The SCarGo carbon fiber intake piping is a work of art. It has larger diameter than stock which is consistent throughout. Stock has several narrow areas and tight bends. It also weighs a lot less than the stock cast aluminum parts. Probably 2 lbs vs. 15-20 lbs.

 

I'm not interested in cosmetics or weight
I'd like to hear from a scientific point of view why these pipes, and the y-pipe should be replaced

every body seems to be talking about the diameter of the pipework
and that this is not consistent throughout on the OEM pipe

I might be wrong but i think the cross sectional area is what matters more than diameter

as long as this is the same (i know the OEM is not) that should be more efficient/effective for air flow

the intake into my K24's is 55mm - therefore i should have a 55mm pipe - any more or less will have an effect of the air speed and pressure

the outlet is 45mm, meaning i should have a 45mm pipe

if the pipe sizes were different to this is would create a bottleneck situation

I think as long as the pipes were 55mm and 45mm and remained of constant cross sectional area there would be no issues

With regards to the Y-pipe - this should also be the same size at the outlet pipe in order to keep pressure and air speed constant

where the two air streams merge in the Y -pipe the cross sectional area should be the size which keep the air speed and pressure the same as when it initially left the turbos

 

The next answer should be good....kuz I've wondered the same thing about the OEM built in restrictions.

 

Marks pictures are obviously less restrictive...but what should we do with the maf?I did not see any maf connected somewhere there...

 

We maxed out the stock tubing where the turbo just couldn't breath in any more air with the stock junk in the 6XXrwhp range. With the evo piping the turbos spool almost 1000rpm faster and we have yet to max them out. The tubing gets really restrictive, it doesn't look that way but it really is once you take it off. Best mod we have done other then the turbo's.
Matt

 

I believe the OEM intake piping is restrictive mainly due to the changing of cross section area

If there was a pipe available with the same size area throughout (which there is) this would be more suitable

The thing i am questioning is where do people get the measurements for the tubing in the first place?

Are they based on anything or are they completely made up as they seem to be

I completely agree that the stock intake is restrictive but i believe it's due to the changes in cross sectional area rather than anything else (ie diameter)

I am also very keen to hear how everyone concluded that a 75mm Y-pipe and TB was required? - where did 75mm come from?

 

The pics posted by Mark are spot on regarding the intake piping itself
It doesn't get much more efficient from the filter to the turbo than that

(Mark has been so helpful regarding issues i'm having with my car and i cannot speak highly enough of him)

My main question is after either the S-Car-Go piping or Proto intake (which both look very efficient) the air enters the turbo and then exits through a 45mm opening (on the K24's at least)

If the air is coming out of the turbos through a 45mm opening why do I need to increase the piping to 70mm before entering the Y-pipe at 75mm?

How will this be of benefit? and where do these two measurements come from?

Surely the piping coming out of the turbos would still work if it were 45mm regardless of the hp being produced?

I think the Y-pipe should theoretically still work if the two "legs" were both 45mm and the main "trunk" had across sectional area equal to twice that of the 45mm "leg"

So if we calculate the area of the two legs which are 45mm each and then ensure that the trunk has the same area, we should have a trunk of approx 63-65mm diameter

This would then keep both air speed and pressure at a constant from the time it leaves the turbo to the time it enters the TB

 

CJV - i remember you tried out an enourmous TB once
What were your findings?
Are you able to provide details of that set-up?

 

Changing the intake piping will benefit even stock turbo's. I am the one who designed and had S Car Go build those cf pipes for my car.

I'll tell you how I came about it. At the time Ruff cars were making way more torque and a little more power than all other tuners. I had examined all the Ruf parts and could figure out what they were doing ........ our parts were basicly the same, but they had an intake that was a little larger with less restrictions.

We conducted some tests and discovered that Ruf really did know what they were doing. We continued our testing and discovered that larger diameters with less restrictions were better, but smoothness was even better. We also learned that getting away from anything that conducted heat (ie aluminum), make for cooler intake air and more power (ie cf). Shortening the distance of the intake will reduce friction resulting in delivering more air. If you bother to work out the formula's you will see how this works. I have posted these formula's somewhere in the KA ..... In Memory of Capt Michael J. Maring thread in Tuning and Modifications.

You have to remember that when you change one part another part becomes the weak link. But basically, motors are air pumps and you add fuel. More air in and out produces more power when fuel is in the proper ratio. Keep as much heat out of the intake channels as you can and keep as much heat in the exhaust channels as you can.

If you simply strap on a larger TB without making other changes you will lose torque in the mid range and pick up a little hp at the very top of the rpm range. Not a good deal.

 

ant,

We started with the stock TB and bored it a few mm's. Don't hold me to the numbers because it has been a long time. I think they were around 66 mm, plus the bore. Then we went to the GT3 TB and I believe they were around 74-76 mm. We finally settled on a 90 mm TB.

Remember what I said about weak links, air pump and fuel? You add so much fuel to so much air. Fuel is what makes the power, but it needs the proper ratio of air. Now intakes become restrictions, heads become restrictions, valves become restrictions, turbo's become restrictions, exhaust become restrictions. You see where I am coming from.

Now throw into the mix the charged air temperatures. Remember, cooler air
is denser and has more oxygen molicules (sp). Oxygen is what combines with fuel to make power.

The key is to choose the power you want and then design everything else so there is no restriction to this power goal. It is a waste of money to just change parts one at a time with no goal in mind.


Turbo, GT3 and 90 mm TB's for comparison.

 

Proto runs 2.5 inch piping on its K24/18G cars (what I have)
and 3" piping on its GT30 and GT35 cars.
Example; when Divexxtreme went from his original Proto Set-up (which has the best
quarter mile time of any stock internal 996 Turbo he had 2.5" piping.
When he went to the big GT30 set up (and later upgraded to 35's), Proto took off
and sold his 2.5" piping and went to a new 3" set-up like Markski's, Peter A's and RobMD99.
I have no idea what Bernoulli have to say about this...

MK

 

It would seem to me that the larger intake pipes would help on any setup. However I do think that because of the cost and the difficulty installing them that for the gains on a lower powered car this is not money well spent. I am curious though, do you guys think this piping would be too much for stock fuel pump with a five bar?

 

I just don't get where the measurments of these pipes comes from

I wouls assume the GTs have bigger outlets and therefore wil most certainly require larger pipework - but the K24s do not

Assuming you buy a Y-pipe with 70mm legs why would the trunk be 75mm?

The goal should be to keep the air speed and pressure the same as the air mixes and enters the trunk

To do this we would need the trunk to have the same surface area as the two legs
So - if the legs are 70mm in diameter the trunk should be 99mm!

But I still think the 70mm legs are too big to begin with

 

OMG... stop trying to reason in your head and buy the intake and be done with it!!

 

I just can't help it!!