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First time turbo talk

Oddball

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Am I on the right path???? Lm7, stock cam, termX, gt45r (comp AR .70, ind 61.4 exd 82, trim 56, exhaust ind 73.8, exd 64.5, trim 76, turbo AR 1.00), stock manifolds, 2.5 od 18 gauge hot side, twin 7psi 38mm gates. Still need a fuel system. I think i need a walbro 4xx, deca 60s and regulator. Also need an intercooler and BOV. Goal is 500 whp through a manual. Quick spooling and done at 55-6000. Is this enough wastegate? I will be plumbing them back in down stream. I went twins due to availability and cost. And if one fails it might not grenade as fast. Thoughts and opinions?
 

this link contains probably way more information than is useful, though in there should be "theoretical" maths for sizing the wastegate.

My thoughts are: I want to know how you like it when you get it all up and running. I've got an LM7 with probably stock cam sitting in the garage and would like to see what you end up with.

are you considering cam swap at all so as to make better use of whatever you do?
 

this is a dope kit, but $1,700. granted, intake, ECU, tuneable, fuel system etc. for 600hp rating. not a bad deal for starting from scratch
 

Upgrading the LM7 Fuel System and Tuning

The factory LM7 injectors were only rated at 22-25 lbs. and won’t support much more than 380 hp.

Plan on upgrading to larger fuel injectors to meet the fuel demands of increased power.

Custom tuning will be required to properly adjust the fuel and ignition timing. Truck manifolds had 1.9-in. injectors versus the longer Gen. III car injectors or the shorter Gen. IV injectors. The connectors are different as well, but adapters and spacers can be used to fit car injectors on an LM7.

Keep in mind, the best injectors are fully characterized which helps your tuner maximize idle quality, etc.

When running boost, you can use a water-methanol system to supply extra fuel and lower-charge air temps.

The factory pump is good to about 430 whp. Many fuel system upgrade options are available. Drop-in fuel pump modules and external pumps are popular. Other options to maintain or increase pump pressure include electronic voltage controllers and hotwire kits.


from this onallcylinders article, which is pretty solid


looks like summit racing says 42-52 lb/hr fuel injectors and fuel pump of ~67 gph



At $87, this walbro GSS341BX looks to should provide enough fuel



60s would probably work, $450 for a set of 44lb/hr on summit though
 

this link contains probably way more information than is useful, though in there should be "theoretical" maths for sizing the wastegate.

My thoughts are: I want to know how you like it when you get it all up and running. I've got an LM7 with probably stock cam sitting in the garage and would like to see what you end up with.

are you considering cam swap at all so as to make better use of whatever you do?
Ill check all these articles out. I've already read a few and that's how I got to where I am now. I think I can reach my goal on the stock cam, and that way It keeps a tame idle and street manners. However, if it's pushing a stupid amount of boost to get there, I'll throw a cam in to drop those numbers. I also don't want to put springs, lifters, trays, pushrods and trunnions in it..yet. Big cams are also harder on cam bearings. will probably do trunnions to safeguard against failure eventually. I want to build it right the first time and not have to remove new parts for new parts. And I don't want to over-power the drivetrain either. It's not a purpose built drag racer or a rock bouncer. But it will both or those.
 
Ill check all these articles out. I've already read a few and that's how I got to where I am now. I think I can reach my goal on the stock cam, and that way It keeps a tame idle and street manners. However, if it's pushing a stupid amount of boost to get there, I'll throw a cam in to drop those numbers. I also don't want to put springs, lifters, trays, pushrods and trunnions in it..yet. Big cams are also harder on cam bearings. will probably do trunnions to safeguard against failure eventually. I want to build it right the first time and not have to remove new parts for new parts. And I don't want to over-power the drivetrain either. It's not a purpose built drag racer or a rock bouncer. But it will both or those.

crower will pay you $10 if you let them pick or build a cam for you.

