14CUX AFM ID

[Chilliman]

Anyone know what the internal diameter of the standard AFM we have on our cars is? The search facility is down (as usual) but there were many threads about the standard AFM becoming restrictive when you're chasing bhp figures in excess of 280.... I'd assumed this was down to the amount of air it could flow rather than any accuracy in the data it fed into the ECU...

I'm in the process of further modifying my induction (I have an ACT triple) so any info on induction hose sizes and air filters would be much appreciated....

Thanks in advance,

Chilli

[SILICONEKID340HP]

Don`t think it matters because you do not have a AFM ..What are you useing for a new pipe ? I wonder if you can get a much longer air filter !

[Chilliman]

SILICONEKID340HP said:

Don`t think it matters because you do not have a AFM ..What are you useing for a new pipe ? I wonder if you can get a much longer air filter !

You're right Daz, the air filter I currently have is huge but only has a neck diameter of around 75mm.... so I was wondering what the AFM ID was..... I'm thinking the 75mm restriction in the induction pipework (filter end) might be similar in terms of limiting power to the ID of the standard AFM.....

[Hoofa]

If your running mega squirt the afm should be removed, the air filter should be updated to one that flows 500-600 hp, k and n do one that fits, just run same size from air filter to charger intake

Edited by Hoofa on Tuesday 11th December 21:16

[SILICONEKID340HP]

Chilliman said:

SILICONEKID340HP said:

Don`t think it matters because you do not have a AFM ..What are you useing for a new pipe ? I wonder if you can get a much longer air filter !

You're right Daz, the air filter I currently have is huge but only has a neck diameter of around 75mm.... so I was wondering what the AFM ID was..... I'm thinking the 75mm restriction in the induction pipework (filter end) might be similar in terms of limiting power to the ID of the standard AFM.....

I wonder how wide the ACT induction kit is ?

[daveparry]

Pretty sure the ACT is 72mm!

[SILICONEKID340HP]

Chilliman said:

SILICONEKID340HP said:

Don`t think it matters because you do not have a AFM ..What are you useing for a new pipe ? I wonder if you can get a much longer air filter !

You're right Daz, the air filter I currently have is huge but only has a neck diameter of around 75mm.... so I was wondering what the AFM ID was..... I'm thinking the 75mm restriction in the induction pipework (filter end) might be similar in terms of limiting power to the ID of the standard AFM.....

There is a nice induction kit for your triple plenum ..



http://www.actproducts.co.uk/tuning-tvr-rover-v8/

Edited by SILICONEKID340HP on Tuesday 11th December 21:34

[Chilliman]

Hoofa said:

If your running mega squirt the afm should be removed, the air filter should be updated to one that flows 500-600 hp, k and n do one that fits, just run same size from air filter to charger intake

Edited by Hoofa on Tuesday 11th December 21:16

Hi Nigel,

Yep it's MS2 no AFM etc, however the airbox on the ACT triple is designed to slot straight into the standard AFM (which as you know I dont have).... so despite the triple throttle bodies the 'airbox' has the same (inlet side} diameter as the standard AFM... So the question is (in my mind) if the standard AFM limits the amount of air you can get into the engine due to it's diameter (how much it can flow?) then despite doing away with the AFM (due to MS2) retaining that same diameter on the ACT airbox must surely limit bhp the same way as the 14CUX AFM did.... Or am I missing something???? The surprise for me was despite the huge air filter the 'neck' of it which goes into the induction hose was only 75mm in diameter.... I suspect the triple throttle body's can flow far more than the 75mm restriction in the air filter (or original AFM) can deliver....

Happy to be corrected here....

Chilli

[Sardonicus]

Chilliman, i can let you know in the morning.

[Hoofa]

Just make what ever the bore of the pipe at the filter neck is the same all the way through , it used to narrow down a bit through the afm and the elbow onto the old style plenum,

[Chilliman]

Sardonicus said:

Chilliman, i can let you know in the morning.

Righto

[SILICONEKID340HP]

Does act sell that induction kit in the picture ? a straight piece of pipe could be used where the afm is fitted .That is a larger afm than standard ,it`s an upgrade .

[Chilliman]

Hoofa said:

Just make what ever the bore of the pipe at the filter neck is the same all the way through , it used to narrow down a bit through the afm and the elbow onto the old style plenum,

Hear what you're saying Nigel, but a 75mm neck on the filter (and the airbox) seems a trifle small for power outputs North of 350bhp? Dunno tho, I'm guessing here really.... I'm just looking to optimise what i've got (and run a sub 12 quarter) before I go SC

[carsy]

Good point Chilli, I have often thought this about the ACT triple like yours. Yes it has 3 nice bodies but these 3 are only fed by a single 72mm or what ever it is.

I think the same as you, surely it is going to prevent the triple breathing its full potential. I wonder what the induction diameter is on the LS3. just for comparison.

So if the intake diameter is holding back the ACT Triple, what you got planned.

[GasMunkey]

75mm tube will flow a st load of air I doubt that would restrict even 400bhp

[LuckyLucky]

A standard AFM has an internal dia of 55mm.

I bolted 2 standard air filters together using a bit of ally tube 72mm internal dia so there is twice the amount of air going in!

[Chilliman]

carsy said:

Good point Chilli, I have often thought this about the ACT triple like yours. Yes it has 3 nice bodies but these 3 are only fed by a single 72mm or what ever it is.

I think the same as you, surely it is going to prevent the triple breathing its full potential. I wonder what the induction diameter is on the LS3. just for comparison.

So if the intake diameter is holding back the ACT Triple, what you got planned.

Being attended to as we speak The ACT CF airbox is being replaced with a bespoke aluminium airbox with larger intake, 100mm (ish) intake hose, and corresponding filter. This should allow the triple to suck as much air in as it can with no restrictions... This will be closely followed by a remap (hopefully Phil at EFI) and a RR session (same one I've used before). I'll post the results when done Forgot to mention, replumbing the rocker cover oil breathers from the airbox/plenum into a catch tank....

[GasMunkey]

LuckyLucky said:

A standard AFM has an internal dia of 55mm.

I bolted 2 standard air filters together using a bit of ally tube 72mm internal dia so there is twice the amount of air going in!

Hate to piss on you're bonfire, but it doesn't work like that,

[LuckyLucky]

I realise there isn't twice, the engine can only suck up what it can through the 72mm intake but....the standard air filter is a one size fits all and therefor is probably lacking.

Without test equipment we will never know but as I had 2 filters it was a free experiment and can't be worse!

[GasMunkey]

I think joolz recently done a with and with out filter on a Chim and there was 3 or 5bhp difference?

I'm going to install a ram air style induction on mine with 102mm(4 inch) pipe work