Hey guys! I am soon going to start collecting parts for my future turbo build to replace my ls1 in my camaro. This will be a semi-budget build to. In the end id like to spend around 4-5k on the engine alone. This is including i do all of the work i can myself. I know everything else will need to be upgraded as, however, im only concerned about the engine for now.

Anyways.. this shall be the first time im getting "into" motors and also turbos so i figure why not combine them . The goal is to have it so i can DD it without much to any problems. Not sure if i want to also have a dual pcm which will have a "street" tune that will be around ~600whp and a "track" tune which will be around ~800whp OR just use a boost controller so i can the power where i want to. Dual pcm seems safer but im not sure...
Right now im pretty much at the basics on what i want...

Main Goals:
-Reliable
-"stock" appearing (i LOVE sleeper cars)
-if i can, stockish sounding.

Engine Mods List:

-Lq4/lq9 rebuilt short block with stock crank and forged dished pistons/rods
-low compression 317 truck heads that will receive some p&p with ls9 head gaskets
-ls9 or a custom grind turbo cam (remember trying to keep it stockish sounding )
-gt76 turbo as i believe its more than enough to meet my power goals. Undecided on wastegate/bov. And plan using reversed truck manifolds and custom piping
-ebay 4" intercooler
-ls3 or ls6 intake.

Like i said this is a very basic list and hope to learn ALOT about building my own motor and dealing with a turbo. I dont think my goals seem to far fetched. I will also start contacting different shops when i start my build so i can get a good idea of the direction i want to go in.
Id love to hear some opinions/set ups some of you have on this. List isnt perfect and im sure it can be improved on
*Also I will have questions that arise im sure. Its been a long day and i cant think of them atm.
(I also made a thread on this at ls1tech, i updated the original post i made there.)

 

Looks good. Run an LS6 cam if you want a mild cam or buy a small turbo grind... keep it well under 220 deg duration to be stock sounding. LS9 I guess can work but its clearly designed as a blower cam and I dont like the long exhaust split for a turbo setup.

LS6 or LS2 intake would work. LS3 wont fit the 317 heads.

Truck manifolds are good if they fit, but I'm not sure. else make some simple mild steel logs.

600whp is easy. 9-10psi will do that. My buddy with a 6.0 with 243 heads and LS6 cam with the truck intake manifold just made 576whp on 8psi thru a 9" rear and 4L80E trans. Still more left in it.

800 is gonna be abit tougher to see. Figure with good race gas to be safe, and abit more boost, you should get there. Bigger cam would really help but you will hear it. 76mm should do it as long as the turbine side is adequately sized. My friend is using a S400 borg warner with the big T6 flange but its spooling pretty well so far. A small T4 is gonna have some back pressure issues up at 600+whp IMO. "P" trims are usually like 64mm/74mm wheels on the turbine side and good to 600whp although some smaller cube guys have seen near 700whp. 6.0 will likely have issues.
The larger T4's turbine wheels should be ok to 700- 800whp but it will depend on how the exhaust is run and flow characteristics of the turbine wheel itself. These wheels can be had in 67mm/74mm setups or larger. Garrett has some larger combos like a 75/82mm setup with very large a/r T4 housings available so it should handle everything that compressor wheel will make.

 

The 800hp figure isnt really "set in stone" but more of a optimistic guess of where id be. I like the car to produce around ~600hp for most driving situations until it hits the track where i plan on upping boost and adding race gas.
A ls6 manifold will work fine im guessing. Should i worry at all about it being to much pressure for the intake? On my setup i feel like it should be fine. And a small turbo cam sounds nice, would they in general be any more stress on the valvetrain than a ls6 cam? Truck manifolds also seem like a good choice and i believe there are quite a few people out there using them without any problems. I dont think theyll be much of a restriction, and building them seems like a pita lol. I saw Thridgen60 build and his custom exhaust manifolds. They do seem like a better setup for sure, but is it worth all the trouble to build/have someone create them?
Im very new on turbos so bare with me...
A t4 sounds like it will have problems? Would a t6 housing and turbine wheel create to much lag or be a better choice? I read up a little and hear it may take a while to spool up on high hp cars, so it may be even worse for a lower hp setup.
And im not also "set" on garret turbos setups. I know there are quite a few options out there.
*Also i never think i told you this but i absolutely LOVE your car and how its setup. The turbos through the hood...:drool:

 

I would go with the LS9 cam because its made for boost and has a near stock sound. Also if you want sleeper run a smaller intercooler to be able to hide it better.

 

Ls9 was made for a roots/twin screw type blower. There's little exhaust back pressure in a blower motor, so the cams are usually very different. Blowers have wide exhaust to intake duration splits, while turbo cams vary from reverse splits where intake has more duration than exhaust, to some being single pattern to some having just a few degs more on exhaust side like my new cam.

Most cams will work ok but there can be a big difference in performance and spool characteristics if cam is far from proper spec.

Valve train life depends on the cam lobe characteristics. Some turbo cams can and will be aggressive and springs will be pounded. Others are mild and will last awhile. Ls6 is mild and will last forever just about. You can bump duration and lift to get more power but still keep lobes mild enough to keep springs happy.

Still haven't confirmed if it is wheel hp you want or at motor. Big difference. Small p trim t4 will spool quick and be good to high 500's to maybe 600 wheel hp on most milder 5.3-6.0's.
With that smaller turbine wheel back pressure will start to become an issue at anything higher. Plus you should limit yourself to 70mm or less on compressor with that p trim sized stuff. Just not enough turbine to drive the compressor. A 70mm is ok for 600-700 crank hp depending on brand. For shot at 800 crank+ most go 76mm but some good 72-74's can make a lot more. Buddy has a 370" lsx with gt4202 Garrett. 74mm and it's made 800 at tires.

