Air Cleaners

[d240zx2]

Getting ready for a track day on the 15th, so I thought I'd re-sync the 40mm Mikunis. To do that, I have to pull the K&N filter assemblies and bolt on the air horns, as the Uni-Syn won't mate up to the backing plate for the K&N filter assembly.

After getting the sync done, I decided to take the old gal out for a bit of a romp before reinstalling the cleaned filters. Holy Moses! Did somebody put a 2.8 in the car today? The difference between filtered air and non-filtered air is phenomenal! That's all I can say! The sync wasn't off all that much, so I can only attribute the increase in performance to the lack of filtration/horns.

Now to my question: Given the increase in performance which I'd like to retain for daily use, can someone point me in the direction to obtain a filtration system that will accomplish this?

All recommendations and suggestions are welcome!

Thanks in advance.

[Zforce]

In looking at your sig you say first and third owner of HLS30-00721, I think you are the second owner unless the second guy sold it to someone else before you right.

I got a stock air filter housing off ebay for 20.00 with some holes drilled in the top of the cover, since it already had holes in it I decided to drill some more and I did notice a big difference in performance. As long as the air has to go through a medium no matter what it is it's a restriction. If there was enough room under the hood you could stack another filter on top to get more surface area, that might help.

[d240zx2]

That's my story and I'm stickin' to it.;-) I bought it new (1), sold it (2), bought it back (3). 1, 2, 3. I was a different person in 1977 than I am today.

With Mukunis (and Webers), space is a bit limited on the left side of the engine bay. The horns are 3" in length which leaves about that much working space between them and the inner fender well. With the coil in the stock location, the first carb is limited even more as to air filter locations....

I've seen pics of a "box" type assembly that bolts to the carbs, the air filter hanging out on the front end via a tube you'd normally associated with a cold air intake for FI or turbo. Aesthetically, that config doesn't quite do it for me, but I know it works.

I guess what I want is an insert for the horns that would allow a filtration effect equivalent to a K&N system, but would be removable and/or replaceable.

[70 Cam Guy]

You could have felt the difference between running air horns and not running them. On SUs, Mikunis, Webers, etc, you should really run the air horns if there's space.

Some of my friends running ITB's on their Toyota's use foam Motorcycle filters secured over the air horns. I would always run a filter on a street car. There is just too much dust and grit that can wear your internals

If this link works, UNI makes foam pods in a number of sizes. Redline also has similar filters (Redline filters in the pic). You can browse your local Cycle Gear or motorcycle dealer to see what they have on the shelf

http://www.denniskirk.com/jsp/tpl/cmn/prodlist.jsp?attributes=48:3035&category=11102&brandId=806&_requestid=592534

Edited April 30, 2010 by 70 Cam Guy

[ChrisZ]

Frank, I want to get this straight, are you not running horns / stacks, when you have your filter on ?, what size of filters do you have ?

Chris

[d240zx2]

Thanks for the link, Andy. I'll check it out...

Chris, no, my K&Ns are too shallow to allow for the use of horns, so I run sans horns. Size? The assembly measures 1 7/8" thick, are 7" long and 4 1/2" wide.

[Zedyone_kenobi]

IF you run the K&N without horns, then I would bet you a shiny OEM waterpump that adding the horns gave you the HP, not the lack of filter Frank.

I think you really need to look at 70 Cam Guy's picture as your solution. The Cda of an orifice (in your case the knife edge of your carbs) drastically influences the way air flows through it Just rounding off the edges a little makes a huge difference in the discharge coefficient, thus upping your air flow and HP respectively. I would find a way to run a filter AND your air horns, and you will get that wonderful feel ALL the time.

[cygnusx1]

You need to run some 2"-3" velocity stacks inside of a 4.25" Deep K&N filter. As a second choice, run longer horns with socks over them. No, not gym socks!

Edited April 30, 2010 by cygnusx1

[ChrisZ]

I agree about the two post above, no air horn's is a no go, you will need one inch clearance, from the mouth of the air horn to lid of filter, can't you just swap your filters and keep your base and lid.

Some say you will loose up to 20% of power with no air horns, think about it.

Here is a little reading http://www.profblairandassociates.com/pdfs/RET_Bellmouth_Sept.pdf

Today i made a sample of a air horn, i think i got it just about right, i still need to mill the base and make 5 more, full radius, mouth is 50 mil, tapering in to 40 mil in the first 30 mil, total length is 60 mil.

It's not that i want to brag about it, but i'm pretty dang pleased about the result.

Chris

[cygnusx1]

Very crafty! General consensus is, use the stacks! You can buy K&N filters in a deeper size and use a longer screw or tabs to hold the covers in place.

[spitz17]

Can't you just purchase the K&N deep filters from MSA...

I think I'm lost. .

[spitz17]

These: http://www.thezstore.com/page/TZS/PROD/PFFC10/11-4016

Dave, your avatar makes me dizzy hahah