Has anyone put a diffuser on a 914? I was playing around on photoshop earlier today and came up with this idea. It kinda keeps the stock valence shape but in diffuser form. In my case with a swapped engine, i cant use the stock valence so im looking for options to cover my exhaust.

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To many Fins for my taste but I like the direction your going. Here's what I have on my Stang.

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Its been discussed but not many have done so. A real diffuser wouldn't be a good idea in an aircooled car as it should start as far forward as possible. I plan on making one for my watercooled project after all my other projects are done and anticipate it will help quite a bit for making the rear air "clean" and helping with rear downforce.

I dont plan on putting a wing on my car and this is my thought to help give the rear downforce.

That's exactly why I wanted to experiment with it. Being rotary powered, the radiator dumps down the spare tire cut out. I was planning to route that air somehow to the beginning of the diffuser.

This was just the first prototype. Ill try less fins and see what that does

Patrick Motorsports did a real clean pan install as I recall. With the engine bay so open in our 914's - a true diffuser would need to extend from the firewall all the way back to the rear valence (or slightly beyond).

Tony

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Is there a reason that they didn't just cover the transmission and oil pan? Seems like it would have been a lot easier to drop the pan a couple inches, almost make it one piece.

I don't quite know there plan or logic but this is an aircooled car - and the front needed to be open anyway. My limited high speed experience with a 914 suggest it just isn't really necessary...if you have an effective balanced wing and splitter package.

Tony

You want the air to exit out the rear of the car as high as possible.

Just cut rectangular holes into the stock valance and cover them with a similar screen material like on the engine lid.

http://www.914world.com/bbs2/index.php?sho...p;#entry2138963

The issue with that on my car is the exhaust system exits inside of valence if I put the stock one on. The exhaust also exist high up on the opposite end. I need a custom valence and I also need to re direct the air coming out from underneath the radiator. My plan would be to run the diffuser all the way to the front of the car. It would basically be a second, lower floor pan with volume enough for the radiator to blow out through.

http://www.914world.com/bbs2/index.php?sho...197645&st=0

How fast do you guys drive that it nessesitates down force? Are we talking in excess of 130mph?

I will see between 165-170 at Road America and Road Atlanta...in lieu of a diffuser, I went with this - at 158 (the fastest I obtained at a small track on my opening weekend) I could drive with one hand. It was ridiculously stable. Any benefit obtained by adding a diffuser would be over shadowed by the potential of 700 lbs of downforce my rear wing can "theoretically" generate. It simply isn't worth the effort.

PS: The second picture is of my race cars diffuser - the "bellows" near the rear are to reduce pressure and increase the airflow speed. Again, to duplicate this in a 914 chassis would be very difficult.

Tony



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I'm thinking something like this.

Probably notice increased stability over ~100mph through sweepers.

You would most certainly notice it over 140mph in the straights. I am sure you know the back end lifts over that speed due to rear turbulence.


Cracker, I see some under trays in there, I would think that would be helping quite a lot for your rear stability.

Are you referring to my first post? If so, that an example of what PM built - not mine. My 914 has nothing - not even a deck lid right now. I was thinking of even running it at the track that way from now on since it worked so well.

...it just looks a little funny but oh well - function over form in this case.

Tony

No I thought I saw some black plastic diffusers under your car (I know which one is yours..)..

I bet the no trunk actually helps! Probably keeps the block and trani a bit cooler as well..

No under trays on mine...I am thinking of relieving/cutting out the panel between the rear trunk cross-member and the rear panel. This is quite common on 914 race cars and I could be trapping air in that pocket currently. At the speeds I should be seeing - it could make a difference. You can see (barely) in this picture that the trunk floor is still currently in place.

PS: I'm still thinking about how I can re-purpose the jack mount/bracket! LOL!

Tony

Tony, does the 6 in your rear 914-6 script mean 6 liter?!

I KNOW you KNOW better than that...THAT would be too small. This goes in today! Sorry for the hi-jack...

Paying "homage" my friend...

T



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That's 5.7 liters more than my car....