Questrions for those who know the BIG ones.

Went to a East Central Iowa pull Saturday.  Those guys know how to put on a local pull.  Anyway, they had a 9,500 or 10,000 lb class that was NTPA.  650 cubes, multiple chargers, 24.5 rubber.  One of them went poof at 270' in front of me.  He opened the side to put the fire out and I swear that turbo was a foot around.  Guy was running 2 stacks, so I don't think they were staged.  I have never heard a more awesome sound in my life that those 3 tractors in that class.  I thought the turbo's had lit when they took off, but at about 25 or 50', I was pretty sure they had gained another turbo and sounded like they were gonna suck us all up.  Just unreal.

Question is, what in the 'ell is under that hood?  Class was 2 binders and a green one that had "3 or 4" turbos'.  Are the 2 turbo guys staged, or are they running half and half?  How much boost and what rpm do those things run at?

Second question.  They also had a 9,300 class with 650 cubes no rpm limit and a 4x4 turbo.  If a guy had the money and desire, what AC would work good in a class like that and what kind of money ground up would it take to build?
AaronSEIA

It was an "Open" class.  Pro-Stocks weighed 9500 lbs had 650 max cubes and one turbo with a 4.1 inch maximum diameter inlet on 24.5 x 32 tires. The Super Stocks (twin stacks) weighed 8200 lbs and were 3 turbos  and probably 540 cubes(unlimited size and in two pressure stages) and 30.5 x 32 tires.   I'd guess 16 to 1800 HP versus 24-2500 HP.   Wheel speeds on 8200 lb SSD of maybe 70 to 80 MPH ?

One big turbo sitting on the exhaust manifold like normal. The exhaust outlet of it splits into a "Y" and then spins each of the top two turbos which then exhaust thru dual stacks thru the hood. The top two feed fresh air thru a "Y" into the compressor of the one sitting on the exhaust manifold. Intake manifold pressures probably between 150 and 200 psi going down the track. Blairstown is this Sunday at noon.