quad TB's AND turbo

gse_turbo · Post by **gse_turbo** » Thu Oct 25, 2007 8:07 pm

for some reason i thought the first cylinder would get most of the air and the other three would get progressively less but with the high velocity the last cylinders gets the most volume and best velocity. in some manifold style the test shows the No.1 cylinder getting NO air.

garrett

gse_turbo · Post by **gse_turbo** » Thu Oct 25, 2007 9:10 pm

i'm a bit rusty so after all this i'm going to ask a 9th grade physics question.

can air volume be compared to water volume?

the reason i ask is because the way i see it, the volume of the plenum or collector (whatever you want to call it) should be an average of a given length of the (4)runners and the piping (2.5") coming from the intercooler. if the values (for volume) are the same, and they should be, then i can test volume easier with water.

the question is important because in a turbo system you want as few pressure changes as possible.

say the manifold is twice the size of the piping going to the manifold then there would be a big pressure drop and that would kill efficiency.

garrett

Audacity Racing · Post by **Audacity Racing** » Fri Oct 26, 2007 12:24 am

Yes and no...

Can you compare them? Not really in this case. What you're dealing with is compressible flow. The volume, pressure, and temperature change wildly inside an induction system. Going from the turbo output to the output of the intercooler is even a huge difference... it's all made up by the flow velocity that occurs. The cooler air is denser, but in order to keep the system efficient the turbo must spit out more air VOLUME than the motor takes in (given the temperature is vastly different).

That being said, within the intake manifold there is large pressure changes, though they only last for fractions of a second (during valve opening). This is actually magnified by the valve slam... the shockwave that occurs when the valve shuts. The reason for having a large plenum on a turbo application is so that these pressure changes are absorbed by the system fairly easily and no ill-effects come from it. That is to say, the more total volume there is in the system, the less stressful the small pressure changes are because as a whole the pressure changes only a negligible amount...

Here is an example...

A hole in a pressurized coke bottle will deflate the excess pressure very rapidly...

A hole in a bouncy castle of the same size will take significantly longer to deflate it...

The difference is in the extra volume. You need the extra volume

gse_turbo · Post by **gse_turbo** » Fri Oct 26, 2007 4:39 pm

something good to consider.

i will be getting Master Cam shortly so i think the next step would be to come up with some 3D prototyping so we have a visual to discus.

i think the quad TB will be the key to the test piece so as i start the rendering what do you guys think i need to consider? example do i need an IAC system or can that be done away with?

garrett

Audacity Racing · Post by **Audacity Racing** » Fri Oct 26, 2007 8:06 pm

Test it virtually in the respect that you won't need to worry about the details as to weather or not to consider the IAC setup.

Let's test a couple designs of both single throttle and multi-throttle with and without plenums to see what the results would be on a 3d CFD... Then you can make the call as to weather or not the effort and money is worth investing into one type or the other.

gse_turbo · Post by **gse_turbo** » Fri Oct 26, 2007 8:33 pm

that's where you may need to help if you're interested and if you have time. i can do 2D parts all day for a Flowjet or mill but i'm just getting into 3D CAD. i'd be lost in creating a 3D model or simulation that would be testable.

my intention was to build one and have it flow tested but if you're able to make a virtual piece then that would be the way to go. i could get all the geometry if you can plug it into a simulator.

tallkid is wanting to do something along these lines (his topic on suzuki-forums is what sparked this one) but he would need to retain the drive-by-wire system. i think (optimistically) that we can accommodate.

garrett

ps. let me know if i'm involving you more then you're willing, there would be no hard feelings.

Post by **PrecisionBoost** » Mon Oct 29, 2007 2:44 am

Audacity Racing wrote:We're so concerned with pulse separation and such in the exhaust stream, why not in the intake tract? Why don't you see a single throttle plate with then sweeping runners of equal distance but separated... like a turbo manifold in reverse...

Also, Chris, BMW does have a stepless design... first in the industry to my knowledge. It's found in the 745i along with Valvetronic and Vanos technologies...

I had a feeling BMW did something like that.... they seem to be the only company out there that is actually trying to put interesting technology into their engines.

One of the ideas I had was to create an exhaust and intake with multiple input paths.

Basicly I'd like to take some smaller tubing (say 1/2" ID ) and create six paths to each runner (merging them 4 inches or so prior to cylinder head)

All tube pairs would be equal length but each set of tubes is a different length based upon RPM tuning.

Ideally I'd install an eddy current style backflow valve (next to zero restriction) so that there is no risk of reversion at the merge into the runner.

