Here is one draw back of a blow through setup that I just read about.


My stock float in the carb is made of plastic. It is VERY possible that it will colapse under the pressure of a forced induction blow through setup. This would be EXTREMELY bad to have happen.

 

Found some more info on blow through vs. draw through. Here is the site where I found the info.........



http://datsun1200.com/modules/nsecti...ticle&artid=35



And here is some of the info............


The principle snag with the blow-through system is that the carburettor calibration becomes difficult. The carburettor is a velocity-sensitive device; it does not know about pressure changes. This means that although the engine may receive vastly increased quantities of air, the fuels supplied to the engine may not go up in proportion.

Draw through was used by many OEM setups. It is reliable, and the simplest otpion. The downside is you can't use an intercooler, as the fuel will condense in the cooler.

The main difference between a petrol and diesel turbo is its seals. Diesel turbos don't have positive seal turbo seals, which means that if put it in a suck-through system they can leak oil under extreme vacuum, which happens when throttle is closed. (the turbo I am going to use is from a gasoline motor)

 

91CavGT you've done your homework.

You've mentioned several yourself. Fuel control is a nightmare. Carbs don't like to be pressurized. They were ment to be a vacuum system only. You have to deal with vents and every single hole or shaft in the carb. A fuel/air mist wants to come out every single shaft and hole/vent in the carb.
Beyond that is fuel pressure. You will have to have at least a 3psi fuel pump over your boost pressure. Otherwise your fuel will not be delivered to the carb and you will lean out under boost. Now this is not a big deal if you are running a 5psi boost system. If you get up to about 10 or more this whole deal can get really nasty to control. Now you can deal with most of these problems with an airbox setup. This is a pain in the butt when it comes to jetting though.
I was going to mention the float deal but you already found out about that.
I also was going to mention the positive seal but you already found out about that too. One word of warning, don't assume the turbo you have has a positive seal just because it's off of a gas engine. If it's a fuel injected turbo, it does not have to have a positive seal because there is no vacuum on the compressor side, just like a diesel.
I would not personally worry too much about the pulse deal. Make a small transition in the pipe and call it good. From what I know about what your doing, you will be fine with the pipe deal. I would look into a braided steel pipe like on the new imports. They have one that goes between the cat and pipe. I would not go with flex pipe myself.
Like I said, you've done your homework and seem like you have most of this deal worked out. Hope it works out good for you.

 

Very true. I wonder if this is something that a local turbo shop can add. Hmm, I might wanna call them up and see A. if this turbo has A. a positive compressor seal and B. if it doesn't, can they install one.

As far as the transition pipe, the braided steel pipe that you are referring to is what I know as a flex pipe. I'm not talking about those cheap flex pipes that you can get at your local autoparts store.

I usualy do at least 2 months of research on anything like this before I dive into it, even though I have experiance with turbocharging. All of my experiance is with fuel injection, not with carbs.

Thanx for your input!!

 

Well, I've got good news and bad news to report.


The good news, the turbo arrived!! Here is a picture of it sitting next to a 12 ounce can of Ginger Ale. Yes, it is a TINY turbo!!


http://i8.photobucket.com/albums/a11...T/TURBO001.jpg



Now for the bad news. This turbo does not have a positive compresor seal and more than likely IHI does not even make one. So, it looks like a blow through carb setup is going to have to be done. [img]i/expressions/face-icon-small-sad.gif[/img]

 

Sent you a PM. E mail me bojevans@hotmail.com

Thanks
Bo

 

Email sent.

 

I didnt recieve that e mail. Somtimes hotmail doesnt work.

Lemme get your e mail and will go from there.

Bo

 

You've got a PM

 

I got your email and responded to it.