STI & Stock Bottom End
Thread Starter
TECH Enthusiast
Joined: Feb 2012
Posts: 631
Likes: 0
From: Orlando
STI & Stock Bottom End So I just raced a random seem to be stock WRX STI vs my stock LT1 from a 40 roll to about 120 and lost by 1 car length and im pissed off. I felt like I would of passed him after about 125mph. I cant believe I got my *** handed to me by a ricer, which gets me more focused on my build. Any words of wisdom to help me feel better? lol But whats the max RPM a stock bottom end can handle with new bearings & rod bolts? Are stock pistons brittle with a H/C/I setup?
I wouldn't be pissed. If it was newer one even with minimal mods they move out. Our cars are old and most high mileage. I would think a full bolt on lt1 would've gave that car a good run. From what I hear its safest to keep shifting around 6200ish. I'm no expert but I read that a lot on here. A stock bottom end is still a stock bottom end and your going to need some valve train to spin high also. People will tell you go ahead so akes everyone's advice and do as you wish.
full bolton with a tune you can shift at 6100 fine, do 1.6 NSA rockers on good springs and you can take it to 6300 before it falls off. good luck. search the classifieds for deals.
Thread Starter
TECH Enthusiast
Joined: Feb 2012
Posts: 631
Likes: 0
From: Orlando
Do a leakdown test. Make sure the rings are good. You get higher cylinder pressures with an aggressive cam. Especially if you go with a thinner head gasket or mill the heads .001" or more for increased compression ratio.
Id at least do some LT4 valvesprings and whatever self aligning rockers you can find used in the classifieds here.
Trending Topics
Thread Starter
TECH Enthusiast
Joined: Feb 2012
Posts: 631
Likes: 0
From: Orlando
Probably a Custom Ai grind with Nextek Springs, 1.7rr shaft mount rockers, Solid Roller setup w/ Full Bolts ons, Monoblade Along with a H/C/I package. Ill be spinning high. Ill refresh the bottom end with bearings, ARP rod bolts, and hell fire rings. With the stock bottom end refreshed 6200rpm is a safe limit? I was hoping for atleast 6700+rpms.
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 Probably a Custom Ai grind with Nextek Springs, 1.7rr shaft mount rockers, Solid Roller setup w/ Full Bolts ons, Monoblade Along with a H/C/I package. Ill be spinning high. Ill refresh the bottom end with bearings, ARP rod bolts, and hell fire rings. With the stock bottom end refreshed 6200rpm is a safe limit? I was hoping for atleast 6700+rpms.
Note your funds too. Even with a rebuild bottom end with head a cam it starts to snowball. Especially when you have the engine on the stand. You start thinking of ways to spend money on more upgrades. lol
Just consider this, once you have that much power **** starts breaking around it. I'm still waiting for my stock rear to grenade.
TECH Fanatic
Joined: Oct 2006
Posts: 1,106
Likes: 0
From: POULSBO WA.
Stock tach is about 200 rpm high. So u were spinning it to probably 6300. I thought the limit on these motors was more to the 6400 range? Which a safe limit would prolly be 62-6300. Which means i shift a little short on my 503 with Pac springs. Probably alot short now that i think about it. Damn it. Ha
I always heard shifting above 6k on a stock bottom end is skating on thin ice... OP Do you have bolt ons? full exhaust, intake, tune, stall/gears? IF not i would certainly tackle all of those things first then do a nice cam swap with some light head porting. If your worried about the bottom end pull it and replace everything with ARP Fasteners. Id replace the pistons at the very least. Crank and rods will support plenty of HP until you go with alot of boost or alot of nitrous. Bump the compression and slap it back together. of course dont forget the fueling if you were to get that deep in it. Fuel pump, filters and injectors. it adds up quick but youd certainly destroy that WRX the next time he pulls up next to you 
Its highly recommended to also alighnhone the mains with the new ARP main fasteners to be properly installed ..
As it is OP new rockers and springs along with exhaust and a stall would get the first stage of performance gain.
Most Turbo ricers i run into are top end rockets.. U Need to spray up there to hang at that 40 roll .Eliminate valve float,replace those worn out springs and gain some topend back.
FWIW
Last edited by defaultexistence; Sep 7, 2012 at 11:44 PM.
Thread Starter
TECH Enthusiast
Joined: Feb 2012
Posts: 631
Likes: 0
From: Orlando
Thanks guys for the boost. As far as I am in my decision to baptis(reborn) my LT1 and I pretty much made up my mind into keeping the LT and representing opti power, but I was wondering how much am I looking at for an LS2 swap? The LS2 come with 400hp and by the time I get LT1's first rebuild ill be hoping for 400hp to the crank. Which 400hp would be worth it? A LS2 swap or a rebuilt LTx?
LT4s have 4 bolt mains. As long as while you are doing forged pistons you put in ARP rod bolts and main studs, you will be fine. That is the weak link in these bottom ends.
