LS turbo advice needed...
 

So I just know somebody will tell me to use a search function for these questions so, in advance, I have. Either I'm stupid or just can't find the answer to this stuff.

I want to turbo my 5.3. It's an 01 with 85k on it and has a stock LS1 camaro cam in it. I have a 4l80e to back it. Looking at doing a 76-78mm T4 with a .96 AR. Seems to be common on 5.3 swaps. Unless someone suggests one that is smaller, and why. I don't really want to do an ebay turbo. I understand they work great, but for how long? I want it to last. There are cheaper units from places like Huron Speed and Precision but are the economy Precision units any better than the Chinese turbo that costs half as much?

1. I THINK I can do 10-12 psi on 91 octane with an intercooler. I already have a big Treadstone intercooler mounted. Seems like some say run less boost, others say more. Ring gap, head gaskets, head bolts all stock. Seen some with stuck ring lands on less psi and some running WAY more without issue. I know the tune is critical, but does that 10-12 psi sound reasonable?

2. Going to try a Trick performance cast stainless manifold rather than welding truck manifolds or a log. Some have good luck with that but there are a ton of them that end up cracking and I want OEM reliability. It comes with a 38mm style 2 bolt wastegate flange. A 44-46mm seems like a logical choice but they are all v band. There are adapters from 2 bolt to v band but does that really work? If the hole in the manifold is smaller isn't that really the choke point? Trick sells the full kit with a Precision 39mm 2 bolt so that might be good enough but want to avoid boost creep.

3. Sounds like I'll need to look into a MAFless tune for my application? Seen it both ways.

Wish there was an LS turbo sticky just like the LS swap sticky. Still trying to learn the turbo do's and don'ts.

Re: LS turbo advice needed...
 

There is a lot of info out there but when I search either the pictures suck or aren’t there. Or the info I found doesn’t answer my question. Maybe someone will take less time to answer than me searching hours to find.

Re: LS turbo advice needed...
 

There is a lot of info out there but when I search either the pictures suck or aren’t there. Or the info I found doesn’t answer my question. Maybe someone will take less time to answer than me searching hours to find.

Re: LS turbo advice needed...
 

I can't comment on the manifold;

How much boost you can run will be determined entirely on the condition of your shortblock and the tune. 10-12psi is common on completely stock internals - adding some ring gap is protection, and depending on how hard you run it, enough heat will cause that ring gap to close (if it isn't wear-widened) up enough to break the ring land or top of the piston. If it were me, I'd start at 8psi... see how the engine likes it, work with a tuner familiar with boosted applications and GM ECU's, and work up from there. Every engine has had a different life and behaves a bit differently.

You don't need to do a Speed Density tune (MAF-Less) - but it does make life easier in boosted applications. If you want to run a MAF for whatever reason, your stock setup is tunable at 10-12psi, and custom OS's are available for 2 and 3 bar applications. The stock MAF can be rescaled but only to a certain point... I'd say 1 bar (15ish psi) would be the limit of rescaling before you run into inaccurate air metering, but it depends on other factors (including your injectors.) It really is about airflow, not boost or no boost. My opinion here would be to do whatever your tuner is most comfortable with and can get you the safest tune on.



All in all, 10-12psi on a stock engine is perfectly attainable... as long as the engine is in good health. If you want longevity, don't beat on it too hard and run a very conservative timing table, "over injector" (i.e. bigger injectors than you need) and "over fuel pump" (more fuel pump than you need) will keep things save, avoid a sudden lean under boost condition, and keep your engine together. Opening the ring gaps would definitely buy you more leeway, but if you're in that far... gen 4 rods and pistons AND slightly wider ring gap... and then it just snowballs from there.

Re: LS turbo advice needed...
 

VERY helpful post!! I just learned a lot thank you!

Re: LS turbo advice needed...
 

i would get a 7875 turbo- vs racing is very popular and very little issues from what i have read. I have their borg warner s475 knockoff on my truck and will be upgrading to a bigger version over the winter.

10-12 psi is fine with stock ring gap. I was running 20 PSI with my stock 5.3. Good tuner will go along way, definitley do your research there because there are some hacks.

obviously plan for all the incidentals- injectors, wideband o2, valvesprings for starters. A custom stall converter will make a huge differnce as well (be forwarned they are spendy for the 4L80).

Re: LS turbo advice needed...
 

I have a set of PAC1218 springs already and was planning on either 60 or 80 lb injectors with a big Walbro pump. Is a wideband required to run a turbo? The o2 sensors are one of the fuzzy things for me. Location, number, and style. Kind of assumed you need one in the downpipe but was thinking you don't really need 2 since there will only be one exhaust pipe.

