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Scoota G

Cold air intake (scoota design)

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Hello peoples

I had this idea mixing around in my head since before the Apollo Bay cruize, which was to convert a rocker/tappet cover into a cold air intake for the Z.

So this is what i had in mind.

Firstly i went to the local wreckers and picked up a Nissan rocker cover (not sure of the make and model) and then gutted all the baffles and reinforcments out of the inside.

 

Then it was down to the aluminium supplier where i got a piece of 2mm aluminium plate 700x200 to which i cut to the shape of the rocker cover and then took a template of the carbs (triple dellortos) and copyed it to the plate.

 

After an hour or so of cutting out the bolt and inlet holes it was only a matter of a good clean and then mounting the custom backing plate to the carbs along with the 2" trumpets.

 

Then the rocker cover needed to be fitted with a TFI Racing adaptor to fit the memorex flexible hose. It's a tight fit which required a fair amount of modification to the adaptor because of the lack of space.

 

Then after a clean it was just like bolting a normal rocker cover on and a short trip to the speed shop to pick up the Hose, Pod Filter and one 45 degree 76mm bend.

 

Cost was

Rocker Cover       $5

Aluminium Plate    $13

Pod Filter            $20

Memorex Hose     $32

Filter adaptor      $20

45 Degree bend   $20

 

So thats it all up $110 and about six hours work.

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Yo scootag, your the man that is so cool  8) looks really good

when are you making me one  ;D

Got to love tripples (i do)

                                        Pauly  mr240z 8)

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Taking it 4 a spin was a real trip after the Mod. The first thing u notice is the sound as it makes a noise that can only be described as Modern. A much more smoother induction sound. Secondly, the 2000-4000 RPM is stronger and it was the first time i had the car sideways through a roundabout in the dry (bear in mind that i run an auto) which was real fun.

 

The next thing that i am interested in is what a L26 is capable of in the flow/cylinder head department. If anyone has had there head (cylinder) flowbenched i would be interested to know some figures.

 

I heard that one 40mm Dellorto can flow at 370 CFM.

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That's some real pretty workmanship you got there.

 

Question, If I were to mod a standard setup (Twin SUs with standard airbox) to create a cold air intake system, Would I simply remove air filter from Airbox, attach flexible hose (Like the one in your mod) feed hose in front of Radiator and attach pod filter to the end. Or am I being naive?

 

Again Scootag your mod looks professional and serious, I envy your setup.

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I don't think that would be too much to ask as long as you can fit the 3 inch 76mm hose over the air cleaner intake it would be all good.

I took the car on the highway today and then pulled over to feel how cold the carbs were and WOW they are really ice cold and i feel that it really simulates that frosty morning air that just makes Z's run soooo nice.

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I don't think that would be too much to ask as long as you can fit the 3 inch 76mm hose over the air cleaner intake it would be all good.

 

Cheers, yeah that would be the tricky bit. Perhaps I will have a look at fabricating a joining mount.

 

Fortunately I have a spare Blue airbox to experiment with.

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That's some real pretty workmanship you got there.

 

Question, If I were to mod a standard setup (Twin SUs with standard airbox) to create a cold air intake system, Would I simply remove air filter from Airbox, attach flexible hose (Like the one in your mod) feed hose in front of Radiator and attach pod filter to the end. Or am I being naive?

 

Again Scootag your mod looks professional and serious, I envy your setup.

 

 

Or you could just run a pipe to the front if the standard air box and leave the stock air filter in place.

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Took a few more pics of the setup as i had bits off polish'in them today. It's really good to hear such positive responses, as i thought u guys would think i was a friggen idiot.

I was thinkin painting the box Red Metallic as the tube and air pod are red too.

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That's a really neat job, well done.

I had been toying with the idea of a cold air intake for mine after the guy at Mauceri Motors, who set up my Dellorto's, was pushing me to install one. He said it would make a noticeable difference. I had been thinking about all aluminum, which means bending and welding.

