Quote:
Originally Posted by BrianRD
From what I've been reading, a positive displacement supercharger does much better things for low end torque than a turbo. My vote is for an engine between 2.5-3.0 liters w/ a supercharger.
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It depends on the engine design and the turbo system. Many turbo engines have great low rpm power. It's just a matter of proper turbo design and size. OEMs are pretty good at that when they can make their own turbos and design the engine/turbo units as a complete package.
The v35A (lexus 3.5 twin turbo) makes 450 ft lb at 1,600 rpms. Our current 4.0 v6 with a supercharger doesn't make 450 ft lbs - ever at any rpm. The turbo 6 actually has a longer stroke (more leverage on the crank shaft = more torque all else equal) than the 4.0L v6 we have and a really narrow bore.
3.5 turbo v6 is 85mm bore 100mm stroke.
The 1GR 4.0 is 94mm bore 95mm stroke.
And the 3.5 N/A engine in the Taco is the same 94mm bore, 83mm stroke.
For comparison the Ford EB 3.5 is a 93mm bore 87mm stroke.
Toyota's v6 twin turbo makes a lot of low rpm power by design. It's a long stroke, narrow bore, high compression engine with twin turbos that are relatively small and spool very fast. So it's very different from a typical sports car turbo design. It should feel closer to a diesel engine than what most people think of as a turbo car engine that usually has a short stroke, wide bore, and low compression to maximize peak power. The Ford EB is very similar to what you'd get with a turbo on something like the Tacoma 3.5 V6 - high revving engine that makes a lot of higher rpm power, but isn't great off idle. The Toyota twin turbo 6 really is a very different engine, that will perform a lot more like what you'd probably think of as a "truck" engine.
And since 99% of the miles are going to be highway cruising - For me - I'd much rather have an engine that great for highway cruising and has a super wide ratio transmission that allows for the performance off road when I need it.