Stromberg type airbox?

[Hal]

Does anyone have a Stromberg airbox for a 1969 + for sale? Also the above radiator closure panel which the intake tube to the airbox goes into?

Seen here....



but missing here...



Also, do the air filters fit inside the airbox? Or does the car have a filter on the end of the tube, as in this one I prepared earlier....

[gjz30075]

Hi Hal,
It's best to post your wanted part in the Classified section
elan-wanted-f4/

There are folks who simply peruse the classified and not the technical forums.

Greg Z

[Hal]

Thanks....I hadn't seen that section.

I'm not 100% in need of one just yet as I haven't bought the car yet! Simply wondering about availability.

[ericbushby]

Hi Hal,
As I understand it, it is better to have the filter in front of the radiator to draw in cooler and therefore denser air to the carbs. and giving more power. This also cools the carbs themselves.
How significant this is I don`t know but cars always seemed to be faster at night when I was a kid and driving on carbs. I don`t drive like that now!!
It looks as if there is enough room for a 3 1/2" tube past the rad if you relocate the coolant bottle.
You just have to make up a suitable filler plate.
Eric in Burnley
1967 S3SE DHC ( Still raining)

[cal44]

Hal,

The filter goes inside the canister in the nose section.

http://www.ebay.com/itm/USED-VINTAGE-LO ... f5&vxp=mtr

Mike

[Hal]

Thanks, guys, that's excellent design. I'd like to see how it fits in front of the rad though...does anyone have a photo?

It could of course have been made lighter in GRP but who am I to argue the toss with Lotus' accountants...

This is exactly why I designed the air induction system for the Caterham SV, which has a 220bhp full race engine. I also fitted some unequal length trumpets we made....70mm and 130mm. The idea being that tests have shown a significant improvement in both top-end power (the short trumpets) and mid range torque (the long ones) compared to an engine fitted with the stock 50mm stacks, or 4 70s or 130s, which would give either torque or top end..

I had to make a more voluminous airbox than the Bernard Scouse unit used on most Caterhams, and because mine is the wide bodied SV, I had the extra underbonnet space to play with.

I still haven't had time to put the oil in, or finish the exhaust, on this car, but it should be very soon.

The cold-air induction system on this car is the prototype, (hence its rough appearance...) but I'm supposed to be fitting the Chapman chassis car of the ex president of the UK Lotus Seven club's car with one...using it as the mule, 'soon'...he lives in France not too far away.



I'll make moulds from the standard chassis version, and sell replicas. It's not worth doing for the SV, as most of them run Jenveys, if they have the 'K' series engines, while this car is running Titan Phantom DTHTBs which are at a quite different angle, so the airbox for this car won't fit one with Jenveys. (Annoyingly )

[cal44]

Hal,

There is a small L bracket that attaches to the filter housing then through a hole in the fiberglass. The two air horns face backward so your hose then can run straight in. If they faced forward, water would go into the intake filter. There will be a hole already there in the floor of the fiberglass, in front of the radiator. I don't have a picture as the P.O sold the parts before I got my car. I have purchased some to restore as my car is going back to stock.........to get away from the those hideous K&N filter housings.........ugly as sin and look cheap.

[Hal]

Thanks..... I must say I can't visualise how the thing fits.....where are the outer open ends of the horns? Still in front of the radiator?

I wish there was a PDF file showing this .....

The biggest problem with the underbonnet pancake filters (apart from looks!) is they are breathing hot air, which is less dense, so will give less power. This is what I find strange about so many Sevens, they have a foam filter, at the back of the engine bay, where the air is guaranteed to be hottest.

Of course some have the pancake filters sticking out of a hole in the bonnet.

I'm glad the Lotus designers thought about this....

[oldelanman]

The biggest problem with the underbonnet pancake filters (apart from looks!) is they are breathing hot air, which is less dense, so will give less power. This is what I find strange about so many Sevens, they have a foam filter, at the back of the engine bay, where the air is guaranteed to be hottest.

I'm glad the Lotus designers thought about this....

The downside with Strombergs is that the rear carb has a tendency to ice up in cold damp conditions and that's not helped by the intake being right in the nose. I used to blank off the grille in winter to try to overcome this problem but it wasn't much help.

[stugilmour]

Hal, take a look at Ray's site at rdent.com.

Under Plus 2 parts he has a picture of a replacement filter housing he sells.

If you click on the Plus 2 parts manual you can see a pdf of the induction system that sort of shows how the thing is mounted. He does not show the Stromberg air box, but I believe the stock setup is similar to the Weber / Delorto air box except there would be only two openings in the backing plate.

I used the air filter setup Ray shows under the Europa parts, which is an oval foam type deal that covers both carb inlets. He supplied the backing plate undrilled as my car is converted to SU's and we were not sure of differences to Stromberg's. This doesn't sound like what you are after as induction air is from hot area under bonnet. Only issue I had is I had to install the filter element upside down and be careful to drill the holes low enough to prevent fouling the bonnet on the Plus 2, which is very close to the valve cover and carbs. I also had to oval out the engine mounts to gain clearance, but this can be a common issue with frame replacement.

Have seen the stock Stromberg air box come up on eBay UK only a couple of times on the last few years, so not that common.

Here is one currently listed:

http://www.ebay.co.uk/itm/LOTUS-ELAN-ZE ... 3a7b762828

HTH

[Hal]

The biggest problem with the underbonnet pancake filters (apart from looks!) is they are breathing hot air, which is less dense, so will give less power. This is what I find strange about so many Sevens, they have a foam filter, at the back of the engine bay, where the air is guaranteed to be hottest.

I'm glad the Lotus designers thought about this....

The downside with Strombergs is that the rear carb has a tendency to ice up in cold damp conditions and that's not helped by the intake being right in the nose. I used to blank off the grille in winter to try to overcome this problem but it wasn't much help.

Hmmmm. I suppose in winter a pair of pancake filters could be fitted....On some cars the horn of the filter box could be turned towards the exhaust manifold in winter to prevent chilled carbs.

[Robbie693]

Does this help?

[Hal]

Does this help?

In a word, yes!
Thanks.

I didn't realise quite how much space there is forward of the radiator.

[Robbie693]

Hi Hal,

There is a fair bit of room but there are a few other things located in the nose too; the actuating pod(s) for the headlights, horns and in my case the solenoid valve for the lights.

In the later cars the air cleaner/filter housing was turned on it's side so that the hose entered the housing from the right rather than the top, presumably to clean up the airflow to the radiator. Important with the smaller rad of the later cars.

Cheers

Robbie