Q about STUFFING VELOCITY STACKS

Walkinshaw · Post by **Walkinshaw** » Thu Feb 16, 2006 7:21 pm

Staggering of horns is an old trick. Many mechanical injected prostock cars of the 60's-80's ran varyed height injector stacks to provide a wide powerbannd.

Top looking manafolds there guys.

510rob · Post by **510rob** » Sun Feb 19, 2006 11:35 am

Old Colt,

If you have some more pictures of high reolution of that manifold (picture dP8100003.jpeg), could you e-mail them to me? I'm bashing a manifold out right now, and it's always nice to have a look at nice things that other people have done...

rob510@_NOSPAM_shaw.ca

Regards,

Robert F.

tony2ltr · Post by **tony2ltr** » Tue May 16, 2006 2:32 pm

Hey guys, I have had to rebuild my laptop since i posted this message, so i have lost some of the manifold pictures you sent me Old Colt.

Anyhow, I have lost my nerve in trying to close my carbon fiber stacks up in a box for stuffing, I figure there will be too many sealing issues, so I went out and found some aluminum cones of similar dimension. The problem is, the radius on top is not real good, these are more funnel-like in design, although i might be able to simulate the radius when i weld the cones to the back plate of my plenum box, by running a nice bead around them, then grinding and polishing the beads to simulate the nice rolled lip of the CF stacks I was going to use.
The other, easier option, is to weld them flush to the back plate.
As far as the rest of the box goes, I plan to use two 2" aluminum mandrel bent U's to form and oval shaped "donut" to form my plenum. Does this sound like a good Idea? The outlet on my turbo is a little less than two inches. And I will elaborate if someone wants me to, but I am not using an intercooler, I have something else in mind, so I can bring the 2" tube right from the turbo to the manifold, and there won't be a significant pressure drop like there would with a conventional intercooler. I have been surfing the water injection forums, and have experimented on my turbo diesel with injecting water directly into the compressor housing with very impressive results. I know that the downside is erosion of the compressor blades. But the jury is still out on that.

Anyhow which way should I try to make the plenum? Is 2" in front of the cone going to be enough?

Thanks,
Tony

old-colt · Post by **old-colt** » Tue May 16, 2006 3:53 pm

Hi Tony
I would if room allows to form the floor at the top of the stacks, and you have the right idea with the mandrel bends.
I would recommend tapering up the tube from the turbo outlet to a 2 1/4 or larger tube just to let the stream slow down. At least let it slow before the plenum so that it wont bypass the first cylinders.
You may be best to spray right after the turbo where the air stream is at it's highest velocity.

tony2ltr · Post by **tony2ltr** » Tue May 16, 2006 5:46 pm

What I have found out, is that, by injecting into the housing, you make the turbo more thermally efficient, effectively making some turbos "think" they are up to 25% larger. On my diesel, it actually adds 3 psi to the 14 psi at max boost! Not to mention the ability of the methanol/water spray to absorb tremendous amounts of heat, and the methanol to act as a fuel/octane booster as well. It seems like everyone who has had trouble with compressor erosion has been running in dirty environments, with inadequate or no air filtration, or they have not used a fine enough mist into the housing. There were other arguments for precompressor injection by folks that at least sounded smarter than me!

Thanks for letting me know that I am on the right track with the manifold, this has been a thorn in my side for a while now. I made a little painting with an "internal view". it is not really in proportion though, the cones would be a little bigger, the cones are 3 inch at the top, the box would be 8" tall.
I think your suggestion for opening up the flow to reduce velocity is the best way, but I already have the very expensive 2" for all the tubing, will the way this tube empties into the box good enough?
thanks,
Tony

old-colt · Post by **old-colt** » Tue May 16, 2006 6:10 pm

I would at least taper the last of the in run to the plenum, the goal is to have the air quiet down so each throat can take a equal gulp.
If it is still moving fast #4 will get a bigger gulp. This can lend to a lean condition with more cylinder fill in #4 than #1 or 2 which may get less air tending to be rich but less cylinder fill.
You have the right idea to bring it in off center, but I would form a cone for the run in from the last bend.

tony2ltr · Post by **tony2ltr** » Wed May 17, 2006 8:29 am

I Had the same thought, about the air moving too fast, but I'n not really sure what you mean by a "cone at the last bend".
Is one of these something like you mean? I made them in MSpaint if you want to show me what you really mean!

old-colt · Post by **old-colt** » Wed May 17, 2006 8:42 am

Your second drawing will be better. For the cone, envision a megaphone as the air enters to allow for the reduction in airspeed.
I will attempt the MSpaint.

old-colt · Post by **old-colt** » Wed May 17, 2006 8:54 am

As you can see I am a rookie at editing pictures.
Hope this helps.

tony2ltr · Post by **tony2ltr** » Wed May 17, 2006 8:57 am

Ok I understand. It might be hard to get that shape, but I'll see what I can fiigure out. Thanks, you have really helped me!

Tony