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I was aware of the ASE warranty requirement stuff. My logic on this was to start with a cheap turbo that should work "alright." In case I do something wrong during my build, I wont fret blowing up a 250 dollar turbo. I know it is too big for 400hp but I plan to fairly quickly up the power to around 600 once I go 4l80e.
Originally Posted by gtfoxy
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.
believe it or not I thought a long time about this. In fact if cheap enough turbos rolled my way I would still do it. The primary downside is that there are three times as many cheap turbos that can potentially fail. What turbos can you get for $128?
Originally Posted by Forcefed86
I doubt the brand matters they all come from the same china plant. You can get GT45's for $190 shipped all day long on ebay.
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...
I was aware of the ASE warranty requirement stuff. My logic on this was to start with a cheap turbo that should work "alright." In case I do something wrong during my build, I wont fret blowing up a 250 dollar turbo. I know it is too big for 400hp but I plan to fairly quickly up the power to around 600 once I go 4l80e.
Just don't get that turbo. I just measured that other one & it is about the same as the one you listed.
Thank you for the advice gtfoxy and taking the time to measure the turbo. My internet research shows that lots of people use these ebay gt45s with good success. if a 5.3 wont spool it what will? Are these meant for use on big block chevys?
A 5.3 will spool it just fine. But when you remote mount the turbos they loose alot of the heat energy that helps drive the turbo. So generally remote mount turbos use smaller hotsides to make up for this loss.
IMO if you mount i behind the cab and keep the hot side piping nice and small you'll be fine. 2" off each manifold merged into 2.25" piping would work very well and easily support your end goal.
any objections to using the stock y pipe without cats?
Originally Posted by Forcefed86
A 5.3 will spool it just fine. But when you remote mount the turbos they loose alot of the heat energy that helps drive the turbo. So generally remote mount turbos use smaller hotsides to make up for this loss.
IMO if you mount i behind the cab and keep the hot side piping nice and small you'll be fine. 2" off each manifold merged into 2.25" piping would work very well and easily support your end goal.
Aren't those pipes after the Y like 2.75" or something? I think the manifold pipes were like 2.25"... Either way I would do a 3" @ the Y & go to the turbo with it. It transitions to a T4 flange very nicely.
Are you keeping the box? Would be neat if you had it enclosed in there & separate compartments dividing the turbo sides. Make the turbine side big enough & put in some high heat header wrap sheets to insulate it so it doesn't get too hot.
any objections to using the stock y pipe without cats?
Like I mentioned earlier, remote mounts tend to be laggy to start with. What people can't grasp is you don't want large piping. It's not an exhaust system, don't think of it as one. 3" piping is way too large IMO and will slow the exhaust velocity WAY down. low velocity gas = slow spool times.
If the factory "Y" is 2.75" it's too large as well. Like I said 2" pipe off each manifold to a 2.25" "Y" then a single 2.25" into the turbo. You want to extend the 2.25" pipe as far into the turbo as you can. Then Slap some 1/8 or 1/4" steel with a 2.25" hole over the back of it weld it all up. The result will be a much faster spooling turbo. Larger pipe pre-turbo isn't flowing anymore than smaller pipe.The turbo is the bottle neck in the system, whether it's in the back or the front doesn't matter. 1 2.25" pipe to the turbo will support 600whp on that setup.
I get wanting to use factory equipment though. If that's what you have and don't want to get involved in making a better system, go for it. Wrapping helps, but you defiantly don't want to go larger that the OEM piping.
I'm not positive but I think denmah has been over 600 whp on 2" pipe. Under the pressure exhaust is preturbo a crazy amount of air can flow through a small tube.
I personally would throw electric fans on it, flip the manifolds and do a front mount. Not have to worry about a scavenge pump for the oil and it would spool faster.
Like I mentioned earlier, remote mounts tend to be laggy to start with. What people can't grasp is you don't want large piping. It's not an exhaust system, don't think of it as one. 3" piping is way too large IMO and will slow the exhaust velocity WAY down. low velocity gas = slow spool times.
If the factory "Y" is 2.75" it's too large as well. Like I said 2" pipe off each manifold to a 2.25" "Y" then a single 2.25" into the turbo. You want to extend the 2.25" pipe as far into the turbo as you can. Then Slap some 1/8 or 1/4" steel with a 2.25" hole over the back of it weld it all up. The result will be a much faster spooling turbo. Larger pipe pre-turbo isn't flowing anymore than smaller pipe.The turbo is the bottle neck in the system, whether it's in the back or the front doesn't matter. 1 2.25" pipe to the turbo will support 600whp on that setup.
