Intercooler Pipe Sizings

Jonnycoupe · 5 Feb 2009 at 08:53

Firestar_3x said:
No, why would i have a MAF in a boost pipe? 4

Did you seriously just ask that?

Jonnycoupe · 5 Feb 2009 at 08:56

Firestar_3x said:
Never heard of a MAF on the boost side, but tbh i've never read or looked about the subject.

My MAP sensor also seems to be called a Thrust Sensor on various other sites, not sure what thats about?

Well dont correct me then about the functionality of something I assumed was MAF rather than MAP when you said it was in a boost pipe. It may not be a MAF sensor then but its certainly NOT a MAP sensor.

Thats cos who ever called it that is an idiot

You know what MAP stands for? Whats that got to do with thrust :confused:

and if its in a boost pipe it can't be a MAP sensor by definition, you wouldn't need two on a car anyway as pressure sensors for boost are usually for enrichment compensation of boost on an alpha -N calibration map rather than speed- density.

gobbo · 5 Feb 2009 at 09:32

MAP sensors are normally fitted onto the intake manifold somewhere right? Hence MAP being Manifold Absolute Pressure?

What the OP is talking about sounds like a MAF sensor to me.

Jonnycoupe · 5 Feb 2009 at 09:53

Well yeah, especially as thats the load measuring method on the VAG 1.8T

Yours may be different as you have alluded to, but thats certainly in a charge pipe.

Firestar_3x · 5 Feb 2009 at 09:59

Yes i did just ask that, i've never heard of a MAF on the pressurised side of a turbo system, affraid i can't know everything all the time, just most

Yes they are usually on the intake manifold, not got an issue with this, but this is clearly called a MAP sensor, so whichever fool at Bosch / VAG / Forge / ECS Tuning should clearly be shot.

http://www.forgemotorsport.co.uk/content.asp?inc=product&cat=260401&product=FMMAPT

http://www.ecstuning.com/stage/edpd/pagebuild_v2.cgi/?html=learnmore.html&productID=9611

MAP - The MAP sensor is located in the OE SMIC end tank. There are two different sized MAP sensors, and VW didnt make the transition based on years but cars from all years might have either the small or large version (rumor has it the small version didnt come around till ~2003). When your upgrading your intercooler to a larger SMIC or FMIC and need to specify which MAP sensor your car is running the only fool proof way to check which sensor your car has. If you are making custom piping and need a MAP sensor flange check out 42nd Draft Design for a universal solution.
Rule of Thumb appears to be:
2002 and earlier cars = large MAP
2003 and later cars = small or large MAP

I know the location of my MAF its just by the airbox on the non pressurised side of the system, i'm talking about the pressurised side of the system hence we are talking about intercoolers.

Firestar_3x · 5 Feb 2009 at 10:09

Firestar_3x · 5 Feb 2009 at 10:12

Jonnycoupe said:
Well yeah, especially as thats the load measuring method on the VAG 1.8T

Yours may be different as you have alluded to, but thats certainly in a charge pipe.

Thats the MAF and its not in a charge pipe, the picture you've posted is the output from the airbox to the turbo intake, see ere.

Charge pipe coming from the intercooler to the throttle body can be clearly seen at the front of the engine, only charge pipes that exist that high up in a 1.8T are for the diverter valve.

Simon · 5 Feb 2009 at 12:22

51mm is a bit small for that power output. Expected really as the turbo is also being pushed for that kind of airflow.

You want the larger piping for as much of the system you can get away with, however you also want smooth diameter changes too.

Lag isn't the issue, indeed smaller piping may help with lag. Smaller piping, too many bends, step changes in pipe diameter, etc all serve to increase restriction and therfore lower the flow rate of the whole induction system. Reducing peak power.

Simon · 5 Feb 2009 at 12:24

Firestar_3x said:
Yes i did just ask that, i've never heard of a MAF on the pressurised side of a turbo system, affraid i can't know everything all the time, just most [/url]

So cause you haven't heard of them you think they don't exist?
Interesting

That thrust sensor seems a bit stupid too unless it is some sort of diagnostic sensor. I can't see how the management system can use it to control fuelling or ignition

Prophet · 5 Feb 2009 at 12:31

Simon said:
51mm is a bit small for that power output. Expected really as the turbo is also being pushed for that kind of airflow.

You want the larger piping for as much of the system you can get away with, however you also want smooth diameter changes too.

I guess the Cosworth crew must have fluked getting over 400BHP using 51mm boost pipes then.

51mm is perfectly fine for the desired power. You don't want "larger piping for as much of the system you can get away with"

Simon · 5 Feb 2009 at 12:35

Orange Peel said:
I guess the Cosworth crew must have fluked getting over 400BHP using 51mm boost pipes then.

