Hollow Head (4/2/2012)
For heaves sake, put a big enough intercooler to your system!!!
When we ran our engine at the dyno, we had 0.7 bar (10 PSI) pressure and the intake air temperature never exceeded 35 degrees celsius (95F). More heat means more risk of detonation.
Good numbers, though .
We are currently running the truck non-intercooled...hence the reason for the charge temps being so high. Keep in mind this turbo system was never designed to run this good...it was originally done to fit the stock 292 and make ~350 HP
The current setup uses a blow through carb (holley 650) with boost referenced power valves (BRPV). I had a fit getting them to run on the original engine, and now the new stroker puts a much different demand on the fuel system it is in a much worse state of tune.
I was also fighting a bad fuel pressure regulator, the diaphram had ruptured allowing fuel to be pulled from the intake vaccum reference port. I replaced the regulator only to find out the pump is going bad and cannot deliver the required fuel.
This week I will be changing the fuel pump and also the BRPV's and jets in hopes of gaining control over the fuel curve. The best pull I made on the dyno started with a 10.2:1 AFR, and slowly leaned itself to 11.2:1. We like to target ~11.8-12.0:1 AFR with a carb to make peak power, so the HP curve will get quite a bit better once the changes are made. But if the carb will not agree with me 100%, it will be changed in favor of EFI.
I am pretty impressed with how easily the little engine made power, and since the original turbo system was never intended to be run this hard I might have some updates coming in the near future.
The current setup is (to the best of my knowledge!)
315" via off-set ground crank from Ted, H-beam rods, forged pistons (~9:1), Un ported factory "posted" heads, stainless valves, custom Isky cam specified by me, factory un ported cast iron 4V intake, 60-1 TO4-B 60mm turbo (all late 1970's technology, for the nostalgic look :cool
Dad drives this thing everywhere...but now that I have my hands on it along with a DynoDynamics full load bearing dyno (thanks to Tommy at Performance Engineering for loaning it to us while his shop is being built!!) it will be getting some much needed updates to the fuel system and turbocharger setup.
I will keep you guys well updated...and hopefully make some useful contributions to the forum!
Thanks for looking,
Reed
Reed Patridge
Birmingham, Al
1936 Ford Pickup, Flathead powered cruiser
Model A Roadster, 292" Y-Block "project" vehicle