I get wanting to use factory equipment though. If that's what you have and don't want to get involved in making a better system, go for it. Wrapping helps, but you defiantly don't want to go larger that the OEM piping.
That isn't too far away from manifold source.
Sure that small diameter pipe will work the way you describe but pumping losses in the midrange are going to be higher vs if you balance the turbine flow in & out.
Add: Yes you have less Enthalpy back there but that is why you go a tad smaller in turbine & housing.
Originally Posted by operatorfailure
I'm not positive but I think denmah has been over 600 whp on 2" pipe. Under the pressure exhaust is preturbo a crazy amount of air can flow through a small tube.
I personally would throw electric fans on it, flip the manifolds and do a front mount. Not have to worry about a scavenge pump for the oil and it would spool faster.
There is no free lunch with pressures. Exhaust pressures are driven by the piston. Yes these motors have some reasonably balanced flowing heads but the engine still has to work to make those pressures. It's a trade off.
Sure that small diameter pipe will work the way you describe but pumping losses in the midrange are going to be higher vs if you balance the turbine flow in & out.
There is no free lunch with pressures. Exhaust pressures are driven by the piston. Yes these motors have some reasonably balanced flowing heads but the engine still has to work to make those pressures. It's a trade off.
I believe you’re mistaken sir. Pressure is dictated by the smallest point in the system. It’s Bernoulli’s principal. The turbo is dictating the back pressure level, not the piping size pre turbo. Ideally you want to keep the velocity as high as possible without going sonic in the pipe. You can actually drop the pre-turbo piping size down and go larger on the turbo exh housing/wheel and have lower overall back pressure maintaining the same spool time.
On the OP’s 5.3…
A 2.25”, 2.5”, 3”, 4”, 5” etc… pre-turbo piping will all have the exact same back pressure amount when placed behind the same turbo.
I log back pressure and ran a 2.5" hot side last year. Switching to the 2" and going from a 5.3 to a 370" 6.0 netted me no higher back pressure levels... Switching to 2" and upgrading my exhaust wheel size actually lowered my back pressure slightly. (same 1.25 exh housing.)
Most remote guys use huge piping because they think it's an exhaust system. Then have to run a tiny turbo exh. housing to make up for it..
Last edited by Forcefed86; Dec 16, 2015 at 03:53 PM.
Seems like from some of the math I remember seeing on here and maybe on the yellowbullet, it appeared that even smaller diameters than what Forcefed86 is suggesting would be "ideal" at the OP's projected power level. Pretty crazy stuff. The rear-mount turbo guys are taking advantage of this knowledge too I think.
I believe you’re mistaken sir. Pressure is dictated by the smallest point in the system. It’s Bernoulli’s principal. The turbo is dictating the back pressure level, not the piping size pre turbo. Ideally you want to keep the velocity as high as possible without going sonic in the pipe. You can actually drop the pre-turbo piping size down and go larger on the turbo exh housing/wheel and have lower overall back pressure maintaining the same spool time.
On the OP’s 5.3…
A 2.25”, 2.5”, 3”, 4”, 5” etc… pre-turbo piping will all have the exact same back pressure amount when placed behind the same turbo.
I log back pressure and ran a 2.5" hot side last year. Switching to the 2" and going from a 5.3 to a 370" 6.0 netted me no higher back pressure levels... Switching to 2" and upgrading my exhaust wheel size actually lowered my back pressure slightly. (same 1.25 exh housing.)
Most remote guys use huge piping because they think it's an exhaust system. Then have to run a tiny turbo exh. housing to make up for it..
I am quite familiar with Bournouli's Principle. Enough that I understand the operation of a pressure differential system as it also pertains to the turbine. & you're right the housing & wheel determine the required back pressures at certain compressor flow rates.
Distinction here is it is a principle that measures flow differential, not energy.
We seam to each have our own experiences.
I've done my own testing as well and once upon a time had a twin system running 2.5" connector pipes off the headers. EGT's were not where I wanted them on pump gas from where I thought they should be, so I went up to 3" connectors & EGT's dropped 150*, went faster & it spooled up faster.
Maybe had I went to larger turbine & maintained the exhaust velocity it sure would have worked out close to the same.
It really mostly matters where you land in the flow & pressure islands on the turbine so it is working efficiently.
For very long piping yeah I agree. You need to maintain a certain velocity, but at a point shortly before the turbo you can transition into a surface area that is closely equivalent to the surface area of the turbos inlet.
I am curious what your combination consists of. I'll check out your build thread.