Don't think you need a "big" cam, but something with maybe a little bit more lift would probably see magnified benefits with boost.

edit: they outta be able to get you something which is making power.

stock camshaft duration 191/190 @ 0.050 & 0.457/0.466 total lift & 114* hydraulic roller

Crower P/N 00574 stage 2 LS camshaft duration 226/231 @ 0.050 & 0.607/0.617 total lift & 118* roller

just as an example. i mean, yeah not exactly cheapest thing. but then you don't have to do it again. even a small aftermarket should flow better everywhere compared to stock
 
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I gapped the rings, shimmed and ported the oil pump, drilled out all the main oil galleys to 9/16ths and radiused all the hard edges, timing chain dampener, billet barbell that I slimmed down a bit more and improved the radius, and ported the heads, mainly exhaust and chamber. Oh and I drill the pistons through the oil ring land to improve scavenging.
 
I gapped the rings, shimmed and ported the oil pump, drilled out all the main oil galleys to 9/16ths and radiused all the hard edges, timing chain dampener, billet barbell that I slimmed down a bit more and improved the radius, and ported the heads, mainly exhaust and chamber. Oh and I drill the pistons through the oil ring land to improve scavenging.
might seem off the wall, have you considered a baffled or chambered oil pan to help out with sidehilling and other odd angles?
 

crower will pay you $10 if you let them pick or build a cam for you.

Don't think you need a "big" cam, but something with maybe a little bit more lift would probably see magnified benefits with boost.

edit: they outta be able to get you something which is making power.

stock camshaft duration 191/190 @ 0.050 & 0.457/0.466 total lift & 114* hydraulic roller

Crower P/N 00574 stage 2 LS camshaft duration 226/231 @ 0.050 & 0.607/0.617 total lift & 118* roller

just as an example. i mean, yeah not exactly cheapest thing. but then you don't have to do it again.
Wow big spenders lol id want a really tight LSA and keep the lift around a half inch.
 
might seem off the wall, have you considered a baffled or chambered oil pan to help out with sidehilling and other odd angles?
That's not a bad idea. The truck pan is pretty deep and it has an anti-slosh baffle. A guy could add some extra baffling i bet. For now ill run it as is and probably over-full.
 
Your link is pretty good. And I get it. But, I just start to glaze over after a while. That's why i picked a hp goal and got a turbo that advertised said amount. Then I sized everything else to suit. I was looking for a single 60mm gate but ended up with two 38s. That will cost me in extra piping and shit. They came with a 7lb spring but id probably need close to 14 to double the output. I'm sure my setup will make a lot of
Back pressure after say 10lbs. But i didnt want to over-size things and get a bunch of lag.
 
Your link is pretty good. And I get it. But, I just start to glaze over after a while. That's why i picked a hp goal and got a turbo that advertised said amount. Then I sized everything else to suit. I was looking for a single 60mm gate but ended up with two 38s. That will cost me in extra piping and shit. They came with a 7lb spring but id probably need close to 14 to double the output. I'm sure my setup will make a lot of
Back pressure after say 10lbs. But i didnt want to over-size things and get a bunch of lag.

It causes me to glaze over as well, bits and pieces is how I have to read it, but I also started it because i was getting waaay to spun around from many sources "on the internet"

I don't understand why you would need to double the spring on the waste-gate. 7 lbs is 7 lbs, if it is coming from 1 or 2, you are just trying to increase the intake air pressure ~50% over atmospheric, seems like you'd want to keep the 7 lbs in both of them.
 
Keep the 7lb springs and run an electronic boost controller. It'll help with spool/lag too since the wastegates won't crack before you hit target boost like a straight spring controlled setup.
 
I’m on a similar journey, I just grabbed a Walbro 450 for plenty of headroom and most pumps are comparable in price.
 
Take a long look at the Sloppy Mechanics YouTube channel.
Sloppy is the main inspiration.

