Phenolic Spacers anyone dabbled with them?

[ae86driftmaster]

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

[radioranger]

I used one on my 302 Ford in the Mustang , very big difference in hot weather after shutdown , a lot less trouble with hear soak, performance wise, i've got a tip I've seen few use, I put some stainless screen , in the shape of a inverted bowl under the carb, I believe it was 8 threads per inch , the fuel would hit it coming from the carb and it would vaporize it much better, , had to lean out the jets a bit, 20 years ago now , but pretty easy to make, keep in mind you dont want it tangled up in the throttle, but improved FE and top end pull .not a new idea and should be good for FE

[Daox]

I highly doubt you'll see an mpg increase with this mod. The general practice is warm air for better mileage in gasoline engines, not colder air. This is especially the case with carburated vehicles which specifically warm the intake manifold to promote vaporization which helps fuel efficiency.

I used to make some of these for the smaller Toyota engines. I specifically didn't install them on the Paseo for this reason.

[justme1969]

Phenolic Glass G3 Laminate Sheet is a glass fabric reinforcement in a phenolic resin binder. The natural color is amber/brown. This grade has good heat resistance, high mechanical strength and low thermal expansion.

This is what we used it never was an issue about wicking fuel though?
Look up Micarta. Very machinable, strong durable fire resistant but not fire proof.
We used red or black sealant because surface is so slick and hard as to need.
Hope this helps ya.
Also permatex has a line of what the call flange sealer great stuff just read carefully to get rite one.

[radioranger]

I agree except in hot weather probably work better, the screen under the carb though would definitely help FE in my experience, breaks up fuel and helps distribution with this center mounted carb, center cylinders get much more fuel most likely . back in the 70's someone marketed them as fuel saving device, one of the few that actually worked for a modded engine like this, i made my own and it did definitely work on my 302 , maybe google up carb spacer with screen gasket, I just did , a few patents on it ,

[ae86driftmaster]

Originally Posted by Daox

I highly doubt you'll see an mpg increase with this mod. The general practice is warm air for better mileage in gasoline engines, not colder air. This is especially the case with carburated vehicles which specifically warm the intake manifold to promote vaporization which helps fuel efficiency.

I used to make some of these for the smaller Toyota engines. I specifically didn't install them on the Paseo for this reason.

im not sure either if it will improve my mpg's ..i just got this car recently never did a mpg test .....but i seen many posts & dyno vids on horsepower gains using these spacers on carb, fuel injected, & turbo..now on the warm vs cold fuel I dont know... i read so many pro/cons about that issue....im going with race teams have been doing...and automotive companies are switching to plastic plenums now ...so there has to be some type gain why they are doing it?...
far as i now the 87 corolla SR-5 from dealer was 25 city 35 highway with the 4ac single overhead 1.6...the previous owner swapped it with a 3tc 1.8 ...

[Daox]

OEMs are doing it because plastic is way cheaper than aluminum.

Race teams have little to no interest in fuel economy. Their philosophy is shove as much air as possible into an engine to get more power, add fuel accordingly.

[niky]

Plastic can reduce heat soak a bit, but seems like it's more a cost- and weight-saving thing, as well as helping them meet pedestrian impact requirements for engines with the intake manifold up front.

Strangely, Honda has switched back to aluminum for the intakes on local Fits here. Maybe because of durability concerns? Know a racer locally who blew his plastic intake manifold twice under nitrous.

[ae86driftmaster]

Originally Posted by Daox

OEMs are doing it because plastic is way cheaper than aluminum.

Race teams have little to no interest in fuel economy. Their philosophy is shove as much air as possible into an engine to get more power, add fuel accordingly.

i kinda figured cost was their main goal..

[TexasCotton]

Need some feedback please. Would making or fabrication of a phenolic intake manifold gasket have in any benefit? The possible application is a 04 Prius like Doax. The current gasket material is metal (almost like shim stock thickness)