Custom Tuned Turbo Exhaust Systems

[Dusty Bradford]

It's been proven you can swap a big block chevy with a single turbo from gas to alky and cut backpressure in half. The alky is a major factor without putting your super sized turbo into the equation. Both of those are the reason your bp is so low.

 

[Alky V6]

It's been proven you can swap a big block chevy with a single turbo from gas to alky and cut backpressure in half. The alky is a major factor without putting your super sized turbo into the equation. Both of those are the reason your bp is so low.

So having a bp ratio of 1.5-1.6:1 with the T76 Q trim was unordinarily low too?

I would have expected the bp ratio to be very favorable with the change to the Airwerks S510 housing. Really. How could it be anything else? That big gigantic turbine housing on a small V6. The point is that my camshaft spec and header design was picked with the expectation that I could accomplish crossover. And now I have it.

 

[Dusty Bradford]

So having a bp ratio of 1.5-1.6:1 with the T76 Q trim was unordinarily low too?

I would have expected the bp ratio to be very favorable with the change to the Airwerks S510 housing. Really. How could it be anything else? That big gigantic turbine housing on a small V6. The point is that my camshaft spec and header design was picked with the expectation that I could accomplish crossover. And now I have it.

No, just imagine what it would have been if the car was on gas.

Not sure what your saying about the camshaft. Are you saying the camshaft design is helping you keep the bp low? Or are you saying the camshaft was spec'd with the idea that your bp will be low due to the large turbo?

There are large power gains in camshaft alone when a car runs twins vs a single. The cam can be spec'd much more like an n/a cam because bp is 30psi vs 60-80 that a single can produce.

 

[Alky V6]

No, just imagine what it would have been if the car was on gas.

Not sure what your saying about the camshaft. Are you saying the camshaft design is helping you keep the bp low? Or are you saying the camshaft was spec'd with the idea that your bp will be low due to the large turbo?

There are large power gains in camshaft alone when a car runs twins vs a single. The cam can be spec'd much more like an n/a cam because bp is 30psi vs 60-80 that a single can produce.

I spec'd the camshaft with the notion that I would eventually accomplish crossover to take advantage of improved scavenging. The cam does have a lot of overlap. Most people would think me crazy for using the cam spec I designed. As you suggested, the cam I'm using is closer to a n/a cam than a turbo cam. Lobe separation is 110. That's only because Crower insisted on going with 110. I wanted to use 108 like I was using in the v2.0 engine. Now you can better understand my header design choice. If you're going to have crossover and overlap, then you might as well maximize the affect with tuned headers.

I have to tell you. The first quarter mile pass with the 91mm was at Pinks All Out at Bakerfield. Due to a pro light start and 0 boost at the launch, the car I was racing had me by about 4 cars by the 330 mark. After the 330 mark my car pulled like a raped ape. It caught me totally by surprise. I couldn't believe how fast I was catching the car next to me. I had to be careful not to run the car up his tailpipe. My car was drifting over towards him just before I came up even with him.
I ended up crossing the finish about 3 cars ahead of him. That pass was a complete rush. A vid of that pass is in my signiture. Listen to the comments after the finish of the race. I think the spectators thought they had just witnessed a UFO or something.

 

[Dusty Bradford]

I spec'd the camshaft with the notion that I would eventually accomplish crossover to take advantage of improved scavenging. The cam does have a lot of overlap. Most people would think me crazy for using the cam spec I designed. As you suggested, the cam I'm using is closer to a n/a cam than a turbo cam. Lobe separation is 110. That's only because Crower insisted on going with 110. I wanted to use 108 like I was using in the v2.0 engine. Now you can better understand my header design choice. If you're going to have crossover and overlap, then you might as well maximize the affect with tuned headers.

Yes, I can see where your coming from.

 

[Alky V6]

Yes, I can see where your coming from.

I knew you'd finally figure it out sooner or later. :wink: