Any input would be so appreciated! Having turbo issues or backpressure woes.

GenIII Sbe 5.3
Rings gapped .028 & .030
stock truck intake and 862s
Pac1218s
elgin 1840p 228/230
BR7EF gapped .022
80lb injectors
walboro 400
Innovate scg-1 wideband/controller
Gen1 cast vs 7875
80e w/ stock converter
3/4 ton ext cab silverado
pump93

2.25� crossover
3� downpipe to a five foot Straight tailpipe turned down under cab.
Log manifold


The first setup was a 6L with stock cam but had the same supporting mods as now. It would spool almost instant and was a blast to drive. Made 498 on 12 psi. Blew it up so I bought this 5.3 from a junkyard, had the block cleaned up and honed, new rings and bearings.

when the old engine came apart it sent metal through the exhaust housing, and dinged the wheel up a little. Nothing major (I thought). So I put it all back together as I had it. On the dyno it falls on its face over 5k rpms. It takes forever to spool it now and will barely turn the tire over. Soft timing until I get this methanol kit installed. Made low 400s on 10psi

I currently don�t know how to operate hp tuners so haven�t data logged anything. But could this be a bad backpressure issue or the wheel of the exhaust housing ? Hard to believe that this setup is having issues spooling this turbo and 3� downpipe especially seeing as how popular it is. This is my first turbo setup so any help or insight on how to verify would be welcome. I�m currently looking for a rebuild kit for this unit. Or probably just buy the billet 78

 

GenIII Sbe 5.3

elgin 1840p 228/230

Gen1 cast vs 7875

80e w/ stock converter

3/4 ton ext cab silverado
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None of that combo is going to spool QUICK

First thing I would do is put the stock cam back in or more of a truck cam, thats a heavy truck for a 5.3 with a cam that big.
Main reason I say that is I highly doubt you want to put a high stall in a 3/4 ton truck, or wannt to be revving it to 7,000rpm I know I wouldnt.

Not sure why its falling on its face at 10psi above 5000 though, you would need a data log

 

what about swapping to a smaller turbo? I don�t want 800hp or anything. 500 would suit me with a quicker spool.

I didn�t want to half *** and put a single disc converter in it, and the billet triples are $1000+. I�m gonna pull the turbo off and swap in a buddies billet78 just to see if there is a difference.

 

Smaller turbo would help for sure, but I would still do the stock cam or maybe a stage 1 truck cam, especially if your just looking for 500hp.
The stock cam with a little smaller turbo would do more torque than Hp and make that beast move without having to spin the engine so high.

 

That�s right. I appreciate the help.

 

As Ls7 stated, the combination is not right. What's the goal for your rig? A triple 12 cam for that weight and converter would be the max I'd go? Tune (timing) can be optimized to get motor/turbo to respond better. Why did previous motor fail? Understanding the details will keep you from making the same mistake and help move your plans forward. With data, you'll be able to better understand why it's falling off at 5K.

 

5-600 wheel
I ran this cam on another setup I had and it worked fine with stock converter. However it was NA.

previous motor went because of a stuck wastegate. Dusted 3 rods etc.

ive since swapped to a turbosmart gate and added the innovate controller. Water meth kit is about to be installed too.

I will be pulling turbo off this weekend, will post pics of the exhaust wheel. It had some damage, but to my untrained eye didn�t seem horrible.

 

That cam is huge for a 5.3 and will shift everything way up in the rpm, but a 6.0 would love that cam.

A smaller turbo would help but in my opinion that's backwards.

Camming it properly and keeping a decent size turbo will be having your cake and eating it too. I'd also try to get a little more stall converter in there.

 

ive been looking and trying to pick one, which converter you like for a truck this heavy? I�ve ran circle d in the 3 trucks I�ve messed with.

 

you are absolutely right on the turbo. I was spitballing ideas. I�m thinking about since this wheel is questionable moving to the next gen 2.5 7875 with a decent converter and being done with it

 

You went from a stock cam 6.0 that makes tons of low-end, to a large cam 5.3 that makes no low-end, all while still on a stock converter, and you don't know why it spool slow?

 

Goal 500-600whp. How is it going to be used? towing, tire burning, street racing, etc. The more details you can provide on goal the more someone can help build a combo that works to achieve goal. As a reference, a stock 5.3 and smaller turbo (builds boost at 2k) can achieve whp goal but maybe more importantly have > 600 ft lbs of low end tq for towing with stock converter.

 

its not a large cam compared to some others out there? I�ve ran it before and didn�t have this issue, albeit a NA truck.


im swapping cams next few days.

i really want to keep to the stock converter. I don�t pull a ton of weight, occasional car and my bass boat.

 

Cam swap will make the biggest difference, that is a decent size cam even in a lightweight car.

 

A 5.3 is 12% smaller than 6.0. For simplicity sake, if you want the 5.3 to operate similar to the 6.0 with 228/230 cam, you need a cam 12% smaller 201/203. A cam to operate in a 5.3 at 1500 to 5000 is much different than 3500 to 7K or 6K to 8500K. Hope this make sense.

 

I'd recommend going online and filling out the comp cam recommendation form. You may be surprised at the amount of info needed to more accurately provide a cam recommendation.

 

lol wut.

 

Made this simple, I bought a btr stage1 truck cam lol

 

What cam duration would you put in a 5.3 to generate the same rpm curve (albeit lower tq/hp level) as a 6.0 with 228/230?

 

This might help the OP.