Dyno tuned the 4.8

[fbs2s]

Went and had the truck dyno tuned today in conway at Carolina Speed shop. We didn't run it above 110mph which was a little over 4000 rpm. We were concerned with the drive shaft. So the number are a little low.
Motor is a 2000 4.8 5 speed with 35k miles
Mods-
TR224 on 112lsa
LPP long tube headers, no egr
K&N intake
Custom tune

Got 272HP at 4000rpm and 361 ft lbs of torque at 3950.

Whats everyones thought on the driveshaft? Is it safe to run it up to 140 mph to get it up to 6000 rpm where this cam will make its power?

[George C]

i have never seen a 4.8 mke that much torque. i seen 5.7s not make that torque

also why is your AFR so lean?

just curious tho

[fbs2s]

i have never seen a 4.8 mke that much torque. i seen 5.7s not make that torque

also why is your AFR so lean?

just curious tho

You can't really tell in the picture because of the color, but its at 13.5 on the final run.

[George C]

even then thats lean for a LS motor but if it works let it work. im still shocked by the torque

[GasGuzzler]

Yeah....I'm shocked by the HP and the TQ.

And George, not only did I see your Pinks episode again this evening but this topic brings up an opportunity to clarify a previous post of mine....I see now that you were quoting OEM flywheel rated HP for a 4.8 (275) I was talking about wheel power. Funny since this modded 4.8 (big cam for a 4.8) is just under 275 (remember we were talking stock) when my 4.3 made 163 HP on a 170 rating....LOL....it made 215 or so TQ which is near what a stock 4.8 makes.

I think this 4.8 has a 75 shot on it 'cause a 75 would add near 75 HP and about 150 TQ at the wheels.

[vista4.8]

wow, cant wait to start building up my little 4.8

[farmtruc]

The HP sounds about right, even if you string it out, you might hit 300hp, that would be nice!
As for the torque, that's a lot!

You mention a/f ratio is "lean" , I agree with quik, that's ok.
If you knew how long GM's calibration ran their engines lean you'd be surprised.
HD trucks are the worse, but you know what, they live for a long time.
When I dyno'd this Project 4.8L, it was 14.7 through the entire run, that's GM for you.
I set this one at 12.9.

thanks for the info,
allen

[fbs2s]

The HP sounds about right, even if you string it out, you might hit 300hp, that would be nice!
As for the torque, that's a lot!

You mention a/f ratio is "lean" , I agree with quik, that's ok.
If you knew how long GM's calibration ran their engines lean you'd be surprised.
HD trucks are the worse, but you know what, they live for a long time.
When I dyno'd this Project 4.8L, it was 14.7 through the entire run, that's GM for you.
I set this one at 12.9.

thanks for the info,
allen

Allen do you think that the tq is accurate? There a few people on other forums questioning it saying its impossible for the 4.8 to make that?

[George C]

id say minus 100 and torque is right

[farmtruc]

Allen do you think that the tq is accurate? There a few people on other forums questioning it saying its impossible for the 4.8 to make that?

I could be wrong, likely lol, but that is a lot of torque for a cammed 4.8L.
Even a cammed 5.3L won't put out that much.

Look at this, a procharged 5.3L - given, not 100% yet, but...
http://www.ls1truck.com/forums/dynod...rocharged.html

take a look at the second cammed 5.3L dyno chart:
http://www.ls1truck.com/forums/dynod...no-graphs.html

matter of fact, the supercharged truck above that 5.3L.

Might want to get a second dyno reading, from a different dyno. Unfornately, they are all different.