Toomnymods
You totally hijacked this thread!
I forgot what it was about!
Anyway, low lift aggressive cam like that makes sense on a dohc setup.
Interesting that the dyno shows no increase until 4100.

Now did anyone figure out what it takes to get 400rwhp on a NA 5.3.

Redneck, you should be up there.


DYNO #S DON'T MAKE YOUR TRUCK FASTER ANYWAY

 

i am fairly new to this game, but is there THAT much difference between the 5.3 and the ls1?

i worked at a lsX specific speed shop for a bit and with their big cam, 240/244 595/609, they were hitting 390+rwhp with cam only in autos and my brother hit 427rwhp cam only in his 6-speed camaro. they were getting 445+ out of the head and cam auto cars and 470+ on the six speed cars. of course, this is whith full bolt ons. all this with the ls1.

i wouldnt say these cars were perfect on the street, but with a good tune, they were fairly streetable. and that was cam only.

seems like you could even go a bit smaller on the cam, with a good set of ported heads, and hit 400rwhp easily.

but, like i said, i am new to this game, and maybe the difference between the ls1 and 5.3 is that signifigant.

 

I think there are three main reasons that people aren't hitting 400 with 5.3s.

1.) Consider that these are primarily trucks that weigh at least 1000# more than a typical f body or vette. A big cam to hit the dyno number won't be a very good performer in a heavy vehicle.
2.) The truck drivetrain has more parasitic loss than a car.
3.) 5.3s have little 3.78" bores, which limit valve sizing and negates somewhat the benefit of heads with big ports.

 

Wait.........are we talking @ the wheels or the crank???? I'll have to back and see what the original thread starter was asking for...........

James

 

Okay. I answered my own question. He's wanting to know @ the wheels. I will be getting mine dyno'd soon. I will be running race gas and more timing on the rollers just for numbers sake. Hope I don't blow it up!!!!!LOL!!!!!

James

 

400rwhp in a NA 5.3 could easily be done with a big cam and heads setup using a single plane carb setup capable of making power in the 7000rpm range.I don't think such a motor would work well in a heavy truck with an automatic transmission.You'll never make that kind of power running a truck intake because it won't flow enough air fuel mixture above 5500rpm.

 

i was sayin at the wheels...

 

HOT ROD magazine just did a test between the gm intakes, ls1, ls2, and the truck intakes. they used a new lq9 for the test and found that the difference was very small, like 5fwhp if i remeber correctly, not enough to scrap the truck intake, especially for the ls2 intake, which actually lost power in their test.

but, they used the FAST ls2 intake, which did produce a signifigant increase in power over the truck intake.

i cant remeber the rpm's they were spinning at, but they were getting peak FWHP of 429 out the lq9 with headers, tune, 1.8 rockers, and the FAST ls2 intake. this is versus the stock FWHP of 355 they got as the baseline.

i would assume they were around 6000-6200 for the peak numbers, but i may be wrong.

i know its not close to 400rwhp, but imo, unless i was going to spend the money on a FAST intake, i would stick with the truck intake if thats what i had to start with.

 

I believe that the runners on the FAST intake dictate a peak around 6400rpm.

 

they used a 90mm TB also. and 6400 sounds about right too.