3 replies to this topic

[Suburu]

Hi all,

 

I'm soon to be running my 1275 motor with a K&N air filter element in the standard box (drilled) and maniflow 13/4 RCM road centre exit exhaust (I like the look haha). 

 

Currently there is a single HS4 fitted and I have been eyeing up HIF44's/ HS6's. I won't be going further than stage 1 for the foreseeable (he says) so I was wondering if it is worth getting the bigger carb or instead just changing the needle on the HS4 ?

 

It's my only car, so it is run often. I'm trying to assess the cost benefit impact to my mpg vs performance (although that probably wouldn't stop me).

 

Thanks :)

[cal844]

I'd just change the needle on the hs4, pointless going to a HIF for little gains

[kiwi topcat]

i have recently removed my HS4 and installed a HIF44

the difference was vastly improved as one would expect when going from a 1.5 to 1.75 diameter carb

 

change to HIF 44 is the way to go

[timmy850]

It does also depend on:

Condition of your HS4

Is the current HS4 needle appropriate?

Is your stage 1 HS4 needle appropriate?

Unless you can measure the air fuel ratio in the exhaust you'll be completely guessing if it's running right or not. 

 

If you get a different carb, it really needs to be rebuilt to as-new and set up by an expert so that the mixture is correct across the RPM and load range.