Yelo

I don't know.....if you figure that the entire intake tract is going to be pressurized to a given PSI (5-6 psi) the lag shouldn't be that bad. sure, you won't see killer boost right off idle but as soon as you get to a usable RPM (over 2000) the boost should be there when you want it.
we already push the exhaust gasses 12 feet or better through multiple restrictions (headers, mufflers) to get them out of the engine so why not put that 12 feet to use to cool down the exhaust gasses and make them more dense and better able to spin the turbo turbine...the only real lag you would see would be right off idle...the time it takes the intake tract air charge reaching full even boost pressure might be 1-2 seconds, but for those of us that are seriously traction limited to begin with that 1-2 seconds would be enough time to get our vehicles moving and to (hopefully) avoid wheelspin

I can see real merit in this system....even if it is rather unorthodox

O3GMC

I agree......I'd rather not have 100+ extra hp right off the line, considering I dont run around with slicks all the time, the slight lag might be an advantage to street trucks - I think they might be using a slightly smaller turbo to compensate for the lag, I always thought the bigger the turbo, the more lag - but I could be wrong.
On their site they have also said that the pressure drop in the intake tubing is nothing compared to having to go through an intercooler. And with all that piping and the turbo being out in the open air, I would think it would stay fairly cool.

Slowverado

well, now that i look at it that way i agree, it's kinda like using a window switch on a nitrous kit. you don't spray until you get outta the hole to avoid traction loss. that being said, i still think it would be better to have the turbo up closer to the front of the truck to run an intercooler. I WOULD NEVER, run a supercharger, or turbo without an intercooelr....yeah, you can do it. but i personally wouldn't since it's so damn hot here 8 months of the year. and an intercooler is just extra horsepower.

kwkshift

Yelo, it's not the exhaust gasses that spin the turbine, it's the heat energy that spins it. That being said, it's desireable that they be closer to the engine for maximum efficiency.

Also, now that the turbo is located sooo far away from the engine, that 6 psi of boost now has to pressurize a much larger volume of pipe than if it was located say, 3 feet from the throttle body. So, there would be more "lag". Keep in mind the flip-side too, with a small turbo and a v-8, spool time is much sooner than say a v-6 with twins of the same size.

Intercoolers are nice, but not a hard-fast rule. Actually, they don't do much until the boost reaches the 10 psi range.

Now, this system may be engineered to compensate for all of these variables, such as a smaller compressor housing/wheel, different turbine housing, etc....but, I'll stick to the systems that are under the hood or make my own.

O3GMC

How does heat turn a turbine? Its the exhaust gas that flowing across the turbine blades that get the thing spinning. They opted for the remote location b/c 1. a glowing hot turbo will not help your under hood temps and 2. the length metal intake pluming dissipates heat just like an intercooler would, without having the pressure drop. True, with 10+ psi, a intercooler might work better, but for 6-8 psi like their basic kits produce I guess it doesnt need it.

Again, from their FAQ's :
"Don't turbos have to be really hot to work properly?
Putting a torch to your turbo and getting it hot doesn't produce boost. What produces boost is airflow across the turbine which causes the turbine to spin. In a conventional, exhaust manifold mounted turbocharger system, the extra heat causes the air molecules to seperate and the gas becomes "thinner" because of the extra space between the molecules. This extra space increases the volume of air but doesn't increase the mass of the air. Because the volume is higher, the velocity of the gas has to be higher to get it out in the same amount of time. By mounting the turbo further downstream, the gasses do lose heat energy and velocity, however, there is just as much mass (the amount of air) coming out of the tailpipe as there is coming out of the heads. So you are driving the turbine with a "denser" gas charge. The same number of molecules per second are striking the turbine and flowing across the turbine at 1200F as there is at 1700F. Front mounted turbos typically run an A/R ratio turbine housing about 2 sizes larger because the velocity is already in the gasses and the volume is so big that the turbine housing must be larger to not cause a major restriction in the exhaust system which would cause more backpressure. With the remote mounted turbo, the gasses have condensed and the volume is less, so a smaller A/R ratio turbine housing can be used which increases the velocity of the gasses while not causing any extra backpressure because the gas volume is smaller and denser. Sizing is everything with turbos. A turbine housing sized for 1700F gasses would have lag if the gasses were 1200F. This is why turbo cars have lag when they are cold and not warmed up yet. Both systems work well if sized correctly."

"Isn't there a huge pressure drop with such long intake tubes?
No, if the pipes were 100' long there would be but we are only talking a few extra feet and we size the charge air tubing so that it will flow without a pressure drop. We typically will get about 1/4 lb difference between the turbo compressor and the intake manifold, which is nothing compared to the pressure drop across an intercooler."

Yelo

kwkshift....heat CAN'T turn a turbine by itself, the exhaust gasses are doing the actual work (think of a pinwheel inside a tube), if heat was doing all the work ALL you would have to do is hit the turbo with a blowtorch and it would start spinning by itself

Slowverado IS right....pressure drop IS going to be a factor because you DO have to pressurize 12' of tubing...but once the tubing is pressurized it will remain that way as long as the turbo is spooled up, according to the info I got from their site it seems the turbo will remain spooled at relatively low RPMs's so it will keep the tubing usefully pressurized during street driving....and WOT high-rpm highway blasts would be ALOT more fun

Slowverado

SO, basically once you get up to speed it's going to be fine....good boost. but once you slow down in traffic or a stop light it's gonna lose pressure.....THAT SUCKS, to me it seems like that would create a surging feeling.

TG02Z71

iTrader: (2)

A turbo is similar in boost production to a cetrifugal supercharger. The boost will be lower down low, but getting the tube up to pressure should not be too hard considering the low amount of boost the tubo makes to begin with. The boost we are talking about is not really that much above ambient air relativly speaking. The amount of volume the turbo can flow is what is important here, to bring the extra few feet of tube up to pressure.

Yelo

it MIGHT lose 1-2psi at idle....but at 2000 it should start to build again....my stock converter will flash to almost 2000 from a WOT dead stop launch so as long as full boost is in by 3000 like it says it should be great to drive on the street.....

a turbo is a strange beast, as long as the exhaust inlet is sized correctly (fairly small) you should see good boost right off idle, the down side of sizing the exhaust inlet to acieve low-rpm boost is that at high-rpm the exhaust side of the turbo can't flow enough to let the engine REALLY spin, this kit probably hits a brick wall at 5500rpm's....the site mentioned 100,000rpm impeller speed is probably achieved at 4500rpm, which would make for great boost between 2000rpm and 5000rpm but if you want to use this kit all the way to 6700rpm your pretty much screwed

I also think it's all the extra intake tubing that has people worried......has anyone EVER really looked at just HOW LONG the intake tract is on a turbocharged/intercooled car??, my '96 TSI Talon had an intake tract that was probably 10 feet long from turbo to throttle body (and it had an itercooler in the middle of it), my buddies '02 F250 also has at least 10' of piping to get air from the turbo to the TB....and neither of those has noticable turbo lag at all

if you were to measure the intake tract length on this kit is is probably shorter than routing tubing from a low front-mounted turbo, to an intercooler, then to the throttle body.....given that the turbo in this kit is mounted down low and in the airstream it should remain ALOT cooler than being underhood, combine that with the composite tubing (which is also in the airstream and cooled by it) and you should see near-ambient intake temps

O3GMC

Do you think having headers and high flow cats would negatively affect the performance of the turbo? And I'm not even sure if they make a kit for a regular cab......might not be enough room for the muffler after the turbo...