The turbos I have been looking at are the VS billet 7875, the Huron Speed billet 7875, and the Precision LS cast 7675. The price gap is a consideration but I definitely want a setup that will last a while.

Re: LS turbo advice needed...
 

Yes, VERY helpful information. The engine situation is a hard call for me. I also have a running 280K mile 6.0. I know with a cam it could make way more power than the 5.3. The rings are probably plenty worn but I'm not sure of the condition of the valve guides, bearings, etc. and I'm trying to avoid a full engine rebuild. I know the 5.3 I have is a great engine, I used it for 7 years in my 56 gmc. Plus, if I don't stick my foot in it all the time I might even be able to sneak past a gas pump now and again. The 6.0 I rebuilt with a 224R cam made me lose 6mpg when I swapped out the 5.3!

Re: LS turbo advice needed...
 

Mine isn't running yet so just my two cents.

I am planning on running 80's and have a walbro 450 in my tank. I plan on running a wideband just to monitor my stuff. I am running one O2 sensor in the down pipe. I got a GT45 for free so that is what I am using. I was planning on buying a case VS 75mm prior to getting my turbo.

Re: LS turbo advice needed...
 

Yes, in order to safely run a turbo, a Wideband will be required. The factory O2 sensors are only accurate at Stoich (14.7) - or within 1% of that. You'll want to tune down in the mid 12's at the very least, where the factory O2's are outside their effective range.

I've seen as many as one per cylinder, or as few as 1 in the downpipe. 1 in the downpipe is adequate for most people.

Go 80lb injectors... you won't need them at first, but as soon as you hit 550 wheel hp, 650 seems tempting... then when you hit 650, 750 seems tempting... you get my point. "Over Injector"'ing is rarely a bad idea.

The VS turbo's are proving more reliable than people expected. I'll be running a VS turbo - either an S475 or an S480. There's a couple of people locally with upwards of 50,000 year-round miles on their VS turbos with zero issues.

Re: LS turbo advice needed...
 

You might want to check out the “drive way engineer” youtube channel he talks a lot about LS’s and bolting turbos on junkyard LS’s.

Re: LS turbo advice needed...
 

Everyones going to tell you what to run turbo wise and what not.
There is already a cheap strategy out there.
Stock LS motor
Pull heads. LS7 head gaskets
Head studs
BTR spring upgrade
Btr stage 2 cam
Gap rings (google will tell you how much)
1000cc snake eater injectors
terminator X ecu
12 psi easy. All day.. Just watch your timing.


I went the other route and built a forged 6.0. If i went the route i recommended to you id be driving it right now.

Re: LS turbo advice needed...
 

Get a terminator x. Thank me later.

Re: LS turbo advice needed...
 

Your recipe sounds awesome but maybe more than what I was planning. I'm trying to keep the truck kind of low key. Quiet and reliable. I don't want a big cam. I have a 224R in my 6.0 and the idle sounds good but rougher than I wanted. Never had headers before until my Dougs full lengths. I fought the ticking noise for awhile until I figured out that there are no exhaust leaks, the pushrods are the right length, nothing is broke, headers are just noisy. Put the Corvette manifolds back on and quiet again. I guess what I'm saying is that I think I can run mild boost on a 5.3 and not have an obnoxious truck. A friend has a Nissan GTR and that car drives like an Altima until you hit the gas pedal and then dear lord hang on. 600hp and AWD has made me a believer. And I'll have half the traction he does.

I do wonder though...is the Terminator X easy for a novice? I've paid for my last two tunes and I would think a turbo motor would be even harder to learn on.

Re: LS turbo advice needed...
 

Term X is hands down the easiest out there. Eventually you will want to get it tuned, but its a self learning system. You can start it, and drive it. Very easy to learn to tune with it also.

You can absolutely just freshen up a 5.3 and run 10lbs on it. The turbo will make the truck very quiet especially if you have mufflers on it. If you want to run more boost through it, those things i recommended arent very hard, or expensive.

Re: LS turbo advice needed...
 

100% what this guy says. I like tuning the GM ECU's, but am a novice at best. What I've seen of the Term X and Dom X are that they are way easier, with a bunch of features. I just like having as much factory stuff as I can possibly have living in the middle of no where.



And yes, a close to stock 5.3 (even the summit stage 1 or stage 2 turbo cams will make a big power difference, with minimal change to drivability) with a moderately sized turbo at 10lbs will be quiet, mild, and easy driving. And will be able to boil the tires at pretty much whatever prudent speed you're interested in.

Re: LS turbo advice needed...
 

