86monte496

So ive decided on going turbo with my 04 silverado 4.8
Before i start, ill say that my goals are efficiency and only around 400hp

Motor is bone stock.

how much hp i can safely make on the stock fuel pump?

what size bov/wg i actually need and optimal placement of the wg as ive seen them on the crossover, and on log manifolds before the inlet flange for the turbo, i could place it either or, what is better?

and most importantly the size of the turbo, ive seen alot of builds with say 76/68 or similarly sized turbo, even much bigger and ive yet to see a relevant topic build wise so i figured id ask for some help, that being said what would be best sized turbo for this application?


The truck will be daily driven and occasionally used to haul the race car to tracks too far to drive to


Hope im not asking stupid questions, thanks in advance guys

Also been very curious about the longevity people are getting from brands like on3 or cvracing turbos, any relative feedback appreciated

newschool72

iTrader: (12)

I will get this started , then the people that REALLY know what they are talking about can take over from there, LOL.
First off, there are compression calculators on the BW and Garrett sites that help make a choice for you, but looking at your goals, Id go with something on the small side, like a 67mm compressor. On the turbine side, its a juggling act. You want to keep the AR ratio tight so the turbo will spool quickly, especially in a truck (read heavy!). At the same time , you don't want to go too small on the turbine wheel, so you don't get a lot of back pressure and heat everything up. Plus a larger turbine will give you room to grow (raise boost) later on if you want a little more.
There! Now someone with real knowledge tell him what he really needs, LOL.

JoeNova

400 HP at the wheel or flywheel?

400 at the flywheel could be done with very minor mods. Mild cam, headers, tune will get you 350 or so. Swap to TBSS intake, some milled 799 heads, and conversion to speed density will put you around 400 without a turbo.

Josh Hopkins

At the tire, really I'm just interested in getting my feet wet in the turbo stuff and I figure this is the perfect project

I plan on properly supporting it so that there is room to grow but for now being my daily I'm saying 400 as a goal to be safe and reliable

Bad Apache

That's a pretty small goal for the investment you'll have in it. Have you considered contacting a company like KB Racing for a kit? They could answer a bunch of your questions from tried and true experience, I'm sure. You'll probably over-achieve your goal though, hahaha!

86monte496

I thought about it, but most of the kits ive seen for the silverado are thin stainless manifolds, my buddy has an exhaust shop and i figure i could fabricate a manifold and hot side for probably 250$ including flanges and vbands, in fact i ordered 1 ls header flange last night

And after talking to matt im considering calling up vs racing, all in all it would be a pretty small investment it seems for the possible gains, and like i said, there will definitely be room to grow.. alot more room lol

Ive already been toying around with the 6.0 4l80 swap in the future, so i could run safe and reliably on the 4.8 and build up a 6.0 at my convenience

My monte carlo is pretty fast so i dont exactly need another impractical 80mph burnout machine ... or do i?

86monte496

any recommendations for a drop in fuel pump if there is one for the silverado?

Might aswell go with something with extra pressure



Also looking at injectors, holley rates their 83# injectors at 1300hp..... Do i really need 80lb injectors or are s/d injectors underrated? what am i missing here lol

Maybe just because your spending the money?

Zizzle

I did a similar project.

Borg S300SX3 - 66mm .88 AR
ebay waste gate
CXracing fmic, bov and piping
Truck injectors modified for 60 lbs/hr
ASPX wideband
HPtuners
custom hot side

Cost around $2k for the above.

86monte496

what sorda power did you make on that settup, what fuel pump and where were the injectors modified at?

Also how do you like the small turbo, .88ar probably sorda big for that turbo id think.. does it spool well? and what did you think about the cxracing bov?

JoeNova

Stock truck manifolds are the best thing to use as a basis for turbo manifolds. Extremely thick and strong, and weld very good.

Deka 80s are good for more power than you'll want and run great, they're also about 320 new for a set. A Walbro 450 pump can go in fairly easy as well and is good for almost as much power as the injectors so they're a good match.

Zizzle

I haven't had it on the dyno.

My goals were pretty modest like yours, mainly because I live at 8,000 ft above sea level which robs a good bit of power, which I wanted to get back.

It's actually in a beat up late 90's 1-ton van. Hardly a sports car, it weighs over 6,000lbs.

The turbo is semi remote I guess, mounted down beside the trans. My hot side piping is also too big. All 3" just because I had it on hand.

But most of the lag is kind of masked by the trans kicking down. I've seen it build full boost at not much over 2k while hitting a bit of a hill while loaded up with some dirt bikes.

It's running a 11psi spring and it's pretty fun to drive despite weighing over 6000 lbs. Not quite rolling burnouts fun, but overtaking is pretty easy. People assume a big old van is pretty slow.

Some of the speed limits around me are 60 mph which with the 3.73 rear works out to about 1950 rpm. This low rpm + turbo lag + cruise control + hills = chaos.

But up at 65 mph it cruises closer to 2200 I think, so cruise control actually works well with the turbo.

Fuel pump is a walbaro 400 which is way overkill for the power this is making. I also butchered up the basket putting it in, so I try not to run below 1/4 tank.

CXracing bov was a bit of a pain in the beginning. The sealing o-ring kept slipping off. I think the turbo blew a little oil onto it during initial startups and it wouldn't stay on. After putting it back on for the 3rd time I just cleaned it up and stuck it down with a little RTV and it hasn't been an issue since.

Fuel injectors were by smartfireinjectors on ebay. About the same price as some siemens dekkas but you don't have to mess with your harness or injector rails. Plug and play. Also came in a nice plastic case with a spec sheet for the offsets.

http://www.ebay.com/itm/191267929580

I recently bought some siemens dekkas for another project and they just showed up in a USPS bag. Luckily all had miraculously survived.

Tuning wasn't that hard, just found a similar setup on hptuners or sloppy wiki and compared with my stock tune. Take some timing out and do some gentle pulls while watching the wideband.

I wired the output of my wideband into the A/C pressure input so I could log it in hp tuners.

http://www.corvetteforum.com/forums/...hp-tuners.html

The 2 hard fought tuning lesson were this:

1) the boost enrichment table in the hptuners 2-bar OS only kicks in if you are already in PE mode. So make sure you set your PE to come in around when you start making boost (40% throttle for me I think).

2) if you don't drop the min injector pulse width when you upgrade your injectors, you'll spend a bit of time fiddling with VE tables wondering why you are still rich at idle and low rpm