Anyone running open trumpets / velocity stacks?

Albrecht

Well-Known Forum User
Running without a filter is tempting because it's easy, sounds good (not for quiet trackdays though) and looks uncluttered - however would you be happy to buy a secondhand expensive modern car that the PO was running without a filter? I know that's a hypothetical situation but what would it tell you about the owner?

Apples vs oranges there I'd say. I wouldn't buy a "secondhand expensive modern car" without a catalytic converter either.

My daily use car specs shopping list would also include a good audio system with DAB, up to date Satnav, heated seats, parking assist with at least a rear camera, a towbar and *at least* full Euro 6 compliance. NONE of which I expect to have - let alone WANT - on any of my 50-odd year old, limited highday and holiday use-only fun cars.

Totally different scenarios.
 

Rob Gaskin

Treasurer
Staff member
Site Administrator
Since when have heated seats been relevant when we are talking about grit entering an engine? Can you imagine when buying a K&N filter - the seller asking what radio or seats you have?

You can run without filters Alan - your choice.
 

Albrecht

Well-Known Forum User
Since when have heated seats been relevant when we are talking about grit entering an engine?

Since:

...would you be happy to buy a secondhand expensive modern car that the PO was running without a filter?

I'm pointing out that they are two totally different scenarios. Of course I wouldn't buy - or run - a daily driver without a filter.

I'm fully aware of the 'risks' of running open induction, and to be honest I find being called "stupid" is one of the most negative trade-offs (as is having assorted knuckledraggers stuff garbage into them), but I don't care.

Anecdote: An old friend of mine fitted individual air filters to the Dell'Ortos on his Lancia Fulvia HF as he was convinced he was a few days away from killing his engine by running open carbs. A couple of days later the engine ingested one of the screws holding the air filters together, and dropped a valve head. Engine rebuild time.
 

Albrecht

Well-Known Forum User
To add balance, here's a previous effort of mine. An 'R-Factory' S20 induction box, turned upside down and fitted to my triple-Mikuni PHH'ed L24.

The 'R-Factory' S20 induction box has an alloy backing/mounting plate with integral full-radius trumpets. The cover has a fine mesh screen at the open end. I modified it with over-centre clips and some Tsuchiya OEM air filter box orange paint:

Sensible.JPG
 
To add balance, here's a previous effort of mine. An 'R-Factory' S20 induction box, turned upside down and fitted to my triple-Mikuni PHH'ed L24.

The 'R-Factory' S20 induction box has an alloy backing/mounting plate with integral full-radius trumpets. The cover has a fine mesh screen at the open end. I modified it with over-centre clips and some Tsuchiya OEM air filter box orange paint:

View attachment 39302

I think thats the most visually pleasing airbox made. you can see how the one sold in the UK has 're-created' it, but loosing some of the visuals.
 

Albrecht

Well-Known Forum User
I think thats the most visually pleasing airbox made. you can see how the one sold in the UK has 're-created' it, but loosing some of the visuals.

Here's what it looked like without the cover. The mounting plate has a channel with a rubber gasket which the outer covers slots into:

Open.jpg
 

AliK

Vehicle Dating Officer
Staff member
Club Member
That is a thing of beauty - the air box too!! [emoji1787][emoji12]

Seriously though that is the beat airbox I’ve seen.

I think Rob makes a great point - all other things aside like heated seats - it would make me think twice about buying. Having said that, a daily driver is subjected to many more miles and harsher conditions than classics being driven 1000 miles a year and in good weather.

The thing that makes me twice about open trumpets and their effects on engine wear is the fine sand / dust I seem to find in the Audi filter housings every time I service them. The flies I’m sure get burnt up and spat out but the harder stuff?
 

peter_s

Club Member
Since:



... and to be honest I find being called "stupid" is one of the most negative trade-offs (as is having assorted knuckledraggers stuff garbage into them), but I don't care.
You are not stupid because you do something stupid or have a stupid idea.

I'm well aware that there are trade offs and a rational around most decisions. When it comes to this issue, I'd rather listen to the advice I'm given by some really experienced people, rather than having to learn a costly mistake myself.


Anecdote: An old friend of mine fitted individual air filters to the Dell'Ortos on his Lancia Fulvia HF as he was convinced he was a few days away from killing his engine by running open carbs. A couple of days later the engine ingested one of the screws holding the air filters together, and dropped a valve head. Engine rebuild time.
Touché!
That's actually really funny. :D


I like that airbox you mounted! I'm actually looking at something very similar from Reverie
 

johnymd

Club Member
I’ll be running these but creating an open topped shield around it a funnel filtered air into it. Not perfect but I just can’t cover these curved trumpets.
 

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