<div class="FTQUOTE"><begin quote>explain your one way valve doctor turbo, and where does the fuel go without blocking the vents??? it comes out the vents due to the boost pressure. boxing the carb is more work than needed and takes up more space that you don't have when running a blow through setup on an atv because you will most likely leave the carb in its stock position. </end quote></div>
The vents are there from the factory for a reason. They are there so the bowl does not build pressure when the fuel flows in. If you have no way to vent the bowl the pressure builds up and equalizes the pump pressure. When this happens the fuel flow will be inconsistant in the best case and at the worst it will stop. Not the best thing when your under boost.
With a one way vent it will allow fuel in the carb to stay in the carb.

In old school days, with a carb, there was a reason you seen mostly suck through systems. Blow through was a bag of snakes. Still is. Carbs don't like to be pressurized.

Fast forward to EFI. With no fuel coming through an air door an EFI does not care if it's blowthrough or not. The compressor can freewheel if it's a blowthrough so there is less turbo lag. That is why most systems on EFI are blowthough now.

If you can make a medium boost turbo carb system work great without boxing the carb, good for you. I've never seen one yet without getting very complex.

 

I see I see.so the on e way valve is in a sense turned backwards, and wont let fuel out, but will alow air in when needed, like under boost. Am i understanding that right? makes sense.
hey and i wasnt trying to be a jerk about your post last night, just grumpy. lol. I have never boxed a carb but man if youve got another minute please explain how to and the real benefits of doing it. i just dont get where all the drain and vent lines would go once boxed?

 

Turbo LTR450 with a boxed carb the pressure on the outside of the carb and the inside is the same. With this being the case the carb pretty much acts like a N/A carb. There is no pressure differential so all is good. All the vents and everything stay in the carb box because the pressure is equal. The only thing that needs to come outside of the box is the carb inlet, the carb outlet the fuel line and the throttle cable. Inlet and outlet are easy; you just flange them. The fuel line is easy. You just use a bulkhead fitting. The throttle cable is a little harder, you should use a collet fitting of some sort. Even then the air and fuel want to climb the cable and come out near the grip under boost.

The bad thing about a boxed carb is tuning. Everytime you do a jet change or anything to the carb you have to take the box apart. This becomes tedious.

All in all, turbos and carbs are VERY hard to do. The easy part is fitting the turbo on the car, bike, quad or whatever. As I'm sure you know the hard part is the tune, especially with a blowthrough system.

Now with modern engine management systems we don't have to worry about any of this carb BS. Blowthrough the airdoor, hook up the laptop and set it where you want it. The only problem is getting the cash to buy the unit!!!!!

There is a reason the turbos of the 70's put out about half the HP as ones now days. The engines are the same. The turbos are the same. Everything is the same............except the engine management systems.

With ECU's you can do a lot of crazy stuff with these engines. Engine management systems are the reason we are seeing 1000+ HP Toyota 22R engines on the strip!!!!

PS: I see in no way you were a jerk in the above post.
Good luck with all you turbo builders out there. Got to go to work.

 

Tuning has been a two day project at least on these quads, it is by far the worst part! ya man, that throttle cable has to be tough to seal in the box. dang!!!
Are you running any turbo quads right now?

Im actually selling my LTR because I trail ride as much as i drag race, and the dang thing is WIDE.

If your still into turbos, let me know ill have to show ya pics of the quads ive done. Not to many people can appreciate the work and patience that goes into these.

 

<div class="FTQUOTE"><begin quote>Are you running any turbo quads right now? </end quote></div>
No, never did get into turboing a quad. I can break enough bones when they are stock. I will leave the turbo quad stuff for the younger people. I did car stuff, mostly SBC with a few 4 cylinders in there for fun.
A guy I know just build a turbo Busa Rappy. He said he wants to take it to the flats and break a record. Who know's whether he will or not? He's kind of a nut so who knows?

Post your pictures on this site so everybody can enjoy!!! I would love to see them!! And so would a lot of other people; I'm sure.

Believe me. I know how much time it takes to get a turbo system working right!!!

 

hi ,the vent lines are connected to a boost pipe so it blocks the fuel coming out under boost,other wise it will let any excess fuel go in the inlet
i did think of putting the one way valve in but did it the other
as i have been experamenting with it ,right the quads got the edelbrock carb on ,no jets
if i have the boost pipe from the turbo to the carb dissconnected it runs fine
when connected it will rev a little then miss or die
could it be possible iam getting too much back preasure in the exhaust from the turbo being restricted due to the boost pipe being connected and not letting enough air onto the engine
i thing its restricting the turbo from letting the exhaust gas go through the turbo and out the exhaust.
so its making back preassure in the headers and stalling the engine
when i did a test a while ago i connected a carb up to the inlet of the turbo to run like draw through ,but because of the distance from the turbo inlet to the manifold i got terrible throttle responce ,but it had power
but on a run up a longish road it blew the exhaust slip joint apart ,and i had to build a new headers set up
ive just rememberd about this ,coz iu was sure its the carb
but now i think its the back preassure in the exhaust
any ideas on how i can over come this
many thanks

 

<div class="FTQUOTE"><begin quote>when connected it will rev a little then miss or die could it be possible iam getting too much back preasure in the exhaust from the turbo being restricted due to the boost pipe being connected and not letting enough air onto the engine
i thing its restricting the turbo from letting the exhaust gas go through the turbo and out the exhaust. </end quote></div>
You have a fuel control issue. It has nothing to do with back pressure or anything on the turbine side.

Like I said, any carb blowthrough setup is a nightmare with fuel control. At the least, you need a fuel pump capable of about 3psi over the boost pressure. That is all and good until you get over about 4 PSI gauge boost pressure. When you get over this you need a boost reference fuel regulator. If you don't, the high pressure pump will override the seat and fuel will flood into the engine at idle.

I have no idea how your system is setup and even if I did it would be to complex to diagnose over the net. Carbs are ment to to suck in fuel. When you have pressure inside of the carb the fuel does not flow in the right direction. The only way to deal with this is box the carb or jack the fuel pressure up to overcome the boost pressure.

 

hey hows the raptor coming?

 

Hi, NEVER BELIEVE BLOW-THROUGH DON'T WORK!!!!! It just takes a few tricks to get it right but unfortunately I never tuned the Edelbrock carb for it. I have done Mikuni, Keihin, Weber, Delorato and Holley though without a box. The box is a nice deal but it comes with it's own problems also. Just to go over a couple basics, you need a boost referenced regulator to bring fuel pressure up on a 1:1 ratio, the fuel bowl vents need to be pilot-tubed so that they will pressurize the bowl when boost comes up (same as the box does)
I also suggest getting a Wideband O2 sensor like an Innovate Motorsports LM-1 for tuning. You need it. Weld the bung in the pipe after the turbo and set your Air/Fuel. I'm going to give you a link to a sight where it has been tried, done, and proved. Use the green search button at the top and when you've exhausted it, register and post your questions. Here's a link to a Turbo Raptor Discussion I'm working on a '68 Camaro that will be blow-through supercharged worth 725+hp to be driven everyday wherever I want to go.

 

hi ,whats this pilot-tube deal
i just have my carb vents plummed into the turbo out lest
could you explain please
yes my regulator is rising rate
i have been thinking on the a/f meter ,just thought i could work around it
but i see it will point me in the right direction fairly quick if it shows its going lean straight on throttle
any other tips you have
thank you