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

[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..

[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..........

[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.

[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.

[Trick1]

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.

Naw different years even make a difference and the mileage is more then doubled. I pulled all the plug last night and all look ok, wrong freaking ones but ok.
We dyno'd that stock truck as if straight from the customer I bought it from.
Today I am going to get new wires plugs, etc, check the fuel pressure to make sure is up and something really stupid like that.

The way its acting its either fuel, or timing, or tune. Maybe its in limp mode or something stupid not sure. But I will find out.
Last night the truck really did not want to run or zing up at all even free wheeling.

There is a glitch somewhere and now I have to find it before moving onto the other swap.

I was hoping to start turning the boost up, but not now.

Hey Quick, yea I know it need springs, but this is something different now. Banging in the exhuast is telling me something in the ignition. I have coils off a 6.0 here might throw those on If I can get the truck to even run down the road with NO boost.
Time will tell

[GasGuzzler]

I thought boost helped weak springs....

[GasGuzzler]

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