I have just fabricated an undertray for my bonnet scoop that delivers air to the entire core of the STI8 IC I have fitted to my MY98 WRX. Before fitting the new tray today the car had the standard ducting/tray in place and held 1.2 bar via a dawes (ecu is 1.2 also) all the way to redline.

Now it hits 1.25 and then climbs to 1.3 bar!!!

What has happened?

Spec is this

Zerosports ECU
Megan Headers wrapped
STI8 IC with all samcos
Zerosports Induction with K&N
Zerosports Open Neck Catted Downpipe
Magnex 2.5" system
Turbo is VF something or other by Zerosports
440cc Inj
6's for the plugs

 

may need more fuel

 

why more fuel? the afr is still at 900mv via the scoobymonitor.

 

The improved cooling through the core will cause the charge temperature to decrease thus increasing its density which will cause the pressure to rise - this will also have a 'knock on effect' to the AFR which I wouldn't over trust the output from the Narrow Band Lambda especially at high EGT's as 900mv could be anything from ~11.0 - 12+ AFR. Would be wise to get it backed up with a wideband lamda or lower the boost on the Dawes to the original setting - plus I see no mention of a Knocklink?
You would also prolly benefit from changing the plugs from 6's to 7's

Cheers

 

Forgot to mention that I have a knocklink!! No activity above the normal flicker of the first green. Hit the block with a wrench to see if the all light up and they do, so it looks ok.

I understand the heat ranges of plugs to a degree but why do you say 7's?

Is it down to the plugs causing det? or not being able to ignite the mixture due to pressure?

Cheers,

Wayne.

 

When running higher than standard boost the in-cylinder temperatures increase thus the plugs are also running hotter than normal which can result in pre-ignition caused by hot spots. I noticed when running around 1.3bar on on the standard 6's I was occassionally seeing flashes of red on the KL even though the wideband was showing 11.2 - 11.6 AFR on boost, the EGT's were ~800degC - I then changed the plugs to 7's and the spikes on the KL completely vanished.

Cheers