New Here and wanted to post pics of my Turbocharged 400ex

[twinty]

With a little R&D and patience here is the finished PROTOTYPE. note that the turbo is a used piece and the exhaust is not finished but none the less it ripps! you can pull the front tires in any gear at any speed above 6000rpm, at that point boost is almost instant!! I am currently running a wiseco 10:1 piston with a .073" head shim to lower compression to 8.3:1, the cam is a stage one hotcam to bring back the torque with the lowered compression, I am running the stock carb right now jetted with a 46 pilot and 155 main and the needle lowered to the lowest clip. 14psi of boost on 50/50 mix of 94 and 100ll av gas, no signs of detonation on the plug and the wideband says 11.9 at full boost. Stock timing curve too, but unfortunatly the stock clutch wont hold the power at all, didnt last one run and spun!... I have a FCR-39 on the way to really bring out the madness, boost is unreal! Next on the list of mods will be an extended swingarm, and maybe a hinson clutch kit if the barnett doesnt last, hopefully the basket doesn't break. I will be putting it on my dyno as soon as the adapter is fabricated, hopefully next week.
Here are some dirty pics, but pics none the less!











let me know what you think, I am new here, but have been lurking and reading up, and love this forum, great information, and seems to be a great group of peeps here, cheers!!
mitch.

[tri5ron]

What???
No Nitrous ???

[twinty]

Originally posted by tri5ron
What???
No Nitrous ???

that you can see!!!....jk who needs nitrous when you have a turbo!!

[Phillburt57]

[my88r]

[GPracer2500]

Can you explain how the fuel system works? Is the carb sealed inside that box? I'm not real familiar with turbo'ing with a carb but am curious how it's done.

[bearair]

So did you just pressurize the airbox and eliminate the filter? I would have thought that a 155 was a bit small on the main, but since you're pressurizing the carb it probably pressurizes the float bowl as well. How did you vent the carb? Which turbo did you use? Looks like a lot of time and effort went into it. Congrats!

[maxfior]

Any videos? That would be awesome!

M.

[bry14661]

i hope you know you cant even ride in dust now let alone the wet mud thats on your fenders. with a turbo spinning at 120k RPM one spec of dust will murder the bearings.

[twinty]

Modifying a carb for blowthrough is simple, just pressurize the bowl vents and any other vents on the carb as well as increase fuel pressure with boost. The key is using what is called a "pilot tube" this is a tube that is inside one of the boost tubes facing against the flow of air, this is where you hook the bowl vents to. It allows smaller jets because it forces fuel out the jets under boost and keeps the low speed drivability of smaller jetting off boost. The airbox needs to be several sizes bigger than engine displacement on a single cylinder though to make it run proper, the pulsing really screws up the carburation if not dampened.
I will post a video once I get the new clutch in it and hopefully the FCR shows up by then too.
The turbo is a TD04-9b off a dodge colt turbo, I tried a IHI-rhf3 ballbearing turbo but it was way too small, it would make 1psi of boost at idle and 15psi just revving it up, there was some great off idle torque, but that was it. The exhaust side of the turbo just didnt flow enough to make any top end horsepower. The 9b is still almost a bit small as it builds 5psi just driving up the road at any speed in any gear. At 45mph it is boosting all the time and really want to go!

As for riding in the dirt, I ride this thing strictly off road, that is what the air filter is for. I have an extension to put the filter up behind the headlights if I am going somewhere real muddy! I really dont know how the dust is going to get in my oil, as that is the only way to get to the bearings, just so you know.
cheers!