What determines a "2 Barrel Piston"......I see these advertised, but just don't get what that means.....Are you not able to use these in a 4Bbl engine? Would they not work in a street/strip type application? Thanks all!!
BradMKY
The reference of "2 barrel" piston pertains to it's intended usage, which is lower HP circle track classes that have a 2 barrel only carburation rule.
These type of piston are very light, with thin wall pins, and are intended to be used in a maximum 400-430 HP engine as they are not considered strong enough to be reliable at power levels above that.
Their light weight allows you to run lighter cranks and rods, for less rotating and reciprocating weight, with the intention of that helping the car to be faster on the track.
These type of piston are very light, with thin wall pins, and are intended to be used in a maximum 400-430 HP engine as they are not considered strong enough to be reliable at power levels above that.
Their light weight allows you to run lighter cranks and rods, for less rotating and reciprocating weight, with the intention of that helping the car to be faster on the track.
I was kinda like hcompton....
The part no. says its designed for '2 barrel class racing.' I'm thinking maybe a class of racing that only allows a 2 barrel carb on the motor?
Pic looks like a typical flat top piston to me..
The part no. says its designed for '2 barrel class racing.' I'm thinking maybe a class of racing that only allows a 2 barrel carb on the motor?
Pic looks like a typical flat top piston to me..
Yes they can be used in a 4 bbl engine. The reference is to carb limit of race engines. There are basically two different 2 bbl classes though this can vary a lot by track and association. However, generally they are as follows:
A) 350 cfm in cam limited engines, these would be engines that are limited to mostly stock components which develop around 300 to 330 horsepower. Pistons used in these classes by rule are castings usually hyper-eutectic. Pistons here can be thought of as "claimer" engine parts.
B) 500 cfm limited Holley on top of and engine that are becoming something toward but not quite at a Cup motor. Here the build will include an aftermarket but production design block where the internal build limits compared to above are much less restricted than paragraph A. But the power is going to be limited by some form of stock unported heads and a carb capacity of 500 CFM. The piston selection for these engines would be 2618 forgings which would be what you see in the link BradMKY supplied. These engines produce in the range of 420-450 horsepower which takes a lot of cam and crazy rocker ratios to suck that kind of power out of 500 cfm Holley and something like production heads. 2618 forgings while they can be run on the street are something of a PIA as this material has a pretty high coefficient of expansion so till the motor gets warm they provide a concert of skirts slapping bore walls. For a street engine running forgings 4032 is a better material while it gives up a little in ultimate strength the coefficient of expansion on this alloy is close to that of hyper-eutectic castings so they can be run with tighter bore to skirt clearance. This has the advantage that they don't need to be warmed up as they don't clatter against the bore, and because of the tighter side clearance they do a better job of stabilizing the rings for better sealing.
Keep in mind that race engines compared to street engines take a huge amount of abuse, it is not necessary to build a street engine to the standards of paragraph B yet pull similar power while retaining excellent reliability and longevity by using internal parts like paragraph A; nitrous or supercharging excepted.
Bogie
A) 350 cfm in cam limited engines, these would be engines that are limited to mostly stock components which develop around 300 to 330 horsepower. Pistons used in these classes by rule are castings usually hyper-eutectic. Pistons here can be thought of as "claimer" engine parts.
B) 500 cfm limited Holley on top of and engine that are becoming something toward but not quite at a Cup motor. Here the build will include an aftermarket but production design block where the internal build limits compared to above are much less restricted than paragraph A. But the power is going to be limited by some form of stock unported heads and a carb capacity of 500 CFM. The piston selection for these engines would be 2618 forgings which would be what you see in the link BradMKY supplied. These engines produce in the range of 420-450 horsepower which takes a lot of cam and crazy rocker ratios to suck that kind of power out of 500 cfm Holley and something like production heads. 2618 forgings while they can be run on the street are something of a PIA as this material has a pretty high coefficient of expansion so till the motor gets warm they provide a concert of skirts slapping bore walls. For a street engine running forgings 4032 is a better material while it gives up a little in ultimate strength the coefficient of expansion on this alloy is close to that of hyper-eutectic castings so they can be run with tighter bore to skirt clearance. This has the advantage that they don't need to be warmed up as they don't clatter against the bore, and because of the tighter side clearance they do a better job of stabilizing the rings for better sealing.
Keep in mind that race engines compared to street engines take a huge amount of abuse, it is not necessary to build a street engine to the standards of paragraph B yet pull similar power while retaining excellent reliability and longevity by using internal parts like paragraph A; nitrous or supercharging excepted.
Bogie
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