Tyler,
We have a problem.
A big problem.
Let me tell you what we're up against:
Here is a thumbnail sketch of our engine:
3.40 + .065" overbore = 234 cubic inches
early drool-tube, 225 ported head with 1.75" X 1.5" oversize valves
un-milled head with less than .001" variance from perfectly flat, end-to-end
Block un-milled; wasn't needed
Stock, un-modified combustion chambers, giving a measured 9:1 true compresssion ratio using a .020"-thick, shim steel head gasket
ARP 220,000 psi head studs
Wiseco forged pistons, .167" down in the hole
K.1 198 (7-inch long) rods
165 pounds measured compression on a gauge with less than 2 pounds variance from end to end
Bullet cam with 210/210 duration @ .050"-lift, .484"-total lift, with 115 degrees of lobe separation, installed "straight up"
small-block (340) valve springs plus a weak inner spring, giving 135 pounds on the seat and just over 300 pounds, fully open
Stock oil pump
Dropped sump (2 1/2") giving more oil capacity and getting the top of the oil level down away from the counterweights; baffled and with a modified pickup
Aussiespeed Hurricane, long runner intake manifold mounting a 4150, Holley 750cfm 4bbl, with blow-thru modifications by Tom Wolfe, including a boost referenced power valve
Adequate-sized waste gate from Turbonetics set to 10 pounds of boost.
550 HP capable intercooler (Spearco)
Turbonetics T-4 turbocharger that was new-in-the-box when we got it
Ignition is a lean burn distibutor with a locked plate (no centrifugal advance mechanism, and no vacuum advance; just a locked plate) set at 18 degrees advance on the crank. That is 1.1 inches (18 degrees) on our stock dampener.
MSD 6-AL II digital module and a Blaster II coil.
Yet to be installed, is an RJC boost controller
Stock rocker arms and pushrods
Electric fan and electric water pump.
Blowoff valve not installed yet, but purchased.
Walbro gsl 60 psi pump, two filters (one before and one after the pump) and an Aeromotive boost-referenced regulator set at 6 psi.
3,500 rpm Hughes converter
904 with a 2.74 first gear, and full manual, reverse pattern valve body; Turbo Action Cheetah shifter
8.75 reaar end with a new 3.55 Sure Grip center section and Yukon axles. Cal Tracs... 7290 U joints 50/50 shocks in the rear and 90/10's in the front.
Disk brakes on tubular control arms and subframe conectors.
6-point roll bar
Total weight, 2,680, not including driver.
This engine runs flawlessly, starts on the first turn of the key, spins the tires in a most healhy way on both the 1-2 and 2-3 upshift.
It will run 5,500 rpm in 3rd gear and doesn't take very long at all to get there; never misfires. 100% ignition, all the time.
So, what is the problem?
Check this out:
On a boost gauge that has been "bench-tested" for accuracy with a pressure-regulated source of compressed air at 10 psi, under no conditions will this motor (turbo) make enough boost to move the gauge needle off "zero."The fitting for the boost gauge line is on the carbureter hat.
No amount of "tuning" has resulted in this system making any boost at all. NADA!
It acts like the waste gate is 100-percent "open" all the time.
I am on my way to the garage right now to install a cover over the waste gate port on the header that will seal it off, completely, negating the posssibility that the waste gate valve is somehow, open.
This thing runs pretty good with NO boost; from a seat-of-the-pants feel, I'd say it will probably run in the high 14's as it sits, normally-aspirated.
But, we didn't build it to run normally-aspirated.
We've got to get this fixed... DUH!!!
I'll keep you up-to-date on what we are doing...
Bill, scratching my head in Conway, Arkansas
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