Some of this may seem a bit juvenile. It is not my intent to offend, but to provide useful information to everyone that might read this.
If you're asking what I think you're asking, I've seen articles on BOP swaps, iirc, up to 455 CID into a Fiero. These are different engines; I think the Buick was used, but I'm not sure. I've also seen an article on a 415-inch SBC into a Fiero-based kit. I can't remember if the tranny was stock, but if it'll survive, you'd have to really screw up to not make killer power.
With aluminum heads, 87 PON gasoline and a modest ("everyday street use, has to be reliable") build ... with average tuning ... you should be able to get at least 75 horsepower per liter (hp/l) from a naturally-aspirated (USA maker) "pushrod" OHV V8, even if you use a carburetor and a "street" intake manifold instead of fuel injection; for each 2 PON numbers above that, add about 5 hp/l. For iron heads, subtract 10 hp/l. If you're using any sort of sophisticated engine management system -- or supercharging (especially if you include an intercooler) -- these figures can be raised significantly; for instance, the Subaru WRX STi (2.5-liter) makes 300 hp @ 6000 rpm, and 300 lbs-ft @ 4000 rpm, from the factory -- and it weighs a little over 300 lbs. when installed in a buggy.
To figure out how many liters you have, divide your cubic inches by 61.024.
Since we're talking about reciprocating engines: to get your displacement in cubic inches, you'll need to know the bore, the stroke, and the number of cylinders in your engine. This doesn't work for rotaries: they don't use traditional reciprocating pistons.
These steps have to be performed in the order that they are listed:
[1] To save space: any dimension that is expressed in millimeters (mm) should be converted to inches by dividing that number by 25.399.
[2] Divide the bore by 2. Whatever that number is, multiply it by itself. You can do the next few steps in any order you choose:
[3] Multiply that number (the number you got in step [2]) by the stroke. Multiply that number by pi (pi is a constant approximately equal to 3.141562654, but you can round this off to 3.1416 if you like: the results won't be significantly different either way). Multiply that number by the number of cylinders.
Let's imagine that you have a 6-cylinder engine that has a 3.75-inch bore and an 80 mm stroke. Divide 80 by 25.399, so that all the measurements will be in inches. 80 / 25.399 = 3.14973030434269
If you like, for convenience, you can round this off to 3.15 -- but since I didn't go into that, I'll use the figure as it appears. Remember, this is the stroke.
Dividing the bore by 2 gives us 1.875 -- which we multiply by itself:
1.875 x 1.875 = 3.515625
We multiply this number by the stroke:
3.515625 x 3.14973030434269 = 11.0732706012048
We multiply this number by pi, and since I haven't been rounding things off so far, I'm going to use the 3.1416 figure for convenience:
11.0732706012048 x 3.1416 = 34.7877869207449
We multiply this number by the number of cylinders:
34.7877869207449 x 6 = 208.726721524469
The engine has a displacement of approximately 208.726721524469 CID.
Rounding this off, we see that it's a "209-CID" engine. It doesn't matter if the cylinders are arranged inline or in a "V" or if they are horizontally opposed or if they are in some other configuration: the displacement is the same -- whether it's a "two stroke" or a "four stroke."
If we want to know how many liters this is, we divide the CID by 61.024. So that you can see how little difference the rounding makes at this point, I'll show it both ways:
208.726721524469 / 61.024 = 3.42040380054518 liters
209 / 61.024 = 3.42488201363398 liters
Either way, you're looking at a 3.42-liter (or a "3.4-liter") engine.
If you follow the preceding guidelines and use at least 89 PON gasoline, you're looking at a streetable 80 hp/l with aluminum heads.
3.42 x 80 = 273.6 horsepower
Taking the 10 hp/l penalty for using iron heads lowers the specific output to 70 hp/l.
3.42 x 70 = 239.4 horsepower
The most common variety of 350 SBC, also known as a "5.7 liter" engine, has 349.81 CID, or 5.732 liters. With aluminum heads, figure on 430 horsepower using 87 PON gasoline; if you can guarantee that your PON will not fall below 93, you can build for 516 horsepower.
Note: the Btu content of gasoline is the same regardless of the octane rating; higher octane will not give you more power: the octane number is inversely proportional to the tendency of the fuel to cause detonation when subjected to prescribed test conditions. At the risk of oversimplification, higher octane allows other tuning and engineering methods to be employed, which methods may result in higher power.
If I find anything on the swaps online, I'll try to remember to post it here.
near perfect murcielago and batmobile turnkeys!!!!
Posted - December 14 2004 : 7:32:24 PM
