[Tom Vaught]

Butler kicked out a 630 hp NA "Street Engine" about 10 years ago (for a great deal less money) for a friend of mine. That being said you assume that you are getting "the best" with a "BES" engine build.

Boosted Engines, just have more mass flow going thru the engine. You build a quality moderately higher horsepower NA engine and you will easily double the horsepower at low boost (15-18 psi). Ed's target was 1600 hp and street driven.

If you look at the engine built by Charlie66 in the Boost Forum and do a comparison to Ed's engine: There are some things similar. Both engines will use a Turbonetics Turbo package with the turbo(s) picked by Dave Austin.

Charlie has a factory 198 cubic Inch Tempest Block. He put 4 Bolt main caps on the factory block. He has a cast factory crank but good rods and pistons. He stepped up and had SD Performance do him a nice flowing head, 300+ cfm head. It is pretty common knowledge that a properly designed head package should make 2 hp per cfm without really special parts. So Charlie would make 600+ hp if he had a 400 cid V-8 engine (lots of these combinations documented on the board). So lets say he makes 300+ HP with his 4 cylinder engine, NA.

So now Charlie adds boost. He was at 15 psi of boost for a long time, before he stepped up to 25 psi of boost. Probably 600 street driven horsepower from a 4 cylinder 195 cid engine at 15 psi boost. Charlie is using a single HP76 Turbo. Even though Charlie now has gone to 25 PSI of boost, he still drives the car daily on the street, using e-85 gasoline.

Dave Austin assumed that Ed's engine would have 750 HP NA. Lynn says the head flows 388 cfm or so. That should allow the NA engine to produce 776 hp using the 2 HP per cfm rule. Ed also has a 535 cid engine vs a 195 engine so making that 750 hp should have been fairly easy with even higher compression. It did not happen!

Charlie is around 8.5 - 8.75 to 1 compression ratio. So Ed's engine is down 116 hp on the normal NA formula with a 9 to 1 CR engine vs Charlies 8.5-8.75 CR engine. Charlie engine would make 300 hp from 195 cid NA or 1.5 HP per Cubic Inch (Home built engine by Charlie with decent parts.)

Ed's engine makes 660 hp from a 535 engine NA so 1.23 HP per CID with the High Dollar heads/engine build. You can see why Ed and others are somewhat confused by the deal.

If we look back at the Turbonetics Sheet Dave Austin assumed that with the larger HPR-88 Turbos Ed could make over 1400 hp with an inter-cooler at 15 psi. With the inter-cooler Dave thought that the engine would make 1680 HP at 20 psi of boost. 5 psi less than Charlie drives around with every day. The HPR-88 Turbos are big HP Turbos, they will make a lot more HP vs Charlies HP-76 Stuff.

So I say, check everything out on the engine, get it fixed to where you are happy, Ed, and then throw some boost at it with a proper Water to Air Inter-cooler or Air to Air inter-cooler. Once Charlie cranked up the boost he was VERY HAPPY with his 4 cylinder project. How about we stop with the BS for the time being, build the package, put it on a proper Engine Dyno with proper instrumentation, and go for a 1600 hp number.

Tom Vaught

Note: (Charlie had excess NA air flow through the head vs the size of his engine). Pastry Chef says Ed has less head flow that he needs NA with the 535 cid engine.