jakebdb56

iTrader: (24)

that's actually how the pcm works anyways. when under a constant rpm range for a few seconds at higher speeds the computer will up the commanded Afr to around 15'ish depending on what os you have. mine goes to 15.5 stock, but when I stomp on it the PE equation allows for a 13.1 afr that's sick on the freeway racing stupid mustangs. like quik said it's all in the tune. I'm still learning a lot using HPtuners, but i've actually been able to increase my highway mileage to about 21mpg at 70mph around town I get **** for mileage though since im a lead foot (13'ish )

moregrip

iTrader: (8)

since this won't be a max effort type build and being silent is a main goal and you have 12 months, the TVS is reported to be significantly quieter than your used to. Beyond that, any of those chargers will work well.

Mr. Sandog

Don't know, that's partly why I was asking questions.

That's why I was thinking forged 5.3L....or maybe 5.7L if the parts are easier to obtain. What about a 4.8L with forged internals and 15-20 (or more) PSI?

I look at the Subaru guys who get 300HP/300TQ from the factory, and with a simple turbo swap, they put out 500/500 on a stock internals 2.5L motor. So obviously displacement isn't everything.

I would like to get better gas around town, too, if that's possible, not just on the highway.

Quik

iTrader: (7)

remember 3800 stall, and alot of hills arond here



i set the target fuel for around 16.1 crusing, yes lean but lean got me the MPG i was shooting for

1slow01Z71

iTrader: (36)

Nobody makes off-the-shelf pistons for the 3.78 bore of the 5.3 now on the other hand the 3.905 LS1 over-bore pistons are a dime a dozen and can be had for pretty cheap(relatively speaking). IMO the diff in displacement isnt going to make a big difference. I got 16 on the highway with my cammed 5.3 and with my 418 with a pig rich tune(mail order to get me back to TX then street tune it) and pulling a 1500# trailer and another 1000 in the truck I got almost 14 on the highway so...

XLR8NSS

iTrader: (4)

The power your old Avy made, is that what you'd be looking for in your new ride? If so then just stick with the 5.3L and boost it with the best suitable blower at the time.

It's a combo you already know so it's not like you'd have to experiment and find out the hard way something didn't work.

I wonder what type of mileage guys with stock/close to stock 6.0L's are getting in RCSB swaps. I know my old 5.3L RCSB would get 21+mpg sometimes which was NICE!! My SS with the radix is lucky to hit 14mpg on the highway now. Fun as hell but, not so nice filling up every 2.5 days.

BLACK04VHO

iTrader: (2)

My old 04 VHO that had a few upgrades got 18-20 on the highway and about 14-16 in the city. This was with heavy 20's and 295/50R20 tires. Mods were CAI, NELSON TUNE, LT, no cats, custom exhaust, descreened MAF. It would hall *** but it always got me from little rock back home to OKC with 50-90 miles left in the tank.

Mr. Sandog

That's pretty amazing, I like hearing stories like this.

From what I understand, camming has a considerable amount to do with mileage, moreso than I originally thought. I remember zippy talking about driving a 408 with a 212/218 hi-lift and getting nearly 20 mpg. That is very appealing to me.

So what do 3.905 pistons with a stock crank in an LS1 block end up equating to in displacement?

What about short-stroking, what would that do? I understand it allows higher revolutions, but what about torque? Does short-stroking help down low? Is it worth it?

I made close to 400/400 in the AV, but would like the exact same stock driveability with at least 150 more RWHP/RWTQ. So we're talking 550/550.

The most converter I would accept would be 2400-2500 max. I would want stock behavior until I really tromped on it, so it would have to be tight.

1slow01Z71

iTrader: (36)

Big injectors and big cams kill mileage obviously. You are correct the smaller cammed strokers get great mileage especially the turbo setup with a mild cam due to "conservative" turbo cams for a stroker being in the low 220s intake and mid 220s exhaust. If it was me I would get either an STS or front mount turbo kit with a 403 and the very popular 220/224 .560 114 +4 turbo cam that alot of the guys on tech run and would net you probably 600 to the wheels and high teens maybe even a 20 on the mpg.

3.622 stroke with 3.905 bore=347

Short stroking will net higher rpm power but less TQ down low, stroking the motor will give you tons of TQ down low. For comparison, my 5.3 with a cam full bolt ons and a 100 shot would net a 4-5 black mark form all four tires on a 4hi launch, with the 418 on a mail order tune, on the same converter N/A it would spin all four for 15 feet, going to a long stroke crank and more displacement makes such a huge difference its not even funny.

Stroker with a 76mm turbo gets my vote for what you want, mileage and tons of power, the 76(according to Parish) has no lag when brake boosting and very little just punching it. He made mid 750s to the wheels on that setup, not too shabby IMO. Food for thought