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All Go No Show: budget bed-mount turbo build thread
Hello everyone. I have been lurking for years and am finally ready to start my car project. The platform is a 2002 silverado rcsb 5.3 l59 base model 2wd 85k miles. The plan is to keep it daily drivable with an end goal of 600rwhp. The first step will be turboing the stock 5.3 to whatever the stock 4l60e (400hp?) can handle. Then after building a 4l80e and upgrading the rear end, crank up the hp. This will be done in my garage with the help of a few friends.
The plan is to bed mount turbo an ebay gt45
The mindset behind a bed mount turbo for me is this:
-Cost savings by using stock configured exhaust
-Retention of all factory parts under hood
-No melted plug wires, etc.
-All the benefits of an STS style turbo setup but with the turbo protected from the elements
-Turbo upgrades in the future will require no hot side modifications.
-And last of all I think it will be unique.
-I am not too worried about lag because I will be running an auto and can load the torque converter
I am fixing to order a Stigan gt45 from amazon. Anyone used this brand gt45 before?
In for results. Turbo has kind of a large hot side for a remote mount but it will work. What are you planning for fuel? 93/meth, e85, and what pump/injectors?
Oh, and personally I wouldn't mess with "building" a 4l80e for 600 whp, i would just buy a junkyard one and throw an transgo hd2 kit in it and call it good.
I'm planning on running straight 93. With my engine being flex fuel it has a large pump and ls2 size injectors. My first mark can be hit without any additional supporting mods because of that. Once I go for 600hp I will likely run ls9 injectors and a second oem fuel pump.
That is what I meant by building a 4l80e. My understanding of the kit is that it comes with some additional parts that can be used if you actually rebuild the engine in addition to the valve body modifications.
You're right, the turbo is pretty huge, but so is my truck bed!
I am going to be taking on the task of tuning myself. I am still pretty unsure on which software to go with (hp vs live). I was pampered with my LT1 cam swap. The tuning software was free.
I'm new to tuning also, only done about three vehicles. I use hptuners, it seems to be more common on he LS engines.
As far as the turbo being big on exhaust I meant the wheel, not the physical size. (Although the gt45 is a beast) I was just talking about being a little laggy, but it should be a blast.
34 lb/hr injectors will be done around 400 whp in a boosted setup but that should be enough to have fun for a while.
Good luck man!
Oh, and if you haven't yet Google sloppy mechanics. Their page has an insane amount of info along with base tunes to start off with on HP Tuners. Read every word on their website.
Oh okay I've gotcha now. Yeah it may be a bit laggy but hopefully brake boosting will compensate.
All my research has shown a pretty good split down the middle on efi vs hp. Therefor Ill probably just follow my wallet and get hptuners.
Yeah I have heard of them, Ill go give them a look. The one downside I see with hptuners is that I would have to pay to view those base tunes if they aren't the same year, make, and model as my truck. Is that true?
Nope, you can open any hptuners files you just can't edit them unless you spend credits. So I just open their base tune and my tune, copy/paste their info into mine. Works perfect.
But c'mon man everyone goes w/ the Gt45 on a budget build. I say use 3 $128 turbos triple bed mounted! You'll be the first triple charged remote mount LS ever...
Last edited by Forcefed86; 12-15-2015 at 01:31 PM.
If you haven't bought a turbo yet I would think about a little larger compressor side and smaller turbine. The gt45 is what I'm putting in my wagon because you can't beat the price, but I now wish I had spent a bit more money and gotten a 7875 or something in that range. With your rear mount I would lean towards the 7665 from vs racing. I think it's $320 so still very reasonable. The small turbine would choke out earlier than the gt45 but would be super punchy and almost no lag.
But c'mon man everyone goes the Gt45 on a budget build. I say use 3 $128 turbos triple bed mounted! You'll be the first triple charged remote mount LS ever...
That is awesome. I second his vote. Tri-turbo! You couldn't cover those up though, you would have to show them off.
There are different GT45's out there. I have seen 64.5-80mm inducers & a crap ton of different exhaust configurations. I see a lot of "T66" listed with up to 68mm compressors. CX has a 76/103 & an 80/108 that is a tad more than the other cheapies out there but they seem to actually share information & use what they sell. & $600 for a BB CHRA isn't too bad.
The 76/103 GT45 they use would be a good choice on this truck with a mild cam. I've been contemplating a few different routes with my GTO & the CX 80/108 is one I have been considering.
I suppose someone can call any turbo a "gt45". The varying compressor units you mention are something a vendor has slapped an aftermarket wheel and housing on. Its a modified "original".
The base model "original" gt45 is one in the link above... they are all form the same china manufacturer.
Turbo Charger GT45
Intake I.D 2.25", O.D 3.25"
Compress Trim 69; .66A/R; IND 68.70MM; EXD 97.80MM
Turbine Trim 92; 1.05 A/R; IND 87.40MM; EXD 77MM
Exhaust Downpipe Flange Standard 3.5" V-band
Exhaust Turbo Manifold Flange Standard T4
Intake Inlet 4"
OK, I measured up a turbine on an extra turbo he had that lost a seal thre days after he put it in.
A word of caution with cheap turbos; Their warranty's often require ASE installation technicians do the instal before they will warranty it. But they are so cheap he said "Fine. Send me another one then." & that turbo has lived for a few years now.
Now that I've measured it I have to agree with the poster above, that butt is going to be too big. I remembered 72-73mm as one of the specs, well, I incorrectly listed that as the Exducer. It's the inducer. Exducer was 60mm w/1.04A/R.
As it turns out he had one 70mm he tried in a 90/78mm in a 1.04A/R turbine. That's the turbo that didn't hit 5psi til almost 5,000RPM.
12-14-2015, 09:09 PM
All Go No Show: budget bed-mount turbo build thread 
