10 replies to this topic

[Steve-O 2014]

will a bej needle work in a 998 with a hif44 carb? thanks

[Dusky]

Will depend on you engine's spec's...

Maybe stating them would help :)

 

grtz!

[wile e coyote]

A '44 is too much for anything other than a race / rally 998.... not impossible to make it go - reasonably.... but guaranteed to be both needle and spring change and will be decidedly difficult to tune.... a single HS4 / HIF38 is the better option if your car isn't a fire breather - or twin HS2's....

Get yourself winsu for the most likely candidates if you're determined to use a '44.....

[Dusky]

Most of the time u can guess what needle you need though WINSU doesn't show th elast letter unless U pay

[KernowCooper]

Hif44 to big unless the engine in a very high state of tune, but have far better response on a 1 1/2 than the bigger carb.

[Steve-O 2014]

Annoying thing is I dont know how tuned the engine is. Its all electronic ignition with no vacuum advance on dizzy, rebuilt engine to 1000cc high compression, Head work, cone filter, maniflow manifold and exhaust system, external electronic fuel pump etc

 

Will try that software and see what it says 

 

thanks

[Dusky]

Do you know what exhaust etc?

When it has an electronic ignition without a vacuum check for any serial numbers on the dizzy..

Probably a fast road dizzy or a programmable unit wich means the engine is tuned( most road engines still have a vacuum)

[KernowCooper]

When we were referring to the state of the engine tune, we should have been more specific, this would have to be a competition engine to use a HIF44 to its best

 

For example its a known fact that for every 1bhp a engine needs 2-2.2 cfm of airflow, so using the known formula we take the cfm of a HS4 1 1/2 SU which is 142cfm in standard form,

 

So 142cfm divide by 2 =71bhp

 

So a engine wont be restricted by a 1 1/2 SU until after that bhp figure, so our 998 engine will be in a high state of tune to need a HIF44 which using the formula will provide enough cfm for 120bhp.

 

But you have to remember that where the secret to BHP on the A Series heads is in the head, and standard heads are not good a cfm airflow, so its not all down to how big is the carb and what will it flow, its always down to where is the biggest restriction and what is the cfm at that point.

 

People with greater knowledge than me like AC and Cooperman can explain it fully.

[wile e coyote]

When we were referring to the state of the engine tune, we should have been more specific, this would have to be a competition engine to use a HIF44 to its best
 
For example its a known fact that for every 1bhp a engine needs 2-2.2 cfm of airflow, so using the known formula we take the cfm of a HS4 1 1/2 SU which is 142cfm in standard form,
 
So 142cfm divide by 2 =71bhp
 
So a engine wont be restricted by a 1 1/2 SU until after that bhp figure, so our 998 engine will be in a high state of tune to need a HIF44 which using the formula will provide enough cfm for 120bhp.
 
But you have to remember that where the secret to BHP on the A Series heads is in the head, and standard heads are not good a cfm airflow, so its not all down to how big is the carb and what will it flow, its always down to where is the biggest restriction and what is the cfm at that point.
 
People with greater knowledge than me like AC and Cooperman can explain it fully.

This! - think you pretty much nailed it!

[blacktulip]

you need a rolling road session regardless so i would just worry about getting it there to be honest.

[Steve-O 2014]

Thanks, think i will just stick the hif38 on when i find out what needle i need