3/1 and 3.5 liters (XJ220), the result is 508 ftlb. The engine is rated at 475 ftlb.
- At 7.7/1 and 2.9 liters (F40), the result is 442 ftlb. The engine is rated at 425 ftlb.
- At 12/1 and 5.2 liters (voodoo), the result is 432 ftlb. The engine is rated at 429 ftlb.

As I’ve previously stated, the consistency of the limit is striking even across OEMs and engine sizes. I’m not arguing the physics or combustion theory; just that the limit is highly consistent and easily modeled based on the data.

 

[BlueCollarDaily]

So if I skipped the more expensive predator block and settled for Gen 3 coyote /3.662 bore .
Callies 3.8 crank = 5.2 L
MMR 3.84= 5.3 L
The Callies crank would seem a better option as it’s seems made specific for boosted applications .

.... and I would already have a 5.2 in the car (3.65 stroke predator Is being built) so I won’t need to make anymore badges . Lol

Yes ,this would be a spare (a second actually- already have parts to rebuild the stock block with stock length rods and pistons ) .
I may drop the compression if I build the stroker though since other are 12:1 CR.

I cant have too many with my luck . Lol
If one goes down and I put in the spare , I will still have a spare(while one is being rebuilt )
Lol

So you saying you have spade pistons and rods for charity? Lol

 

[BlueCollarDaily]

Ok for port injection, the limit would be:

Max torque = 0.262 x CID x (17.24 - Compression Ratio)

Try it out for yourself, but here are some examples:

- At 9.5/1 and 6.2 liters (Demon), the result is 766 ftlb. The engine is rated at 717 ftlb.
- At 9.5/1 and 5.2 liters (predator), the result is 638 ftlb. The engine is rated at 625 ftlb.
- At 8.3/1 and 3.5 liters (XJ220), the result is 508 ftlb. The engine is rated at 475 ftlb.
- At 7.7/1 and 2.9 liters (F40), the result is 442 ftlb. The engine is rated at 425 ftlb.
- At 12/1 and 5.2 liters (voodoo), the result is 432 ftlb. The engine is rated at 429 ftlb.

As I’ve previously stated, the consistency of the limit is striking even across OEMs and engine sizes. I’m not arguing the physics or combustion theory; just that the limit is highly consistent and easily modeled based on the data.

Wow that explains why my 440ci BBC with 1.9 rod to stroke 3.75 stroke 4.320 bore ( 372cfm intake flow) will pull to 7500rpm and has twice lost the meth pump and lived with no intercooler on 93....engine I'd at 17 psi peak but since it's a F1A-94 it drops back several psi on shift which I assume is the only reason it lived....torque dropped below that....

 

[sigintel]

LMAO the formula assumes a lot. So if you have a 17.39 compression ratio, you can't make any torque, and if you go higher than 17.39, you have negative torque, what the gasoline isn't powerful enough to turn the engine over? SMH

By this formula maybe if we left the valves open during the entire compression stroke, we would make more torque. Who needs compression, our FI is going to boost air pressure up to 13 bar before it even enters the cylinder. Think of how Jet engines do it! Oh wait.

Maybe if you used a natural logarithmic function It would be more believable, but then you would have to admit that the higher the compression ratio, the more potential the engine has of making torque. Octane is a limit, lowering an efficiency factor doesnt get you around it, it just hurts output over all. You want air flow, not pressure. Think of what the compression ratio does to the intake stroke.

So should I just cut the trunk out and drop in a helicopter turbine instead?
Everyone knows we need to build one final dino fuel insane mustang before everything goes all electric.
3200 whp AWD?

 

[markmurfie]

So should I just cut the trunk out and drop in a helicopter turbine instead?
Everyone knows we need to build one final dino fuel insane mustang before everything goes all electric.
3200 whp AWD?

I think like ten years ago, some one did this to a VW new bettle or Jetta wagon and registered it as a hybrid in California to get around emissions.

 

[schmeky]

Having a hard time getting forged pistons for my 2019. Want to retain the stock 12:1 CR with a 3.662 bore. Really want the Mahle pistons, which are the ones Ford uses to build their factory Aluminator engines.

I have been trying to get these Mahle's for nearly 2 months. Found some JE's in stock, but are quite a bit higher in cost. Never thought these would be so hard to get.

Any thoughts on the JE's?

 

[BlueCollarDaily]

Having a hard time getting forged pistons for my 2019. Want to retain the stock 12:1 CR with a 3.662 bore. Really want the Mahle pistons, which are the ones Ford uses to build their factory Aluminator engines.

I have been trying to get these Mahle's for nearly 2 months. Found some JE's in stock, but are quite a bit higher in cost. Never thought these would be so hard to get.

Any thoughts on the JE's?

JE with perfect skirt is nice for plasma bore, they did a blanksheet design too slipper skirts, offset pins...

I was looking a good while back and their 11 to 1 Gen 3 ultra i swear this is off 6 month old memory, is like 373grams which im pretty sure is what the Mahle 12 to 1 no rebalance are...
Their 12 to 1 with the right pin, their plasma bore compliant rings and their K1 Rod...is plus or minus 2 grams as well....

This fall, im thinking HARD on dropping back to their 11 to 1s ultras thermal barrier, for 93 and boost ( up the psi to stock blower speed maybe 1.5 or so get peak torque up out of it ), weigh the stock stack vs it and see how far its off....if the balance pads can be worked go with it....if not buy a hbeam with arp2000 bolts and just toss it together....

The longer this engine holds the less corners or should I say the nicer engine I can build....get the short block ready and the engine is still alive and I might think cams...
Yes i know stock is good to 1200hp id be trying to raise peak rpm...keeping same boost...tune for the cylinder pressure at peak torque as a way to make more power as safe as possible on 93.... so say I raise peak HP with boost cams up 500rpm...PSI same or lower; same or less heat....torque is raised and hp is raised without narrowing the tuning window, adding timing up top....
Then id probably get the blower ported, not to make more max power but more power with the same pull aka less heat being generated...already have catless long tubes....plus let's face it I got WAY to much torque for even a drag pack on the street so moving my peak rpm and torque up a bit serves many purposes...
The nice to generate the heat of 2psi like while making 70hp plus more and higher in the rev band....
Id like around 750whp with 93....it may require a killer chiller to be dead nuts reliable....

Been kicking it around but of coarse i pop another and while a short block without a forged piston will not go back in the car it will be the cheapest quickest path to get it in there....longer it lives more options it opens up...

Then build the 10r80 if that doesn't come first lol...btw i called them a few months ago too and they were out, but said they were going to make some more ( Mahle)

 

[Toy Cobra]

I have the JE pistons in mine. Have had them in for year making 1000+ wheel with zero issues. Very nice quality for sure.

 

[BlueCollarDaily]

I have the JE pistons in mine. Have had them in for year making 1000+ wheel with zero issues. Very nice quality for sure.

Which ones exactly bud? Thanks and also glad to hear of your success...what rod are they hung on?

 

[Toy Cobra]

Which ones exactly bud? Thanks and also glad to hear of your success...what rod are they hung on?

JE Part number 353906
Manley H-tuff Rods.

 

[bauern]

I have the J&E 2018's in a 5.2. Haven't run it yet. You can get them for less than $700. https://www.vividracing.com/pistons...e-1201-70cc-dome-pistons-set-p-152657250.html

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