I could understand that idea in a car with one exhaust manifold, but isnt the gain of having both exhaust manifolds contributing to the turbo more or at least the same as if you had the turbo mounted directly off of one side?

 

All you're trying to do is spin the impellor. So you're looking for velocity. You're not going to get a faster impellor speeds from MORE exhaust gas, you going to get it from higher velocity gas. Thats why they are almost ALWAYS packaged as close to the head as possible when they are designed on the car. That's why you'll see bi and quad turbo (not sequential units which are different) hooked to only one manifold. It's not the quantity of gas moving past the impellor as it is the velocity of the gas.

 

Ah have to disagree. Your explaination would be correct if the what you were trying to spin had no friction/mass. Also you have to consider you are trying to compress the air(that takes energy). So you ARE going to need a certain amount of exhaust gas also. So just installing it on let's say the front 3 cylinders is not nearly has good as having all 6 cylinders feeding the turbo.

There is good reason turbo people crutinized turbo maps to properly size their turbo for application/engine size. Because if it was just about velocity, everyone would be running huge T70 or large turbos and making the piping leading to the flange super small. Very high velocity due to the venturi effect but very little mass behind it.

You also have to consider that the exhaust coming out of each cylinder is not linear like ____________________. It's more like _ _ _ _. Pulses. So the more pulses you have ie... 6 vs 3, the more like ___ ____ ____ _____ you get. ie.. more energy/mass to turn the turbo impellers.

 

I'd have to agree with Jeff as well. I don't think my turbo would spin any faster hooked up to one manifold very close to the heads if even at the same speed as having it hooked up to all 6 cylinders. I could probably get it to spool a bit quicker if I changed the design of my crossover pipe though.

That's kind of like throwing a 6 lb. bowling ball compared to a 12 pound ball. Sure you can make the 6 pound ball go fast but it doesn't have as much mass to knock over the pins as the 12 pound ball does. I've done it before and know that I'd rather have a 12 pound ball thrown at the pins at a slower speed. (i know... its a corny comparison but you get the idea)

 

Ridiculous! Volume of gas is absolutely important. It determines the size of the turbine wheel and the compressor wheel. The larger the compressor wheel, the more boost it can produce.
Think of a simple model. How fast do you think you can blow wind out of your mouth? 20mph? Is there enough velocity to spin one of those propeller ornaments that go in your yard? Sure. But can you blow hard enough to spin a wind mill? Well why not, you have enough velocity? Ahhh, VOLUME.
Yes, you COULD run the turbo off one side of the engine. Infact, there is an org member doing that right now. But to get the most boost, you need to either two small turbos hooked up to each side, or one large turbo hooked up to both sides. YES, the later IS possible. The 300zx z31 which uses the ever popular vg30et, has an exhaust manifold that ties both sides together and feeds into a single turbo. WHY would they build such a complex manifold if it offered no additional benefit?

 

Good points here, I just want turbo.

 

I started test fitting yesterday.

 

 

niiiice, did you get my email about the brackets? what is your take on a 12"?

 

you guys are all forgetting that heat is a huge part of how fast a turbo spools. run 6ft of pipe thats designed to increase velocity significantly to a turbo, then run 1ft with just plain old wrapped pipe to the turbo and see which spools faster.
before you tell me i'm wrong, whats the point of wrapping turbo manifolds? yes to decrease underhood temps but it also decreases spool time
i'm NOT saying its only heat that spools the turbo, but it has just as much to do with it as velocity and volume.

 

you'll get plenty of heat when boosting. enough to turn the manifolds red hot very quickly

 

You seem to be a little confused here. Heat doesnt spool the turbo, infact the temperature of the exhaust driving the turbo doesnt matter. Since its so hot if it cools down quickly, VELOCITY will be reduced. So wrapping is only to prevent loss of velocity. However, you would never notice the difference a wrapped turbo and an unwrapped one.

