Just saw this last night...CB Drawthrough

[modok]

[oprn]

I have heard of puddling issues before in N/A V8s where they are running a very radical cams and have to make the idle mixture very rich in order to get them to idle at all.

In my mind a radical cam is a waste of time and money on a street driven turboed car and would have more than a few drivability issues. My experience was with a stock cam so idle mixture was virtually unchanged as was idle performance.

My intake runner between the carb and turbo compressor was only a few inches long too as I used a side draught carb. The Corvair was the same.

One of the advantages in my mind of the suck through the carb system is that there is no real need to have huge carbs to get the power. This keeps the air velocities higher and gives you better atomization. Perhaps that helps to keep the mixture from dropping out and puddling too.

Or maybe I was just lucky...

[modok]

Nice. You don't see those type of setups as much these days, but it sure does work.
I'd like to see folks try that with mikuni hsr motorcycle carb, which didn't exist back then.

[clonebug]

It's all in the packaging.

Put a low spot in the intake and slow airspeeds and you can get fuel puddling.

A long intake and a few extra bends and you have an even better chance.

I wonder if CB has thought about building a smaller diameter turbo header.

Having one in 1.5 or 1.375 inch exhaust would make the market a little larger.

That turbo setup is going to be for a very small market if the exhaust is 1.625 and a bigger turbo.
Try finding a turbo set up for draw through that is small enough for a 1.6-1.9L engine for a cheaper hp kick......

Building a 2276 for $6000.00 plus and then adding $2200.00 for a turbo will make for a small customer base.

Building it for a smaller engine would be a better plan to me since they would be looking for the hp increase.
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[DerrickfromNC1]

What's the maximum CFM of a single 44IDF? Just trying to get a comparison to the pull thru turbo setups using 600 Holley 4 barrel carbs and larger.

Thanks

[Boolean]

290 CFM with stock venturis according to J. Raby.
http://www.shoptalkforums.com/viewtopic.php?t=1949
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[DerrickfromNC1]

[oprn]

[oprn]

I don't know if this helps anyone or not but the first carb I tried on my 1600 was a Weber 40 DCOE. I really had no need for two barrels but I used it because of how versatile these carbs are with jetting and vent sizes. I don't recall what configuration I ended up using but never felt that it was ever under carbed even at 6000rpm and 15psi boost.
Sources at the time estimated that a turboed engine would have double it's original HP a 11psi and this engine was 74 HP stock.

[oprn]

[clonebug]

[Splitdog]

I think the biggest mistake people make building a turbo deal is too big on everything. Big cam, big pipes, big intake runners, etc. They make tons of power, but not until it's too late for street driving. I remember driving in a 2007cc bug with an AJ Sims turbo kit on it with a 120 cam. It was waaaay too big. It didn't come on until exactly 3000 RPM. All hurky-jerky and off the cam before then. Absolutely no fun on the street.
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[oprn]

[SBD]

[Maddward]

Since CB doesn't have the header in other dia's can that be compensated with a smaller turbo on smaller cc engines?

[clonebug]

Good luck finding a smaller turbo that is capable of drawthrough without reworking it for the correct seal......if it is even possible to change it.
I buy turbos for $20.00-$60.00 and run them till they puke.
Only one has worn out of the five plus turbos I have.
None of them are capable of drawthrough without fogging oil smoke everywhere.
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[Dauz]

I don't have puddling/icing issues anymore. Even with a 770CFM four-barrel. Even after idling for over 10 minutes @ 1k rpm. I have a petcock valve on another compressor housing that I've verified this with. I used to have to drain it daily until I brought heat up to the manifold. Now I don't have to blip or rev it and it's smooth off the line. You'd know you're puddling if you flick your throttle arm and the RPM dumps. Although it's not purpose built for the street, my setup is very streetable.

But here's the disclaimer - the motor has to be up to running temps. Otherwise it's hard to start and stumbles. Something EFI does definitely fix. And that's EFI in general. Doesn't necessarily have to be blow-through.

Also, T3s are a dime a dozen and so are their carbon seal back plates.

[clonebug]

And a T-3 is too big for a 1600 if you want any boost before 4000 rpm.
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[myb356]

Kit looks good, but if they could flip the oil fill/ breather to the middle of the engine, this thing could fit into smaller engine compartments and spark plug changes would be easier.

[oprn]