Secondary Throttle Spring

[AdamP 0]

How have people done it? Looking for ideas!

 

Adam

[miamichris 9]

what is a secondary throttle spring?

[swordfish210 20]

I used to have 2 throttle springs on my old Weber carb, i dont think i have any pics but i basically made a small plate with a hole in it that i bolted to the HT lead holder on the cylinder head and attached the spring to that and then on to the throttle arm on the carb. IIRC the solex arm goes the other way compared to the weber so what i just described is effectivly useless, unless you wrap a particularly long spring right around the throttle arm.

[EdCherry 34 1 Cars]

You have a spring so the throttle returns to closed once you let off.

 

We have a little plate mount made up to meet blue book regs but we use webers... Can upload the picture if it gives you an idea?

 

Ed/

[AdamP 0]

Cheers guys. The problem is that there doesn't appear to be anything in the area to even mount a plate on! A picture might be useful anyway if you have one to hand

[swordfish210 20]

[Lan 24 1 Cars]

is that a weber i can see? ifso any noticable performance increase?

[EdCherry 34 1 Cars]

Obviously this isn't going to exactly the same but might give you an idea of what could be done.

 

[AdamP 0]

I used to have 2 throttle springs on my old Weber carb, i dont think i have any pics but i basically made a small plate with a hole in it that i bolted to the HT lead holder on the cylinder head and attached the spring to that and then on to the throttle arm on the carb. IIRC the solex arm goes the other way compared to the weber so what i just described is effectivly useless, unless you wrap a particularly long spring right around the throttle arm.

 

Yeh, it appears to rotate the other way. I'll have to have another good look and ponder! It's strange, it wasn't picked up on until a sprint in April.

[swordfish210 20]

is that a weber i can see? ifso any noticable performance increase?

 

It made a big difference over the old solex carb. I made that airbox for it and piped in a good cold air feed from the front of the car and then had the whole lot dyno'd. It made 86bhp with no other modifications other than a 4branch manifold (this is on a 151,000 mile engine) and it made 83bhp without the airbox and the bonnet down. That was after having the carb jetted and the ignition timing set.