The Triumph Dolomite Club - Discussion Forum

hi all
got a set of twin carbs and manifold coming
now,what air filters are best for them.......standard filter system(big metal housing thing) pancakes filters or something else
what do people recommend?

thanks nic

You're going to get a few differing opinions on this one, but unless you can isolate the filter from hot underbonnet air then I'm not a fan of pancake filters, and rather put a quality panel filter (K&N do them too) into the original airbox and make sure that it has it's cold air feed intact. You might be able to get a pancake filter in the original airbox though.

My reasoning for this statement is that with a pancake you are sucking in all of the hot lighter air from under the bonnet, rather than the denser cool air from outside, so your mixture will lean out, the car will run hotter and all that wonderful BHP increase that the manufactures allege will occur not only doesn't happen, but you will actually lose BHP. Sounds good though, which is why every boy racer (myself included) fitted a K&N along with a the waste paper basket sized exhaust back box...

Edit: Thinking Sprint, and just realised you have a 1300, which doesn't have a cold air feed, other than a tiny radiator and lots of gaps up front for a nice stream of cool air into the entire bay!

It may sound silly, but your best starting point is the stock metal box complete with the 2 plastic pipes that draw cold air in from outside the car.

Anything else draws air from under the bonnet, leading to hot running fuel vaporisation problems, especially on OHV cars and K+N type "freeflow" filters make the stock carbs run lean at high revs. To get the best from these needs a rolling road session with a man who knows about SUs - not cheap!

Steve

Ideally you want some trumpets. MGB's had them fitted as std, nice short ones
http://s929.photobucket.com/user/V8EKwa ... 9.png.html

Next, you may find something like a K+N round filter elemnet that can be fitted into your airbox, my old vitesse had them just glued in place with some silicone. And then tubes on the airbox the feed cold air.

http://www.knfilters.co.uk/search/univ2.aspx?id=S0001

Not sure what needles you will need in your setup, I suspect the 1500 ones will be too weak! Probablyneed stronger springs in the dashpots too.

clear as mud then looking at the options,sounds like back to basics is on the cards,,standard metal tin box

Heavier springs? Reading the su tuning literature some say to even not use springs in some applications. I'm keeping the original springs so have the heavier ones for sale shortly if you want them.

Heavier springs? Reading the su tuning literature some say to even not use springs in some applications. I'm keeping the original springs so have the heavier ones for sale shortly if you want them.

What are you doing about your exhaust?

I did not get much benefit from putting twin carbs on my 13/60 until I put a Vitesse exhaust on. Having said that, the original one was a bit of a pea shooter. Perhaps you could put a 1500 one in.

I could not fit the filter box on my Herald so I used Simota filters similar to these

http://www.ebay.co.uk/itm/CLASSIC-MINI- ... 2408960704

They are OK but you must install a heat shield.

I think that the standard filter box is a good place to start.

Alan

AlanH wrote:What are you doing about your exhaust?

I did not get much benefit from putting twin carbs on my 13/60 until I put a Vitesse exhaust on. Having said that, the original one was a bit of a pea shooter. Perhaps you could put a 1500 one in.

I could not fit the filter box on my Herald so I used Simota filters similar to these

http://www.ebay.co.uk/itm/CLASSIC-MINI- ... 2408960704

They are OK but you must install a heat shield.

I think that the standard filter box is a good place to start.

Alan

I'm pretty sure you have to use the 1500's twin downpipe exhaust manifold with the twin carb inlet. Which then implies a 1500 downpipe (obviously) and from there back I think you can use 1850 bits (may be wrong, haven't got the book handy) Or wait a bit and get one of the (coming soon) club 4 branches!

Steve

You have to go twin carbs if you want to use the twin pipe exhaust manifold but you can use the single pipe exhaust manifold with the twin carbs. I'm just putting a twin HIF38 setup together as these flow much better and actually use less fuel! I was going to use a single HIF 44 that I'd rebuilt and polished only to find it didn't fit over the better flowing 1500 twin exhaust manifold! That's going for sale soon too and would be a straight swap.

I think that I wanted to improve performance I would look at the exhaust first.

(Here we go off track again, you only asked about filters Nic).

Slightly off topic, but I remember a post on what the bracket at the front of the car looked like to fix the flexible hoses to (part of the radiator mount I think)

Can someone post the pic up again as I need to re-make mine as its not fitted and with a KN panel filter, Id like to use the cold air intakes as intended?

Thanks and +1 for the standard box + K&N panel filter.

exhaust....ive have two twin manifolds and three twin downpipe in my loft,,,so that solves problem
i already know about the heatshield....got one on watch list

On my 1500tc I had 4 into 1 style exhaust manifold with twin carbs, and the engine these carbs came off was a spitty mk4 with 1500 engine and that also was 4 into 1 style exhaust manifold.

cheers

darren