Laying it all down
Thread Starter
Intermediate
Joined: Oct 2019
Posts: 45
Likes: 3
From: Hilton Head, SC
Laying it all down
Ive got myself a pretty trick former 4.8 LS retaining the factory crank after having it polished and cleaned, custom forged rods rods and a 3.903 inch bore. I wanted a screamer motor for my 84. But my question is, because its an LS, i would love to see anywhere from 800 - 1000 hp in a boosted application. My question however, is if my dana 44 with a detroit trutrac diff and hardened half shafts is going to
1. Survive at that power on sticky tyres, and
2. Actually be able to hook it all up
Sure 1000hp would be lovely for bragging rights. But i want to do a bit of everything in motorsports and if it isnt going to hook then im really not interested. What should i cap the build off at so im not struggling for traction all the time given the fact it's a c4? Car has a 12 point cage going in soon, and may do a semitub at some point depending on if i need more rubber.
1. Survive at that power on sticky tyres, and
2. Actually be able to hook it all up
Sure 1000hp would be lovely for bragging rights. But i want to do a bit of everything in motorsports and if it isnt going to hook then im really not interested. What should i cap the build off at so im not struggling for traction all the time given the fact it's a c4? Car has a 12 point cage going in soon, and may do a semitub at some point depending on if i need more rubber.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Even 800...Id be looking to put a solid axle in it right off the bat, you will be breaking that IRS. Some here have gone sub 10s but eventualy put a 9 inch in after breaking all the "unbreakabe" irs stuff you see advertised. Sure wouldnt want a failure at 130mph
Thread Starter
Intermediate
Joined: Oct 2019
Posts: 45
Likes: 3
From: Hilton Head, SC
thought real long and hard about that option. My only debauchle is i want to road race and track this thing in addition to drag racing and street events. I dont want to lose my handling to the solid rear. But if something like say, a 3 link with a watts link could cut it without killing off most of my cornering capability, then i would be sold.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
Parts survival will dependent on tuning ability. Enough power to launch without out spinning and increase power while keeping traction. I would sell IRS and install either 8.8 or 9 inch.
Le Mans Master
Joined: Feb 2005
Posts: 6,479
Likes: 565
From: Clearwater Florida
..... The Dana 44 is a lot tougher than many of you think ! ... lt's shock loading that does the most damage ... think high rpm clutch dumps or trans brakes ... torque will hurt 'em too ... nitrous anyone ? ... like most parts , they don't appreciate a lot of abuse ... do your thing sensibly and you will be OK .....
Thread Starter
Intermediate
Joined: Oct 2019
Posts: 45
Likes: 3
From: Hilton Head, SC
..... The Dana 44 is a lot tougher than many of you think ! ... lt's shock loading that does the most damage ... think high rpm clutch dumps or trans brakes ... torque will hurt 'em too ... nitrous anyone ? ... like most parts , they don't appreciate a lot of abuse ... do your thing sensibly and you will be OK .....
Burning Brakes
Joined: Sep 2016
Posts: 1,133
Likes: 319
From: Ohio
I've ran multiple 9 second passes in a stripped down C4 with a turbo 4.8 and a bone stock Dana 36 and stock rear everything else.
I dont understand the point of boring out a 4.8 block and then adding boost. You're not increasing the peak power potential at all, you're just increasing torque and thinning the sleeves. The block kept at stock 4.8 displacement is virtually indestructible. The thick sleeves combined with low side-loading from the excellent rod/stroke ratio along with reduced torque will put incredibly low twisting force on the block. Other than lifting a head, you wont be able to harm the block. As soon as you bore almost a quarter inch off of the sleeves, a lot of this goes out the window.
I dont understand the point of boring out a 4.8 block and then adding boost. You're not increasing the peak power potential at all, you're just increasing torque and thinning the sleeves. The block kept at stock 4.8 displacement is virtually indestructible. The thick sleeves combined with low side-loading from the excellent rod/stroke ratio along with reduced torque will put incredibly low twisting force on the block. Other than lifting a head, you wont be able to harm the block. As soon as you bore almost a quarter inch off of the sleeves, a lot of this goes out the window.
Last edited by JoeNova; Jul 15, 2020 at 10:48 AM.
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Thread Starter
Intermediate
Joined: Oct 2019
Posts: 45
Likes: 3
From: Hilton Head, SC
I've ran multiple 9 second passes in a stripped down C4 with a turbo 4.8 and a bone stock Dana 36 and stock rear everything else.
I dont understand the point of boring out a 4.8 block and then adding boost. You're not increasing the peak power potential at all, you're just increasing torque and thinning the sleeves. The block kept at stock 4.8 displacement is virtually indestructible. The thick sleeves combined with low side-loading from the excellent rod/stroke ratio along with reduced torque will put incredibly low twisting force on the block. Other than lifting a head, you wont be able to harm the block. As soon as you bore almost a quarter inch off of the sleeves, a lot of this goes out the window.
