4 stroke turbos?

what company makes the turbo kits for thumpers. ive seen ads for them before in magazines

Turbos dont really work on single cylinder engines due to the exhaust pulse. The turbo will spool then lag, spool then lag... you need more cylinders. I know in the back of Dirtrider there is always an add for some 2-stroke "turbocharger" that is just some funky intake pipe.

Extended spool time and lag in a turbo installation is due to the exhaust side scroll housing being too large. Thumpers can be turbo charged, but the fact that they have only a single cylinder does make scroll sizing more critical.

Turbos are simply not practical on a dirt bike in any real way. They are very bulky, which makes it hard to find anywhere to put it where it is out of the way, and protecting the bike and rider from the heat is also a major problem.

It has alot to do with the size of the turbo and exh housing. Saying it will spool and lag and repeat is completely foolish and made up.

A turbo on a dirtbike is not really a good idea, esp for mx. I mean, you want to hit boost as you leave a jump face and over shoot it by 50 ft? LOL Location would be easy since there is so much space up front, but weight would be an issue since you are going to add a minimum of 30 lbs with a turbo system. Comp ratio would need to be lowered, esp on these new bikes with 13:1 comp. Its easily possible, but not really a good idea.

Now, if i had a street supermoto, I would consider it :thumbsup:

It has alot to do with the size of the turbo and exh housing. Saying it will spool and lag and repeat is completely foolish and made up.
I'm fairly certain he meant that it would do that on subsequent accelerations. The turbo will spin down when the throttle is closed, then back up when it's opened again. If the scroll size is too large, the lag will occur every time the throttle is reopened.

as if 450s weren't already a handful...cant imagine putting a turbo on it

agreed if i had a supermoto street legalized id want it turbo'd

Have you guys seen Uncle Bob's turbo charged Suzuki DRZ400? That thing wheelies in every gear. Though it is a supermoto, not an MX.

There's a huge thread over on Supermotojunkie, and a couple of videos on Youtube

An RHC 60HP 450 on all motor will wheelie in every gear too, esp on the street with all that traction. A t3 exh housing is still pretty big for a single cylinder, even at the smallest A/R ratio they sell. Im sure you would have to use something off an old volvo or something that has a super small housing on it.

Wait till fuel inj is on every dirtbike. Alot of turbosystems will start showing up. Mark my words.....

Nothing big enough for a Volvo 2.4L is going to be anywhere near small enough on either side for a 0.45L WR450.

yea you need to go with like a gt12 turbo from garret. most people turbo there qauds though not there bikes. because the way a turbo works its not gonna be good for the bike as much. its gonna have a wierd powerband and if you ride in the dirt i will be a waste of time. even the turbo quads ive rode are kind of lame in the dirt. but if you ride sand most of th time itll be fine thats the only place youll hook up is with a paddle.

I'm fairly certain he meant that it would do that on subsequent accelerations. The turbo will spin down when the throttle is closed, then back up when it's opened again. If the scroll size is too large, the lag will occur every time the throttle is reopened.

Basically what I meant. You are on and off the throttle so much on a dirtbike. I also meant that a turbo on a single would have a very narrow range of RPMs in which you are making decent boost without getting outside the map.

If you really needed the extra boost of power , you would be better off using a NOS system. much more simpler in desing and only on when you wanted it.

You would need a place to mount the bottle and a way of introducing the extra fuel needed for the nos hit, may need an external electric fuel pump for the extra fuel charge. That may take away from the simpler design, but still simpler that a turbo with waste gate system, and more user friendly at the higher compression ratio.

I'm just going off how a typical system would work on a race car. I'm sure it's out there and ready to install in a kit form. I know the kits are out there for sport bikes.

turbo only weighs 6 to 8 pounds. Gets just as hot as a aftermarket exhaust. There's no lag worth mentioning, in fact, the GT12 is by far the fastest spooling (initiating) turbo's bar none....not too surprising considering how little inertia it has

The power band is super linear. Feels like a big bore bike with big cams. Bottom end power isn't super impressive, but the higher you rev it the faster it goes.

all that said, I agree. In the dirt, its major overkill. In the dunes or on the street, its the sheit though

A swedish garage makes turbo kits for Yamaha 3 cylinder 500 cc snowmobile (Phaser)

Very usable and popular option. Guess 3 cylinders make it easier and the thing needs that turbo in deep snow with 500ccs.... Cooling comes handy with snowmobiles too :prof:

There is a company that makes a turbo system goes between the carb and the air boot, MXA did a test on it, they said it did not work and was a pain in the ass to install. Yhey gave it 1 star. Dont waste your time, if you are looking for a boost, and dont mind spendign some cash, send your carb to Tokyo mods. They'll get it done for you.

I have seen a quite a few YFZ450 and TRX450 quads with turbos on them and they were all making well over 90hp at the ground but I have yet to see a turbo on a dirtbike.

These 450 motors dont have anywhere near strong enough cases to go much over 75-80hp with any resemblence of reliability if you ask me.

There is a company that makes a turbo system goes between the carb and the air boot, MXA did a test on it, they said it did not work and was a pain in the ass to install. Yhey gave it 1 star. Dont waste your time, if you are looking for a boost, and dont mind spendign some cash, send your carb to Tokyo mods. They'll get it done for you.
In the first place, that was not a turbo. It was a particularly lame attempt at a supercharger. Real superchargers and turbochargers are much different. IMO, MXA hurt their credibility by giving the air box fan you are talking about the one star that it got from them. The thing was laughable on its face.
In the first place, that was not a turbo. It was a particularly lame attempt at a supercharger. Real superchargers and turbochargers are much different. IMO, MXA hurt their credibility by giving the air box fan you are talking about the one star that it got from them. The thing was laughable on its face.

what he described is a draw-thru system. IMO, they are always crap. Horrible drivability. Needs to be blow thru. Only problem with blow-thru is you have to have a fuel pump, so you have to have a charging system and battery.

On an MX track I think a turbo would suck big time. Too much lag. A super charger would be a whole different story, I'll bet that would be neat and almost usable. Especially with fuel injection. Someone made super charger kits for the GSXR bikes several years ago, I wonder if they have anything small enough to be fitted to something like a YZF?

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