 

no pics up yet but 99% identical to mtcooksons setup....hes a super super huge big help, and for the one manifold turbo people....the turbo is bolted to one manifold but gasses from the 3 cylinders on the other side are sent to the turbo via a CROSSOVER

 

how much more beneficial is doing it that way compared to the reverse Y setup, is it a noticable gain?

 

IIRC mtcookson has his turbo mounted ON the crossover pipe, not on either manifold.

The nice thing about using the y-pipe way is that its more equal length, but with the other setup (mounted on one manifold with a pipe feeding the other (rear) bank into it) is really really nice because the front exhaust gases dont even have to travel ~10" to the turbo. IMHO, manifold w/feed pipe idea is probably the best because it uses the shortest possiable route for the exhaust gases. Since it is a 1-2-3-4-5-6 firing order, and cylinder 2-4-6 are all right next to the turbo, it just spells out kick *** setup. Plus if you dont use an IC, I think the turbo will 'come on' almost instantly, vs. having lag.

I say wait for Jeffy, sounds like he's making good progress with his kit, seems pretty promising IMHO

 

the reason us VG turbo owners have to mount it on the crossover is because the way the driver side manifold bolts up, the turbo is hitting the radiator, so its either relocate the radiator or mount it on the crossover. i myself was a bit confused of the design but mtcookson came up with a very intelligent design to mount it on the crossover. then you just need to seal up the flange on the turbo side and you have a well rounded turbo exhaust manifold/crossover

the only thing that is holding me back from getting full potential of a turbo VG is the tranny, i need a 5 speed, so if anyone has tranny and linkage (i can pretty much get everything else eaisly) PM please

 

the way mine is setup should give the shortest possible passage from the heads to the turbo. its right in the middle of the crossover pipe so the length of the manifolds to the turbo should be nearly identical. the only problem with my current setup is the exhaust from both manifolds collide with each other right at the turbo which i'm sure is a power killer. once i get around to making a different crossover pipe that problem should be solved. with the stock 84-89 300ZX turbocharger this thing spools around 2000 or so rpm and is probably fully spooled by 2500 rpm.

 

A company named Prowerks make a modified T crossover to help combat some of the Collision.

 

link to site please

 

I know summit carries them, but mostly their BS parts like quick connect battery chargers.
and I can't find the prowerks catalog at the moment
not too mention they want a $4000 opening order

 

i can't find prowerks on summit's site.

found out the name is actually pro-werks. http://www.pro-werks.com/

http://www.pro-werks.com/detail.php?...ENTER+SECTION#



i might be able to use that. i'll have to do some modifying to it to make it fit but that might just work.

 

DOH!
but that is what I was talking about.

 

in the diagram of their mine is actually setup even worse which is why i'll need something like that t pipe.

mine looks something like this:



it works but just isn't as efficient as it could be.

 

1. Heat doesnt spool a turbo? Perhaps your not aware that a heated gas has this little natural tendency to expand. Its called back pressure. It is a direct combonation of the velocity and the expanding heated gas that spools the turbo.

2. You contradict yourself in back to back sentences, saying heat doesnt matter, then saying keeping the heat helps spool through velocity.

3. Not noticing a wrapped turbo? OH!! Thats why most people with half a brain wrap their downpipes/manifolds and see gains in spool of 200-300 rpms most times!!

 

WOAH

1. Yes, gas expands AS its heated. Once it leaves that engine, its constantly cooling down. What does a cooling gas do? (which leads us to number 2)

2. MAINTAINING the heat MAINTAINES velocity. If you allow the gas to cool, you are REDUCING velocity. It’s not important what the temperature of the gas is, only that it doesn’t cool down. THATS IT!

3. Ive wrapped a few turbos and felt NO difference. I dare you to find a dyno of a turbo before and after a wrap with documented gains.

 

actually i hear wrapping eats up the turbo and piping very quickly... makes me wish i didn't have to wrap mine but since there's wires overhead i can't unwrap it until i find a good heat resistant wire cover thingy.

 

umm, wrap the wires then

 

Smarta s s

 

i need to find some wrapping stuff for the wires first. once i do i'll wrap them.