I dont understand the point of boring out a 4.8 block and then adding boost. You're not increasing the peak power potential at all, you're just increasing torque and thinning the sleeves. The block kept at stock 4.8 displacement is virtually indestructible. The thick sleeves combined with low side-loading from the excellent rod/stroke ratio along with reduced torque will put incredibly low twisting force on the block. Other than lifting a head, you wont be able to harm the block. As soon as you bore almost a quarter inch off of the sleeves, a lot of this goes out the window.
Burning Brakes
Joined: Sep 2016
Posts: 1,133
Likes: 319
From: Ohio
under normal circumstances i would agree with you entirely. More cylinder wall thickness is always better for boost. The block i bought however, doesnt agree with you. Idiot who owned it before me didnt really take care of it. It had scuffing on some of the cylinder walls and needed to be bored over to fix it. He also managed to snap a valvespring in half and drop a valve on No. 6 piston leaving a lovely little gash there. So the whole bottom end except for the crank was basically useless. To preface. Im a ripe 20 and i know that a junkyard 4.8 could be easily purchased for the same cost of machining as what ive done here. However i recieved these pistons and the block for free. (Pistons were from a buddy who builds engines not the idiot who owned the block). And im trying to just budget this thing together for now. Its definitely not the most ideal. But its saving me a bit of money. 600$ for a junkyard 4.8 and 500$ for these pistons. So im somewhat forced to go with it.
Or you can put it together with the thin sleeves, attempt to make big power on your first ever turbo LS build, and destroy everything you have and have to start all over without the parts to sell anymore.
You're basically putting something together that is already leaning on a crutch, waiting to fall. I'd consider much more mild boost goals of 500-600 HP with that setup.
The forged rods and pistons will be doing you zero favors if you've weakened the block below the point of what the stock rods and pistons can handle.
Never go full potato on your first build. You'll lose more than you learn.
Le Mans Master
Joined: Feb 2005
Posts: 6,479
Likes: 565
From: Clearwater Florida
i really like the above mentioned idea of keeping the torque low and just making gobbs of hp. I finally got the exact math and the motor will be a 312ci or a 5.1 retaining the stock stroke of a 4.8 with the bore of a 5.7L at 3.903. So it will probably rev real well and be a fun little oddball combo motor. As for the torque. Some people prefer their vette to have that characteristic testosterone fueled shove of torque from the get off, personally, i prefer the motor to make it all in mid to high so my... uh.. shall we say spirited driving habits dont have me hooning around on public roads. As for the d44 i think i may try to go for that option and just keep the motor away from any stroker kits. Any reccomended d44 mods in addition to the detroit trutrac and cryoed half shafts?
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
Trying to have all purpose car will add to the challenge as opposed to a dedicated drag, suto x or road race car. The chassis set up will need to.be adjusted for the different events. Not that it can't be done; you want to build car for primary event. Then adjust toward secondary.
Burning Brakes
Joined: Sep 2016
Posts: 1,133
Likes: 319
From: Ohio
Trying to have all purpose car will add to the challenge as opposed to a dedicated drag, suto x or road race car. The chassis set up will need to.be adjusted for the different events. Not that it can't be done; you want to build car for primary event. Then adjust toward secondary.
Then again I've put about 300 hours of work into it.
Le Mans Master
Joined: Aug 2017
Posts: 6,941
Likes: 1,490
From: New Jersey
I've ran multiple 9 second passes in a stripped down C4 with a turbo 4.8 and a bone stock Dana 36 and stock rear everything else.
I dont understand the point of boring out a 4.8 block and then adding boost. You're not increasing the peak power potential at all, you're just increasing torque and thinning the sleeves. The block kept at stock 4.8 displacement is virtually indestructible. The thick sleeves combined with low side-loading from the excellent rod/stroke ratio along with reduced torque will put incredibly low twisting force on the block. Other than lifting a head, you wont be able to harm the block. As soon as you bore almost a quarter inch off of the sleeves, a lot of this goes out the window.
I dont understand the point of boring out a 4.8 block and then adding boost. You're not increasing the peak power potential at all, you're just increasing torque and thinning the sleeves. The block kept at stock 4.8 displacement is virtually indestructible. The thick sleeves combined with low side-loading from the excellent rod/stroke ratio along with reduced torque will put incredibly low twisting force on the block. Other than lifting a head, you wont be able to harm the block. As soon as you bore almost a quarter inch off of the sleeves, a lot of this goes out the window.
You can make anything work excellent with the correct amount of effort. I've seen combos do ridiculous things that it just shouldn't be able to. Can't explain why it works but it does and we just leave it at that. Why mess with it if its already doing things it shouldn't be able to do lol.
Burning Brakes
Joined: Sep 2016
Posts: 1,133
Likes: 319
From: Ohio
Valve shrouding, valve size, quench, and even head flow matter significantly less when you're relying on boost for power.
The stock 4.8 heads (the worst flowing of the LS heads) have been over 1000whp completely unported with stock valves thanks to boost.
The stock 4.8 heads (the worst flowing of the LS heads) have been over 1000whp completely unported with stock valves thanks to boost.