stock airbox + snorkle vs. free intake

[nize]

i've compared performance with the stock air box and snorkle versus just a filter attached to the compressor inlet.

the difference is significant, and it's definitely worth removing the stock air box and snorkle if you want maximum turbo performance.

all things being equal, the spoolup is about 200rpm faster without the stock afm/snorkle, but the real difference is after 4500rpm when the air restriction becomes really noticeable. the result is way more area under the curve and a gain of over 36whp.

it's obvious that most of the power and performance gains from a MAF setup is actually coming from removing the stock intake restrictions. if your mods can support it (MAP or MAF), i would highly recommend removing the stock AFM and snorkle for best performance gains.



i have heard from a local 951 track junkie that a stock honda intake snorkle is a perfect fit for a 3" turbo inlet on the 951. so over the holidays, i went to the local junk yard and managed to find a rubber intake pipe from an old honda prelude for a whopping $2. it does fit almost as if it was custom-made for the 951. does this make my car JDM ? yeah, i know, someone get me a k&n cone filter so i can get rid of this retarded sponge filter, please.



update 9/8/2008:
finally found a nice filter that doesn't have a blocked top.

RX-2820 K&N Universal X-Stream Clamp-on, around $60

[sayporsha]

I love it! You must be running a MAP sensor by the looks of it. JEG's can hook you up with a K&N cone filter:
http://www.jegs.com/webapp/wcs/stores/servlet/KeywordSearchCmd?searchTerm=cone&catalogId=10002&N tx=mode%2Bmatchallany&Ne=3&Ntt=cone&N=4294967283%2 b1010269%2b1143204&langId=-1&storeId=10001&Ntk=all

[nynor]

from your graph, it looks like over 50HP and about 35 lbs of torque. pretty amazing. would it make sense to get rid of the stock airbox and snorkel if i am still using the stock AFM?

[soxnail]

Nope you get most bang by getting rid of the afm....
Sox

[nynor]

ok. i just don't have the funds for an MAF, nor the time to tune it. i guess it will have to wait until i am out of school.

[nize]

yeah, the afm is a restriction too.

the whole snorkle+afm is a bad combination for power.

MAP is better than MAF, but is usually more $$ to get a MAP-capable tuning setup.

now i'm trying to figure out how to fit a filter into the fender hole to draw cold/dry air.

[Marcone]

Ok.. im reading here.. and i want to know what i need to do to get the MAP or MAF system on my porsche?

[nize]

maf conversion kits:

maxhpkit;
http://www.maxhpkit.com/prod_scivision.htm

lindsey;
http://www.lindseyracing.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=LR&Category_Co de=944MASSAIRFLOWKITS

map-capable EMS conversion:

wolf3d;
http://www.randomems.com/

also available from lindsey;
http://www.lindseyracing.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=LR&Category_Co de=WOLF3D

there are a lot of other stuff out there if you want to go to MAP, such as motec and tec3 EMS. you've got a lot of reading and research to do.

[myskyon]

Originally Posted by nize

yeah, the afm is a restriction too.

the whole snorkle+afm is a bad combination for power.

MAP is better than MAF, but is usually more $$ to get a MAP-capable tuning setup.

now i'm trying to figure out how to fit a filter into the fender hole to draw cold/dry air.

i don't think the MAP is necessarily "better" than MAF. I would say it provides a very good fail safe if you blow a hose off. I think the best setup would be a system that used a MAF and when there was a fault with the MAF it would fail over to the MAP. don't know if that is possible or not but it sure would be nice. Maybe i am completely off kilter. I know a lot of people who race would prefer the MAP to the MAF due to the fact that if they blow a hose off they can still get back to the pits with a MAP and would just Die with a MAF.

[nize]

MAF has a lower initial investment cost than MAP, but a higher replacement cost due to wear and tear.

from what i have read and understand, MAF tuning also varies between MAF setups, even on identical cars, because no two MAF sensors return identical values. thus, when you have to eventually change the MAF sensor due to wear and tear, you'll have to re-tune the car.

