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TT AWD TBSS Jeep
TT AWD SS Pwrd Jeep
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Discussion Starter · #1 · (Edited)
Check out Sept 2011 Hot Rod. They wanted to see if they could grenade a 5.3l truck motor. They hung two 76mm EBAY cheap turbos on it, and started uping the boost. The went up to 26.8psi and made 1,203hp before the ignition failed and they ran out of dyno time. In fact they made over 60 passes at 1,000hp plus, one cylinder even had a rust spot in it that the ball hone wouldnt take out......AMAZING! Funny part was, what they thought to be a 5.3l, turned out to be a 294ci 4.8l !! That is over 4HP per cubic inch...wow.

They did 3 things to the engine before doing this, not too hard to do.
1. Increase ring gap top two rings to .28 to keep from butting and breaking the ring lands under high boost. FREE MOD!!
2. They put in an off the shelf 228/230 grind from comp cams
3. They shipped stock heads to Total Engine Airflow for porting and went from 1.89 to 2.0 intake valves. Went from 230cfm to almost 300cfm

Kinda makes me feel good about down the road putting a single 88mm on my stocker now. 750 AWD HP suddenly seems achievable with just some ARP bolts, and ring gap adjustment. I cant believe they got away with the stock rod bolts. The mains maybe, but rod bolts? The stock cranks sure are tough in these engines. I cant wait to see if they push it til it blows, just to see how high they can take it!!
 

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Supercharged TBSS
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thats pretty cool. 1200 on a near stock motor. on a 4.8 thats just redic
 

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Trailblazer SS
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WTF that's just crazy!
 

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2007 TBSS AWD
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A 5.3 or 4.8 can take boost a lot better then an LS2 with 9.5:1 compression. You can make it live at 700 bit above that you are on borrowed time. Still goes to show you can make a lot of hp for pretty cheap.
 

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TrailBlazer SS AWD
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These motors love the boost. Atleast mine does. :biggrin2:
 

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TrailblazerSS
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A 5.3 or 4.8 can take boost a lot better then an LS2 with 9.5:1 compression. You can make it live at 700 bit above that you are on borrowed time. Still goes to show you can make a lot of hp for pretty cheap.
What is the difference in static & dynamic compression? The higher the compression the lesser the boost #'s it can handle. Correct? Is that why you are saying ours cant handle the high boost levels?

Also turbo psi is different than a roots type too. Roots type maintain the high psi level longer than the spike of a turbo. I bet if you dialed up a roots blower it would have blown sooner than the turbos.
 

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TrailblazerSS
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Also Iron block vs. Aluminum LS2.
 

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2007 TBSS AWD
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What is the difference in static & dynamic compression? The higher the compression the lesser the boost #'s it can handle. Correct? Is that why you are saying ours cant handle the high boost levels?

Also turbo psi is different than a roots type too. Roots type maintain the high psi level longer than the spike of a turbo. I bet if you dialed up a roots blower it would have blown sooner than the turbos.
High compression limits boost assuming you are running pump gas.

Turbos and roots/screw blowers are harder on the motor then a centrifugal type blower. The boost comes up sooner and is maintained across the rpm range. Centrifugal blowers make boost linearly with rpm so unless you are up in the3 rpms the motor is under little extra stress.
 

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2wd Turbo
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Check out Sept 2011 Hot Rod. They wanted to see if they could grenade a 5.3l truck motor. They hung two 76mm EBAY cheap turbos on it, and started uping the boost. The went up to 26.8psi and made 1,203hp before the ignition failed and they ran out of dyno time. In fact they made over 60 passes at 1,000hp plus, one cylinder even had a rust spot in it that the ball hone wouldnt take out......AMAZING! Funny part was, what they thought to be a 5.3l, turned out to be a 294ci 4.8l !! That is over 4HP per cubic inch...wow.

They did 3 things to the engine before doing this, not too hard to do.
1. Increase ring gap top two rings to .28 to keep from butting and breaking the ring lands under high boost. FREE MOD!!
2. They put in an off the shelf 228/230 grind from comp cams
3. They shipped stock heads to Total Engine Airflow for porting and went from 1.89 to 2.0 intake valves. Went from 230cfm to almost 300cfm

Kinda makes me feel good about down the road putting a single 76mm on my stocker now. 750 AWD HP suddenly seems achievable with just some ARP bolts, and ring gap adjustment. I cant believe they got away with the stock rod bolts. The mains maybe, but rod bolts? The stock cranks sure are tough in these engines. I cant wait to see if they push it til it blows, just to see how high they can take it!!
How did they not know it was a 4.8 went the tore the thing down?

You need to pull the pistons to hone or work on rings? Never worked on the bottom end...

Still very nice numbers. That's making some power!!!! :coolthumb:
 

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Trailblazer SS
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How did they not know it was a 4.8 went the tore the thing down?

You need to pull the pistons to hone or work on rings? Never worked on the bottom end...

Still very nice numbers. That's making some power!!!! :coolthumb:
Yep the pistons need to come out. Pretty simple job to re gap the rings if the heads are off and you are going to replace the rod bolts too. Cold be done with the motor in the car still, though id be terrified of even attempting to hone it with the motor in the car! Too much risk for me. These guys just had the motor on a stand though, so different story.
 

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Trailblazer SS
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Pretty sure the displacement is stamped on the side of the block too.
 

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TrailblazerSS
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That is some wild HP from a 4.8
 

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stupid white guy
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Guy local to me is running 10's on a stock block turbo 4.8 in a RCSB SIERRA. fastest in the country I think. Apparently they are solid motors.
 

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2007 TBSS 3SS
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Pretty sure the displacement is stamped on the side of the block too.
5.3's and 4.8s have both numbers stamped on the block
The only way to tell is VIN on truck or if out of truck piston and stroke. 4.8 had flat top pistons and 5.3 had dish. Bigger stroke for 5.3 than 4.8. They use the same head gasket.
 

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Trailblazer SS
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the ls2 has no issues at that power
I don't know why people think alum block can't holder power. Hell the fastest tbss in thr country is running a ls2 and he is at 1000+ hp.. :2cents:
 

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As long as the motor is built correctly and there are no tuning issues I believe they are just as strong as an Iron block.
 
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