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Discussion Starter #1
just checking odds and sods under the bonnet as you do. thought i'd check out the alignment of the air feed pies etc to see if there was any modification that could be done to improve airflow etc

and shock of shocks the top of the air filter 'box' is not attached to the main unit all 3 bolts/screw have been completely stripped of thread. its all there but not actually attached.

i was just thinking that the pipe work looked fairly straight and no tortuous bends or twists and constrictions, but the [email protected]@dy thing is n't fixed together!

what's the best step from here.

replace with OEM bits
replace with a suitable induction kit and if so how do i set it up properly to ensure cold air etc.

[midlandsgtv photos of your set up would be quite timely if your viewing?]

also when trying to lift the pipe out to get a better look how do i disconnect the electrical connection on to the main pip just above the air filter box?

and what's the box half way between the air filte and the injection unit?

i've been looking at threads on upgrades for other Tsparks [ie 147, a56 etc] but none of them look like this. any gtv hints tips and suggestions gratefully recevied.

Cheers
 

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The Mod ive done to the air intake, is take off the box that you mention thats in between the filter housing and point of entry to engine. i'll try and get a pic sorted for you
 

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Discussion Starter #3
thanks Midlands much appreciated.

has anyone used one of the CDA airboxes? any comments or suggestions would be of use.

any photos of induction kits and conversions would also be much appreciated.

initial panic now reduced as a temporary stop gap solution has been provided by my local specialist as attached photo using smaller boltrs but with oversized washers top and bottom.




cheers
 

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The only mod completed so far was taking the second box off, but ive heard so many different stories of damaging the air flow meter with after market kits, i havent touched the original filter. Maybe this is the reason that when you research induction kits, nobody makes them. I have seen the BMC one, but its alot of money for it. Just have to wait and see, i might be tempted to try my own 'kit' but i wouldnt be happy if it all went wrong !!
 

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Discussion Starter #5
i think the big problems with the AFM's are more related to moisture and vibration. some of the after market systems do not provide the same level of support for all the 'gubbins' etc. i know some people move the afm further down the line from the filter to approx where the resonator box is normally mounted, not sure why tho'?

cheers
 

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Discussion Starter #6
there's a damn interesting thread re airboxes and filters on the 147 and 156 forum

http://www.alfaowner.com/Forum/showthread.php?t=43763&page=3&pp=15

has anyone increased the size of the feed into the standard air box?
JamesG recons that this could be the biggest restriction on the induction system. the main pipework is 70mm which is probably a bit tight but as this matches the AFM/MAF not much can be done but the feed into the airbox is only about 50mm at the most. this should be at least 70mm if not 100mm.

has anyone done anymods with forcing cold air into the inner wing area where the original feed is taken from? to try and improve the air load.
 

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Discussion Starter #7
photos of anyones modded induction or intake system greatly appreciated.

cheers

GTV4me
 

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Discussion Starter #8
finally got a second hand air box to replace the broken one, but now having looked at at the standard box close up its raised a few more questions.

the inlet pipe is actually 90mm dia [100mm ext dia] which is good news, but the pipe feeding it narrows down from there to the intake. why?

there is a plastic insert that sits in the top of the air filter to connect/align with the lid. however this extends halfway down the air filter. surely this restricts the air flow through the filter and into the engine. anyone know why this extends so far down and if its actually necessary? presumably the filter wont collapse without its support if so will drilling a load of holes in the sides of it help or cause too much turbulence to be of any benefit assuming you cant just cut half of it off? if its to ensure smooth airflow over the afm this could be moved further away from the airbox.
 
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The plastic insert or "trumpet" is there to help produce torque at low revs,and so is best left in place.
Drilling holes in it would probably be of no benefit as it is already enclosed within the airbox...........probably just another way to bugger up the already fragile AFM on most GTV's
 

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Discussion Starter #10
something funnies going on i've added 2 replies and neither have appeared?

thanks Flo don't want to loose any low down power or torque, quite the reverse really. if the afm was moved down the inlet pipework towards the throttle body where the resounder currently sits this should resolve any air turbulence i pressume.

attached are a couple of images from the manual showing the intake pipework. there is a better detail on the eper online pages but can't get on them at the moment.

jamesG your comments following my pm's would be appreciated as would anyone elses. re the 'top hat'/'trumpet' insert or the restriction in the intake pipework that sits just inside the inner wing.

cheers

GTV4me
 

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Discussion Starter #11
found the eper file re the pipe work. it maybe my memory playing tricks with me perhaps the inlet pipe does n't have arestriction in it its just where it slips over the air box inlet. not sure though need to check it in the flesh unless anyone else knows?

i assume that item 24 is the alternative inlet pipework to items 10,9 and 16. model dependant.

the top hat/trumpet is n't very clear but it is shown protruding from the bottom of item 1 the lid to the air box item 22 being the afm.
 

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Sorry, for the slow response, i've been far too busy scratching my arse and generally drinking beer and watching telly...


