My goals are 250Whp, but I dont think a 7100 redlinewill do. What would be the best choice? Put a K20A2 head on the K24 (TSX Engine) or upgrade the internals (probably Ferrea)? Will I have any reliability issues with the long stroke of the k24?

 

The TSX head is already comparable to the K20a2. Type R cams would help out on the top, but you're not going to make any power past 8,000 without something more radical cam-wise. Much less 8,500 rpms. And at 8,000 rpms, you're definitely going to want upgraded rods for any kind of reliability on the bottom-end.

 

i have heard that simply putting a k20a head on a k24 and revving it to 9 grand simply will not work because of the very very high piston speed. like higher than any ls/vtec.. which has the highest piston speed of any b-motor.

 

Look at it this way . . .

B16 stroke: 77.4mm
F20c stroke: 84mm
K20 stroke: 86mm
B18c stroke: 87.2mm
B18a/b stroke: 89mm
H22 stroke: 90.7mm
F22c stroke: 90.7mm
H23 stroke: 95mm
K24 stroke: 99mm

Making power past 8,000 rpms on a K24 is going to take a LOT of work.

 

Can I push 8000rpm safely?

Its going to be fun having a 7500rpm fuel-cut off and a 8300rpm redline

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SkRiBLaH &raquo;</TD></TR><TR><TD CLASS="quote">i have heard that simply putting a k20a head on a k24 and revving it to 9 grand simply will not work because of the very very high piston speed. like higher than any ls/vtec.. which has the highest piston speed of any b-motor.</TD></TR></TABLE>

an lsvtec has very high piston speed? o.k., so let me get this str8. long stroke motors have higher piston speeds than short stroke motors? oh yeah, i forgot. that's what you heard.

 

yea it has to do with rod/stroke ratio.

 

long stroke motors will have faster piston speeds, b16c1. want to explain it simply to you?

two motors are revving at 7000 rpm. motor A is a short stroke. we'll say a b16 with its 77mm stroke (correct me if im wrong on that figure. Now motor B is an LS motor, revving at 7000 but with an 89mm stroke. the pistons are covering more area (longer stroke) but in the same amount of time (7000 rpm) therefore, the long stroke motors piston speeds must be higher than the short stroke.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B16C1 &raquo;</TD></TR><TR><TD CLASS="quote">an lsvtec has very high piston speed? o.k., so let me get this str8. long stroke motors have higher piston speeds than short stroke motors? oh yeah, i forgot. that's what you heard.</TD></TR></TABLE>
Rpm for rpm, an LS block does have the fastest piston speed of any B engine, simply because it has the longest stroke.

Some more numbers, this time in feet per second @ 8,500 rpms:
B16 - 4,317 fps
F20c - 4,685 fps
K20 - 4,797 fps
B18c - 4,864 fps
B18a/b - 4,963 fps
H22 - 5,059 fps
H23 - 5,299 fps
K24 - 5,522 fps

A K24 @ 8k rpms is pushing 5,197 fps, which is faster than a redlining F20c S2000.

Rod/stroke ratio is another factor, but is actually fairly decent in the K24 block because of it's tall deck & long rods. The raw piston speeds are going to be the biggest problem when we're talking these extremes.

So 8,000 rpms on a K24 block is probably doable. But again, it's gonna take some work on the top end to actually make the trip up there worth your while, and you'll still want forged rods to keep it together on the bottom.


Modified by Daemione at 9:32 AM 4/9/2004

 

Can't you just give a k24a a shorter stroke and then possibly it can rev to around 8,500 rpms with a shorter stroke say around 89 mm to 90 mm?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by H_doubledeuce_A1 &raquo;</TD></TR><TR><TD CLASS="quote">Can't you just give a k24a a shorter stroke and then possibly it can rev to around 8,500 rpms with a shorter stroke say around 89 mm to 90 mm? </TD></TR></TABLE>

thus defeating the purpose of using the k24 block at all...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Daemione &raquo;</TD></TR><TR><TD CLASS="quote">
So 8,000 rpms on a K24 block is probably doable. But again, it's gonna take some work on the top end to actually make the trip up there worth your while, and you'll still want forged rods to keep it together on the bottom.</TD></TR></TABLE>

So, Ti Valvetrain, Forged pistons and Rods, Sleeves, and you are good to 8k rpm?

 

How about trying to use a 04' s2k crank inside the K24 block?

Reduce the stroke a bit, and then get custom pistons and rods with a relocated wrist pin to aid with the rod/stroke ratio..

You could also therefore run a cam with more duration..

 

Many people seem to think destroking it is the way to go.