Next question is this...
Which is better for turbo use, a fuel rail with no return, or the one with the vacuum regulator built in and return line? I have both styles from 99-06 truck intakes and I'm sure people have used both. Just wondering which one is the easier to setup, run, and or tune for. I think it makes a difference which rail you use in the tune when naturally aspirated in HP tuners because it changes injector pulse width. I downloaded the Terminator X software and don't really see where a person has control over that so I suppose the software self adjusts?

Re: LS turbo advice needed...
 

Also, you guys have told me, and I've read it a few hundred times on other threads to stay conservative on timing. But nobody gives an actual target number. What is a considered the range of conservative timing on a 5.3 engine when turbocharging?

Re: LS turbo advice needed...
 

it really depends on the gasoline you have availabile and how effective your intercooler is. We have 90 octane at the pump here in alaska, i also supplement that with methanol injection using a devils own kit.

This is a nice visual that matt from sloppy mechanics put out. He might be the most well versed LS tuner out there for stock PCM's. He has put alot of good info out and backs it up with explanations.

Re: LS turbo advice needed...
 

Been on here for hours looking for something like that. Been all over the sloppy page and never saw it. That is flat out awesome.

Re: LS turbo advice needed...
 

You have to take some of the stuff you see online with a grain of salt. Sure, you saw a guy that ran a stock engine with 12 psi for years with no issues. Well, thers 234 other guys that ran 12psi and it blew up on their second pull.

Take some time, and fix the weak points and you can run 10psi all day..

Last weekend i went through my old harness to get the coil pack wiring. Say we can agree that a SUPER nice LS harness is 500 bucks. You also need a wideband o2 when doing this also. Thats probably 200 bucks. If you spend another 300 dollars you will get your wide band O2, and a computer, and a harness that isnt 15 years old. You will spend DAYS, if not longer screwing with the factory harness.. And in the end, if you run into an issue, you have to second guess whats screwed up on your old harness.

Buy the X, with trans control for your 4l80, then come back on here and thank me. lol. Seriously. Dont waste your time shipping out your computer, and all that so you can save 300 to 500 bucks. Best money you will ever spend on that.

Re: LS turbo advice needed...
 

If you aren't already setup to tune yourself, and don't already have a harness and are jumping straight to turbo... listen to this guy, Term X is definitely the easier route.

I will be setup to tune GM PCM's for various reasons regardless, so I started with a GM ECU and a PSI Harness, but once I go bigger boost (2-3 years from now) I'll use my harness and PCM for another project and likely go Term X just for the built in functionality.

Re: LS turbo advice needed...
 

I dont think the other guys realize he is going turbo. Sure, if you want a stock ls, then maybe save a few bucks and go that route.

Re: LS turbo advice needed...
 

You've convinced me on the Terminator X. Looks like the way to go. Just trying to figure out what I have to do differently on that path. So far it looks like it only uses the wideband O2 so I won't need to put a bung in the crossover pipe for a second sensor. The IAT plug pic in the instructions is pretty grainy but I assume the MAF is deleted so I also have to assume you have to use an LS1 car style IAT but is it better to put it pre throttle body or post TB in the intake manifold? That's a question for Holley I guess. My question about which fuel rail is better still stands, but it does seem like maybe the vacuum regulator on the return style fuel rail may work better with less work (if I can believe the internet). I've been going through the Term X software and I think I may understand about half of what I'm seeing. Will just have to figure out the balance between what the ecu self learns and what the user has to input to get going. I saw on the injector drop down menu that Siemens deka 60 injectors are on the list but 80's aren't. I planned on the 80's but without the info to insert into the program it probably wouldn't run so good. I could do the 60's for ease and I "think" they'll be good enough for me since I'm staying super mild and on low boost levels but who wants to be wrong? Just so many questions in this here brain...

Re: LS turbo advice needed...
 

You want to put the wideband about 16 inches down the downpipe. They include a bung in the kit.

IAT, is 25036751. Thats the part number. Put it in the intake boot close to the throttle body.

MAF is deleted. You need a MAP sensor. Map sensor you plug a line into the intake for vacuum and then mount on firewall somewhere. PT# for the gm map sensor is in the instructions. You need the additional harness, holley has that also.

Rails and regulator are easy. Tons of info out ther on that. I went aftermarket.

I have had all these thoughts, and im the same way. Once you start doing it, it answers itself. The self tuning will get you up and running. Then you can either take it to be dynod, or do your own.
I run the SEP 1000 injectors. That way i wont have to mess around when i up the power. You could decap the 60s and you will probably be fine if you are only at 10-12 psi ya know.

Im wiring my engine now. So, any questions i can help, cause its super fresh right now.

Re: LS turbo advice needed...
 

Also, alternator. If you are running a 4 prong alternator, get this.

https://sloppymechanics-com.myshopif...-combo-harness

Plugs right into your alt, and right into your term x harness. DONE. No more alt. bull**** to worry about.

