06Saleen3V

I was PM'd about this last night from an inquisitive mind and this is my response to him regarding stroking the motor. Increasing the stroke increases the swept volume (which is the volumethatthe piston is "sweeping" inside the cylinder)of each cylinder andincreases an engine’s displacement. With more displacement, comes more power. Remember though, when you increase your displacement (your going from a 4.6L to a 5.0L) without increasing the combustion area, your compression ratio will go up. If your compression ratio is too high, you wont be able to run as much boost. Here is BBR's stroked rotating assembly click . Kits like these usually add 40-50rwhp on average.

baha

+1 but I wish I know how much power or what is the percentage of power gain with increased compression. and this is why Corvette Z06s and Porsches, BMWs have compressions of even more than 11:1

Philostang

+1

The moral of Dex's point is that you need to know what your induction plans are before you do your build.

The particulars of each build and available fuel are very important, but here's a simplified outline. Though you are likely to lose hp with a stroked and lower compression engine, you'll be able to run more boost (on the same octane fuel) than the same engine built to the original (or moderately higher) compression. Since you'll gain more hp for the additional boost you run than you would from the points of compression, the low compression higher boost engine is going to have greater power making potential than its high compression low (or no) boost counterpart. These are super-wide generalizations, so you really need to have a goal firmly in mind (power, use, longevity, etc.), and talk with your builder about the best way to achieve them.

Best,
-j

forensicsteve

I bought the MMR 950 (rated at 950 rwhp). It's still in transit from CA. with upgraded fuel rails. Also sent them the heads to be ported and get comp cams. A mate of mine bought my stock block and since he is extremely mechanically inclined, he's going to build it up with a stroker kit. I chose to go with the whole block because I'm useless at car mechanic stuff.

Told MMR what I was doing, what my power goals wereand what other things car had, turbo, tranny, fuel systemetc. and they took it from there.

ADudeInNewJersey

My plans are to sqeeze out every bit of up and torque out of this bad boy motor. And after all that, just have nitrous maybe 2 stages for the track. I want an all motor car. So what should I do? What compression ratio should I go with and what else should be wanted out of the strokes kit? I know that this motor can't produce 500 rwhp but I still want to keep in NA. How much rwhp. Can I get out of this motor after the strokes kit?


-John

Mustang3GT07

Stroke it to a 302 and go FI!! Now that would be sweet!

sleeper2

Some people have said it is better to build to 298 than 302. Less problems, knock sensors still work, etc. You'll have to search for this. This is just what I've read, and I'm still trying to read everything I can and sort everything out on this topic.

Sleeper2

06Saleen3V

But what good would come out of that? Hold on, let me think.....Oh yea...the 620hp Saleen Extreme

Dex

I dont think i know of anyone who has done a 11:1 n/a motor on the s197. seems like everyone is going FI

Philo is right on.
with a 8:5 compression you should be good for about 15-20lbs.
8:1 20-25lbs

Something like that.

Philostang

John, two comments: first, if you claim to want "an all motor" car, then you've defeated yourself with plans for nitrous. You'd be on the juice. That's the classic cheater (read: "non-all-motor") route.

Anyway, the other comment is more of a question. What is your drive for avoiding forced induction? Generally speaking, most plans to "squeeze out" as much as you can from the existing motor are likely to result in as much or more money spent on mods with less return in hp and torque than if you went FI. So I was just wondering what the fascination was with the all motor route.

Best,
-j