I know what your thinking, "not another max effort build" but this one is a bit different...Ok I was thinking of a way to build a motor that would do even a better job at daily driving than a stock 5.3L or 5.7 LS1 as far as reliability and geting good gas mileage but still being fun and make better power than a bolt-on LS1, and give you enough to have fun with it at the drag strip and take it on road courses and autocross events. The reason is so it would go into a lightweight (~3000lb) resto-mod car(6spd) that could be driven daily to work and not have to drive a boring 4cyl to get good gas mileage (35+mpg). Now obviously cost is an issue so dont get carried away on exotic parts.

So anyway I was wanting to know ls1tech members thoughts on this...Would it be benificial to say destroke an LS2 6.0L so that you could have a bigger bore for making more hp up top with heads with bigger valves, but have a shorter stroke to conserve gas mileage while puting around town in lower rpm's? Obviously it would be best to have high compression since this would be an N/A build, and since E85 is available in my area, would it be better to use E85 vs pumpgas for this build? Hard part would be trying to match up a good intake to do it all (lowend torque and high end hp). using an LS3's VVT would also be a big help, and has anyone done any testing on rhoads V-max lifters? Has anyone tried doing anything like this with great results? Thanks in advance

 

damn, nobody cares about drivability?

 

GM spends literally millions of dollars on engineers to come up with the absolute best drivability (while meeting DOT requirements) possible.
LS3 or LS7s are going to be pretty hard to beat. Especially for the money.

 

yea but in this case your unrestricted in DOT, emisions since its going into a 72 or earlier model, and aftermarket parts that have spent more money in R&D to make a better product than stock.

 

if you take a stock ls1 and open up the intake and exhaust restrictions in a lightweight car like that I bet thats about all it would take. port the heads maybe I got 31mph highway with boltons and full weight. underdrive pulley, good cold air setup, get the gears and tires right, etc. i bet you could do pretty well.

i wouldn't go to the bigger engine if i was trying to maximize fuel economy

and to answer your question. no, we bought the cars for power, not gas mileage

 

yea but I want to have my cake and eat it too!

 

Then go back to sleep cause youre dreaming kid.

 

Then you need a 6.2L w/ VVT out of an Escalade or Denali, without AFM (aka DOD)

I show this a lot to people, I plan on having VVT for myself one day! This is a VVT 6.2L, they test it on the dyno in stock form with headers. THen they swap in a small cam(222/236 .566/.578 114, 918 beehive valve springs, and phaser limiter. They dont loose any torque, because of the VVT, and gain 70hp!

To me that is "having your cake and eating it too!" You couldnt do that without the benifit of VVT. No cam swap, on our engines, will gain 70hp and not give up a ton of torque.

The 2010 4.8L, 5.3L, 6.0L, and 6.2L now come with VVT acording to GMs website. JUST watch out for AFM, because you cant do a cam swap when you have that without retrofitting it back to non AFM, which is about $1200+ . You can tell if an engine has AFM or not by looking at the valley pan under the intake. If its very bumpy it has AFM. If its smooth, it does not!

 

First, the short stroke / large bore combination is a superior clean sheet power design but in a modified engine only a crutch for more power. More (equally efficient per CC) engine is more power, end of story. These engines were not designed severely over square likely because it is generally LESS fuel efficient and dirtier for emissions. The larger bore and shorter stroke makes flame propagation more difficult and shortens the amount of time that the mixture has to burn, resulting in a two-fold decrease in end result mileage. For mileage you need a more efficient air pump (that's the engine, not the emissions part) or less of it.
That aside, E85 is also directly against what you are looking for. Ethanol, despite the propaganda to the contrary is less efficient. It is precisely this reason that racers preferred it, it offered greater cooling because there was more liquid going through the motor. Additionally, though E85 costs less at the pump it is VERY heavily subsidized and in the end costs more than traditional gasoline.
I'm not trying to got on a soap box here, just trying to educate you on what you likely have NOT heard.

 

only use E85 for FI.you won't gain much gas mileage with a shorter stroke,to offset the cost of a custom rotating assem..the right cam will help improve mileage.