chillman88

Hey all,

I've got a 4.8 from a 99 Silverado that I'm retrofitting into an older truck. I am just putting the truck together N/A for now, but I would like to eventually put one or two smallish turbos on it. I realize this is where it gets crazy with tech, but I gotta learn some how! This would not be a "race" build, but more of an economy build only pushing about 7-8psi. What size should I look at, and would there be any reason to go twins? I'm sure a single would "work" but I'd like to aim for efficiency, and if smaller twins work better than a larger single I'd do that.

The vehicle in question will weigh 4000-5000lbs, have a 4l60e, and 3.50 gears with approximately 29" tires.

Thanks in advance!

-- Chris

IronBlocked

Anything from a 53-57-62mm turbo will work, but I'd choose the smaller if you arent chasing big power, also the 4l60e probably will not take the power the turbos will add.

chillman88

Yeah the 4l60 isn't long for this world. I'm on the fence about rebuilding it or getting an 80e. I'm thinking I'd be better with the lower 1st of the 4l60 and a good rebuild.

As far as the power goes, it's going to be a summer daily driver if i get it set up right. I don't need high rpms or anything, just a little added grunt.

chillman88

Truthfully I'd want a t56 6spd if they had a cheap way to mate to a transfer case.

LLLosingit

iTrader: (4)

I have a 2009 4.8 and 2008 6.0 and there is night and day difference between the two. The 4.8 is a dog off the line and doesn't make power until at least 3,500 and like to rev. The 6.0 makes lots of low end power and pulls hard until around 5,500 and starts falling off. There is no way I would bother with a 4.8 in anything heavy even with boost.
For the money it's going to take to get the 4l60e to hold decent power you'd be better off just putting a shift kit in a 4l80e.

redss82

Your talking economy and twins were you need to buy pretty much two of everything and why are you limiting 7 to 8 psi doesnt matter if you dont have a specific turbo in mind. Economy build Id shoot for 500 to 600 whp because the parts are cheap to make that kind of power and you can beat on it at that power level for a long time. A single borg turbo s366 will come on great or you can do any of the chinese turbos 70,76,7875 turbos will all make that power just need fuel and valve springs rest of the engine can be stock. Also cheap and t56 never seems to work out but depending on the truck you could run a divorced tcase depending on which side the output needs to be on

chillman88

@LLLosingit:
I'd love a 6.0, but I'm not going to get one for $100 COMPLETE with exhaust and wiring harness like I got this 4.8. I'm doing this cheaply to start. I can always throw in a 6.0 later if I feel the need. Besides, a bone stock 4.8 should easily see 18+ highway, whereas I've never heard of a 6.0 getting better than 18 REGULARLY. Sure there are times, but I'm looking for something I can drive to and from work during the summer, and wind up and p*** off that little honda that thinks he's hot stuff on the way home.

@redss82:
I haven't decided on twins, I'm more or less inquiring as to if there's any benefit to twins over singles for low hp application. I'm limiting to 7-8psi only because when I first do this the motor will be completely stock. My understanding is there is a point with boost on a small motor where it becomes more efficient (when driven sensibly), and after that you end up sacrificing mileage for power.

My goal is a small motor, driven with a light foot (except when said ricer decides he's "awesome") as an efficient but fun daily driver.

Really the only reason for me choosing a 4l60e is that it won't cost me a dime. I've got it sitting here from when I swapped my truck to a 5spd. I figured with a slightly higher stall converter, say from a 4.3 powered S10, it would get me up closer to where the 4.8 likes to be.

66Chevellelq4

I realize these are completely different engines, but i feel like the same general principles apply when choosing twins vs a big single turbo. The video is long but thorough

chillman88

Thanks for the replies guys.

So it sounds to me like this: http://www.ebay.com/itm/GT45-TURBOCHARGER-TURBO-600-HP-BOOST-UNIVERSAL-T4-T66-3-5-V-BAND-1-05-A-R-92-/190592393465?hash=item2c603120f9&vxp=mtr
Would be a little on the high side, but might be great for a first turbo? That listing says it's a 68mm.

DavidBoren

That will be just fine, sir.

You can push it to 17psi and get 600hp out of it, too, if you want.

But it will live forever @ 10psi and 450rwhp.

Forcefed86

iTrader: (4)

This does not apply to a boosted engine and is total BS. Are either of your setups turbocharged? A mild turbo 4.8 will run circles around an NA 6.0 for a fraction of the price. Look at Denamhs 4.8 stock long block Silverado truck build. Never had the heads off and it was in the 9’s.

Any auto turbo car worth a damn will have a converter that stalls over 3500 once in boost. The 4.8 has a better bore/stroke ratio for a turbo engine. It will rev out higher and have a wider RPM range after peak torque. This makes it a better option for the budget minded. It allows for cheaper converter choices and turbo(s). Having gobs of torque below 3500rpm is just going to fry tires. For a budget setup like the OP is planning a 4.8 makes the most sense.

Gotta say a manual trans is a horrible idea though. They don’t handle the power without a ton of money in them. The good news is you don’t need a heavy *** 4L80e either. Run a simple TH400. OD is not needed with a property setup turbo car. You can gear it high enough that OD is not needed. A mild TH400 (clutches, shift kit) and the “budget” $450 PTC 10” converter behind a boosted 4.8 IS the cheapest and best option for the OP’s budget build… period.

DavidBoren

Forcefed86,

Your post, along with the quote, should be a sticky/bulletin. You just outlined the perfect budget build in the most idiot simple and to the point terminology possible.

I'm actually amazed by how seldomly the TH400 is brought up. People dump big money into 4L80e's and go through great lengths to make it fit. The TH400 has a proven performance record. It's been handling triple digit power before GM knew what an LS motor was. Yet it seems all but neglected these days.

Forcefed86

iTrader: (4)

I’m usually a glide guy but that suckers too heavy to do a cheap glide. TH400 is cheap/easy.

Good example…

https://ls1tech.com/forums/forced-in...-jy-5-3-a.html


2.73 gear in a 4000lb full weight 4 door LTD with a 26” tire. 5.3 single turbo… Easily trapping over 140 and netting 19mpg on E85 without OD through 6 mufflers.

DavidBoren

I really like the powerglide/gearvenders combo for lightweight turbo applications.

But gearvenders and budget don't belong in the same sentence.

Forcefed86

iTrader: (4)

If you look around they sell that same gt45 for 199 shipped to your door on ebay.