sepsis

iTrader: (7)

I know this an old article, but do the 4.8's and 5.3's have forged rotating assemblies?

http://www.hotrod.com/techarticles/h...g_bang_theory/

These guy put 26 psi on the 4.8 and made 1,203 hp, on 60 dyno pulls.

How is it that the 4.8 can handle that much boost and not grenade, but the LS1 can't deal with more than 8-10?

HRHohio

It's all in what fuel you use (Octane) and your tune (Timing).

Not sure I've ever seen anyone test the LS1 under the same conditions.

sepsis

iTrader: (7)

They were using 118 octane, but still, 26 psi.....

You'd think you can get more than 10 psi on a good tune and 93?

I dunno. I'm not very knowledgeable in forced induction.

slowlsx

iTrader: (28)

I suggest you get to reading. These motors are no forged they just take alot of power when done properly

cory32690

My hey had gapped rings on that motor to help live also had a pretty nice head cam setup..I believe ignition was breaking up is why they stopped upping boost..and several people have ran well over 10psi on stock bottom ls1there a guy with one that has like 11:1 compression making 700-800hp to the tire and he's over 10psi it's all in tune and good fuel setup

HRHohio

I'm at 10psi on 91 +50/50 water/meth. My tuner is keeping my timing "safe". LOL. Only pushing about 500 rwhp on stock bottom LS1 (running LS9 cam though).

HexenLord

PSI does not equal power. More power could be made with less PSI on the same motor with bigger cam and turbo (s).

There are dozens of people kissing that 1000 HP mark at the flywheel on stock short blocks.

Stock rods (at least 4th gen) are technically forged BTW.

TurboAv

iTrader: (6)

754rwhp on my stock LS3 when I ran E85+meth with 17* of timing. Shooting for 800+ with new larger headers and smaller pulley. I'm at 12psi now and will probably be 14-15 after the pulley swap. 91 octane and meth.

sepsis

iTrader: (7)

I did some reading about powdered metal rods, and it seems like they are pretty good.

WheelsUp84z

iTrader: (14)

at 24lbs on a stock bottom end 5.3 (gen 3) i was making 850 ish (by calculation). This is on E85.

stock48

iTrader: (17)

I've put 27 psi of boost to both of my stock bottom end lq4's and both still going. Car ran the 8.39/164 on 23 psi. Induction skews things so you can't really go off boost. One persons 26 psi with restrictive heads, and high back psi turbo will be less power and air in cylinder than another ones 23 psi with good heads, and free flowing turbo.. The engine only knows how much air is getting into the cylinder not how many psi pushed it there.

I would also like to see these magazine ppl put one of these combo's in a 3000+ lb car and show close to 1200 HP... A honest 1200 HP @ the flywheel is 170 +mph @3000 lbs..

Heavy H.P.

I agree with you.
You would think the extra cubic inch would yield moe power at less psi but the 5.3's do seem to be stronger for most as far as getting real close to 1000hp and poping.

silver_82

I've hit 26 psi on my 5.3 and its still going strong.

ezstriper

It's just russian ruliet...only a matter of time...

HRHohio

Correct! And if you'll notice, they DID do some modifications to the system to reduce the restrictions (Heads/Cam/TB). Theoretically, you would probably have to push closer to 35 psi of boost on a totally stock engine (LS1) to get to 1000 rwhp.

The real question is, has anyone seen a stock LS1 tested in the same manner (118 Octane) under controlled environment. Then you could compare apples to apples.

mrstepheneades

16 psi on my stock longblock ls1 with tick cam. Pushed water after 6000 rpm at 775rwhp. On the street its hitting 21 psi and still going strong. I don't rev it high enough in 4th on the street to push enough water to worry about. Wouldn't make but 16psi on the unloaded Dyno is why I don't have numbers for 21 psi. On pump 93/meth. All in the tune. 12-13 degrees timing up top. Still stock bolts and gaskets. Motor never been apart.

HRHohio

Very nice! Hell, what more could you ask for on a stock bottom, pump gas, streetable car.

DBRODS

iTrader: (1)

On my aluminum 5.3 I ran 27-28psi with ls9 cam and ported 317s with twin turbonetics billet T7668s. It would bend rods at 29-30psi and 15* of timing. Switched to Tooley TFS heads and a Lil John cam and it would bend rods at 22psi and 16* of timing. The rods would bend in high gear at 6500ish rpm. E85

mrstepheneades

Well if its pushing water rods bending are not to many miles away especially 5psi past the water pushing point. But with my slicks and gearing I rarely hit 6000+ rpm in fourth. Thats 150+mph lol. So that's why it lives I guess. Bone stock drivetrain all but clutch so stays off the track till I can afford a rear. My afrs stay 10.8-11.0 all the way up with the meth helping out.

stock48

iTrader: (17)

Converter locked?