HP limit on junkyard 5.3?
02-06-2015, 06:03 PM
#1
HP limit on junkyard 5.3? I know it's impossible to tell about every motor but every general range is it? Long story short I have a motor that needs rebuilt it replaced and was thinking of going the 5.3 route.
So with a 76 mm turbo what would be a safe HP to run or what are people running? Would it do 750 rwhp?
So with a 76 mm turbo what would be a safe HP to run or what are people running? Would it do 750 rwhp?
02-06-2015, 07:49 PM
#5
Restricted User
Depends on the year. Gen 3s are a bit weaker but there are lots of them at 700whp. The gen 4 rods can take a serious beating but they're a bit heavy so you'll need to keep The RPM down and stay off the rev limiter.
As always, keep your cast pistons cool and they'll live. Heat+detonation=cracked ring lands. There are a couple 1200+ hp 5.3s with stock pistons on straight methanol.
As always, keep your cast pistons cool and they'll live. Heat+detonation=cracked ring lands. There are a couple 1200+ hp 5.3s with stock pistons on straight methanol.
02-06-2015, 08:14 PM
#7
I bent a few rods at 846rwhp threw a locked 4l80e
700-750rwhp all day long though.
Gen IV style rods too
Id be willing to bet that their are a few high power 5.3s running around with bent rods. I didn't know mine was bent until it bent enough where I was tapping a counter weight lol
700-750rwhp all day long though.
Gen IV style rods too
Id be willing to bet that their are a few high power 5.3s running around with bent rods. I didn't know mine was bent until it bent enough where I was tapping a counter weight lol
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02-06-2015, 08:30 PM
#9
It's either that or buying a forged short block which I'm not opposed to. I have 2 turbos right now, a Precision 7675 CEA. 96ar and Comp 7679 1.32ar, one of those will be used. I was looking at the TSP 370 iron block and having piece of mind that is built for it but not sure I have the compressor for that big of a motor.
02-06-2015, 09:10 PM
#11
No I bought this car already "built" and it has turned out to be the nightmare of all nightmares. Basically it started out as a 383 with twin 60s but the kit was total **** so I went with a Huron Speed single kit that had a Precision 7675 and when we tried upping the boost it fell on its face at 5800 rpms and we assumed it was exhaust side being too small . Got the Comp with the 1.32 and the motor starting clacking so Im redoing it bit at an empass as to what to do. Forged 370 and hope there are no back pressure issues or 5.3 junkyard and hope it doesn't blow up. Looking for 750 to 800 at the wheels. Guess I could try and find a forged 5.3.
What direction would you guys go?
What direction would you guys go?
Last edited by necrocannibal; 02-06-2015 at 09:20 PM.
02-07-2015, 01:40 PM
#12
Restricted User
No I bought this car already "built" and it has turned out to be the nightmare of all nightmares. Basically it started out as a 383 with twin 60s but the kit was total **** so I went with a Huron Speed single kit that had a Precision 7675 and when we tried upping the boost it fell on its face at 5800 rpms and we assumed it was exhaust side being too small . Got the Comp with the 1.32 and the motor starting clacking so Im redoing it bit at an empass as to what to do. Forged 370 and hope there are no back pressure issues or 5.3 junkyard and hope it doesn't blow up. Looking for 750 to 800 at the wheels. Guess I could try and find a forged 5.3.
What direction would you guys go?
What direction would you guys go?
02-09-2015, 09:48 PM
#15
The limited amount of feedback I have found says Comp turbos have BP issues(on LS engines). It really depends on what you are trying to accomplish. It will work, but you won't make as much power as a max effort build.
For example, I have a Comp turbo on an LQ4. I went with a divided 1.52 housing and a quick spool valve (rear mount turbo configuration) in an attempt to maintain decent spool and keep BP in check. As a front mounted configuration on an LS1 I was able to make 11psi on a 10lb spring. I never measured BP on that combo, as the ring lands on #7 have up after ~1000 miles. I purchased the larger housing in preparation for more boost (listening to all the stories about too much BP) and to facilitate the Quick spool valve (divided housing needed). I'm crossing my fingers that it spoils like crazy and pulls to ~6200 rpms with this configuration.
Have you considered a 4.8 or 5.3? The smaller displacement should work well with the Comp turbo (helping to keep BP in check). If you are worried about less power, you can add boost. The stock 4.8 and 5.3 short blocks are extremely stout. A forged one would be easy to make a ton of power with.
For example, I have a Comp turbo on an LQ4. I went with a divided 1.52 housing and a quick spool valve (rear mount turbo configuration) in an attempt to maintain decent spool and keep BP in check. As a front mounted configuration on an LS1 I was able to make 11psi on a 10lb spring. I never measured BP on that combo, as the ring lands on #7 have up after ~1000 miles. I purchased the larger housing in preparation for more boost (listening to all the stories about too much BP) and to facilitate the Quick spool valve (divided housing needed). I'm crossing my fingers that it spoils like crazy and pulls to ~6200 rpms with this configuration.
Have you considered a 4.8 or 5.3? The smaller displacement should work well with the Comp turbo (helping to keep BP in check). If you are worried about less power, you can add boost. The stock 4.8 and 5.3 short blocks are extremely stout. A forged one would be easy to make a ton of power with.