Finally dyno'd for the stock 5.3 + turbo:(

[Trick1]

Things did not go as well as we hoped. This is with a 62mm turbo at 9psi. The 5.3L engine is stock, all parts except the turbo, injectors and the exhaust, and it has 167000+ miles on the clock. So its got to be a little tired.
But we did pick up just over 200 extra power and 257 extra torque.
Then the truck started to bang out on the 2nd pull and got worse on the 3rd and just stupid on the 4th.
Driving home the engine will not excelerate into boost. Pulled the plugs they look ok, wrong ones but look ok. Going to pull a valve cover tommorrow and see if I broke a stock spring.

The graphs below show the first base pull on this engine and then with the turbo.

[ducky]

now thats a damn good dyno slip. im excited to see what mine does

[casey23]

Replace the valve springs......... I killed mine the dyno also @ 10psi.......... You need to start Selling at least a set of 918 springs with your turbo kit..... I think ANYTHING ls thats boosted looks Valve spring upgrade..........

[GasGuzzler]

I thought boost helped weak springs....

[Trick1]

Replace the valve springs......... I killed mine the dyno also @ 10psi.......... You need to start Selling at least a set of 918 springs with your turbo kit..... I think ANYTHING ls thats boosted looks Valve spring upgrade..........

What did yours do with dead springs.? This thing would not even rev tonight prior to pulling the plugs, very rough, almost like a dead miss. I will look tommorrow what code it may have throan.
If I add springs to the kit that will raise its price, but will start recommending them.
I would like to find out the problem before I pull the engine.

[Trick1]

now thats a damn good dyno slip. im excited to see what mine does

Thanks I will depressed when I was told the hp numbers. I was hoping for 400+ but maybe with the glitch fixed it would have. Wonder is this problem was also what was causing my surging..

[GasGuzzler]

Not revving is a good sign of spring problems...

[casey23]

What did yours do with dead springs.? This thing would not even rev tonight prior to pulling the plugs, very rough, almost like a dead miss. I will look tommorrow what code it may have throan.
If I add springs to the kit that will raise its price, but will start recommending them.
I would like to find out the problem before I pull the engine.

My dyno pulls were like 10-12 sec long it was decent @ 6psi... but soon as i went to 10.. I was able to gain 60hp early yada yada but it didnt want to RPM.... dyno pulls were 10sec long....... and DEAD at 5500@10psi......... motor didnt want to RPM for crap...... Flat lazy....... didnt want to spool..... build boost..... I changed the cam and springs 2 days later........ so i didnt do alot....... but it was a running mofo after the spring swap !

[r.barn]

Stock base line pull of only 170rwhp say something was wrong from the
get go to me.

Just dyno'd my bone stock 70k 4.8L Tahoe at 205rwhp baseline

I'd put a compression tester on it too.

[George C]

just proves the theory again of LS motors and HP per boost. its roughly 20 to 22 hp per pound of boost

nice numbers and i wouldnt have aboosted motor without springs