Jet size questions - WRX
 

I've used the 'lovely' PHPBB search facility and have found a few entries of the jet sizes people are using...

But is there a specific formula to use, I understand that 10 - 15% of the fuel used is the guideline, but given that the fuel used across the entire rev range will be different is it a compromise?

I run 4 x 700cc injectors at about 68% IDC (@ 7000rpm), currently around the 199kW @ the wheels mark.

Currently I'm using the 0.5mm jet in a 1S system but would like to know if running a 0.7mm jet as a few others are using would be a better solution.

Jet location is in my FMIC piping, about 700mm before the TB.

Cheers and thanks
Brett

Re: Jet size questions - WRX
 

In order to keeping the ratio relatively constant, you need to consider upgerading the 1s to a 2d system. The 2d tracks the fuel delivery and you can keep your w/f ratio much consistantly. If you need other ratios, just change the jet size.

Richard

Could you post some pictures ?

Hi Richard I'll grab some pictures as soon as I can.

I'll be looking at the 2d system when I get a chance, as well as upgrading from my current aftermarket engine management (a Link) to a Motec in the near future.

Cheers
Brett

Some pictures:

Jet Mounting.
http://www.griffin.net.au/WRX/WI/DSC_11932.jpg

Relative to the Throttle Body.
http://www.griffin.net.au/WRX/WI/DSC_11936.jpg

Another angle of the above.
http://www.griffin.net.au/WRX/WI/DSC_11939.jpg

Cheers
Brett

They are excellent pictures.

I just wonder if you can increase the methanol percentage since you are in the middle of summer months. 0.5mm for neat water and 0.7mm with 50W/50M mix to aid induction cooling.

Richard