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Author Topic: Sketchy turbo hardtail XS  (Read 4231 times)

Offline rusche

  • Posts: 126
Re: Sketchy turbo hardtail XS
« Reply #30 on: Dec 01, 2016, 19:31:08 »
Another question, I've got two ports on the turbo for boost gauge/wastegate

Can I use this port in place of a pitot tube?

Offline jimmer

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Re: Sketchy turbo hardtail XS
« Reply #31 on: Dec 01, 2016, 20:57:12 »
Pitot tube controls bowl pressure to balance fuel flow under boost-because atmospheric pressure won' t push fuel into the jets when boost pressure builds.Waste gate  controls the max boost. You also need a blow off (pop off ) valve in blow through setups. In between boosted shifts or closing throttle abrubtly will spike boost and it needs to be vented asap. If not you can blow carbs out of manifolds, stick carb slides, and even destroy the turbo compressor. Borrow a turbo book or buy one. There is good info out there. Auto books help a lot and are readily available. Hope this helps. P.s. The Suzuki Gsxr cv flatslides work great in blow through systems.
Yamaha Blaster Bike                                                                  Suzuki T500 Titan Twingle

Offline jimmer

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Re: Sketchy turbo hardtail XS
« Reply #32 on: Dec 01, 2016, 21:03:34 »
If your Garrett turbo has carbon seals you could draw through one carb in a much simpler/ cheaper setup. Probably not what you want to hear.
Yamaha Blaster Bike                                                                  Suzuki T500 Titan Twingle

Offline rusche

  • Posts: 126
Re: Sketchy turbo hardtail XS
« Reply #33 on: Dec 01, 2016, 21:37:10 »
I read alot about poor drivability from draw through set ups, blow through seemed to be much more forgiving, although more work and money.
From my understanding blow through setup will yield better off idle performance/smoothness. I have a plan to hide the fuel pump, well see how it works out
Also the turbo doesnt have carbon seals, another reason I decided to stay away

I understand the concept of pressuring the bowls so the bike doesnt lean out under boost, but why do I need to use a pitot tube instead of simply the port on the turbo? Shouldnt that be referencing the same pressure?


Offline xb33bsa

  • Posts: 7727
Re: Sketchy turbo hardtail XS
« Reply #34 on: Dec 01, 2016, 21:49:33 »
you will want to vent the carb slide caps to boost as well as the bowls otherwise boost could give you wot when you dont really want it but there really is no reason for a turbo unless you are running at wot anyway
does the xs oil pump give enough volume and pressure to support the turbo ?being a 100% rolling element engine it certainly doesn't need a lot of pressure or volume ,nothing like a plain bearing automobile engine puts out anyway

Offline rusche

  • Posts: 126
Re: Sketchy turbo hardtail XS
« Reply #35 on: Dec 01, 2016, 22:20:58 »
I've seen several people do it successfully with the XS,   even required a restrictor, apparently too much pressure. Should survive it seems

Offline rusche

  • Posts: 126
Re: Sketchy turbo hardtail XS
« Reply #36 on: Dec 02, 2016, 00:08:00 »
I am tickled switch the overall height

Offline der_nanno

  • Posts: 253
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Re: Sketchy turbo hardtail XS
« Reply #37 on: Dec 02, 2016, 05:51:11 »
What do you think caused the turbo failure, and what turbo were you using?
I was under the impression that CV carbs didnt respond well to turbos do to the slide being blown open
Unfortunately, I purchased the bike without carbs. Those VM34s were brand new and cost me about $200. So Im going to try them lol
I was under the impression that round slides were prefered. I dont plan on running real high boost

The main reason was bad build quality - it was the cheapest T3-turbo that I was able to find back then. I am still not 100% positive, that the oilflow to the turbo is/was sufficient and if all of that wasn't enough, it seems as if the drainage wasn't drilled correctly.

CV-carbs just need pressure ABOVE the diaphragm as well, so they only respond to the pressure-difference and not the actual boost.

Another question, I've got two ports on the turbo for boost gauge/wastegate

Can I use this port in place of a pitot tube?

A pitot tube will actually return a pressure, which is slightly ABOVE the pressure present in the system as pressure (aka. boost) and the pressure resulting from the airflow add up. So the floatbowl will be pressurized slightly OVER boost level.

You can leave the wastegate plugged in, where it is plugged in on the turbo and if you want (and have no other port) install a T-piece to take off boost pressure for the gauge there.

I've seen several people do it successfully with the XS,   even required a restrictor, apparently too much pressure. Should survive it seems

Oilpressure will definitely be enough, even in a rolling element engine. Make sure you put in a restrictor, because otherwise in case of turbo-fail you'll loose a lot more oilpressure in the system, which could turn out to be a serious issue and cause even more damage.

I read alot about poor drivability from draw through set ups, blow through seemed to be much more forgiving, although more work and money.

You can run carbs without carbon seals in a draw-through setup, but the fuel-air-mix will always wash out some oil from the bearings. Not much of an issue, when you've got enough oil going to the turbo, yet still your ride will always be a bit smokey. (Although I wouldn't do it again.)

Carbon seals are available for the GT15 though.

... there really is no reason for a turbo unless you are running at wot anyway ...

Actually that's wrong. Even at 0 PSI boost on the clock (which is actually vacuum generated by the engine plus boost generated at a certain RPM), you will feel quite a noticeable difference in torque, when the turbo comes on. I have a tuned hi-comp TR1 and the Turbo Bike and even at 0psi the Turbo made a lot more torque than the hi-comp naturally aspirated.

Hope this helps a bit, Rusche!

Cheers,
Greg
« Last Edit: Dec 02, 2016, 05:53:09 by der_nanno »
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My Turbo TR1.1 (XV1000) build here on DTT:
http://www.dotheton.com/forum/index.php?topic=72571

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http://www.dotheton.com/forum/index.php?topic=74211

Offline rusche

  • Posts: 126
Re: Sketchy turbo hardtail XS
« Reply #38 on: Dec 02, 2016, 23:54:47 »
Great information, I appreciate the input.

Whats your opinion on the Mikunis? Ive heard a handful of reasons to go either way
Unforunately, those carbs werent super cheap, and theyre here and brand new lol
I understand there are benefits to CV carbs, but do you think it will cause large driveability concerns?

 I think Im going to follow the backbone of the frame with charge pipe to the turbo
I had to clock the turbo in order to fit where I want, and removed the internal wastegate I've been looking at external wastegates, but they are all huge. I know there are benefits to large wastegates, but I want to try to keep the front of the bike clean..

Offline rusche

  • Posts: 126
Re: Sketchy turbo hardtail XS
« Reply #39 on: Dec 03, 2016, 00:01:56 »
Actually, now that I switched the tank, theres lots more room up there...
I might be able to fit the internal waste, with a bit more creative charge piping

One thing I also hadnt taken into consideration, is the heat offput by the turbo, right there by the tank...