It will result in a drier cake...something like a fatless sponge.
You can add the oil by folding it to the mixture but the batter
specific gravity will be higher( about 0.60 or more) meaning the cake
will come heavier....but it depends on your skill.
You will not need to fold it all the oil but just a half or two thirds
of it to minimize that increase in batter specific gravity.
In the past I have experienced making chiffon cakes like that...but the
recipe I was using have higher amount of egg whites( around 110-% based
on flour and when I folded in the oil( around 45% based on flour ,the
batter specific gravity was still in the light side ( around 0.45 from
0.35) therefore the cake still comes out satisfactory....

Richard Hollenbeck wrote:
> I suspect a major disaster. I never made lemon chiffon cake so I went by a
> recipe which called for about a cup or so of salad oil. I got all my mis en
> place and went to work, step by step by the recipe. I have no idea what the
> batter should look like since, as I said, I've never done this recipe. I
> folded in the whipped egg whites and put it in the pan then into the oven.
> As I started to make the glaze for the top I saw a little bowl on the table
> full of the oil that I measured out. I'll find out in about ten minutes but
> I have a question: How disastrous will this be that I forgot the oil?