Hello everyone.,

i have a great wall 2 door ute with a mitsubishi 4g69s4n engine which was turbo charged by previous owner . was in an accident so i have been repairing it .

recently got it on the road after a new diff install . it’s running around 10psi , however under hard throttle i notice the boost feels lacking and fumbling around the 4-6k rev range .

i’m wondering is my intercooler too small for this amount of boost ? ( size is 30cm x 30 cm) or is the piping too small ? 2 inch piping ? or could this be something else causing this ?

any feedback would be appreciated

 

Explain what you mean when you said “under hard throttle i notice the boost feels lacking and fumbling around the 4-6k rev range”. If you explain clearly I could give you my opinion.

Boost is a measure of restriction so I wouldn’t worry about the piping/intercooler sizing.

 

Do you have a boost gauge?

 

What’s the spark plug gap? Afr?

 

the gap is 1.1 currently , and what i mean is it feels like it’s loosing consistency when you have your foot to floor when it approaches that 4-6k range , almost like the power band drops and it isn’t smooth , rough almost .

i haven’t got the boost gauge currently installed as i removed it to install a newer one , but i may just chuck it back in to see what’s happening on the gauge if it drops

 

You need the boost gauge connected at intake manifold after throttle body to be able to properly determine issue. Based on what you have said you are either having spark blow out or you are having too rich moments causing misfire or both. But until you have the boost information I can’t confirm that is the answer. Let us know.

 

Also IMO a 1.1 spark plug gap is more than double too big

 

when i had the gauge in it was showing 10 psi and also forgot to mention tuned with the haltech 1200 .
what would be an ideal gap ? 0.8 ?

 

I can’t really give you a correct answer for your motor/setup/plugs being used, but for gas engine .028 . The reason the boost monitoring matters is because you need to see what the boost could be doing throughout the vehicle operation.

 

Assuming that you are giving numbers in MM... Snake's 0.028" number equates to 0.71 mm