Anyway.
Yes, the stub beneath the top of the filter housing is there to smooth the airflow into the MAF.
Yes this stub is restrictive.

To improve matters you'll want to chop the stub off (make sure the filter can still seat securely) and add a section of pipe between the filter housing and MAF. As a general rule of thumb you want to have the MAF at a distance away from the filter equal to 3 times the outlet pipe inner diameter. You can go down to 2 times, but you can pick up turbulence at higher flows.

When going for a revised inlet pipe, (from airbox to the air source at the front of the car) it's best to start from scratch and use a section of brand new pipe that feeds to a nice cool [stagnant] air supply. Bypasses the whole resenator & v6 intake mod issue, and eliminates any uncertainty.

James
 

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Discussion Starter #13
due to the close proximity of the maf to the air filter and the existing stub being approx 125mm long there may not be much option to cut this down and stay within the 3xDIA rule. however if the maf was moved away from the main filter box would this compensate. if so is 3xDIA optimal or is longer ok just not shorter?

the stub is slightly shaped into a trumpet but only minimally. at its intake the int dia is approx 65mm increasing to marginally over 70mm. i was assuming the taper would be the otherway round if there was one at all.

thanks James, will have to get the tape out to check distances and how much if any can be cut off. [can't blame you for catching some R&R] you've been very prolific in your 2 months as a member.

re inlet pipe work most readily available ducting only seems to be 60mm dia or less. aimed at the saxo and corsa market no doubt. the only lager dia substitute i've found so far is washing appliance stuff which is available in 100mm and 125mm dia but seems a bit flimsy. not checked out silicone hosing yet, mainly cos it sound expensive. anyone sourced suitable material from elsewhere?

not sure the V6 intake mod or similar is actually applicable to the GTV as the layout is slightly different anyway.

cheers

GTV4me
 

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You've got the right idea. Move the MAF away from the filter. It can certainly be more than 3xDia from the filter. The main constraint is space.

Don't worry about the stub / trumpet. Cut it off and you'll gain more effective filter area by unmasking than you'll loose to eddies forming at the filter edge. The trumpet would naturraly reduce in diameter from the filter to the maf, and would look like the port on a subwoofer - no shock, they serve the same purpose!

Silicone pipe such as samco is expensive. There are less expensive reinforced rubber types available. Have a search on the net. Failing that you can always make up a rigid pipe using drainpipe (main waste) sections. You can fabricate corners with fibreglass, or smooth pre-fab bends with P38 & P40. Weekend in the shed and anything's possible!! Well, almost...

James
 

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Discussion Starter #15
checked various dims last night

centre of maf to end of trumpet is approx 195mm
inlet int dia of trumpet 65mm
outlet/maf end int dia of trumpet is 70mm
int dia of maf is a 59.5mm
int dia of feed to throttle body is 70mm

therfore if i assume min 2x dia of maf ie approx 120mm i can cut 75mm off of the trumpet

or 2x dia of pipe approx 140mm i can cut 55mm off of the trumpet

and if i move the maf cut the whole thing off.

i'll start with cutting 55mm off and take it from there i think and see what happens. also probably change the standard filter for a BMC unit and make sure i run it for a couple of minutes without the maf in place to make sure there is no excess oil to damage it.

cheers.
 

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Maybe for your interest.

The 156 T.S. have the MAF right on top of the filterhouse with a cilinder filter and have the trumpet 2, like the GTV. The 156 JTD got the the MAF on top of the filterhouse 2 but it hasn't the trumpet or such thing. The JTD suck much more air than the T.S. I think that the trumpet is only to decrease the noise.
 

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Discussion Starter #17
thanks ClaSSic.

i think i'll gradually work towards no trumpet just incase the NA petrol does n't like the lack of trumpet, but certainly worth noting.

cheers
 

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Don't worry too much about oil from the filter. A BMC or K&N will come oiled correctly. Most of the damage people have suffered in the past is because they haven't fitted filtration for the crank case breather, and simply fed the pipe into the intake after the filter.

The original Pipercross Viper, for example, had a connection to fit the breather pipe directly after the filter housing. Bad news. MAF's died. Now, you get breather filters.

P.S. In the UK it's a legal requirement for any emmision control car, that the breather doesn't vent to atmosphere.

James
 

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Discussion Starter #19
ah!
so all those little K'N mini filters for the oil breather are technically illegal. wont replace that section of pipe then unless i allow for the breather to remain in place

is this a potential MOT failure? also wondered if the standard set up is why the engines use so much oil on top of them being a 'loose' design.
 

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The separate K&N breather filters are for pre-92 cars.

It's very easy to make up an in line filter, since the oil droplets are large and some fine sponge will pull out all the nasty stuff. You can adapt a large bore line fuel filter, replacing the element with sponge, and feed the output in BEFORE the main filter unit. Safe as houses... ;)

Not too sure about the oil consumption. I'd have to look into things more closely before i venture an opinion there!

James
 
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