home made spiral air intake

[junaid786]

Hey guys

Im so thrilled with the result I have gotten with my home made intake that I had to post this up here.

Firstly, its 100mm inlet that’s twice the size of the stock 50mm. I heat shielded the inlet with ssn coupling.

I used a heater hose for the crankcase breather system. Drilled a small hole in for the vacuum line of the fuel pressure regulator.

I draped a piece of cloth folded twice over the airflow meter and the clamp of the pvc flex pipe holds it in place

Ok, so there has been much debate on the benefit of those spiral intake jobbies.

Well I know for a fact that spiral air intake works coz my previous Mercedes 190e had a spiral shaped intake tract.

Those aftermarket ones have been known to be a restriction. So I cured that by not placing it in the intake path but rather giving it a separate intake path.

So the total intake are is closer to 150mm. and the spiral effect works like a small supercharger( at highway speeds) I have also noticed that I require much less foot on the throttle to get the car up to speed and to maintain speeds. This was all great when the engine was cold and the mixture was rich.

But with the engine properly warmed up, the car was pinging like crazy from a lean mixture. 1/8 turn on the fuel distributor and still going lean at high rpm. Turned it another 1/8 turn and have yet to test it.

Parts used
-   110mm flex pipe( pvc plumbing type)
-   Black duct tape
-   Simota spiral intake
-   Ssn coupling with 2 clamps(127mm)
-   Heater hose
-   Multi purpose cloth

The entire job cost me about R 300( $42)

[nutz4benz]

Where is the vacuum line for the fuel pressure regulator plumbed in at?

[junaid786]

i plumbed it into the crankcase breather. wrong place? i had it in the intake but it seemed to be leaning out the mixture with more vacuum.

[nutz4benz]

Yeah, it should be plumbed near the venturi of the airflow sensor.

[junaid786]

ok, help me understand this... it increases fuel pressure with vacuum? and decreases fuel pressure with positive pressure?

[nutz4benz]

As air is being sucked into the venturi, the line that goes to the FPR activates.

My set up, yellow line for the FPR. Without that line connected, it's gutless at high rpm.

[junaid786]

great info

thank you so much for that

[nutz4benz]

My only other concern is where is the air filter? If you could find an R107 280SL rotting away somewhere, you could use the intake off of that and utilize that tornado thingy still and get way better flow. That cloth bit over the plate will clogg in no time, and heaven forbid if it gets sucked into the intake....eek!

[junaid786]

Yeah, its ghetto i know.

its on pretty tight so it aint going nowhere. and i plan on changing it often. every few months or so. i like to clean the airflow plate with carb cleaner every now and then so i will change it then.

my stepdad has the r107 280sl. but he warned me not to steal parts off his car. hehehe

[junaid786]

by the way, thanks for the great website.


such an awesome car. probably one of the greatest cars ever built. nice that somebody dedicated a website to it.