Need some help deciding LSX or LT4
Registered User
Joined: Jan 2006
Posts: 778
From: Shillington PA
Re: Need some help deciding LSX or LT4
Moe Baily.
Bryan Herter.
JD Performance
Three tuners off the top of my head..covering TEXAS. OHIO. Pa/NJ
ALL specializing in LT1 tuning.
soooo AGAIN....they are out there. U just have to know where to look.
Larry (Popo8) Co-owner
LTXtech.com
Bryan Herter.
JD Performance
Three tuners off the top of my head..covering TEXAS. OHIO. Pa/NJ
ALL specializing in LT1 tuning.
soooo AGAIN....they are out there. U just have to know where to look.
Larry (Popo8) Co-owner
LTXtech.com
Thread Starter
Registered User
Joined: Mar 2013
Posts: 55
Re: Need some help deciding LSX or LT4
You have to choose what you really want from your build. NA and boost can be worlds apart when it comes to engine building and you really need to keep your final power goal in mind when building any shortblock or swapping any motor. You already have half the parts needed to build a fire breathing LTX monster and to part it out would be a complete waste.
Why are you so obsessed with going forged? This is sort of thing is gratuitous and completely unnecessary for the street. The LSX376's bottom end doesn't really have that much of an edge on your current LTX. The only reason it's "built for boost" is because the pistons are forged rather than the hyperpathetics that are standard on most NA street cars. Like the LT1, the crank is still NODULAR IRON and the rods are still POWDERED METAL which is nothing fancy. Realistically, the only big difference between your LTX bottom and the LS bottom would be the forged pistons, added main bolts, and a marginal difference in displacement. Don't let the 2 bolt mains scare you, they can take a beating with some decent studs. If that still makes you uncomfortable then pick up a used 4 bolt Vette block for $200 or less.
That being said, how much power do you really want? You're have very little headroom left NA on the street. Boost it and don't look back.
My suggestion for a bargain basement build that could be boosted to a certain extent (I would feel uncomfortable over 550whp)...
Line hone your 2 bolt block and use ARP studs
Get stock crank turned and reuse
Get stock PM rods resized with ARP bolts and reuse
Loosen main/rod clearances from stock with fresh bearings
Upgrade spring in stock oil pump for higher pressure (not HV)
Hone block to 355
Install forged pistons but BE CAREFUL! Do not choose a piston with large valve reliefs or dishes because they have a tendency to cut too far into the top land and piston crown making them really weak (so when it detonates you will loose chunks on 4032 pistons easy)
Shoot for 9:1 scr and pick up a decent used supercharger. You will have no trouble making 550rwhp and beyond with your current heads and the right blower cam. You probably won't even have a stupid amount of boost because your motor probably already flows a ton with those AFRs.
If you want more than that then just swap out the crank for a 14088532 forged GM unit, add some cheapo 4340 Scat rods, and find a Vette block for not that much more. The bottom end will be rock solid.
And are you insinuating that nobody tunes LT1 cars anymore or something? It's OBD1 for christ's sake. You could tune the damn thing in your driveway if you really wanted. Read a book and buy an ALDL cable.
Why are you so obsessed with going forged? This is sort of thing is gratuitous and completely unnecessary for the street. The LSX376's bottom end doesn't really have that much of an edge on your current LTX. The only reason it's "built for boost" is because the pistons are forged rather than the hyperpathetics that are standard on most NA street cars. Like the LT1, the crank is still NODULAR IRON and the rods are still POWDERED METAL which is nothing fancy. Realistically, the only big difference between your LTX bottom and the LS bottom would be the forged pistons, added main bolts, and a marginal difference in displacement. Don't let the 2 bolt mains scare you, they can take a beating with some decent studs. If that still makes you uncomfortable then pick up a used 4 bolt Vette block for $200 or less.
That being said, how much power do you really want? You're have very little headroom left NA on the street. Boost it and don't look back.
My suggestion for a bargain basement build that could be boosted to a certain extent (I would feel uncomfortable over 550whp)...
Line hone your 2 bolt block and use ARP studs
Get stock crank turned and reuse
Get stock PM rods resized with ARP bolts and reuse
Loosen main/rod clearances from stock with fresh bearings
Upgrade spring in stock oil pump for higher pressure (not HV)
Hone block to 355
Install forged pistons but BE CAREFUL! Do not choose a piston with large valve reliefs or dishes because they have a tendency to cut too far into the top land and piston crown making them really weak (so when it detonates you will loose chunks on 4032 pistons easy)
Shoot for 9:1 scr and pick up a decent used supercharger. You will have no trouble making 550rwhp and beyond with your current heads and the right blower cam. You probably won't even have a stupid amount of boost because your motor probably already flows a ton with those AFRs.
If you want more than that then just swap out the crank for a 14088532 forged GM unit, add some cheapo 4340 Scat rods, and find a Vette block for not that much more. The bottom end will be rock solid.
And are you insinuating that nobody tunes LT1 cars anymore or something? It's OBD1 for christ's sake. You could tune the damn thing in your driveway if you really wanted. Read a book and buy an ALDL cable.
Well, for me it's pretty much this. I had always planned to turbocharge the car. But, I wanted to get it as fast as I could with the stock motor first. I've pushed the car about as far as I want to go N/A but the LT1 isn't capable of making the numbers I want to see in N/A trim without it being completely non streetable. To stay competitive today you need a power adder as most cars worth mentioning now have either a Turbo or Charger in them.
