An idea...

[Installshield 2]

So I recently discovered that MAMotorsports will create custom cranks soon...in anything you want...stroked, if your nuts...and DESTROKED!!!!! for us NA people that are not...

So I may be rearranging some of my build status...I made a phone call, and will soon start working on some longer replacement rods for my engine...like a lot longer than the longer than stock pieces that are in there now...and use a new crank with about 87-88mm of stroke...

that will affectively pull displacement down to about 1900 or so (too lazy to do the math right now)...and thorougly remove a chunk of our lowend torque...but the good news follows:

with 88mm of stroke and forged aluminum rods...You could easily get up around 9,000rpm...it would take some crazy ass headwork to breath up there...but theoretically this is where we could start to see upwards of 220whp pretty realistically...

Now remember though, you are lowering stroke, and lengthening the rods...which lowers the piston acceleration, which makes it way better for highend anyway...and then some well laid out cams, and you have one hell of an engine...

I will know more after I give beau a call this week...not sure on price yet, but figure a little over a grand is what most custom billet cranks go for...I can wait till june to get another 1,000 rpm...

but discuss anyway...

 

[toucci]

Sounds awesome, I love reading about this kind of stuff. Maybe some day there will be a NA optimized long block for people like me! hehe.

 

[bonesmp5]

I love RPMs and would love to run mine to 9 grand ---

im not engine liturate -- so could you tell me whats different between stroking and destroking --- pros and cons of either -- thanks

 

[Dimitrios]

Awesome idea; it's the same reason why the Chevy 327 is my favorite small block: shorter stroke (3.25" if I remember right) for optimal acceleration and a nice combination of hp/tq and lower rotating mass.

Good idea indeed!!

 

[Pretzellogic]

Subscribing for any more info.

 

[SpicyMchaggis]

It would be interesting. It really is too bad we're so far apart jaime. It'd be fun to make a few motors together.

 

[Pretzellogic]

No one who tunes a car wants to live where there is snow.

 

[Rogue]

you mentioned loosing some low-end tq...any idea of how much of a loss it would be?

 

[tyusha]

Sweetness Jamie. But hasn't that engine been seating around for like a year already? I mean That's all cool and stuff, but i can't wait to see it in your car

 

[Installshield 2]

haha yeah...I am having a hard time parting with the cash for a standalone...I am not good at spending a huge chunk at once (one reason I stayed away from turbo'ing when I was a protege no0b)...and the grand it takes for the standalone is slowing me up...

I have the cash though, so yeah...I will probably throw the built engine in at least for some test runs...see how streetable that high of compression is...mathmatically its fine...but you know how that goes...

and kyle: you are damn right...I thought you were far away in CT, but now its like the moon or something...soon enough we will meet up, katie (my girlfriend) has been bugging me to take her to Disney World at some point...

but anyway, for anyone who asked...stroking an engine refers to increasing the stroke of the engine, which is the distance the piston travels in half of a rev (or the height of the volume of the cylinder, but that can be misleading, because not all engines have pistons that use all of the cylinder)...

and for a little background...Stroke mostly applies to an engines ability to turn the crank with force, so it mostly applies to torque...lots of stroke is horrible for high rpm, for a bunch of reasons (and you will find that the FS has A LOT of things that hinder high end)...first of all, stroke is directly related to whats known as the MPS (Mean Piston Speed)...more stroke, higher piston speed per crank rpm...that on its own isn't bad (actually this is one point where it applies to torque...max V.E. is reached in engine's at a particular piston speed, not rpm...basically more stroke means the pistons travel faster at a lower rpm...which means your torque band peaks lower in the power band), but once the revs are high...it equals difficulty in breathing, and creates another messy oiling problem...the pistons travel to fast to pull in air affectively, and way more wear is put on the crank, rods, and pistons...

Now apply everything I just said in reverse with destroking an engine...great for highend, but you lose some lowend...how much you lose will depend on what else you do (if you raise compression and destroke the engine, you may not lose any lowend...cams more or less determine what is going on in low revs)

So this is what makes an FS slow in stock form: (some of it I won't get into in this post...but with searching the answers are not hard to find)

poor engine computer...
"torque" cams (lowend grind)
short ass rods (extremely short relative to stroke, which are directly related to piston acceleration...a whole other beast)
and 92mm of stroke

92mm of stroke is perfectly livable with todays available rod and piston materials (for highend I mean)...its the short rods that kill us...a 1.37 rod ratio is among the lowest of any production gasoline engine...one reason why I went with longer rods, but I was still limited...but you can build the engine as exotic as you want...and get it to hold 9k with short rods...but you can literally get into areas where the piston out accelerates so fast that it simply cannot pull anything in...it doesn't breathe, and you make nothing...slowing the pistons down during high rpm is key to high rpm breathing, and overall how to make a small displacement engine make great horsepower...

but overall, I expect to move my peak torque closer into the mid to upper 4,000 rpm range with this mod...I was peaking at around 155lb/ft before, and at about 3800rpm...which I was extremely happy with, despite the annoying flat spot thourgh upper 4's and low 5k's...this mod will probably overall smooth things out...I know it will be a dog until at least 3,000rpm...but who cares...I don't do anything at 2,000 rpm now anyway...

 

[flat_black]

Well, lets see... 88mm of stroke with an 83mm bore yields about 1905cc. Or, you could go with an FP-DE crank/custom rods/pistons/etc, and run 85mm stroke with 2mm of overbore, bringing you to 85mm bore as well, and that would yield 1930cc. Just some food for thought. =)

Or you could overbore 2mm AND get a custom crank, bringing you to 85 bore with 88mm of stroke, which lends itself to an increase in displacement, up to 1998cc, 7cc more than stock.

Never forget about the FP parts! Hehe.

 

[Installshield 2]

true...but I always questioned the quality of the FP parts...now this is dated too, but TheMan always claimed that the FP did not have a forged crank, ever (he said the FS didn't have a forged crank either until 01), and that the entire engine cradle is different, resulting in flywheel problems...and that the cradle itself is weaker as well...

You basically have to change a lot of things to get an FP crank in from what I hear...not just swapping cranks, like with what I am looking at...I know it would probably be cheaper...but I don't want to have any worries of a rod coming through my face at 9200 rpm because of a questionable crank...

who knows...I will do some research on it...maybe tear one out of a wrecked car and run some tests on it...

 

[flat_black]

Ohh, really? Well, I can beleive that. It did feature a 6500rpm redline as well. If it's not forged, then really, it's not worth the hastle.

Alas, swapping ANY crank will require a redesign of the rod and/or pistons, as you'll be changing compression and cylinder volume significantly by stroking it shorter, and keeping the same rods on there. So, I don't think a redesigned 'drop-in' crank will have the degree of 'drop-in' that you're talking about, as several things need to be changed with any crank adjustments.

Hrrm. I'm really curious about the FP crank, now.

 

[Installshield 2]

understood...Longer rods, and new pistons will be redesigned by me...

what I was getting at is that the cranks MAmotorsports are offering seem to be designed around the stock FS cradle...the FP has the same block, but a different cradle and lower bracket...all that needs to be changed in order to use the FP crank...where as what I will most likely go with will use the stock everything, except for rods and pistons...

the whole point of this is so I can use even longer rods than what I am now...and gain higher revs by less piston speed and gain better breathing by lower piston acceleration...

 

[flat_black]

Ooooh, okay, I gotcha. =) Very good. Sorry about that, I was just trying to wrap my mind around what you were looking for.

Muchly a good plan! Got a question for you, though; You say you're going to design new pistons... How much do they cost to get made to your specs? I ask because I was looking for a good place to get lightweight slugs (Trying to reduce the amount of weight those rod bearings are seeing, and all), at 11:1 compression, or so.

 

[Gen1GT]

It's so crazy, it just might work. I don't feel like crunching the numbers, so what's the new rod ratio going to be? You'll still make more torque than any FS with just bolt-ons because of your CR.

Some good stuff happening here.....

 

[Installshield 2]

well, in order to be to my specs (at least my current ones), they would need to have a larger wrist pin sleeve (located nearly 7mm higher than stock), 13:1 static CR with a point break crown (this may be a gimmick, but it helped my grade, and shouldn't hurt anything), and smaller ring lands...

the point break crown would probably cost more, if they would even do it...I used nearly 3 different design programs (mostly AutoCad based, one SolidWorks Plus A2) for the pistons design (not creation)...and one autolathe/jig plus a flow machine for the rods...but remember these were from billet aluminum, so I didn't have to do anything with forging compensation ($$$$$$ and time), or spend much on stock...some of the programs I mentioned wouldn't even be possible if I was forging these things after I cut them...

compression won't really change price, actually nothing other than the crown would change the overall cost and time to make...

But forged aluminum rods of good quality average around $200 or so for a piston (each, from what I remember), and about $150-$500 for a longer than stock rod depending on the company, and mostly on whether or not they are billet aluminum (billet is cheaper, but a little weaker)...

the best place to look would be a good metallurgy company, or engine internal specialist that knows what you are saying when you need a rod for revs, not power...as well as pistons...

may I ask why 11:1?...not saying anything is wrong with that, just trying to get an idea of your goal...and how are your ITB's coming?