juno
04-06-2006, 10:15 AM
OK Motorheads!!
There is a lot of talk about what the limit is on our stock motors. Some people claim 450 rwhp or 9-10 psi of boost.
Assuming no detonation the limit appears to be the rods which may stretch at high rpm’s or break at low rpm’s/high load. (Actually, an automatic might eliminate the low rpm/high load problems)
So some food for thought.
It’s been said a million times. It’s all in the tune.
Assuming the tune is safe and the motor in good condition in the following scenarios, let’s talk what-ifs.
If your motor is putting 450 rwhp to the ground safely, what about the difference in an automatic and a standard?. It should be about 5-6%. So an auto car is really making 25 more HP at the motor, but is this still considered safe?
You add UDP’s and an electric water pump which frees up about 20 rwhp. Now your crank and the rods are not seeing any more force, but you just added 20 RWHP.
Now to get to the mythical 450 RWHP mark on a stock motor you have to stuff some air down it’s throat.
Your blower is pushing out 450 RWHP (say 560 crank HP) The belt on the front is consuming another 80 – 100 rwhp. So does that mean the rods are actually seeing 530 + RWHP?
OK, this is where I am headed. A turbo does not load the front of the crank. Say it uses 30-40 rwhp. There is an additional "safe" 50 hp available to go to the wheels. Can you theoretically run 500RWHP safely with the turbo? Can you add another 20 safe RWHP with an electric pump and UDP’s?
Another plus is that the turbo puts a little exhaust pressure on the top of the piston. Will this alleviate some rod stretch? Will it make for a more uniform Rod loading?
The final scenario. Running a turbo with a 3000 stall and limiting the rpm’s to 6200. Will that allow a safe 500 hp tune by eliminating the belt load on the front of the crank, limiting stretch at high RPM’s, and limiting loading at low rpm’s?
Or is the HP limit really the wrong glue we have been sniffing? Is it really torque that is the problem? Is it work over time or just that big peak torque number that does the damage?
What’s the C of C? (Consensus of the Collective)
There is a lot of talk about what the limit is on our stock motors. Some people claim 450 rwhp or 9-10 psi of boost.
Assuming no detonation the limit appears to be the rods which may stretch at high rpm’s or break at low rpm’s/high load. (Actually, an automatic might eliminate the low rpm/high load problems)
So some food for thought.
It’s been said a million times. It’s all in the tune.
Assuming the tune is safe and the motor in good condition in the following scenarios, let’s talk what-ifs.
If your motor is putting 450 rwhp to the ground safely, what about the difference in an automatic and a standard?. It should be about 5-6%. So an auto car is really making 25 more HP at the motor, but is this still considered safe?
You add UDP’s and an electric water pump which frees up about 20 rwhp. Now your crank and the rods are not seeing any more force, but you just added 20 RWHP.
Now to get to the mythical 450 RWHP mark on a stock motor you have to stuff some air down it’s throat.
Your blower is pushing out 450 RWHP (say 560 crank HP) The belt on the front is consuming another 80 – 100 rwhp. So does that mean the rods are actually seeing 530 + RWHP?
OK, this is where I am headed. A turbo does not load the front of the crank. Say it uses 30-40 rwhp. There is an additional "safe" 50 hp available to go to the wheels. Can you theoretically run 500RWHP safely with the turbo? Can you add another 20 safe RWHP with an electric pump and UDP’s?
Another plus is that the turbo puts a little exhaust pressure on the top of the piston. Will this alleviate some rod stretch? Will it make for a more uniform Rod loading?
The final scenario. Running a turbo with a 3000 stall and limiting the rpm’s to 6200. Will that allow a safe 500 hp tune by eliminating the belt load on the front of the crank, limiting stretch at high RPM’s, and limiting loading at low rpm’s?
Or is the HP limit really the wrong glue we have been sniffing? Is it really torque that is the problem? Is it work over time or just that big peak torque number that does the damage?
What’s the C of C? (Consensus of the Collective)