Piston/rod package.

[MPNick]

Nick, what's the maximum overbore you'd think is feasable with the FS block? I'd like to bore up to 84.5mm (.060") or 85mm (.080"), but I havn't really been privy to exploring the block terribly much. I have a spare downstairs, but I havn't measured any wall thickness, or really seen how much clearance the water jackets have, and so on. The head gasket seems to have plenty of clearance for an 85mm bore, though. Anyway, let me know what you think, if there's any way I can get to 84.5-85mm bore, even if it requires additional building.

For the NA it is not the problem with the block. The wall are fine. It is i getting a ring set to fit that bore. We are working on an .080 over right now with a ring company. Also looking into a 2.2 stroker kit. The number are close but not there yet.

 

[flat_black]

Ooh... Hey, let me know if you get the .080 over kit working. If you remember what we discussed about the block earlier via PM, I'd gladly arrange something like that, with the Massive Overbore (tm) setup.

 

[MPNick]

Ooh... Hey, let me know if you get the .080 over kit working. If you remember what we discussed about the block earlier via PM, I'd gladly arrange something like that, with the Massive Overbore (tm) setup.

So are you telling me to fast track the .080 over big bore slugs because you are ready for them?

 

[Greensleeper]

A 2.2 kit would be killer... What power we should expect (NA) with a stock head and EMS? And with a p/p head and big cams? Assuming all this with a AWR header and 2.5'' straight exhaust. Thanx!

 

[MPNick]

A 2.2 kit would be killer... What power we should expect with a p/p head and big cams? Assuming all this with a AWR header and 2.5'' straight exhaust. Thanx!

With good gas and a good MPI Tuner tune you have to be over 200whp.

 

[Greensleeper]

200 whp with a good p/p and big cams right?

 

[MPNick]

200 whp with a good p/p and big cams right?

Yes with a fully done head and manifold package.

 

[Greensleeper]

MMMMmmmmmmmmmmmmmmmmm, tasty! Maybe my project for next winter. Meantime, someone buy this to see what it can do

 

[smo0f]

Hey Nick,

Just curious, how is all this stuff comparable to what I'm getting done? Do I need any of it?

P.S. I'll be dropping by tomorrow or day after with some mula

 

[MPNick]

how is all this stuff comparable with some mula

You always ask the right questions.

Long rod yes, that what we are doing. stroker no.

 

[smo0f]

lol did you mean to mangle up my quote and turn it into a joke, coz i'm missing it heh. what is stroker?

 

[Kooldino]

What about increasing displacement? How bout a 2.2l or 2.3l stroker kit????(thumb)

at 83x92mm, the LAST thing these motors need is more stroke.

In fact, the 2.0L is basically a stroked version of the 1.8L...which was already undersquare to begin with.

If I was looking to increase displacement in these motors, I'd bore. The piston speeds of a stroke significantly greater than 92mm at 6000+RPM are mind numbing.

...but that's just one man's opinion.

 

[smo0f]

bleh, can someone define bore, hone, stroke for me please? And I think Nick told me about gas porting before and I said I want it but i don't remember what it is. Little engine 101 please!

p.s. all 3 words sound sexually explicit, what's up with that

 

[Kooldino]

bleh, can someone define bore, hone, stroke for me please?

in layman's terms:

Bore (noun) = the diameter of the cylinder.

Bore (verb) = The act of increasing the diameter of a cylinder.

Stroke = the distance that the piston travels from it's highest point (TDC, or Top Dead Center) to it's lowest point (BDC, or Bottom Dead Center)

Hone = a process similar to boring a block, except only VERY mildly...just enough to clean up the cylinder walls.

 

[smo0f]

awesome!

now, can you explain in detail/technical (while maintaing as much newbie words as possible) how each of those benefit? My guess is boring allows more fuel/combustion/etc and increase in volume/displacement thus more hp. I'm also going to assume that the shorter the stroke the more fuel gets dumped/ignited also allow more hp. Just a guess though based on the definitions. Don't hate.

 

[igdrasil]

...I'm also going to assume that the shorter the stroke the more fuel gets dumped/ignited also allow more hp. Just a guess though based on the definitions. Don't hate.

Ill give some examples:

Shorter Stroke = Motorcycles, High Revving Honda engines, LOW TORQUED, Slower piston speed, capable of more power as revs go higher

Longer Stroke = Trucks, V8's, Proteges, SRT4's. HIGH TORQUED. Faster piston speed, outrun flame speed, so high revs are not as optimal as the shorted stroked engines.

 

[smo0f]

so based on that i guess a balance of some sort will give optimal results? not too short not too long?

 

[Kooldino]

so based on that i guess a balance of some sort will give optimal results? not too short not too long?

Yeah, basically.

Consider this:

Square engine - An engine with an equal bore and stroke. So 85 bore and 85 stroke would make a square engine, for example.

Undersquare engine - An engine with a stroke bigger than it's bore. So a 81 bore and a 95 stroke would make a VERY undersquare engine, for example.

Oversquare engine - An engine with a bore bigger than it's stroke. So a 95 bore and an 81 stroke would make a VERY oversquare engine, for example.

In short, for a given displacement, and all other designs equal, an undersquare motor will generally have more low end torque, but will be very RPM limited, which may lower peak horsepower in the high rpms.

On the other hand, the oversquare motor will usually have less power in the low rpms, but will be more rev happy, which may help with high rpm power.

 

[igdrasil]

so based on that i guess a balance of some sort will give optimal results? not too short not too long?

I would say It depends on application. But long stroked engines are quicker, fun to drive because of its high-torqued low rpm response, but you feel it looses power up top. Basically the car can jump @ mid rpms.

Short stroked and big bores is the "best" combination overall for racing, this is only my opinion. Its weak torque and slow internal speeds makes it less prone for breaking parts while keeping a decent amount of power and unleashing more power as revs go higher.

Transmission plays a big role when taking advantage of engine properties.

 

[Kooldino]

now, can you explain in detail/technical (while maintaing as much newbie words as possible) how each of those benefit?

Well, a bigger bore will just make your motor bigger. And generally speaking, a larger version of the same motor will usually end up making more power. An oversimplified way to think of boring a motor is this:

Let's say we start with our 2.0L motor, and you bored it out and and made it a 2.1L. Your motor is now 5% larger. You could probably expect somewhere near a 5% increase of power due to the size.

Basically, with a bigger bore, your motor is doing the exact same thing, but just on a slightly larger scale. It's a bigger version of the same engine. Boring a motor doesn't really change the power curve, it generally will just add power to the entire curve.

My guess is boring allows more fuel/combustion/etc and increase in volume/displacement thus more hp.

You got it.

I'm also going to assume that the shorter the stroke the more fuel gets dumped/ignited also allow more hp. Just a guess though based on the definitions. Don't hate.

You're off on that one. At a given RPM, a shorter stroke will allow LESS air into a motor. Make no mistake: if you increased the stroke on an FS-DE
from a 92 to say...100, and you revved your motor to 4000rpm, the 100mm stroke motor will make more power than the 92mm. At any given RPM that are within safe operation ranges of BOTH of the motors, the 100mm motor will make more power.

HOWEVER, the problem is that the 100mm motor is so extremely undersquare that it can't safely rev as high as the 92mm motor could (for various reasons). You'd lose hundreds of RPM off of your redline from the 8mm difference in stroke. See, when you change stroke instead of bore, you're changing the physics of the motor more, which may have negative effects, depending on what you're trying to accomplish.

Cliff notes:

GENERALLY SPEAKING*:
adding bore = more power everywhere.

adding stroke = lower redline, but more power than non-stroked until the new redline is reached.



*This isn't true in all cases, but most.