low end torque and s6 (93) Irons
07-11-12, 02:09 PM
#1
low end torque and s6 (93) Irons
So i'm building a car right now and my whole build has been directed towards having a nice low end and mid range monster. My question to all of you guys is what is the breaking point of torque on a 93-95 motor. Without extra dowels...just oem studded and doweled motor.. My goal is 400-480 RWHP and as much torque as I can muster up out of her.. All advice would be greatly appreciated! thanks much!
- Ap
- Ap
07-12-12, 02:39 PM
#2
You're all set with the factory design (structurally) for your power level/levels. More importantly when it comes to porting; what turbo will you be using, what boost pressure, and what's the cars purpose...?
I've built a couple motors with tight tolerance cryo-treated rods that do tighten the what I call "housing shifting". Next comes running rods in 5 high stressed points of the engine that go all the way from the rear exterior iron to the front exterior iron. That's much more than you need to know though...
I've built a couple motors with tight tolerance cryo-treated rods that do tighten the what I call "housing shifting". Next comes running rods in 5 high stressed points of the engine that go all the way from the rear exterior iron to the front exterior iron. That's much more than you need to know though...
07-12-12, 02:47 PM
#3
Forgot to add the other most obvious variable... your chosen tuner! Make sure he can answer the balancing principal where the same power may be made using a lean mixture with less timing or a rich mixture with an increased advance if you choose to sacrifice fuel for a safety margin.
Lean is mean and can also "help" the engine live longer due to less hydrocarbon build up on the rotors. If I were to advise you on the topic I would throw some water-injection on the car and increase the timing with liberal use of fuel
Lean is mean and can also "help" the engine live longer due to less hydrocarbon build up on the rotors. If I were to advise you on the topic I would throw some water-injection on the car and increase the timing with liberal use of fuel
08-01-12, 12:00 AM
#7
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Nice project, and perfect choice of turbo!
But... (and there's always a but!) there's no way you will make 450 ft-lbs of torque at the wheels with 22 psi boost. Torque is a representation of efficiency and displacement (whether strictly engine displacement or forced induction as well). If you look at a very efficient engine, such as Logan from Defined Auto's N/A semi-pp 20B, which makes 80 ft-lbs of torque per piston-equivalent liter naturally aspirated, and scaled it to a 2-rotor at 22psi (2.5 BAR which is equivalent to roughly 2.5 x the torque), you would get ~450 ft-lbs of torque at the wheels. However, this is an engine without a turbo (restriction), with higher compression, semi-peripheral porting, and that has been designed from intake to exhaust and everything in-between to be efficient.
A more realistic comparison is this auto-x FD, designed for great low-end torque: https://www.rx7club.com/single-turbo...d-dyno-956766/ Here, with a small turbo and stockports, they make 350 ft-lbs of torque with 19 psi in a narrow power-band, or ~67.5 ft-lbs of torque per liter N/A equivalent. This engine @ 28 psi would make nearly 450 ft-lbs of torque, if the turbo could handle it.
Not trying to be a Debbie downer here, just trying to help you on the right track!
I'm sure you will be happy with the results regardless of the numbers.
But... (and there's always a but!) there's no way you will make 450 ft-lbs of torque at the wheels with 22 psi boost. Torque is a representation of efficiency and displacement (whether strictly engine displacement or forced induction as well). If you look at a very efficient engine, such as Logan from Defined Auto's N/A semi-pp 20B, which makes 80 ft-lbs of torque per piston-equivalent liter naturally aspirated, and scaled it to a 2-rotor at 22psi (2.5 BAR which is equivalent to roughly 2.5 x the torque), you would get ~450 ft-lbs of torque at the wheels. However, this is an engine without a turbo (restriction), with higher compression, semi-peripheral porting, and that has been designed from intake to exhaust and everything in-between to be efficient.
A more realistic comparison is this auto-x FD, designed for great low-end torque: https://www.rx7club.com/single-turbo...d-dyno-956766/ Here, with a small turbo and stockports, they make 350 ft-lbs of torque with 19 psi in a narrow power-band, or ~67.5 ft-lbs of torque per liter N/A equivalent. This engine @ 28 psi would make nearly 450 ft-lbs of torque, if the turbo could handle it.
Not trying to be a Debbie downer here, just trying to help you on the right track!
I'm sure you will be happy with the results regardless of the numbers.
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08-01-12, 07:45 AM
#9
I don't have any experience with the GTX turbos yet ironically. If you want to pickup low and midrange torque be conservative with your exhaust system. Meaning don't run a straight through system and don't run larger than you need. I'd suggest honestly sticking with 3" for what you seem to be going for.
I wish you lived on the east coast man! LOL, next time I'm out west I'm gonna visit!
I wish you lived on the east coast man! LOL, next time I'm out west I'm gonna visit!
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