I don't know if you get what I mean exactly so I'm just going to use and example...

I will have 4 tubes that are 6" long --> set #1
I will have 4 tubes that are 8" long --> set #2
I will have 4 tubes that are 10" long --> set #3
I will have 4 tubes that are 12" long --> set #4
I will have 4 tubes that are 14" long --> set #5
I will have 4 tubes that are 16" long --> set #6

So each set is of equal length and they all meet up at a reserve tank that had the throttle body on the other end.

My thought is that at various areas of the RPM band each of the six sets of tubes will be a perfectly tuned port.

It's very much like a variable geometery system but there are no physical valves.... reversion is kept in check by the eddy current reversion system.

Given you have a total of six 0.5" pipes feeding each runner that gives you 1.18 sq inches of area for the air to flow through..... which is roughly the same intake area as a 1.22" feed pipe.

I don't know how well it would work at this point.... perhaps I will download your program and fool around with it.

Chris

Post by **PrecisionBoost** » Mon Oct 29, 2007 2:56 am

I wasn't sure if you would know what an eddy current valve is.... I wasn't sure if they are taught in engineering or not these days.

Imagine the following tube..... but rotate it around 360 degrees..... the center part of the eddy current valve has to be supported by a number of "bridges" to the main tubing

gse_turbo · Post by **gse_turbo** » Tue Oct 30, 2007 4:19 pm

interesting, what is the manufacturing process?

garrett

Post by **PrecisionBoost** » Wed Oct 31, 2007 2:25 am

To make the eddy current reversion valve??

Well... I've yet to make one.... but I've put quite a bit of thought into it and the easiest method is one where the outside bell slides over the tubing.

Basicly you could make 1/2" wide slits in the steel tubing all the way around ( leaving 1/8" pieces between )

Then you slide over the machined central portion and tack weld it on the 1/8" pieces

Then you would have to have the outer portion in two halves.... you would clamp it over the tubing and center part... position it just right and weld it to the tubing.

You could also make it via welding wedge pieces of steel together ( outer edge is thicker than inside and as you weld them together it turns into a circular piece )

Nicola Tesla used these valves in a number of his designs.... but I'm not entirely sure how he managed to make his valves.... I think it was with punched plates put together.

I would imagine that you could also so something in the way of Urethane molding for the intake.... Kenny sent me a link for some cool material that would work pretty good for an application like this.

I don't have the link handy but I think the material was basicly a foam that could be machined.... then you do your mold... and if I remember correctly the foam simply disolves in water.

It would be great for fiberglass work, which was the subject at that point.

Chris

Audacity Racing · Post by **Audacity Racing** » Wed Oct 31, 2007 2:33 am

Aquacore

Use it all the time

http://www.acrtucson.com/products/Aquacore/index.htm

gse_turbo · Post by **gse_turbo** » Wed Oct 31, 2007 4:16 pm

very interesting!

garrett

Audacity Racing · Post by **Audacity Racing** » Wed Oct 31, 2007 4:37 pm

I'll let you guys in on the secret to my carbon boost tubes and CAI's

Step 1: Make PVC tube model of tubing... inside of pipe should be the size you're after

Step 2: Cap off one end

Step 3: Fill entire pipe with Aquapour... the castable form of this stuff

Step 4: Let cure (best in a vacuum or powdercoating oven... both if possible (I fit another cap on it, drilled with a brass fitting and attach a vacuum line during baking))

Step 5: Use cut-off wheel to split PVC off the form

Step 6: Use Aquafill to fill in cut lines and any other bubbles

Step 7: Sand smooth like butter

Step 8: use Aquaseal to seal any new pours

Step 9: Sand, again

Step 10: Standard layup of CF tube (aerosleeve) over form... typically 2 layers will suffice

Step 11: Wash out CF tube with water

Step 12: Finish ends of tube with grinder/cutoff wheel

And voila....

gse_turbo · Post by **gse_turbo** » Wed Oct 31, 2007 5:27 pm

you little shit!

this Aquapour stuff is the shit!

before i'd have to do all my molding then an overlay in glass, two separate pieces mind you. then mold the two together, do a bunch of cleanup and then go over it all with the carbon sock, and that is the short version!

now i really have to order this stuff.

garrett

Audacity Racing · Post by **Audacity Racing** » Wed Oct 31, 2007 5:33 pm

Forgot the link to CHEAP carbon tubes...

They have hybrids and glass too!

www.aerosleeves.com