L33 Power AND MPG??
I have an L33/T56 that I'm going to be swapping into a 2001 Miata. In current factory 4cyl trim, the vehicle gets about 30mpg...but is pretty-much gutless. I drive this vehicle about 150 miles/day, so fuel mileage IS a bit of a concern on this next build....as is longevity.
I saw somewhere online that a comp "thumper" cam yielded a bolt-in 90hp gain with no other mods on a 5.3, but I'm not so sure that it is the way that I want to go. I'm thinking that the rough idle would get annoying in stop/go traffic, even though the conservative lift looks somewhat appealing. On the other hand, I'm pretty sure that a mega-lift cam would probably NOT be all that great for engine longevity (ie; guides,springs).
I'm really wanting to get to as close to 400 rwhp (with a 5.3) as possible with this car. I know what I'm asking for is not ALL going to be acheivable, but I'm wanting to see what y'all think might be a good compromise.
So now to the question:
What are my best options given the above desire for;
-normal aspiration
-30mpg
-400rwhp
-longevity
-a smooth an idle as possible.
Last edited by salemetro; Jan 17, 2011 at 05:38 PM.

Gareth
I may not hit your 400rwhp mark, but it wont be far off
I may not hit your 400rwhp mark, but it wont be far off
I'm thinking that combo would probably net me closer to 300-325 rwhp. It would definitely have great street manners, but I'm hoping for at least 350 at the wheels.
Any other cam ideas?
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So now to the question:
What are my best options given the above desire for;
-normal aspiration
-30mpg
-400rwhp
-longevity
-a smooth an idle as possible.
A mild 6.0L would have a better shot at your goal, and should only cost a little more than the 5.3 if you can tolerate an iron block. Starting with an LS2 would be much more costly.
The other alternative is to drop your N/A requirement. This way you keep the longevity and smooth idle of a stock engine, and retain fuel economy when you are not under boost. Again, you are talking about more money, but you don't have to go boosted right off the bat.