S400 t6 turbos are very popular and can do 800 hp. Great turbo for the money. But it's big frame so it can be harder to package. It will spool ok on a 6.0. Tune helps a lot there.

You can do that or a larger t4 with turbine of around 68mm on small end up to 75 or so mm. Turbine like that should handle 800 crank easily with a larger .96 to 1.xx a/r housing

 

I think the hardest thing was sitting back and figuring out turbo placement and routing. Also where to mount the intercooler. But I also wanted a/c... I am shooting for a nice reliable build. I went with a TU1 Camshaft. But research stock48. He runs a tripple 12 (I think) and swears by it. He's over on ls1 tech. Or my vote is the ls6 cam for stock driveability. With a little 76 turbo should have good boost right of the bat. Keep us posted!

 

I plan on getting it tuned at frost which seems to be a very reputable shop. Thats crazy with a 72mm! Im thinking ill go ahead and do a t4 76mm turbine. Now this is the turbo wheel, the compressor wheel what are some specs i can use for that? and the housing sizes also are a little more confusing for me.
the p trim doesnt sound good either as it seems to be too small and cant spool up enough. So what are other "trims" i can use? And trims i guess are a housing for either the compressor or turbine?
*sorry if i these seem like stupid questions.

Most of that im not to worried about atm. Id rather get all the **** then do it one step at a time. I have a idea of how im going to do it so ill go from there

 

Depends on who's turbo you use...there will be different designations. Like Precision, PT7675 is a 76mm compressor, 75mm turbine. Good size for 1100 hp they say, which is gonna be 900's whp. You can run any of their PT7275-PT7675 turbos and make your numbers.

Read the Garrett turbo website turbotech articles. Turbo 101 thru 103 It will explain the meanings of turbo words like trim and a/r, etc.

 

That really helped understand things. Very glad i read it. Ill more than likely read it x10 more times before somethings click but at least i know its there .

So a 76mm turbine sounds like it should do some good... with a larger 1.xx housing.
The pt7675 you mentioned sounds like it may be a good choice also. Ill sacrfice a little hp in order to make the car more... streetable/fun which means less lag.
I cant remember if i mentioned it or not... but i can deal with some lag which i expect but not a crazy amount.
How would you say the lag would be on a pt7675?
On borg warners website im trying to see if i can spec out a turbo..

-FI66 S3 cover 76mm compressor wheel and 1.00 a/r. Im assuming it will be a larger t4 flange also?
I hear borg warners are very reliable but use old technology? The price seems very... good to. Any input would be appreciated.

Edit: I have been looking around a bit more to and want to get a electronic wastegate if its not already obvious. Im not sure what needs to be done or even if everyone has one, but any direction on that would be helpful! Thanks guys!

 

Still got a couple unanswered questions

 

my setup might be for sale soon.

 

Yeah a larger T4 frame with a larger turbine wheel like that would spool really quick on a 6.0. Alot of that has to do with the tune. Probably have 800hp potential in it no doubt. I think I mentioned it before, but my buddy's GT4202 is 74 mm on a 370" motor made over 800 at the wheels at 17psi.

 

You have and thats... crazy!
Im sure you know the answers to these so ill go ahead and ask...(anyone can really answer btw)

-piping: i was thinking 3 inch piping. I have a buddy with a 07 tt 350z pushing about 500whp using 2.5 inch piping. Do you think that 3 inch would restrict it? If so at what hp/boost levels?

-radiator: is it fine in its stock location? Ill probably upgrade to a be cool rad. and fans for the added power/heat.

-bov: i was really hoping to get an electronic one to adjust the boost inside the car rather than tweaking with a screw. However i dont even know who sells good bovs. I do know i want a externally mounted one. Same as my wastegate.

Wastegate: same concerns about bov really. Who makes a good brand?

 

3" piping wont be an issue. It will support it. Depends on the turbo tho, some have 3" outlets, some have 3.5" or larger. IF using intercooler, some may have 3", 3.5" or 4" inlet/outlet. Use whatever size is on the turbo's compressor discharge end.

BOV's just release pressure after you shut throttle. Most guys run TIAL as they are really good for the price. Some guys run other brands for sound. Its up to you, but I am not sure they make electronic ones? Its a simple spring loaded device, not much to it.

Wastegates, need to size accordingly. For a single turbo, I'd probably run a bigger single wastegate if you want to beable to hit lower boost levels safely. 44-50 mm sizes probably would work. I run JGS wastegates. Good gate for a good low price. My twins use the 40mm, but a big single turbo should consider the 50 or 60 mm IMO.

For the wastegate vacuum lines, running the pressure port straight to manifold will control boost to the set wastegate spring. My JGS ones come with 2 springs, 6-7lb spring and a 12-13 lb spring. The 6-7 is installed. It would make 8-8.5 psi on my old setup with just manifold pressure. If you want adjustability you will need a manual boost controller or electronic. Electronic ones work best and I have a AMS-500 setup to put on my car. I did use a TurboXS manual controller and have no complaints. Worked well too. You can typically get up to 2 times more boost than the wastegate spring. Sometimes 2.5 times. I know I been to 18psi on the 6-7lb springs with the manual and did ok

Depends where you wish to mount the turbo but the rad should be ok in stock location. Stock rad may work well to keep things cool. Or you can upgrade but make sure you have a good set of fans with shroud to move air. Moving air is what keeps things most cool.