I'm hanging up on the configuration. Like, where to put the turbo, do I mount it to the frame and run flex joints or mount it off the engine. I'm leaning towards off the engine just to limit flexing the hot side. I'm not game with the exhaust supporting the turbo. Either will require brackets. The fabricator at work says he will tig weld the stainless for me. I just need to come up with a plan and fit it. I think the best place for the gates is on the outer radius of a bend. They will probably go right before the turbo to simplify the down-stream tubing. The engine bay will have a shit load of heat/splash shields to separate the hot and cold side. And I'd prefer a liquid to air IC but cost might prevent that.
 
Look at Holley, Trick,KBracing, Fahler manifolds. All beefy manifolds that mount the turbo on the motor and all seem to have good success. Whatever vehicle it’s going in is gonna matter for room but those manifolds seem to keep it close to the motor. I picked up a cheap eBay log, it fits but needs lots of casting flash clean up with a die grinder.
 
I think I will chop the stockers and add V-bands. Atleast i know they will fit. Turbo will probably mount off the left front corner of the block and accessory bracket. Being a 4x4, this setup needs to handle hard hits and landings. And so, it needs to be over built. Last thing I need is a cracked manifold out in the bush.
 

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crower will pay you $10 if you let them pick or build a cam for you.

Don't think you need a "big" cam, but something with maybe a little bit more lift would probably see magnified benefits with boost.

edit: they outta be able to get you something which is making power.

stock camshaft duration 191/190 @ 0.050 & 0.457/0.466 total lift & 114* hydraulic roller

Crower P/N 00574 stage 2 LS camshaft duration 226/231 @ 0.050 & 0.607/0.617 total lift & 118* roller

just as an example. i mean, yeah not exactly cheapest thing. but then you don't have to do it again. even a small aftermarket should flow better everywhere compared to stock
226/232 .500 lift 106- 110 LSA and 8° of advance would be an absolute stump puller.


Saw this in another thread here. If I went with a cam, this would fit my vision.
 
 
That’s the cam I grabbed, 7875, LQ4, T56. Hope to be doing burnouts this summer
 
I'm really in the "less is more" boat with choosing a cam. Hence why I'm sticking with stock for now. I'm fairly certain I can reach my goal with a stock cam and still have all the tame idle and driveability. Once I reach clutch slip, I'm done. The trans I'm running only has a 1 1/8" ten spline input. If it was a drag car running a th400 or glide, I'd be turning it up for every ounce.
 
So my bro says 38mm gates won't be enough. I think I'll trade them in for 44's. I don't think there is such thing as to much wastegate. Thoughts?
 
So my bro says 38mm gates won't be enough. I think I'll trade them in for 44's. I don't think there is such thing as to much wastegate. Thoughts?
I don't think so, so long as you can get enough spring behind it for the boost level you want to achieve. With a decent size turbo and low boost level, definitely no such thing as too much

Also, the wastegate isn't the place to save money. We made that mistake on a turbo 4.8, had boost control issues we fought and fought until we put a quality gate on it that actually flowed as advertised.

I had great luck with this one on my last 4 cyl build.

Also, do your future self a favor and put a cam in that thing. Even if it is a really mild one. Those stock LS truck cams are absolutely dismal. I think i'm the one that recommended that Howard's cam in that other thread.
 
Time to bring this thread back with more questions. It's time to work out turbo placement. Down pipe needs to exit under the driver side engine mount, need an air box, cold side needs to steer toward a front mount intercooler and rad needs room to exist. Do you guys see anything wrong with either of these two locations? EDIT I did some searching and realize that the turbo angle is a no no. Guess I need to start again. Dang, I didn't think it would be so tough fitting this little turbo in with a rad, intercooler and everthing else.
 

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Why not set it up like most do on Silverados ?

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Hmm, well the crossover isn't in the back. If I tried that, I'd have to turn the turbo around so the down pipe could wrap around the front. Then it would be competing for space with the crossover ( they would have to cross paths). I might be able to adopt some aspects of that setup.
 
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