30 replies to this topic

[Parptoot]

Help and sage advice needed.

I currently have a pair of old an gnarley HS2s and the aforementioned airbox. The carbs are in dire need of cleaning and a rebuild while the engine is out, however, Ive been advised that the plans we have for the engine would be better suited to a pair of HS4s.

I'd like to keep the old airbox. Is this possible?
Can the old air box fit onto the HS4 carbs?

Thanks.

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[Dusky]

You ll have to cut it .

[Parptoot]

Just open the two holes up a bit?

I presume I can't use the original elbows then
I'll need to get two similar for the HS4s, does such a thing exist?

[Parptoot]

"I'll need to get two similar for the HS4s, does such a thing exist?"
lazy lazy lazy

Found them!

[Dusky]

Just open the two holes up a bit?

I presume I can't use the original elbows then
I'll need to get two similar for the HS4s, does such a thing exist?

You ll need to cut the front as well. The dashpots hit the box.

[Spider]

Given how hard it is to come by the Air Filter Boxes, I wouldn't be rushing ion to modifying the one you have.

 

Also, on a recent thread on another forum, a fellow had his new engine run up on an engine dyno (bone standard Cooper S Engine) and they found these Air Filter Boxes lost 9 HP at the flywheel.

 

Respectfully, it must be a highly tuned engine that's proposed to need twin HS4's. Twin HS2's are good up to about 110 HP. 

[richmondclassicsnorthwales]

Leave the box as it is, don't cut it !

 

As Moke rightly says, those boxes are hard to come by     use something else   and keep the box

[Parptoot]

WOW! I've just seen some on Ebay. They're worth a fair bit!! I think it's going to be sold and I'll use the funds to make a bespoke airbox for the HS4s.

[surfblue]

Given how hard it is to come by the Air Filter Boxes, I wouldn't be rushing ion to modifying the one you have.

 

Also, on a recent thread on another forum, a fellow had his new engine run up on an engine dyno (bone standard Cooper S Engine) and they found these Air Filter Boxes lost 9 HP at the flywheel.

 

Respectfully, it must be a highly tuned engine that's proposed to need twin HS4's. Twin HS2's are good up to about 110 HP. 

Twin Hs4s does seem excessive on a mini. What spec of engine are you going to be running?

[Parptoot]

Given how hard it is to come by the Air Filter Boxes, I wouldn't be rushing ion to modifying the one you have.
 
Also, on a recent thread on another forum, a fellow had his new engine run up on an engine dyno (bone standard Cooper S Engine) and they found these Air Filter Boxes lost 9 HP at the flywheel.
 
Respectfully, it must be a highly tuned engine that's proposed to need twin HS4's. Twin HS2's are good up to about 110 HP.

Twin Hs4s does seem excessive on a mini. What spec of engine are you going to be running?

It's just what has been advised by the engine builder who's been in the business for decades and is something to do with an old Austin owners club so he's suitably qualified. Part of the block and head work is being done by another A series expert. I can't remember his first name but his last name is Walker.

[Parptoot]

Rob Walker!

[Parptoot]

I realise there'll be a number of different views and opinions but I have to respect his years and knowledge in the field.
If it later turns out he was wrong then that can be dealt with and HS2s fitted but I like to think he'll be on the money.

[Parptoot]

Just to clarify to those that may ask. The picture at the top is from Google and is the picture I later followed to see the price of these things on Ebay.

Mine is in original condition. I don't think a brush or spray can has been anywhere near it, ever.

[carbon]

Given how hard it is to come by the Air Filter Boxes, I wouldn't be rushing ion to modifying the one you have.

 

Also, on a recent thread on another forum, a fellow had his new engine run up on an engine dyno (bone standard Cooper S Engine) and they found these Air Filter Boxes lost 9 HP at the flywheel.

 

Respectfully, it must be a highly tuned engine that's proposed to need twin HS4's. Twin HS2's are good up to about 110 HP. 

There are regular comments posted along lines 'I got much more power when I changed from HS2 to HS4 carbs'. Even without a dyno an additional 9 bhp at the crank would be pretty noticeable on the road.

 

But it does sound like a lot of these additional horses may have been as result of removing the standard twin carb air filter box.

 

Losing 9hp because of air filters is a massive drop. It would be very interesting to find out how much of this is the air filter box (ie power readings taken without the filters in the case) and how much was restriction due to standard air filter elements.

[Spider]

 

Losing 9hp because of air filters is a massive drop. It would be very interesting to find out how much of this is the air filter box (ie power readings taken without the filters in the case) and how much was restriction due to standard air filter elements.

 

 

I did ask that question, but while it was on the brake they didn't think to try that.