LS turbo advice needed...

[OKGMC4]

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.

[prodjay10]

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.

[prodjay10]

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.

[skyphix]

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.

[MySons68C20]

Originally Posted by skyphix

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.

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

[OKGMC4]

Originally Posted by skyphix

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.

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!

[akdg87]

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).

[OKGMC4]

Originally Posted by akdg87

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).

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.

[tinydb84]

Originally Posted by OKGMC4

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.

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.

[skyphix]

Originally Posted by OKGMC4

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.

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.

[Factory Guy]

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.

[lyrikz]

Originally Posted by OKGMC4

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.

Get a terminator x. Thank me later.

[OKGMC4]

Originally Posted by lyrikz

Get a terminator x. Thank me later.

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.

[lyrikz]

Originally Posted by OKGMC4

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.

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.

[lyrikz]

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.

[dag19]

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!

[lyrikz]

Originally Posted by dag19

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!

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

[gmc684x4]

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

[dag19]

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?

[71cadc10]

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

[dag19]

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

[OKGMC4]

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!

[71cadc10]

I'm using the 80# Deka 'long style' on a magnuson supercharged 6.0L
I felt the car idles just great, and low speed drives great.
Sorry I do not have experience with TermX system...to know what it works with.


The knock offs area real problem...I have set of 60# knock offs now in a car...and they have to be swapped. Can't get the AFR where we need it, they don't respond like they should. Idle sucks...no atomization. These were sold by "TRE" The Racers Edge. Total junk.


this place sells real Siemens stuff:
http://www.siemensdeka.com/product-c...uel-injectors/

depending on the year and type intake you are using, if you have an injector out of it just measure the length from o-ring to o-ring to determine if you need short, mid, long (37/48/60mm). otherwise mockup the rails and try to get a measurement.
For connector style, this would be driven by your harness connector choice. if your harness has the USCAR connectors on it, get the EV6 connection type. USCAR type connectors are the ones with gray or green plastic CPA that you seat after they are mated. Earlier EV1 type use the metal wire clips in them, and the latching features are on the sides of the interface. There's likely more choices in the later USCAR type EV6 in my opinion

[71cadc10]

I'd be vary wary of any of these aftermarket injectors, after what I am seeing with the TRE stuff. Yes your car will likely run if you get the flow rate close in the table, but not as well as it can. also if one sticks open, you quite possibly lose an engine (hydro lock).

I looked at the latest DW 95lb. and they do seem to be using a genuine Bosch injector EV14 series. so that product from DW should be decent

[OKGMC4]

another question...at the time it seemed like a good idea to run the wastegate to it's own tiny muffler instead of looping it back into the main exhaust but I'm wondering if the injection system will or won't like this? Will it screw up the AFR readings or will it be ok?