MODS_Carb Changes

Carb Changes

Standard 1 1/4" Twin SU's

These have a set of sports pancake filters instead of the original big paper ones

As you can see access is improved over the paper filters but as to performace improvement it depends on how good the filters are.

This pair has a 3 piece heat shield to fit around a Janspeed LCB exhaust manifold.

Weber/Dellorto

What can I say they make a lovely noise and give great accelleration

You'll notice with this inlet manifold there's not a great deal of room for an air filter. I know many people will be quite happy at that and run with out one, but dust and stones do not make for a happy engine, or bank balance.

A number of options are available to you, some people cut out part of the wheel arch and reshape it around the filter. Some will make an airbox around what you got. Some even cut away the the whole inner arch. You'll note the twisty shape of the inlet manifold to marry up the 2 chokes of the carb with the 2 ports in the head

Some people, in the search for ultimate power, fit two of these carbs using one choke of each, which allows the use of a straight inlet manifold. This is Simon Page's you can see uses an alloy I beam to support the 2 unsupported ends of the carbs, which also give him something to mount the carb linkages to. You can also see he has made an air box and removed the whole of the wheel arch. This is a Race car and not used on the road. Sharp eyed people will also notice the small air filter on the crankcase breather and the bleed screw for the water system.

SU HIF 44
This, and it's manifold were off the MG Metro's. There also a smaller HIF 38 but I'd go for the biggest on a 1275. Loose the 90 deg air filter mount. I cut this one down and radiused it to improve the air flow in the air filter I made up.

You'll have plenty of space around using this setup but you'll need to put a hole in your bonnet see below. The main mod was to thin down the flanges for fixing as they were thicker than the exhaust manifold flanges. Some people have used stepped washers to do the same thing. There nothing wrong with this but I though it was easier to make it the same as standard manifold which makes it so much easier to fit.

This air filter was one of a pair of K&Ns that came off of a Rover 3.5
I've fitted a Filter King and set the regulator at 2 p.s.i. there is also an inline filter between the tank and pump.

On the left you can see the hole I needed to make, to clear the dashpot, and below you can see the small teardrop fairing I made to cover it. This was done by making a wooden carving and then glassing it. I have hear of people cutting the dashpot down and rethreading it and shortening the rod on the damper.

This is it, fitted. It's a simple mod, looks neat and feels as good as any of the other carbs I've tried. If as I did your making up your own filter back plate arrange it so you can get to the jet adjuster. The water pipes haven't been connected at this point as it all has to come off to fit the LCB manifold, later.

If your fitting new air filters remember you need at least the choke size clearance passed the end of any ram pipes. If you don't have ram pipes the sqaure edge on the carb or air filter back plate will not give you a good air flow so think about making up a radiused ring. If your making up your own back plates or gaskets make sure you don't blank off any holes you need.

MODS MENU

	Standard 1 1/4" Twin SU's These have a set of sports pancake filters instead of the original big paper ones
	As you can see access is improved over the paper filters but as to performace improvement it depends on how good the filters are.
	This pair has a 3 piece heat shield to fit around a Janspeed LCB exhaust manifold.

Weber/Dellorto What can I say they make a lovely noise and give great accelleration
You'll notice with this inlet manifold there's not a great deal of room for an air filter. I know many people will be quite happy at that and run with out one, but dust and stones do not make for a happy engine, or bank balance.
A number of options are available to you, some people cut out part of the wheel arch and reshape it around the filter. Some will make an airbox around what you got. Some even cut away the the whole inner arch. You'll note the twisty shape of the inlet manifold to marry up the 2 chokes of the carb with the 2 ports in the head
Some people, in the search for ultimate power, fit two of these carbs using one choke of each, which allows the use of a straight inlet manifold. This is Simon Page's you can see uses an alloy I beam to support the 2 unsupported ends of the carbs, which also give him something to mount the carb linkages to. You can also see he has made an air box and removed the whole of the wheel arch. This is a Race car and not used on the road. Sharp eyed people will also notice the small air filter on the crankcase breather and the bleed screw for the water system.

	SU HIF 44 This, and it's manifold were off the MG Metro's. There also a smaller HIF 38 but I'd go for the biggest on a 1275. Loose the 90 deg air filter mount. I cut this one down and radiused it to improve the air flow in the air filter I made up.
	You'll have plenty of space around using this setup but you'll need to put a hole in your bonnet see below. The main mod was to thin down the flanges for fixing as they were thicker than the exhaust manifold flanges. Some people have used stepped washers to do the same thing. There nothing wrong with this but I though it was easier to make it the same as standard manifold which makes it so much easier to fit.
	This air filter was one of a pair of K&Ns that came off of a Rover 3.5 I've fitted a Filter King and set the regulator at 2 p.s.i. there is also an inline filter between the tank and pump.
	On the left you can see the hole I needed to make, to clear the dashpot, and below you can see the small teardrop fairing I made to cover it. This was done by making a wooden carving and then glassing it. I have hear of people cutting the dashpot down and rethreading it and shortening the rod on the damper.
	This is it, fitted. It's a simple mod, looks neat and feels as good as any of the other carbs I've tried. If as I did your making up your own filter back plate arrange it so you can get to the jet adjuster. The water pipes haven't been connected at this point as it all has to come off to fit the LCB manifold, later.
If your fitting new air filters remember you need at least the choke size clearance passed the end of any ram pipes. If you don't have ram pipes the sqaure edge on the carb or air filter back plate will not give you a good air flow so think about making up a radiused ring. If your making up your own back plates or gaskets make sure you don't blank off any holes you need.