Viet Nam Vett
Well-known member
- Joined
- May 28, 2004
- Messages
- 2,410
- Location
- Egg Harbor Township NJ
- Corvette
- 65 BB 502 Cp /MSD ATOMIC EFI/ 2009-HUMMER H2
I'm trying to determine which way to go when it comes to sidepipe size.
Since I have puechased a BB 502 I have to address the exhaust. There are several different schools on this subject and it starting to get me a little confused.
I will be doing steet driving and not exceeding 5500 RPM. I want all my torque in the upper midrage ...The 502 makes 567 LBS @ 4200 RPM.
I have already desided on the headers. In speaking with Rich Lagase he has suggested the Sanderson headers which are designed for the 502 BB and the midyear. They are designed to mate up perfectly with the exchaust port of the 502 and fit real nice under and around the motor leaving access to work in the engine compartment.
Rich uses this header on his beautifull 67 502 and it does fit and look great. Now here's the Rub... The stock 2.5 " side pipes flow down to 1 7/8 ' inside the tube which is restrictive.
School of thought #1 is ..If you are not running any more then 5500 RPM this isn't a problem. In fact..because of the smaller pipe the velocity of the gas is speeded up improving low end torque. The problem is after that 5500 RPM back pressure becomes an issue.
School of thought #2 is... The Allen's 2.5 inch "all the way Thru" Sipe Pipes will give you more HP and Torque thru the entire range. Draw back is that they are much louder. Or in other words a 2.5 inch pipe is better then the 1 7/8 pipe.
I wonder if ant one has done a shoot out between these to schools of thought. It would be nice to get some real data on this and not just rely on what the MFG tells you on his web Site.
I know that John Z has thoughts on the Factory 1 7/8 pipes in regards to not being very good as far as HP goes as well as SWC Duke.
Yes I know...This subject has come up before but it is still confusing.
Does any one have any real worl data here and or dyno comparison swithing between these two sizes? Or just some seat of the pants feel between the two.
Also I do understand that the Header pipe is also part of the equation..
but at this point I'm just trying to determine the best way to go as far as the side pipe.
What are your feelings and or opinion's on this topic. This would be a good subject for one of the Corvette mags. A side Pipe shoot out..