So the good news is that I'm down to this level of detail with the build (car is up and running).

Can I ask for ideas and recommendations for those running carbs that will clear the engine lid?

Any specific vendor solutions I should be thinking about?

Thanks!

On my factory 914/6, I ran regular K&N filters, with no clearance problems.

Good morning/afternoon. Thanks for the response.

Do I just need to track down the pretty common rain hat set up?

The only issue would be if you had 4 cylinder rain tray …..then answer is remove it.

Thanks for the response. Raintray has been removed so I should have some clearance.

I'm running Weber 40's on PMO intake manifolds with Rain hats on my 3.0 and no clearance problems at all.
Hope this helps!


Click to view attachment

Same here. No.raintray with pmo/webers should work fine. I wonder how tall.stack.mfi would fare??

I ran the K&N watershields on the 2.2 MFI Mag stacks with no clearance issues. Well, there were no clearance issues with the engine lid. I had to trim one edge of the watershield to clear the MFI pump lines.

Mine with 40 PMO's and there filters, rain tray delete with double GT engine lid.Click to view attachment

Webers with rain hats and GT lid.

Thanks, super helpful and great to see all the builds.

I did some basic clearances to make it work. I absolutely hate the k&n filters they filter terribly and the noise is to much for me anywaysClick to view attachment

What Manifolds do you have ?? stock / tall ??

Anything that allows any possibility of water getting in the carb throats is risky. More than one Porsche engine has hydro locked from rain water intrusion.

I agree. The intake manifolds are important.
My rainshields fit fine with stock 68mm Porsche manifolds.
with 82mm PMO manifolds the pass. side had interference.
The front engine mount on conversion cars is also an important part of the issue.

Yes absolutely 100%true

My /6 build may be coming together this year (fingers crossed) and I will be looking to use this setup. factory I believe

I know two people that have had that happen with the rain hats pictured above.

If you notice mine is a converted 911 unit but Very happy with how it looks

I have had several different engines with factory air cleaners in my -6 conversion. With MFI everything fit fine with T-bars removed. Webers with tall manifolds required a little massaging like MB911. Standard height manifolds with Zeniths fit fine. I have had engine fill with water after being outside in heavy rain with stock air cleaners. I have Rain hats (with small mods) that use paper filters to test soon.

john

ditched my K&Ns after filtration issues and also I got tired of the noise ,I swear there is somewhat less fuel smell also.
Didn't use the stock paper filter as I picked up a quality BMC reusable filter for a great price , had to move one spring clip as it fouled the rear bulkhead ,a fiddley job but got it to work.
I guess the real downside is the cost of the stock unit...prices have gone mad and the plastic ones are often melted due to back fires,mine was a bit cooked on one side but managed to repair it.

K&N filters = cam lobe tip reducers...

[Would you please elaborate


quote name='live free & drive' date='May 11 2023, 01:00 PM' post='3077197']
K&N filters = cam lobe tip reducers...
[/quote]

[quote name='sixaddict' date='May 11 2023, 03:40 PM' post='3077224']
[Would you please elaborate


quote name='live free & drive' date='May 11 2023, 01:00 PM' post='3077197']
K&N filters = cam lobe tip reducers...
[/quote]
[/quote]


They don’t filter well so lots of dirt makes it way into the engine. I did studies on this back in the day when I was building aircraft engines for a company

Well the of all the places in an engine the part of the cam lobe profile furthest from the center axis in a high lift performance grind will see the highest overall contact pressure.

If you run an engine with a high cam lift and use K&N filters and the same engine with paper filters you will notice a very measurable lift difference after running less than a 1000 miles between the two scenarios - In my case with a 2 liter Alfa engine running .660" lift cams and an extremely ported head; the cams lost ~.080" lift with K&N filters. I replaced the cams, used paper filters and the same oil type - no more cam tip lift reduction (this was in the early '80's using Kendal GTX 20/50).

I had the same problem in the late seventies with the piston rings in my dirt bikes after I got one of the "new" hp adding K&N filters. I did not cop on at that point why I kept having to replace the rings as the power faded quickly...

Cost of a real one is presumed to be both worth the number of kidneys it will take.

I bet it does help with noise.

@mb911 - how did you modify it?

Looks very tidy.

Shortened the snorkel then a indent next to the latch

Ah, so height wasn’t an issue then.

Thanks

@MB911 Ben that looks terrific. I know the difference the stock filter housing makes when it comes to rain-hats and intake noise. Well worth it and it looks pretty stock too. Well done.

I always heard this: K&N Rockstoppers.

Because everything smaller than a rock gets through.

There are always paper filters for IDF carbs. I'm not sure they have much more surface area then the K&N filters though. Which means that if they are filtering more, they are letting less airflow through.

Or you can go the other way and spend a bunch of money on ITG foam filters. Still a 10 micron oiled filter. Desert people seem to really like them.

Zach

So much for liking the “look”.
Still learning!……unfortunately…

I have a stock six intake air filter housing on my 2.7 with Webers, and enjoy the ease of removal and replacement as well as the reduced intake noise. I did not need to modify it to fit, but reduced the snorkel length to increase it's intake diameter efficiency (theoretically anyway!).

It all depends on height of the engine mount.

Oops replied too soon. Mine still rubs in a few spots and that’s because 1 of two things. Possibly 3 . I use a stock manifold which I assume is short intakes. The engine mount is stock height to a factory six but might put the engine up too high. The other thing is could the hinges be a bit lower on mine than others? Absolutely. I need to clearance the engine lid in a few spots but no waaaaay in hell will I run K&N s again if I can

so true,I was concerned as after my engine went in I was test driving on very dusty roads,bought my K&Ns used but in good condition ,cleaned the filters and fitted them after a few drives and checked them to find they were very dirty even on the inside.
Solvent washed them with K&N product and was amazed @ what came out,I had a set of Outerwears and fitted them as a further test and found the filters were now clean on the inside...told me what I already knew .
Click to view attachment
Click to view attachment

I used ITGs for a while - look great and suspect they filter better than K&N but have not checked for data on that. They are however unbelievably loud! Also no provision for water shielding on typical Weber applications but that was not an issue for me.

Currently I'm running flat-top K&Ns (car never gets wet). I have some watershields in storage but they will not fit without a little modding. IIRC I do have PMO tall manifolds.

I run ITG’s and ear plugs on the racecar

But no noise restrictions out here
They don’t last real long
The foam starts to degrade …. Probably from the fuel vapors after 3? Or 4 years. I’m on my 2nd set