Re: LS turbo advice needed...
 

Does the Term X use the connector for the coil harnesses or does it have each individual coil connection? Thinking of relocating the coils off the valve covers and wondering how hard that might be to do as far as the wiring goes.

Re: LS turbo advice needed...
 

You will need to buy the coil harness or source a harness off the old engine.
You can absolutely move the coils, you just will have to lengthen roughly 8 or 10 wires per side to wherever you are going.

Im doing this now. Debating. I have the holley valve covers that cover the coils but i keep getting the wrong ones. First ones wouldnt plug in, 2nd ones are to tall for the cover to fit. Debated just moving them all together.

Re: LS turbo advice needed...
 

This is a fabulous thread, thank you guys for all the knowledge! I am just about to get started on my LQ4 turbo build.

Have any of you looked into or know anything about the kit CX Racing offers? https://www.cxracing.com/turbo-kit/t...10-6772-IC-RAD

Also, lyrikz, what did you end up doing with your coil relocation? I would like to move mine as well. Hook it up with some pics if you got em!

Re: LS turbo advice needed...
 

I got the holley valve covers that hide the coils.
I think i have a pic, one second. Theres covers that go over them.

http://67-72chevytrucks.com/vboard/a...1&d=1591365844

Re: LS turbo advice needed...
 

So I was checking out the harness you suggested to purchase and he was talking about the Flex Fuel sensor harness for E85 as well. Is this a required sensor? Or is it only required if you are running E85?

Re: LS turbo advice needed...
 

Great thread i have someone keep talking about sloppy mech have to check them out

Re: LS turbo advice needed...
 

only required if you plan to run E85 or a mix of it.
for a turbo app, if E85 is available in your area...I personally would run it. Plan your pump and injectors accordingly if you plan to use it

Re: LS turbo advice needed...
 

I would like to run E85 since I hear you get more out of it that way. The trick will be finding somewhere that sells it around here in western NE. Where at in the fuel system should I mount the sensor?

For injectors I intend to go with Deutschwerks EV6 95lb/hr injectors. I was looking at a Boyd's Welding tank with an Aeromotive Stealth 340 fuel pump. Would that system suffice?

Re: LS turbo advice needed...
 

12-14 PSI is doable on a factory engine if your AFRs stay right. Most of the guys who blow up a stock engine either had a boost spike or a fuelling issue and just didn't even realize it. A lot has also been learned with timing. Sloppy Mechanics now recommends pulling timing back a few degrees at torque peak and then adding it back at high RPM. This helps keep cylinder pressures down and keeps pistons/HG happier.

I'm on stock HG (not even MLS) and TTY bolts and I run 12-14PSI on the street, but I usually pull boost back to 10psi mid summer when it's 100 degrees in Central TX. I also have a wideband readout going 24/7.

Seriously buy the Terminator X though. I'm on a megasquirt MS2 and I've been eyeing the X for a while now.

Re: LS turbo advice needed...
 

sorry didn't see this till now.
If using a return style system the sensor you'd want on the return side...it's 3/8 line size.
If you are running dead head setup you can run the supply fuel thru the sensor if needed...but if you are planning larger supply lines -8AN then the sensor would be a restriction.

I'd skip anything Deutschwerks and look for a real Siemens or Bosch injector, 80#/hr
that 340 pump sounds good...I've also used Walbro 450 with good success on E85

Re: LS turbo advice needed...
 

No worries, I appreciate the input at any time!
I do intend to run a return style system. I haven't decided on supply/return line sizes. I assume what size comes out of the tank will be my limiting factor and just stay with that size throughout the system.

Good to know on the injectors. Is there a big price difference? Or its a moot point due to the quality of Siemens or Bosch?

Re: LS turbo advice needed...
 

Siemens 80# are in the $400 range for set.
less than DW and higher quality (thank GM or Ford for footing the R&D)

Re: LS turbo advice needed...
 

Excellent! That's really not terrible... especially with the good quality. Thanks for the tip!

Re: LS turbo advice needed...
 

Stupid question...or really a verification of what I think I've figured out...to use Siemens Deka injectors you'd need the mid length 48mm style for an early truck intake? Looks like the long version is if you are using a car style intake. And wouldn't it be better to go ahead and get the EV1 connectors? The Multecs don't seem very common. The Terminator offers several connector options. And where can you reliably get the genuine Siemens injectors to insure you don't get the fake knock offs? Still seems like the 60lbs would get me down the road fine, 80's would be a sure thing but there are all sorts of rumors out there about idle quality with 80's. Plus the Term X software only lists the 60 in the drop down menu. Any experience with the Deka 80 and the Terminator system? Thanks for all the great advice!