HEre is IB's K24 Killer short block

PACKAGE 14: IB K24 Block
&lt;&lt; Back Next &gt;&gt;
Description: K24 Block "Killer K Series" is what a lot of people are saying nowadays. This thing is the perfect block. By far the best block for a Honda/Acura we can think of. How about a 90 MM IB Spec Crank, with IB Spec Rods, IB Spec pistons and a Rod/Stroke Ratio of 1.71? How about that? That makes it a 2.2-2.3 depending on bore size! Notice we have DE-STROKED it from 99 MM to 90. So you can make more top end power and rev this thing!
IB Spec Pistons
Compressions come in 9:1, 10.:1, 11.5:1, 12:1, 13+:1
New Type-S oil pump
IB Spec Forged Rods, Ultralight
Crank balanced and Polished
Sleeved so you can bore up to 90 MM!!

 

ahh see from the looks of this Import builders "destroked" the K24a for more mid to top end power. interesting...

 

so de-stroke the k24 by 9mm.

 

yet no one has tooken into account that the rods in these motors are longer. plus anyone who is racing cars and have strokes of above 99 mm ( some top all motor cars) they still rev to 9500 rpms. with rods not as long as these motors k series have................. I just think of these motors as a huge motorcycle engines designed to rev there little hearts out. mr honda knows hoe to build them. but reving that high is not for everyone, just people who want to be fast.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Nikos &raquo;</TD></TR><TR><TD CLASS="quote">Many people seem to think destroking it is the way to go.

HEre is IB's K24 Killer short block

PACKAGE 14: IB K24 Block
&lt;&lt; Back Next &gt;&gt;
Description: K24 Block "Killer K Series" is what a lot of people are saying nowadays. This thing is the perfect block. By far the best block for a Honda/Acura we can think of. How about a 90 MM IB Spec Crank, with IB Spec Rods, IB Spec pistons and a Rod/Stroke Ratio of 1.71? How about that? That makes it a 2.2-2.3 depending on bore size! Notice we have DE-STROKED it from 99 MM to 90. So you can make more top end power and rev this thing!
IB Spec Pistons
Compressions come in 9:1, 10.:1, 11.5:1, 12:1, 13+:1
New Type-S oil pump
IB Spec Forged Rods, Ultralight
Crank balanced and Polished
Sleeved so you can bore up to 90 MM!!

</TD></TR></TABLE>

with 90 x 90, youd have a square motor too! sounds like a good idea, im sure the price on that package is a lot though

 

according to the site, it is $5500 shipped. not cheap, but pretty good for what it is in my opinion. if i had the money right now to put that in an eg, i would have it done by now!

 

Damn I almost hate to post this but...

From what I gather (from some normally reliable sources) the weak link in the k24 rod is the studs. The rod itself is fairly sturdy.

Were shooting for *gulp* 270 whp. With any kind of luck well know something in a week or two.

 

would you mind putting up a parts list?

What you used to build the motor, and maybe things to watch out for?

 

not to high jack this thread but
is doing a k24 vtec just slaping a rsx type s
head on a k24?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tomtomloc &raquo;</TD></TR><TR><TD CLASS="quote">not to high jack this thread but
is doing a k24 vtec just slaping a rsx type s
head on a k24?

</TD></TR></TABLE>

Yes it is.. BUT if you do just that, without changing anything else, the motor will not be able to rev high. The K24 block has a massive 99.0mm stroke, which is very long. A K24 @ 8000 RPMs, the pistons are moving up and down the cylinder walls at much greater speeds than a F20C (S2000 motor) at 9000 RPMs.

Destroking it, is probably to best way to go.

 

thanks i ll just keep it under 8k rpm
anything else i should swap out

my buddy has a rsx type s that has a rod knock i he wants to just sell the block and put a k24 in

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tomtomloc &raquo;</TD></TR><TR><TD CLASS="quote">not to high jack this thread but
is doing a k24 vtec just slaping a rsx type s
head on a k24?

</TD></TR></TABLE>

It's not a frankinstine or making a k24 VTEC, all K-series are VTEC. The purpose of doing is for a certain VTEC function. The k24's 99mm is dangerous to use. NO V8 that I know of has a 99mm stroke and I know corvettes that Rev 8500 street.

(With a complete motor build it's doable with some exotic materials and a lot of blueprinting.)
Now about swapping the k24 head to a K20's, what your exactly doing is putting a 2 liter head for an 86 mm bore on a 2.4 liters block with an 87mm bore (Also 2 liter cams).

Downsides.
Power gains are suppose to be met sooner than the k20 but it does not happen because of the cams and head. Whats really suppose to be happening, torque either is close on # to HP, or shoots straight pass horsepower numbers, but the air flow is limited.