twin turbo questions?
 

Hey im build a mean daily driver aka 130 miles a day and was wondering if these turbos would be a good fit?
the engine is a LQ4 stock crank, forged pistons and rod's, port and polished 799 heads, holley hi-ram, 90mm throttle body, Texas speed ms4 cam with 112 lsa

http://vi.raptor.ebaydesc.com/ws/eBa...=1429506811749

Re: twin turbo questions?
 

Im going to move this to the LS forum for you. Your more likely to get better answers.

Re: twin turbo questions?
 

I don't know anything about that particular brand of ebay turbos, tho in general I'm not the fondest of them. Some are fine, but its company-to-company and batch to batch. Some guys use to run the MP turbos with great success from ebay, but others had catastrophic bearing or seal failures. It sucks ruining an engine with a turbo grenading itself.

That being said, thats a fairly large a/r. A pair (I assume non-sequential), would take a while to spool. In traffic you'll be running without boost most of the time, so your biggest issues would be controlling surge and keeping it manageable. A smaller wheel would let you build low boost quicker, meaning you'll spend more time in the power and face less of the boost spike. If you do want to run a big turbo or 2 around town, then getting the tune dialed in, and keeping control of boost via the wastegates will be far more critical.

This would actually be a good time for Wasted Income to take over the thread and finish it with a more comprehensive explanation as to exactly "why" and what a better option would be. IMO the turbo size you posted would make a decent single turbo.

BTW thats a divided flange T4 setup.

Re: twin turbo questions?
 

Those are actually really decent turbos for a good price. Lots of guys making 600+ rwhp on 4.8/5.3s with that exact turbo.

I have one sitting on the shelf in the basement that I was planning to use on a build, before I decided to go with twin Borg Warners instead.

This turbo is kinda in no-man's land. It's big enough as a single, on a smaller V8, but chokes off fast once the cubes grow....and in my opinion is was too big as twins on a smallblock....at least for a fun and responsive setup.

If you want to stick with cheap ebay turbos, take a look at the ON3 turbos.

http://www.on3performance.com/shop/o...-turbocharger/

Re: twin turbo questions?
 

Wow its been a long time, but I'm slowly collecting parts for my truck, I did little mock up my engine last week to see the how much bigger the holley hi rams intake runner where than my 799 heads intake ports because I was going to match port and polishe the heads to the intake and it finds out the hi ram matches the stock intake ports perfectly so I'm going to leave it be, I know it's not the best power choice, I really like that turbos wasted income posted, I do want to remote mount them, and I'm hoping the holley dominator efi can handle a setup like that and as of now the truck is no longer a daily driver

Re: twin turbo questions?
 

Oh now that I think of it what would be a good set a waste gates and blow off valves? something adjustable I can turn the boost up when I want to play around

Re: twin turbo questions?
 

TiAL (the company, not a compound of Titanium and Aluminum)

Re: twin turbo questions?
 

Awesome thank you i like the look of the 38mm waste gate and the 50mm bov from TiAL not a bad price wise either.

Re: twin turbo questions?
 

So does anyone on here run a remote mounted turbo setup on there truck

Re: twin turbo questions?
 

Define "remote". If you mean full rear-turbo (like mounting it where the mufflers go), I haven't seen any here. I've seen plenty in real life tho, and its usually the "last" option.

If you wanna do a low-mount (end of headers basically), then its plenty doable, but you'll still need a scavenge pump for the oil.

If you have the room, front mount is the way to go from a thermodynamic perspective. Turbo's want to keep heat IN the exhaust for velocity, and a rear mount turbo has drawbacks in that aspect.

Re: twin turbo questions?
 

I agree with Br3w on this one. Remote turbos should be a last resort. Twins shouldn't be an issue room wise in our engine compartment.

Re: twin turbo questions?
 

Yeah rear mounted turbos and I've always heard about bad turbo lag with that type of trubo system, so definitely under the hood, and save the money from not needing to buy a scavenge pump, and the extra pipe, and since the turbos a good size it sounds like a good idea to just dump them right out side of the fender then

Re: twin turbo questions?
 

You can do that, but I'll present a few options for fun;

All the way out the back (boring)
All the way out the back with a cutout for fender dump (no tickets, push button loud)
Fender Dump (tickets, but fun)
OR, may I offer
Full exhaust, with dump tubes on the wastegate ONLY. Why? Because IMO its the coolest sounding option.

With that much turbo, you'll be running two wastegates and using them to bleed pressure pretty often. At WOT, you'll be dumping a ton of pressure and STILL make big boost. When you dump the WG, it lets you run a full nice tame exhaust..but when you nail the throttle, the WG's dump all that extra hot air out a short fender dump. Its sorta the best of both worlds...and nothing sounds like a WG dumping 40+psi of 1200* gas out the fender...IT WILL MELT SH!T NEXT TO YOU...and its awesome.

Re: twin turbo questions?
 

That sounds awesome I would have never thought of that so a 44mm waste gate would be perfect and run some big quite mufflers so it would, similar to the active exhaust system on the higher-end sports cars

Re: twin turbo questions?
 

two of them

Re: twin turbo questions?
 

Yes two 44mm waste gates. But I think two 38mm waste gate should be fine because from the turbos Wasted income posted two of then on a v8 are good for 900hp and the 90mm throttle body can support 750hp or so and I'm going to keep the 799 heads stock so 700hp maybe posible which shouldn't need 44mm waste gates maybe if I was going for 1000hp+, but I had the idea just now of taking and making a sort of mega phone for the waste gate

Re: twin turbo questions?
 

Hey what are you guys running your timing at? I'm trying to figure out a timing curve because due to budget I'm going to run the stock pistons and rods and I'm trying to get a safe starting point. So please any advice would be really sweet

Re: twin turbo questions?
 

What combo of parts did you end up running? On mostly stock swaps you just start with low boost and stock timing and watch kr/log it, and build up from there. If your still on stock compression and have enough fuel then you won't be "blowy-upy" right away.

I'm not sure what kind of timing figures you had setup for the MS4 (And if you had timing ground in), but you can always back it down. I believe the rule of thumb on pump gas is 1* per pound of boost over ~4-5lbs. That being said, if your logs are clean and your not melting plugs, its possible to run waaay more timing than that would suggest.

Re: twin turbo questions?
 

You plan on keeping the MS4 cam? Larger waste-gates aren't for more power per say they are more for controlling boost so that there isn't any creep or higher than needed/wanted boost #s. Bigger wastegates will control lower(lbs) boost, so if you plan to keep boost under 10-12 lbs then the bigger gates will be better suited for your application. There are alot of people making way more than 700hp through a 90mm tb and stock heads.

Re: twin turbo questions?
 

As far as the cam yes I'm going to keep it, and I haven't got any parts for the turbo system so I think I will get the bigger waste gates just for pice of mind, and my C/P ratio is 10.0 : 1 so I think it would be best to stay under 10-12 lbs of boost