4.8 vs 5.3 vortec? (1 Viewer)

Sensible motor choice for a 40

  • 4.8 vortec

    Votes: 2 16.7%

  • 5.3 vortec

    Votes: 9 75.0%

  • The biggest motor we can find

    Votes: 1 8.3%
  • Total voters
    12

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B

blueBJ70

Joined
Jun 11, 2012
Threads
6
Messages
45
Location
South Arica
Hi guys.
I'm new to the 40 section and swaps in general. My brother in law might be getting a 40 soon and asked me which motor he should go with. It will be a mixed use vehicle in Montana with about 40% off-road/trails and 60% daily driving.

The main aim is a reliable vehicle with fuel injection that can drive in the mountains without downshifting all the time.
Will the smaller motor give better fuel consumption if coupled to the cruiser 4spd and maybe 31"s or 33"s with a small lift?(all things being equal)
Or should we just go with the age old tradition of bigger is better?

Thanks for your votes and opinions,and don't feel bad to tell me i'm being stupid,i need that sometimes.
AJ
 
I once bought a boat for water skiing, dealer had a boat with 4.3 V6 and 5.7 V8. Dealer told me the V6 would out-pull the V8 because of it's lighter engine weight, I guess we know which boat he wanted to get rid of. I didn't do my homework, bought the V6, it would barely get double skiers out of the water. Soooo, my guess is the 5.3 will get almost as good of milage as the 4.8, and has better torque.
 
SSCR said:
5.3 actually gets better mileage than the 4.8.
Click to expand...

I'm sure that depends on the application and the driver. For a '40 it could well be true. OTOH, they pretty much give away 4.8s and you may get a better deal on the tranny if you take one off their hands.

I am a fan of the old adage, "There's no replacement for displacement." Pony up for a 6.0. :)
 
Either way, it's more power than the F/2F you're likely pulling out.
 
I bought a 5.3 to stick in my daughter's FJ40 project. Prices around here are pretty much the same for either. I figured the longer stroke would make it harder to stall taking off (I'm keeping the toy 4 speed too).

One day, I'll tell you how it drives.
 
I was originally looking hard for the L33 but went with the newer generation LC9 all aluminum and a custom harness from Pacific fab. Maybe one day I can tell you how it drives too;)
 
Flipper1938 said:
I bought a 5.3 to stick in my daughter's FJ40 project. Prices around here are pretty much the same for either. I figured the longer stroke would make it harder to stall taking off (I'm keeping the toy 4 speed too).

One day, I'll tell you how it drives.
Click to expand...

I like Flipper's line of thought. We have a couple Astro vans with the 4.3 V-6 Vortec. I like the motor as it is a very reliable motor, but it has drawbacks in the low RPM torque area. For a vehicle that is used like the 40 the low end torque is very important.

Don
 
Of the last two 3rd gen conversions, a 4.8 and 5.3, the 5.3 owner is ecstatic and the 4.8 owner is looking to go 5.3 ..or 6.0

Both were coupled to a 4L60. I think any v-8 coupled to a US 3/4 speed is a waste of effort
unless you really enjoy stalling in boulder fields..... go auto , granny gears, low range t-case or t-case doublers or a combination of them
 
Thanks for that lcwizard. Although I have noticed that the rear driveshaft gets quite short with an auto. Or am I missing something?
On different note,what's the opinion on efi systems like fast ez-efi 2.0? It looks quite cool with the self tuning and a display screen for gauges and troubleshooting.
 
@blueBJ70 If you mean for a 2F , I'm not familiar with that particular brand. We built a system for Man-a-fre from 2000 to about 2005 but it didn't sell enough to warrant continued production. We probably were priced too high but I wanted to use a full system including knock sensors and the esc module
and full spark control, a thing that others were programming around to reduce cost. I ran that one , it ran the best but I have used Howell and Turbo City systems with good luck. All of the GM based injections seem to improve fuel economy and smooth out the power band. HP increases are hard do distiguish, seat of the pants because a 10% increase is like 12 hp... Even 20% or 25hp in a 3800 ~4000 lb truck is hard to detect.
My last 2F in a 60 was pretty worn out and I was getting around 11 mpg at 65~70 mph on the highway. The injection pushed it to 13.5~14.
3.5 mpg doesn't sound impressive unless you think of it in %'s . That's over 25%
 
lcwizard said:
Of the last two 3rd gen conversions, a 4.8 and 5.3, the 5.3 owner is ecstatic and the 4.8 owner is looking to go 5.3 ..or 6.0

Both were coupled to a 4L60. I think any v-8 coupled to a US 3/4 speed is a waste of effort
unless you really enjoy stalling in boulder fields..... go auto , granny gears, low range t-case or t-case doublers or a combination of them
Click to expand...

Unfortunately/fortunately I don't live near any boulder fields.

The gear ratios in the US 4 speed seem like they should make for a fun ride on pavement with a V8 up front (geared better than an old school muscle car). With a stock low range, it seems like it should be good enough in everything but a boulder field. Anybody in the south east running a 5.3 / Toy 4 speed / split case?
 
Flipper, I had the same thoughts on the gear ratios of a 4spd as im not going to do crazy stuff like boulder crawling or climbing up walls or huge tyres.
On the efi front,a friend of mine had a reprogrammed stock ecu and he had worlds of issues from crazy fuel consumption to to harness issues but I guess that's more to do with the vendor.
 
blueBJ70 said:
Flipper, I had the same thoughts on the gear ratios of a 4spd as im not going to do crazy stuff like boulder crawling or climbing up walls or huge tyres.
On the efi front,a friend of mine had a reprogrammed stock ecu and he had worlds of issues from crazy fuel consumption to to harness issues but I guess that's more to do with the vendor.
Click to expand...

Did he use a speed sensor that used a 40 tooth reluctor? or did they go to one with fewer pulses? or did they try and delete the speed sensor all together?
 
They didnt use a speed sensor as it is in a offroad buggy with a transaxle.
 
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