What is a "shuttle valve"?

This piece which is removed when installing a long neck.



http://forums.pelicanparts.com/uploa...1401111671.jpg

I don't believe that a simple change from 3LDZ to K27, without increasing boost, would cause or contribute to detonation. FYI, the K27 was the stock turbo on the 964 turbo, so even your infallible Porsche engineers agreed they're better than 3LDZ's. I believe the factory also used them on 930S's and other special 930's they built in limited numbers.

"it is only because i have not had my meds"

you guys are lucky you are on another continent.....

Damn.... This thread makes my head hurt. I just keep hearing that line from the movie Forest Gump, stupid is.................... Back to my holiday.

Let's just make this simple: The original poster said

I'm sure a more advanced intercooler will be beneficial, but is it really necessary?

And the answer is "Not necessary, but YES if you want some performance gains". Put on a nice IC that's twice the size of stock and flows air much better, and you can't lose. I don't know that 3LDZ's or shuttle valves or rubber centered clutch discs have any place in this intercooler discussion, but we all do tend to drift off topic once in awhile.

And oh....I lust after hippy chicks, flawed with cracks and all. Fondled memories....

Neill,

You are welcome to come by sometime and you can test out my upgraded longneck. My car is down currently as I am working on a suspension overhaul. We can swap it on sometime if you'd like to test it out first hand and see if you like the difference.

Honestly, the biggest improvement you will notice with the longneck setup is getting away from the shuttle valve setup. The longneck simplifies things drastically.

You have my email - I just haven't had time to respond!! Send me an email or reply here. Happy to help out.

Chris.

enjoy your holiday SmileWavy

I completely agree, Porsche always improves as time goes on thats why im also trying to keep up with their advancements and making my 930 more (Porsche Factory modern)

:p

Re Previous posts the facts are there, So I agree with the benefits of larger IC that said, does the Power gain of a larger IC also give more (Torque) ie; acceleration down low??

More to the point is responsiveness,

IS a Larger IC the best upgrade for that? i think many people when they say they want more power a lot of that relates to they want faster response,


Big IC ok more area leads to more cold charged air rammed down the tb,

The TB opening is about 3 or 4 inches diameter the TB is constant regardless of the size of the IC so there must be a faster velocity down the TB in order for those gains? doesnt there?

This is where it confuses me, this is prev i posted in a (sarcastic way)) how the hell can a larger IC if you dont make any other changes give more power at your foot??

How can a larger space make faster velocity from the Turbo, Is the Addition of a larger IC moot if you do not add a larger Turbo?

Does this need to be done hand in hand? or is it a waste of time?

I havent personally noticed a big change adding an IC to my Non IC car other than its a great place to put my tools when im working on the engine bay, but then again, many have said the factory IC is crap so maybe thats why.

Physics. Boyles Law
PV=nRT
as the temperature drops (due to the intercooler), the volume of a given volume of oxygen molecules drops, so you can get more oxygen/fuel mix into the cylinder, leading to a bigger bang.

Robbie Robbie Robbie. Omg Robbie.
I'm only going to try and touch on the volume part of the question.
Ok, cool air is more dense...so that means that when the charged air(pressurized) is cooler, there's more of it.
Does this help?

Velocity really isn't part of the equation here; cooler, denser air is.

Yes, No, Maybe, possibly

But :cool:

So how do you move it QUICKLY
because (there is more of it) this is where the bigger turbo comes into play for the bigger IC

So there must be different sized IC's to match different sized Turbos,

cant have small with big, or vice versa, it needs balance

A larger amount of mass (including air) is harder to move and needs more energy to move and will need even more energy to move the larger (colder mass) at that equal speed or faster, or you have a large box with much more volume of cold charged air floating around wondering what to do with itself?

So theres a way out, the exit is the TB opening right?
IT hits that area, no matter how big a Turbo we put on our engines or IC's or whatever, there is potentil for bottlneck, if its too wide velocity can be lost, i think.
This is similar to the action of the headers joining forces and hitting the single inlet on the base of the turbo, you've got all that energy there waiting to be used,

The next post says velocity not part of equation, but how can that be?
not only that Engine (system pressure overall must be taken into consideration)
doesnt it?

Velocity has to be important,
wheres Steve from TK?? must be late there, need some Tech info on this

WAKE UP STEVE :)

:rolleyes:

Anywhos, it is too much information for me to learn but still a curious and interesting subject to how it all works

I am sure that there is great room for development yet to be carried out on the Charged/pressurised system for optimum hp gained from a turbo,

I can see in the future Turbos being welded together to increase the velocity into the engine, that will be some serious gain to see, not just two but even 3 imagine that , 600000 rpm and more

Anyway again im getting into too much Tech babble for a simple post Question

Have a nice week all,

Thanks to those with patient answers for us newbies and QR theyre all well noted and taken into consideration :p

that's where it has me stumped see above

Robbie, in all seriousness you need to read turbocharging by corky bell. Cover to cover twice before coming back the Intercooler/turbocharger questions here.
Questions in the turbo oil tank, fine. But you need to seek education on your own learning time with a book that let's it all flow in an orderly fashion in order for you to receive it without confusion. It's how many of us learned. Asking random questions doesn't get you as far forward as just reading about a subject in a text type book on a subject. I read it, it taught me about turbocharging.
And his name is Chris. Not Steve. Steven is from imagine auto which is now no longer, the business not Steve. He's fine.

Velocity is a BIG factor here. If the core of the IC is too restrictive (velocity/air flow). Then the IC ability to flow air from a larger turbo will bottleneck and hurt performance. Having increased flow capability (velocity/air flow) will allow more power, IF, the current IC can't flow the cfm the turbo is rated for.

Example you have a air cleaner rated for 750cfm, and turbo rated for 900 cfm and a IC rated for 850cfm.

The air cleaner is choking the turbo, and then the IC is bottle necking the flow capability of the turbo. Here you have 2 negatives.

The IC is not going to change responsiveness of the engine even if it is a crappy little inefficient unit. It will only suffer as far as velocity on the top end.

Adding a larger IC is only going to benefit mid range and top end which relates directly to air flow (velocity through the IC).

Having a bigger IC WILL drop intake air temperatures, that are generated from the turbo. By lowering the temps from the turbo using a IC will help longevity of the engine by reducing thermal loads on the pistons, rings, valves and guides.

The only way to increase low end response is to raise static compression.

When these cars came out, in all reality, they were crude as far as tuning goes. They had 7.5:1 compression, fixed ignition timing with vacuum advance assist (very limited).

It was thought, that having low compression would allow for more boost and reduce risk of detonation. In all reality it was partially true but the low compression causes poor low speed drivability, poor transition onto boost, poor low speed fuel economy and massive lag.

The main limiting factor early tuning had was lack of ignition timing control. The complete control of timing allows for more compression, which improves performance at all RPM levels.

It's not that you are asking stupid questions, it's the fact that you are making blanket statements that you think are fact. Then when people who are much more educated on the matter try and correct you, you ARGUE with them. Just sit back and enjoy the reading man. You will learn a ton...




THIS!!!

On a Porsche no, but I added one on a M3 that I built and it added to the lag quite a bit. This was sue to the fact that there was a large volume in the intercooler and charge piping that you first had to "compress" before the intake actually saw that pressurized charge. But after that, oh boy, hold on....... and counter steer... :D

Cause and effect. At that point then the IC was larger in capacity then the flow rate of the turbo. A higher flowing compressor section would have remedied that. Problem is change one thing drastically on a turbo car then the next bottle neck shows itself, balanced components is key. Did you traded up to the 930 from the M3? Or do you still have it?