Help estimating HP
Thread Starter
Teching In
Joined: Feb 2012
Posts: 24
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Help estimating HP I just got my 5.3L back from the engine shop that I am going to put into a kit car that I building (a Factory Five Daytona Coupe). This is going to be a track car mostly, so we put some money into some reliability mods that didn't add power, but should help with the longevity of the engine. The builder didn't have a guess on the power so I wanted to see what you all thought.
Here is what I got:
2004 5.3L bored .020" over
stock 706 heads with 2.00" SS intake and 1.59" SS exhaust valves
stock rockers
flat top pistons with -4cc valve reliefs
Calculate compression to be 10.0:1
Comp cams LS1 277Lr HR-113 cam
(227/235 @ .050, .614/.621 lift, 113 deg lobe separation)
98 LS1 intake and stock ported TB
85mm MAF
1 3/4" shorty headers into a dual 3" exhaust (no cats)
planned redline of 6500 rpm
Here are some of the reliability mods:
nitrate coated crank
forged rods and pistons
dual valve springs
LS7 lifters
Comp cams rocker trunion kit
ported oil pump
Thanks
JC
Here is what I got:
2004 5.3L bored .020" over
stock 706 heads with 2.00" SS intake and 1.59" SS exhaust valves
stock rockers
flat top pistons with -4cc valve reliefs
Calculate compression to be 10.0:1
Comp cams LS1 277Lr HR-113 cam
(227/235 @ .050, .614/.621 lift, 113 deg lobe separation)
98 LS1 intake and stock ported TB
85mm MAF
1 3/4" shorty headers into a dual 3" exhaust (no cats)
planned redline of 6500 rpm
Here are some of the reliability mods:
nitrate coated crank
forged rods and pistons
dual valve springs
LS7 lifters
Comp cams rocker trunion kit
ported oil pump
Thanks
JC
TECH Addict
Joined: Sep 2009
Posts: 2,481
Likes: 5
From: PA/MD
What you have will work, and work good...but look for a deal on an ls6 intake and port, or pick up a ported stock throttle body...I'd also ditch the MAF and run an SD tune( this will give you a crisper throttle response).
I am also guessing you are going to be running a manual tranny so that will give you less drivetrain loss.....I'll guess 450 at the crank and closer to 380-400 at the wheels. If you don't have the heads on yet get a little bit more milled off of them to bump your compression up to around or just over 10.5:1.
Sounds like a sweet project, so we need pics
I am also guessing you are going to be running a manual tranny so that will give you less drivetrain loss.....I'll guess 450 at the crank and closer to 380-400 at the wheels. If you don't have the heads on yet get a little bit more milled off of them to bump your compression up to around or just over 10.5:1.
Sounds like a sweet project, so we need pics
TECH Enthusiast
Joined: Nov 2004
Posts: 714
Likes: 0
From: Tampa FL
I would tend to agree with what the other guys said. Pick up an Ls6 style intake and you should see 400/385 at the wheels. If you can grind the casting flash out of the intake runners and smooth and polish them and have a good valve job done on them and that will give you mabey 20 more HP. Plus its cheap the minor porting can be done by you with a Die Grinder or Dremel and the valve job will cost less than $250.
Thread Starter
Teching In
Joined: Feb 2012
Posts: 24
Likes: 0
Well if I get 400-450 at the crank that is what I was aiming for. The car will only weigh 2500 lbs when it is done so that should be a good power to weight ratio.
Mark: you are correct, manual transmission
Gunslinger: The engine shop did a valve job with the new valves and ported the area in the head for the bigger valves.
I agree on the LS6 intake. I just couldn't find one in my price range. This one will get me going and I'll keep an eye open for a LS6 one.
Here are some pictures.
This is the kit when we picked it up from the factory
Junk yard motor
The machine shop layed out all the parts for us before he assembled it
Engine back together
The headers have to dump forward for the side pipes
Mark: you are correct, manual transmission
Gunslinger: The engine shop did a valve job with the new valves and ported the area in the head for the bigger valves.
I agree on the LS6 intake. I just couldn't find one in my price range. This one will get me going and I'll keep an eye open for a LS6 one.
Here are some pictures.
This is the kit when we picked it up from the factory
Junk yard motor
The machine shop layed out all the parts for us before he assembled it
Engine back together
The headers have to dump forward for the side pipes
