Air pump on the 18-RG?

[Jester]

i have an ra24 celica with an 18-RG engine that im building up to be a hillclimb race car. there is an air pump in the engine bay that runs of the fan belt and it pushes the air into the inlet manifold. some people have told me that it is used for anti-polution and have also said that it should blow air from the exhaust manifold into the inlet manifold but it doesnt. when i got the car the origional air pump had siezed but i managed to track down another one and put it on. The car has a modified exhaust system and when i put the new air pump on it started to backfire on de-acceleration but tuning fixed the problem. anyway if someone could help me out by giving me more infomation on the air pump would be greatly appreciated.

EDIT~
Note: This is a Post for and by a friend.

[river]

Hi,

Just remove it and plug up the hole.

seeyuzz
river

[Jester]

So it's useless? what does it actually do though, my current info is just speculation.

[Dazza]

The air pump used to pump air directly into the exhaust ports so any unburnt fuel could be burnt in the exhaust. It is supposed to reduce the amount of hydrocarbons and carbon monoxide.

[bnicho]

RA24? Sounds like a US spec car.

The air pump is a pollution control item that saps power and weighs a bit. You don't need it on your 18RG, especially on a track car where saving weight and power is important. The only reason you would keep it is to pass a smog test if you live somewhere anal about such things like California.

[maurice c]

Yes just bin it, save a few kilos and stick a bolt in the hole. I did it on my 18r-c and probly gained about .005 of a kilo watt. I couldnt believe the difference.

[Jester]

Just to comment on my friends post here, i actually think it's an 18R-C engine, not G, it's Carby version and my understanding is the 18R-G is fuel injected.

Am i Right?

[cameron lt2000]

nup......18rc is a boat anchor....its a single cam single carb...stock anyway.....
18rg is twin cam twim carb much cooler..

18rgeu is fuel injected

[river]

Hi,

Does the 18R-C have an air pump? I think the 18R-U did and the 18R-GR did. I'll check this tonight when I get home.

18R-G => Twin carb (approx 145hp)
18R-GR => Twin carb with air-pump and slightly different head (approx 140hp)
18R-GU => Twin-carb with lower compression and different head again (approx 125hp)
18R-GEU => Fuel injected, lower compression and different head again. (approx 130hp)

Of course, the above details is from memory, which has, at times, left me floundering.

seeyuzz
river

[bnicho]

Some (if not all) 18R-C have an air pump. My RT132 still has it sitting there on the stock motor.

I've never seen an 18RG of any type with an air pump. But maybe they were usually binned before the motors even left Japan!

[MWP]

Does the 18R-C have an air pump?

It did.
The original 18R does not.

[bnicho]

It did.
The original 18R does not.

Neither does a 16R for that matter.

Cheers,

[timbosaurus]

Sometimes people re-configure these air pumps to eliminate pressure building up in the crankcase.

Still don't understand the point/need/value though.

My experience leads me to agree with Brett. All the dead-original 18R-C's I have seen have had them, but most of the stripped/modified ones dont. Never seen a twin-cam with one.

Timbo

[brett_celicacoupe]

Hi,

Does the 18R-C have an air pump? I think the 18R-U did and the 18R-GR did. I'll check this tonight when I get home.

18R-G => Twin carb (approx 145hp)
18R-GR => Twin carb with air-pump and slightly different head (approx 140hp)
18R-GU => Twin-carb with lower compression and different head again (approx 125hp)
18R-GEU => Fuel injected, lower compression and different head again. (approx 130hp)

Of course, the above details is from memory, which has, at times, left me floundering.

seeyuzz
river

my 18r-gu didnt have an air pump but it had all the peripherals for one. ie bracket on the block, flared fittings in each exhaust port...

it had a 253 head for memory