i heard from the old school racers that they use to use wood gaskets in between the intake manifold and carburetors to reduce heat soak, denser intake temps and keep away from the fuel bowl..but after a while you have to replace the wood because it will wick fuel ..now they are using phenolic spacers..i was interested in this so i purchased some sheets and one pre-cut from summit racing i did before and after temps....i used craftsman temp gun
to measure results...also from what i been reading using these will give your plenum more volume depending how thick you go & For every 5 degree reduction in temperature, increases power by 1%....i added a inch thick between carb / intake and 1/4 inch between intake / head
i think it was 58 degrees outside when did this
engine toyota 3t-C
carb holley 4 barrel 600cfm
my findings:
BEFORE: OEM
75 inside carb throttle body
90 runner closest to the (carb side)
141 runner closest to the head
AFTER:
55 inside carb throttle body
60 runner closest to the (carb side)
90 runner closest to the head
DIFFERENCE:
20 inside carb throttle body
30 runner closest to the (carb side)
51 runner closest to the head
im going to try this on my 1zzfe & 4agze..i was kinda hesitant because my plenum is already plastic on the 1zzfe but i saw on the net..someone with a nissan with plastic plenum still managed to drop temps with the spacer and has youtube vids of it on the dyno
