Turbo 383 in a A-body Barracuda

bjkadron said

I'm not a turbo genius, But I do know that turbo's hate restriction in the exhaust. The standard exhaust that most people run for NA BB's is dual 3" which gives about 14.14 sq" of flow area. To go to a single 4" you would be cutting that down to 12.56 sq" of area. If you went to the 5" you would have 19.63 sq". There is a reason the turbo has a 5" housing. Turbos pump a lot more air than NA engines. Just some food for thought.

Click to expand...

The reason guys reduce the exhaust down is to get the exhaust to the bottom of the car. A bodies don't have a bunch of room to sneak the exhaust out by the firewall & bellhousing area. There will probably only be 3 Feet of reduced exhaust at the most. Once the exhaust is at the bottom of the car at 4" he can SPLIT the exhaust into a DUAL 3 or 4" which should work just fine.

This is one of the reasons guys use Twin Turbo's instead of 1 bigger single................Most of the time it is easier to sneak a 3 or 3.5" Down pipe by the firewall...............

I went with Twins for this reason. I couldn't figure out how to get the exhaust out of the engine compartment without chopping the car up alot! I am using 3.5" Down pipes stepped up to 5" Home made Oval exhaust tips.