51mm is perfectly fine for the desired power. You don't want "larger piping for as much of the system you can get away with"

They would have made more on bigger piping though...

Obviously you know more than Graham Bell.

Prophet · 5 Feb 2009 at 12:48

Simon said:
They would have made more on bigger piping though...

Obviously you know more than Graham Bell.

lol yeah and even more if they used a bigger turbo, higer flowing injectors and a flux capactor!

Quite a silly thing to say really as the setup he has is fine. Larger pipework would be a waste of time.

Why would you assume I know more than Graham Bell. I'm going off proven figures many other people have produced using 51mm pipework. My old Turbo produced 300BHP on 51mm pipework and a Hybrid KKK16 turbo (which is tiny) with no problems at all. I know of numerous other engines that produce more power (circa 350BHP) on a similar setup using a larger turbo.

Its OK to be wrong. Just take it well and don't get *****.

Simon · 5 Feb 2009 at 12:52

No one has said you cant make that much power, just you are reducing flow rate by having too small a pipe. There is only so much air a 51mm pipe can fit down it.

By going for a bigger pipe you will increase the maximum flow rate, as Graham Bells book states: 51mm is suited to maximum outputs of around 255bhp, this is limitation due to physic and gas flow.

You seem to have misread the comments and think just because you know someone with a cosworth making 400hp then 51mm is the perfect size for that engine.

Prophet · 5 Feb 2009 at 12:57

Simon said:
No one has said you cant make that much power, just you are reducing flow rate by having too small a pipe. There is only so much air a 51mm pipe can fit down it.

By going for a bigger pipe you will increase the maximum flow rate, as Graham Bells book states: 51mm is suited to maximum outputs of around 255bhp, this is limitation due to physic and gas flow.

You seem to have misread the comments and think just because you know someone with a cosworth making 400hp then 51mm is the perfect size for that engine.

you have to pair the pipework with the turbo. Larger pipework with the smaller turbo isnt going to help. Sure it may spool up quicker but its gonna take longer to pressurise. What about pressure drop?

No, I've not missed anything. Didn't say I know someone with a cosworth. I know that a few cosworth owners have made that power. It documented in a few publications. I never said that 51mm is the perfect size either. I said there's no need for anything larger with his setup.

Simon · 5 Feb 2009 at 13:03

Orange Peel said:
you have to pair the pipework with the turbo. Larger pipework with the smaller turbo isnt going to help. Sure it may spool up quicker but its gonna take longer to pressurise. What about pressure drop?

You still have a larger throttle body, more important for me would be getting the transisition nice and smooth. When you do this won't make much difference in terms of lag however you will help peak airflow.

Everyone wants peak numbers too

Jonnycoupe · 5 Feb 2009 at 15:52

Firestar_3x said:
Thats the MAF and its not in a charge pipe, the picture you've posted is the output from the airbox to the turbo intake, see ere.

Charge pipe is still the pre turbo section as its carrying the inlet charge. Its a charge pipe on all the EBOM's at my work anyway

Dont reference some monkey website about MAP sensors when your pulling me up on 'charge pipes', MAP sensors are pressure sensors located in a manifold, if they are not there then they are not MAP

I think we've been through a similiar themed thread before on something like this anyway...

Firestar_3x · 5 Feb 2009 at 16:00

Its a case of JohnnyCoupe vs the world then, whilst i agree its not in the Manifold so its name is somewhat strange thats what everyone is calling it including the people who design and make the dam thing, if i hadn't called it by that someone would have pulled me up on it.

This low level analysis is all irrelevant anyways, the semantics about what a pressure sensor is called depending on its location in the system doesn't matter, what does matter is i got the information i needed so i could order the parts for the weekend.

Also the quote about the sensor was simply to identify its location to youselve and to show i'm not seeing things (again)

Simon · 5 Feb 2009 at 16:13

I think it looks for Maps that may have made their way through the airfilter

Jonnycoupe · 5 Feb 2009 at 16:29

Orange Peel said:
I guess the Cosworth crew must have fluked getting over 400BHP using 51mm boost pipes then.

Did the actual 'Cosworth crew' design the cossies with that size intake system back before CFD was in the realms of automotive design?

Most NA cars have throttle bodies that big.

Maybe you could do a MAP against post turbo pressure datalog to confirm what you are trying to think you might mean? Post the results and we can discuss them?

Jonnycoupe · 5 Feb 2009 at 16:32

Orange Peel said:
you have to pair the pipework with the turbo. .

No you dont, you size it for the expected air mass and the resultant air speed, with 300ft/s being sweet spot area. Maybe you could suggest what the air speed of a 400bhp engine consuming intake air through 51mm piping so I can compare it to my calculations?