Eight Stack Air Filters

I have a Borla EFI eight stack with 50mm throttle bodies. I have been on a waiting list trying to purchase the K&N filters with no production or delivery date. The price for all eight filters is $357. I just bought these from Amazon and they fit great and look good. They also have different diameters and the cost was $100 for all eight. I thought I pass this information since many are waiting for the K&Ns. I am in no way a vendor or sponsor and just wanted others to know.
 

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Neil

Supporter
I have a Borla EFI eight stack with 50mm throttle bodies. I have been on a waiting list trying to purchase the K&N filters with no production or delivery date. The price for all eight filters is $357. I just bought these from Amazon and they fit great and look good. They also have different diameters and the cost was $100 for all eight. I thought I pass this information since many are waiting for the K&Ns. I am in no way a vendor or sponsor and just wanted others to know.
Their small size looks like they will be rather restrictive.
 

Brian Kissel

Staff member
Admin
Lifetime Supporter
I’d much rather have a little restriction than stones and sand in my engine. If he was running flat out all the time I would be more concerned.
The efi should self correct any air fuel demands due to the filters.

Regards Brian
 

Jim Albright

Supporter
Check out the Filterwear socks for 8 stack injection as an option - various sizes from 3" to 9" available, hydrophobic monofilamet polyester, keeps sand and particles down to .005 out and a whole set is around $100.
 
Filtersocks;
 

Neil

Supporter
I’d much rather have a little restriction than stones and sand in my engine. If he was running flat out all the time I would be more concerned.
The efi should self correct any air fuel demands due to the filters.

Regards Brian
It should not be a question of restrictive filters or no filters at all. Instead, a larger, less restrictive air filter would be a better choice. An EFI system could only compensate to maintain a correct air/fuel ratio, not for the reduction in power due to low air flow.
 
I ran my car with screens, switched to the Amazon filters and can’t tell the difference. I don’t track my car and maybe there could be a difference.
 
Rouch sources those from K&N but currently unavailable and supposedly on order. There is a long waiting list and no delivery date.
 
Hi, small filters of that nature (in the top post) can really kill performance. You could lose 30-50hp on a 400hp engine, and get something that looks cool but would get smoked by a 4 barrel on a dual plane intake. The ideal filter flow requirement for one cylinder is not that far below what the whole engine requires. One approach is to use two of the filter types (ITG, Pipercross, etc) that normally get used on a 4 cylinder engine with twin side-drafts. They are available with blank backing plates that can be water-jet cut to suit, with the backing plate sandwiched under the trumpets, or fixed to the underside of the return lip on the trumpets.

Cheers, Andrew

20211210_143554.jpg
 

Ian Anderson

Lifetime Supporter
So how about puttin in a Turkey pan and sealing it to the top of the rear clip.
seal up the front of the rear clip with a second window.

then add filter material to the 2 inlets ..No fuel near the filter material

See post 962

Ian
 

Bill Kearley

Supporter
I haven't read all the thread but you can buy the K&N filters from Borla. K&N wont sell them to jo blow so Borla can gouge people who want them like me.
 
This is what ITG say about fire hazard (https://www.itgairfilters.com/faq/):

``Are the filters flame proof?

All of the Megaflow, JC70, JC71 and trumpet socks contain a self extinguishing layer within the foam, which prevent the filter setting alight from engine spit back.

If there is a particular concern that an engine is susceptible to fuel stand-off where a fine mist of fuel hovers over the ram pipes at certain points in the rev range and can be ignited if the engine misfires or spits back a flame, a stainless steel flame trap layer can be added to the inside of domed filters and the underside of panel filters to prevent this happening. This is also recommended for high value classic cars running carburettors or throttle bodies where the risk of an under bonnet fire far outweighs the extra cost involved."

I've had an under-the-hood fire from back firing DCOE45 Webers and ITG filters (no flame trap layer). Flame trap layers must be installed during fabrication and the filters are special order (at ~ GBP 80.- extra cost). Seems backfiring with EFI systems is less common but flame trap layers should be a worthy investment.

Also, I would recommend one or two ``global" air filters rater than individual socks. The latter may become quite restrictive at high rpm (learned this a long time ago with a 1 liter SCA engine :))
 
I had a hot start heat soak spitting carb on a tripple DCNF carb't V6 once that inmidiatly went into flames with ITG foam filter. ITG foam filter was soaked in fuel fumes that only needed to be ignited.
Since then I went to K&N filters and never had those issues again.
 
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