Is a 2.5l stroker crank worth it?

[dannyman742]

Im building a 93 240 drift car and im going to do rods and pistons. I thought about swapping the crank while in in there for 86mm and 2.5l of displacement. How much difference does this 0.2l make throughout the powerband? And is it worth it?

Specs:
Ported 531 head
93 squirter block
Yoshi rods pistons
Holset he341 30 psi
Enem k15 turbo cam
E85
Haltech 1000
Kl racing turbo manifold and cast intake manny
Do88 intercooler with 2.5 inch piping

[poulrais]

Originally Posted by dannyman742

Im building a 93 240 drift car and im going to do rods and pistons. I thought about swapping the crank while in in there for 86mm and 2.5l of displacement. How much difference does this 0.2l make throughout the powerband? And is it worth it?

Specs:
Ported 531 head
93 squirter block
Yoshi rods pistons
Holset he341 30 psi
Enem k15 turbo cam
E85
Haltech 1000
Kl racing turbo manifold and cast intake manny
Do88 intercooler with 2.5 inch piping

It's also a forged steel crank btw...

[culberro]

Originally Posted by poulrais

It's also a forged steel crank btw...

Cast redblock cranks aren't exactly known for failing....

[Stiggy Pop]

I'm not sure anyone has any real data to answer the question but my thoughts on this:

I bought a complete boat engine for $100 and the 2.5l crank is sitting in my shed. If I ever have to build another engine/replace my current forged rods & pistons I'll certainly take advantage of it and build a stroker. I'm not sure I would spend ~$500 to buy a crank from someone else, though.

side note: I have 158mm rods in my 2.3l with Wiseco pistons and the lighter pistons make a difference in how quick the car revs over the regular 156.

[JohnMc]

I'd comment, but really, have no experience with a stroker motor.

I do have a B20 in my old car with another .2(ish)L of displacement added to it, but that was with bore, not stroke, and AFAIK a stroke change will make more of a difference than a bore change. The .2L of added bore displacement didn't really add much in the way of peak HP, but did add torque, especially down low. And I think it has continued to benefit the HP as I've added other mods which raised the torque range.

But that's normally aspirated, and I think the effects of .2L on a boosted motor would still exist, they'd just be relatively less important than all of the other aspects - efficiency of the turbo, how much boost, intercooler, intake manifold, etc.

In other words, yes, it would make a difference, but so would turning the boost up another psi.

[Harlard]

Expect a specific output increase commesurate with the change in displacement. I'm swapping in a 2.5L block into my car, which would correspond in a ~20 lbs-ft bump in the 2000-3500 range where my current engine makes very little torque. You can expect a minimal improvement in spool time out of that turbo also.

If you are already forking over money for rods and pistons, figure out whether the incremental cost increase is worth the nominal performance improvement and go from there.

[Stiggy Pop]

Originally Posted by Harlard

2000-3500 range where my current engine makes very little torque.

16v problems

[Harlard]

Originally Posted by Stiggy Pop

16v problems

Show me them 8000 RPM pulls from your tractormotor

[Stiggy Pop]

Originally Posted by Harlard

Show me them 8000 RPM pulls from your tractormotor

[dannyman742]

Originally Posted by Harlard

Show me them 8000 RPM pulls from your tractormotor

But tractor motors are cooler beacause theyre like... from a tractor or something

[linuxman51]

Originally Posted by Harlard

Show me them 8000 RPM pulls from your tractormotor

speaking of, where are your 8000 rpm pulls?

I've had both cranks up to 8000+ rpms

[mikep]

*ABIGGERHAMMER has entered the chat

[dannyman742]

Originally Posted by linuxman51

speaking of, where are your 8000 rpm pulls?

I've had both cranks up to 8000+ rpms

Is that 8v or 16v power?

[culberro]

Originally Posted by Harlard

Show me them 8000 RPM pulls from your tractormotor

The rally car with its stock b230 bottom end went to around 8k+ for an extended period of time on many occasions.

[culberro]

~8% power increase from displacement alone + ~4% torque and power increase from longer stroke.

[2manyturbos]

Originally Posted by culberro

~8% power increase from displacement alone + ~4% torque and power increase from longer stroke.

With a small engine, those are huge numbers. Well worth the cost difference if you are budgeting for an engine build.

[linuxman51]

Originally Posted by dannyman742

Is that 8v or 16v power?

16v. stock crank and pistons.

[Harlard]

Originally Posted by linuxman51

speaking of, where are your 8000 rpm pulls?

I've had both cranks up to 8000+ rpms

Closest log I have is when it threw the power steering belt at 7750

[Harlard]

As is customary, I fail to deliver:

[linuxman51]

typical.

[culberro]

The scene:
Harlard gets ready to make pull to 8500 and data log it, just to make Kenny proud.

I patiently await the text about something breaking.

[Harlard]

Originally Posted by culberro

The scene:
Harlard gets ready to make pull to 8500 and data log it, just to make Kenny proud.

I patiently await the text about something breaking.

Joke's on Bobbert: Pig has failed to move under its own power since 8/1/2021

[linuxman51]

Originally Posted by culberro

The scene:
Harlard gets ready to make pull to 8500 and data log it, just to make Kenny proud.

I patiently await the text about something breaking.

hahaha

[apachechef]

Originally Posted by linuxman51

speaking of, where are your 8000 rpm pulls?

I've had both cranks up to 8000+ rpms

how is this graph curving under itself like a breaking wave?
brown line?

[redblockpowered]

what happens to power and RPM when you lift?