My goal is to make 750-800 to the rear wheels. Which will come down to needing an Immortal bottom end and a HEALTHY Turbo. My thoughts about the LSX376 weren't to exactly keep it untouched. It still would have to have work put into it but still I'd be starting out closer to 383 power than actually spending the extra money on machine shop services.
Before my LT1/4 went down I was mostly gathering parts and pricing on getting the job done but you know... that was 10+ years ago and better stuff is out now. with an NA LTX we know pretty much what it's limits are by now. When you do start boosting that throws in the wild card factor which still makes it a relevant motor.
Going for an LSX is still an open window as there's still plenty of potential with it and that platform is still breaking records. As far as GM motors go we're the new TPI's. The LTX is yester years power.
Registered User
Joined: May 2012
Posts: 660
From: idaho
I agree with both popo8 and Jason but your talking a different beast all together. Truth is just because someone can change tunes and call themselves a tuner doesnt really mean much. Once you hit a point in any car you have limited who can and should tune the car. You usually hit a point in high power setups were you compromise power for dependability or durability. So many tuners will just go for the number and in time you pay for it. A good tuner finds the balance. A setup with that kind of power also takes a bit of maintainance to be sure everything stays functional. Truth be told you need a top notch tuner either way and you need to do plenty of monitering and upkeep yourself. I am not sure whats available in stand alone ecms but you might want to look at that also. Personally I would find a few cars with the setup you want or very similar and get feedback from them of the challenges they have faced and overcome. Taking the time before you commit can make it much easier. There will probably be more available for the ls but sometimes options dont work in your favor. Proven setups happen because things work together and the tune is part of that.
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Posted from Camaroz28.com App for Android
Registered User
Joined: Apr 2011
Posts: 54
From: Philadelphia, Pennsylvania
Re: Need some help deciding LSX or LT4
Well, if you want to make 750-800 at the wheels then that LSX crate motor is a gigantic waste of money. I wouldn't trust one of those motors at that power level any more than I would trust a 4 bolt LT1 being that the crank and rods are the same material. Yes, there are a handful of people out there pushing the limits of stock LSX parts but you could say the same for the LTX crowd. Too many people underestimate the LT1 because it was succeeded by a motor that's better in almost every way out of the box and I'm not denying that. Despite this, it's still a capable platform for your goals. There are plenty of LTX cars making good power out there. Scroll through this:
https://www.camaroz28.com/forums/for...llcall-482086/
Now, there's a big difference between what can be done once and what can be done repeatedly with some degree of reliability. First, the crank and rods have to go in both motors. There's no way I would feel comfortable with a cast crank and PM rods in a motor makes that much power because it would be a time bomb. For the LSX376, this means buying a 4340 crank, decent H beam rods, then rebalancing and any other machine work that's needed. That's going to run you another few grand plus the motor itself. Still seem worth it?
But hey, if you really want to ditch the LT1 then I'd be more than willing to take those pesky AFRs off your hands for about tree fiddy.
https://www.camaroz28.com/forums/for...llcall-482086/
Now, there's a big difference between what can be done once and what can be done repeatedly with some degree of reliability. First, the crank and rods have to go in both motors. There's no way I would feel comfortable with a cast crank and PM rods in a motor makes that much power because it would be a time bomb. For the LSX376, this means buying a 4340 crank, decent H beam rods, then rebalancing and any other machine work that's needed. That's going to run you another few grand plus the motor itself. Still seem worth it?
But hey, if you really want to ditch the LT1 then I'd be more than willing to take those pesky AFRs off your hands for about tree fiddy.
Registered User
Joined: Nov 2002
Posts: 4,784
From: Jacksonville
Re: Need some help deciding LSX or LT4
Do some research on LS1tech. You would be amazed at what you can do with a 5.3 truck motor these days (even in stock form). The best part is you can find them for next to nothing if you look around the local salvage yards.
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Joined: Jan 2006
Posts: 778
From: Shillington PA
Re: Re: Need some help deciding LSX or LT4
Larry (Popo8) Co-owner
LTXtech.com
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Joined: Oct 2006
Posts: 654
From: Snow Belt, PA
Re: Need some help deciding LSX or LT4
I'm going in next month for my 2nd dyno tune from Bryan. He's also done a handful of "mail order" tunes/updates for me. He's great to deal with and very flexible.
Registered User
Joined: Jan 2006
Posts: 778
From: Shillington PA
Registered User
Joined: Sep 1998
Posts: 45
From: Oxford, MI (Detroit)
Re: Need some help deciding LSX or LT4
Wow your story is almost a mirror image of mine, except I had been on this board for 15 years. I had the same decision to make with my 93Z. As soon as I sold my 2011 SS Camaro I found a built 383 LT1 with low compression for boost here on the board. I got it for a decent price and decided to go boosted 383 LT1. I work for GM and had the exact thoughts of an LSX motor, but am also shooting for the 700-800hp mark. I know that it can be done on a boosted 383 LT1 so that's what I'm doing. I have a lot of work to do yet but it should be fun. Now I'm trying to decide supercharging vs turbo...... decisions decisions.
Darrick
Darrick
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