TWM Stack Air filter

[Snakebit]

Any pictures?? I purchased a set of slip on filters that look like they cut holes in black pantihose and sewed elastic around the edges. I have not tried them yet. I,m worried they might get sucked in the carb.

[fastrods]

I hate to differ with you 800hp.
I am using a hexagonal screen which gives over 80% percent flow.
This is also the same screen and filters that Inglese uses for his weber setups.
At any rate, they work just fine on my engine.
If anyone out there is interested, let me know.
Thanks!

[aldersonjames20]

Originally Posted by fastrods

I hate to differ with you 800hp.
I am using a hexagonal screen which gives over 80% percent flow.
This is also the same screen and filters that Inglese uses for his weber setups.
At any rate, they work just fine on my engine.
If anyone out there is interested, let me know.
Thanks!

Everyone I talked to about the screens, including Inglese, told me that these will work on the street for modest driving, but that if you plan on winding out the engine on a track etc, these will not work. They do not have the surface area required to feed the air hungry monsters we use for engines. Again, they are fine for driving around and getting on it once and a while, but the reason the ugly K&N, as well as every other viable filter, have the design they do is surface area to suck air through.

James

[fastrods]

I will take a 20% reduction in airflow with my filters over a box covering my expensive stacks.
I believe that was the original question, what to do instead of a box.
The "surface area" is the same regardless of a box over the stacks or a filter over each stack - limited by the actual stack's diameter. The box still trickles down to the stacks!
I will not argue that a K&N may not flow better, I do not know that and neither do you unless you flow test both.
I do think a box with a K&N will reduce flow at least 20%, if not, I would question the efficiency of their filter, which a lot of people do.
Some of us want to show their stacks when they open their hoods and I am one of them.
James, I can appreciate your induction setup and what went into it's design - I just chose to fabricate something different.

[btsai]

Check out this solution on a coupe. The workmanship was beautiful.

The reddish areas were rubber that was flexible and allowed a bit of overlap (about 1/4") for "wiggle room" when resting on top of the velocity stacks. The long tubes lead to twin, cone-shaped K&N filters.

[traindriver]

Snakebit,

I have tried the slip on 'pantyhose' type covers...

On my 351 they do depress in in the middle when you gun the throttle...No fear of ingestion though. The bad news...at 4500 rpm it starts running real fat....very noticable. I used to have a racing go-kart with a huge stack on it, we literally used "leggs" pantyhose and electrical tape..no effect..I might try that as an experiment when my wife isn't looking.

Chuck

[lamaluv]

I finally got to try the different filters for my fuel injection on the dyno. The chassis dyno was not working properly so I was only able to do comparitive runs to see how much difference there was in the two filters.


To my surprise there was only 5.2 HP difference. The tuner basically said that for all practicality they were both the same. This did not seem correct to me as with a carb you see a difference in HP by changing or eliminating the filters.




I called Bob Ream at Imagine Injection to see what the factory had found the difference to be. He confirmed my dyno results by saying their tests showed no difference in HP between either types of filters or no filters at all. He thinks that because the FI is controlled by the computer that is continually compensating for changes in air, fuel, temp, ect you don't see the differences in HP you see with a carb.

If there is no difference I just need to decide which to use. The small individual filters sure show off the injectors. I'm thinking thats the way to go, what do others think?

Dick

[Rwillia4]

If this is the case fro HP, I agree the small ones look better. Do they filter as well?

[lamaluv]

The small ones have a foam element between two screens and will keep out small rocks but seems prone to getting holes in the foam if you get a back fire through the air valves. The big filters are more of a paper type element and probably do a better job of cleaning the air.

Dick

[bobcowan]

The dyno doesn't tell the whole story - as is usually the case.

At speed (100+) there's certainly a differance between the open stacks and the oval filters. I'v tried it. I get about 8mph more on the front stretch with the open stacks, compared to the oval filters. I have not tried it with just the "tea strainers". Maybe I'll try that the next time out.

[Peo]

I have a TWM system on my 384 Stroked Clevland using their one piece F1 type filter that covers all of the trumpets. It has special foam that does not ignite but is very expensive to replace, I had to send to UK then back to Australia.The system breathes very well, and on the Dyno did not make any difference with restriction when the filter was removed or when it was left on.It is very easy to remove, it has 6 snap on screws attached to a base plate. The only disadvantage is that the trumpets cannot be seen unless the filter is removed.Motec is used with 500 rear wheel HP.I love it!

[Terry Brown]

I started with the RamFlos which work well but are not easily removed. I followed up with the K&Ns which are made for FI stacks but work well on the 48IDAs. They slip over the stack with a rubber sleeve (grommet) and are easily removed by pulling off. They are made specifically for Roush by K&N.

[Rick Parker]

When using either of these is the auxilliary venturi (tall tube in center of velocity stack) left untouched?

[Terry Brown]

Rick:

In both cases the center tube was left untouched. In the second case (K&Ns) I had to go to a 1 1/2" velocity stack to get the necessary hood clearance (older style SPF). This would not be necessary on cars after about number 1200 (approx I believe).

Terry

[Rick Parker]

Where are these Air filters purchased? Approx $$

Thanks

[Terry Brown]

Rick:

I got the K&Ns from Hillbank Motors in southern Ca. (Frank: http://www.hillbankusa.com/ 1-949-900-1966. I save all my receipts but, of course, I can't find these - about $45 ea I think.

I passed the Ramflows to Brent Mills. If he still has them he may make you a deal. They are $65 each new.

http://www.racetep.com/ramflolynx.html

Good luck!!

[J Persons]

Below is a picture of the Ram-flo filters I currently have. They may work with your stacks but do not "slip-on." Takes a little time to remove or replace.

I had a pair of those ram flow filters on a Lotus Cortina with 40 DCOE's and couldn't get enough air through them to run at anything above idle! Switched to some modified K&N filters and it ran great.
This is probably your best bet for an affordable and efficient air filter. Scroll down to the Weber section for the applications. Available for both the IDA and IDF.
http://www.knfilters.com/Racing/customcarb.htm

[James Baldwin]

if anyone is preparing to dyno a 427 with 58mm TWM setup, I have an aluminum air plenum I would ike to test. I never mounted it on the car I just sold because the new owner wanted the exposed horns.

let me know if you are willing to do it. thanks

baldwin007@aol.com