WisdomWarlord
Registered User
I am doing some brainstorming about the limits and limitations of the IDI engine in my 93 F350.
What if I could feed the engine double the amount of fuel at the same time as the stock "turned up" pump?
Lets first assume its doable.
With that much fuel, would it be reasonable to expect the stock shortblock and head studs to produce reliable power if I blew in 45 psi of boost? How about 60? Im thinking that somewhere between 45 and 60 the fuel system would be maxed and adding more boost would just add more stress without a real payoff on additional torque.
The engine would have the stock pistons, so the cr would remain in the 21:1 neighborhood.
My untested assumption is that the head gaskets would be questionable at that boost level, and possibly the head studs.
I've read that fire rings aren't practical on the IDI because the precombustion chambers will get in the way.
If the rings could be cut into the head successfully, is there enough material to do so and not weaken the head?
If the fire rings are a no-go, then there needs to be more clamping force on the heads to hold them down. Is there enough meat in the block for drilling and tapping for thicker studs? 9/16" should be enough of a bump. Let's assume that the machine work can be done and the stud kit is available. Is the block going to provide the material needed to put in bigger studs and not just create new problems.
Or, would both fire rings and bigger head studs be needed to hold the heads down at that level of boost?
I'm assuming that a big beefy cradle will be needed on the bottom of the block to help keep the crank from dancing a jig at full power, and thats not a problem.
This theoretical engine is still expected to be a daily driver and be pretty reliable, but a non-stock cam grind is ok, as long as drivability doesnt suffer. After all, this is still an engine for a work truck.
Sorry this is a bit scattered, it is a brainstorm after all.
Oh, and... What kind of chassis dyno numbers would you expect such an engine to deliver? Lets assume a 2wd srw with an E4OD.
Oh, and lets assume that the compressed air is cooled enough to maintain intake manifold air temps close to the non-turbo engines. I know we can just heat air to some ridiculous temp and increase the pressure to 45psi and not increase the actual oxygen density in the manifold. After all, the actual goal of a turbo is to feed the engine more oxygen, and not just pressure.
Thanks
Keith HP
What if I could feed the engine double the amount of fuel at the same time as the stock "turned up" pump?
Lets first assume its doable.
With that much fuel, would it be reasonable to expect the stock shortblock and head studs to produce reliable power if I blew in 45 psi of boost? How about 60? Im thinking that somewhere between 45 and 60 the fuel system would be maxed and adding more boost would just add more stress without a real payoff on additional torque.
The engine would have the stock pistons, so the cr would remain in the 21:1 neighborhood.
My untested assumption is that the head gaskets would be questionable at that boost level, and possibly the head studs.
I've read that fire rings aren't practical on the IDI because the precombustion chambers will get in the way.
If the rings could be cut into the head successfully, is there enough material to do so and not weaken the head?
If the fire rings are a no-go, then there needs to be more clamping force on the heads to hold them down. Is there enough meat in the block for drilling and tapping for thicker studs? 9/16" should be enough of a bump. Let's assume that the machine work can be done and the stud kit is available. Is the block going to provide the material needed to put in bigger studs and not just create new problems.
Or, would both fire rings and bigger head studs be needed to hold the heads down at that level of boost?
I'm assuming that a big beefy cradle will be needed on the bottom of the block to help keep the crank from dancing a jig at full power, and thats not a problem.
This theoretical engine is still expected to be a daily driver and be pretty reliable, but a non-stock cam grind is ok, as long as drivability doesnt suffer. After all, this is still an engine for a work truck.
Sorry this is a bit scattered, it is a brainstorm after all.
Oh, and... What kind of chassis dyno numbers would you expect such an engine to deliver? Lets assume a 2wd srw with an E4OD.
Oh, and lets assume that the compressed air is cooled enough to maintain intake manifold air temps close to the non-turbo engines. I know we can just heat air to some ridiculous temp and increase the pressure to 45psi and not increase the actual oxygen density in the manifold. After all, the actual goal of a turbo is to feed the engine more oxygen, and not just pressure.
Thanks
Keith HP
Last edited:
