I installed these mods today w/ little problem because I snapped two lower plenum bolts...but i used 70mm bolts that came w/ the spacer... so i have two loose bolts for my upper plenum... i drove about 20 miles on local and 70 miles on freeway... and i didn't have any problem at all... except when i checked my mpg it was 25.3 ~ 26.5 instead of 20.0 ~ 22.00... i think this is a good result...
i ordered 6 plenum bolts from rivierside infinity... and my question is how do you tell if there's an air leak or not... friend of mine said the hissing sound is coming from the popcharger...but when i had my friend turn the engine and press the acceleration i heard some hissing sound from the plenum...
also, after installing Motordyne 5/16 Spacer, i couldn't get the two lower bolts tighten on the engine cover... did any of you guys have this problem too?

thanks a lot guys.

 

lol nope. . .you've got the exact same mods as i have on my coupe. . .the hissing is the pop-charger (sounds nice!)

which 2 bolts are loose in the upper plenum?

as for the engine cover mine went on perfect. . .it's very easy to over-tighten them and strip them. . .

 

id check and make sure you didnt over tighten and crack the bolts on the plenum

 

I have done this in the past. Get a can of "starter fluid" (ether) and spray it in the areas of the intake that are suspect while the engine is running. If there is a leak, you will hear the RPM increase slightly.

 

umm...i was worried about leak on the plenum not the intake...is it okay to spray it in the areas of the plenum???i hope i get these bolts by wed as jason from riverside infiniti said...

thanks guys!