MAP tuning is more consistent between identical cars, which makes it easier to swap tunes with other people running the same setup.

MAF vs. MAP is an interesting and ongoing debate, though. either way, i think we can all agree that the stock AFM is the worst.

[Marcone]

Damn you guys!

Now i apparently NEED a map or maf system. Because every body else is doing it! HAHA
and im gonna need that super cool dual bearing turbo because of the really good write up on it....

Please just tell me stock is waaaayyyy bettter than the upgraded stuff so i can sleep at night!! LOL

[soxnail]

All stock,and I sleep just fine
Sox

[nize]

you can't go wrong with stock. seriously, the only reason i've 'upgraded' is because my stock stuff broke and i figured if you're gonna replace it, why not replace with something better?

my next upgrade will probably be a spec stage2 clutch when the stock clutch dies.

[snbush67]

You might need to get the matching exhaust set up;




Just kidding........

[chitown944]

I remember seeing a stealth MAF system someone..should post on this thread since the others have been posted too. The stealth MAF goes where the stock AFM goes. Anyone finds it post here please as another option.

[chitown944]

Hey Nize,

Did you remove the air meter with your setup. Can you clarify. From the looks of it it seems you removed the AFM and stuck a cone/sponge on the intake is this correct or am I missing something.

[nize]

Originally Posted by chitown944

Hey Nize,

Did you remove the air meter with your setup. Can you clarify. From the looks of it it seems you removed the AFM and stuck a cone/sponge on the intake is this correct or am I missing something.

that is correct. my car has been converted to run MAP, so it doesn't really need anything pre-turbo.

[chitown944]

So what happens to the air meter. Lemme ask you like I'm a 5 year old. Can I do this with my setup. I have AFM attached to a cone. If I remove the AFM will my car still run correctly with just a cone filter attached to the intake or is there something additional I would have to do. In other words by deleting the AFM and replacing it with a cone filter is it harmful to the car.

[nize]

Originally Posted by chitown944

So what happens to the air meter. Lemme ask you like I'm a 5 year old. Can I do this with my setup. I have AFM attached to a cone. If I remove the AFM will my car still run correctly with just a cone filter attached to the intake or is there something additional I would have to do. In other words by deleting the AFM and replacing it with a cone filter is it harmful to the car.

do NOT remove the AFM unless you're converting to MAP or MAF. basically, the engine needs some way to measure the amount of air that's entering the system and these are three different ways to do it.

AFM (air flow meter): aka 'barn door', uses a spring-loaded trap door that incoming air needs to push against to enter the engine. since the spring pressure is known, you can measure how far the door is 'open' and calculate how much air is entering the system. the obvious drawback is that the incoming air has to push against the door, so it is a restriction. this is the stock 951 setup.

MAF (mass air flow): aka: 'hair dryer', uses a heated wire (usually looks like a target crosshair) that's in the path of the incoming air. as air blows past the wire, it cools it (think of a hairdryer). since the amount of voltage to keep the wire in a heated state is known, the voltage drop can be measured to determine how much the wire has cooled, and this can be used to determine how much air is flowing into the system.

MAP (manifold air pressure): aka: 'speed density' uses a pressure sensor (much like a boost gauge) that takes a reading of the air pressure in the intake manifold. using a combination of how far the throttle is open, what the air temperature is, and what the air pressure at the manifold is, it can calculate how much air is entering the system.

you MUST have some method to measure the air entering the system in order for the car's computer to provide the correct amount of fuel, otherwise you could seriously damage your motor.

if you want more information regarding how these different systems work, google will turn up enough information to keep you busy for the next year.

[chitown944]

Ok I think I know what your talking about. I had a Nissan Frontier SC and I put a cold air intake in it and remember putting the air meeter into the cone filter. SO if I remove my AFM how do I replace it with an air meter similar to whhat I did with my Nissan SC. Am I correct in I would need a similar style air meter(target style) and just stick that in the cone. How did you wire yours and do u have pics.