 

What is the clearance between the end of the trumpets and the rocker cover? Is there a recommended gap or doesn't it make much difference?

 

Warren

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What is the clearance between the end of the trumpets and the rocker cover? Is there a recommended gap or doesn't it make much difference?

 

Yer good to read about the noticable differences from Scoota. Warren, I remember reading in that Des Hammil book that when the old Ford GT40 engineers played with the location of the cover over the trumpets for one of the Lemans races. They managed to get different horse power figures from the engine when they varied the distance at which the cover was placed directly above the horns/trumpets. Maybe not so relevemt to the old L series but interesting to note either way.

 

Sulio

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I notice there is some 10mm odd holes in the aluminum backing plate Scoota. Are these a mistake? Do they let un-filtered air into the air box? Or do they allow access to adjustments screws on the carbies?

 

Looks special by the way.

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I read somewhere that when Gavin Strongman put a cold air box (CAB) on is 260z it made 3-4rkw extra on the dyno.  Same day, same dyno only dif was they put on the CAB. 

 

So there is some proven evidence that it works on the old L series.

 

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been thinking the same sort of thing for mine

 

one Question:

 

whats the weight like hanging off the dellortos?

 

Mike

 

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I notice there is some 10mm odd holes in the aluminum backing plate Scoota. Are these a mistake? Do they let un-filtered air into the air box? Or do they allow access to adjustments screws on the carbies?

 

Looks special by the way.

Those holes are for the fuel over flow just in case the float level goes all haywire.

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been thinking the same sort of thing for mine

 

one Question:

 

whats the weight like hanging off the dellortos?

 

Mike

 

 

I didn't weigh the sucker but it's very light and i'm actually wondering about the validity of the soft mounts as with all th carbs joined there's not a lot of movement in the soft mounts.

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i'm actually wondering about the validity of the soft mounts as with all th carbs joined there's not a lot of movement in the soft mounts.

I thought that the soft mounts were to stop the fuel from foaming more than anything else? They are going to be more rigid now they are connected as one after the soft mounts.

 

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Don't get of the soft mounts!!!!!

 

They help a hell of a lot with the overall reliability of your setup, in that the carbies are not shaken to death. A lot of guys using triples on Hemis in Valiants have dramas because most kits don't include the soft mounts.

 

I have had a couple of 4 cylinder L series powered cars with twin Webers and would never have run them without the softmounts. My Charger will also have the soft mounts fitted when the motor is built and the Webers go on that.

 

Another way to isolate the cold air box from the carbies to reduce weight would be to mount it to the inner guard and then sealing the trumpets to the plate using some insertion rubber. This will allow the carbies to move with the motor but still provide a resonable seal. Will also take all the weight of the cold air box off the carbies, though from what it looks like the weight shouldn't be too much for them.

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scootag : thanks for the weight issue. Been thinking of modding a jaguar xj6 Cold airbox to fit but it is quite heavy.

 

DONT GET RID OF THE SOFTMOUNTS! Yeh I meant to shout that as well. Fuel frothing issues suck a crapload with dellortos ( cant talk about webers but dellortos work really well with softmounts i found out ! ).  Apparently you can also shake the needles to crap and back as well as hurt the delicate fuel float parts with shaking. I learnt this the hard way.

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Just thought i would put a couple more photos of the finished air box. Did it Metallic Red and got some Black Hex key bolts to tidy it up.

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I notice there is some 10mm odd holes in the aluminum backing plate Scoota. Are these a mistake? Do they let un-filtered air into the air box? Or do they allow access to adjustments screws on the carbies?

 

Looks special by the way.

 

Those holes are also on the carb body and from memory are just an atmospheric vent. Its not recommended to block them off.

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Kinda diggin up a year old thread but i modified the Cold Air Box. The filler cap, logo, and the other stuff have been smoothed. Next one (seeing this was the Prototype) will be the other way around so all the lumps are on the bottom.

post-762-144023551741_thumb.jpg

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