boosted ly2 lr4 4.8 rod question
Thread Starter
Teching In
Joined: Dec 2013
Posts: 8
Likes: 0
boosted ly2 lr4 4.8 rod question hi everyone been on here a while never post much im in the process of building a boosted 4.8 down here in Australia and im hoping to try and keep it as reliable as possible my combo so far is looking like this gen 3 4.8 lr4 block, gen 3 lr4 crank, gen 4 ly2 rods, mahle forged pistions, arp rod bolts, arp main studs, 862 ported heads, ls9 head gaskets, speedmaster head studs, sloppy stage 2 cam, and my turbo is a vs racing billet 7875, will be run on e85 duel wallbro 450s 1150cc bosch injectors.
Now my big question is to do with the gen 4 ly2 rods im curious to know how far people have pushed them reliably can anything be done for extra insurance (shot peen or cryo) ive got arp bolts would love your input looking for a 700rwhp and ill be happy.
Now my big question is to do with the gen 4 ly2 rods im curious to know how far people have pushed them reliably can anything be done for extra insurance (shot peen or cryo) ive got arp bolts would love your input looking for a 700rwhp and ill be happy.
TECH Resident
Joined: Oct 2009
Posts: 793
Likes: 0
From: Michigan
Seems to me that since you're on E85, and therefore pretty safe from detonation, the stock rods and definitely the stock bolts should be able to handle what that turbo can dish out. I don't think that turbo makes crazy power on an engine of even 4.4L like I have it on. They seem pretty happy on a 2JZ though.
Last edited by Tjabo; Aug 12, 2018 at 04:02 PM.
Thread Starter
Teching In
Joined: Dec 2013
Posts: 8
Likes: 0
Thread Starter
Teching In
Joined: Dec 2013
Posts: 8
Likes: 0
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
Restricted User
Joined: Mar 2014
Posts: 7,192
Likes: 109
From: Ohio
Thread Starter
Teching In
Joined: Dec 2013
Posts: 8
Likes: 0
Restricted User
Joined: Mar 2014
Posts: 7,192
Likes: 109
From: Ohio
I would skip ARP bolts as well. 99.99% of the time someone snaps a gen 4 rod in half, the big end is still free spinning on the crank with the bolts intact.
TECH Fanatic
Joined: Feb 2015
Posts: 1,080
Likes: 178
TECH Resident
Joined: Oct 2009
Posts: 793
Likes: 0
From: Michigan
Yeah, if he gives you an RPM lower than 9k or something, call bullshit on him. Lol
Especially with a turbo in the mix. It helps to cushion the tensile loads on the rod bolts in the TDC area of the exhaust stroke where the highest stresses would normally be.
Especially with a turbo in the mix. It helps to cushion the tensile loads on the rod bolts in the TDC area of the exhaust stroke where the highest stresses would normally be.
TECH Fanatic
Joined: Jun 2014
Posts: 1,533
Likes: 12
I’m with you. I think the whole stay away from 7K u less you did rod bolts is urban legend.
Thread Starter
Teching In
Joined: Dec 2013
Posts: 8
Likes: 0
I more want to do the rod bolts just for the extra clamping force on the rod ive personally havent seen a rod bolt fail and my old burnout car would sit at 7200 on the limiter for a straight 3 minutes plus. Im looking at the arp bolts to prevent any pontential walking of the cap
I managed to bend a few Gen4 4.8 rods around 800-900 crank. Not saying they bend at that power level, but something in my tune or RPM range was off. Make sure not to give it too much at low RPM. I ran a 100 shot to spool an S476 with a super tight converter and a baby 212/212 @112 cam. I think that's what did it. No signs of HG leakage or detonation I could see. I didn't even know I bent it till I took the engine apart. Was trapping 151 or so a little over 3000lbs. Also had it geared super tall. 3.10 gear and 29" tire at that time I believe. getting the boost control sorted it may have bounced off 30lbs or so briefly... a few times! 
Thread Starter
Teching In
Joined: Dec 2013
Posts: 8
Likes: 0
I managed to bend a few Gen4 4.8 rods around 800-900 crank. Not saying they bend at that power level, but something in my tune or RPM range was off. Make sure not to give it too much at low RPM. I ran a 100 shot to spool an S476 with a super tight converter and a baby 212/212 @112 cam. I think that's what did it. No signs of HG leakage or detonation I could see. I didn't even know I bent it till I took the engine apart. Was trapping 151 or so a little over 3000lbs. Also had it geared super tall. 3.10 gear and 29" tire at that time I believe. getting the boost control sorted it may have bounced off 30lbs or so briefly... a few times!
