Not sure if this is the right forum, but when deciding whether to semi-bluff with significant money behind, shouldn't we consider the fact that if called we are able to make a bigger bet on later streets if we hit because the pot is bigger?

For instance, say there's $100 in a pot on the turn. We're heads up in position with Villain and have $500 behind. Board is A267r and we have 98. We're fairly sure V has an ace. V checks the turn and we are deciding whether to semi-bluff for $50. We have 20% equity. If we bet $50 and are called, we have 20% equity in a $200 pot, so lose $10. However, were also heading to the river with a larger pot that we can bet bigger if we hit. If 20% of the time when we hit we can get a $50 bigger bet called on the river, aren't we breaking even when called, such that any fold equity on the turn is gravy?

Of course, who knows at what points we break even and what not, but in general this seems obvious. Just something to consider, we can get blown off our hand, and also, villian can often call.the bigger bet anyways, in llsnl.

You're talking about pot sweeteners, a favorite tactic of recreational players. It is the logic of all those people who insist automatically straddling every chance they get. So let's look at this situation.

The first is whether you have any fold equity at all. On this board against a player who has TP (which you asked us to assume), you have almost none. He's not going to fold to a $50 bet.

So this is a matter of what has a higher EV, checking the turn or betting $50 at the turn. If you check, you get a free card. It costs you nothing to chase your draw. If you hit and he c/f, you win the pot. You'll hit this 18% of the time. So your equity is +$18.

If you bet $50, you'll get called. If you miss (which you will 82% of the time), you lose $50. If you hit and he c/f, your EV = $150 * 0.18 - $50 * 0.82 or -$14.

Therefore, you need to pick up $32 more in equity by betting on the river when putting the $50 than you would get by not betting the $50. Given the 18% chance of hitting, it means that he will have to call $178 more than he would if it checked through. If he'll call a 1/2 PSB on the river with it checked through, that means he'll have to call over a PSB on the river if you bet $50 on the turn. That's just to make the move break even. You need to make even a bigger bet to make money.

If the villain is willing to make a call over over a PSB, after you take the betting lead on the turn, he'll do the same thing if you didn't bet. Therefore, sweetening the pot is a bad idea if you are drawing.

Now if you add in fold equity, this can be a good play. But not in the case you outlined.

Read & heed venice10's words.
The way you played your hand before making the raise OTT has to tell a believable story.
Question: If you are HU OTT, then some people folded OTF obviously?
This must be 2/5NL. How did you end up with $100 in the pot going ITT when you only had a gutshot & BDFD?

If semi-bluffin' was worth it at all, wouldn't we want to at least have picked up a flush draw OTT? Maybe not, if your V understands that the Turn card may have given you more outs, but what cards on the board are in your suit when you turn the flush draw?
What is your opponent's perception of your range? How was your hand played to get to the Turn with 98s?

Then there is all the possible Ax hands your V could have. AT & A5 has to be 2 of those, [24 combos if he plays them unsuited] so a certain percentage of the time you will have 7 outs instead of 8. Now you only have 16% equity.

One would think we'd make more money if V has AT & the River brings a T, but the board now reads A267T. What's he think you have when bets OTR & you raise when you make your str8?
Top 2 pair or a set? How'd you end up with top 2? It's gotta' be a set or str8, amirite? Unless it's a bluff.

IMHO, when it comes to getting a fold, is what your V thinks your range is. I had a V fold bottom set [after much deliberation] to me OTF of Q42r last night, when I checked in the SB, he bet $10, 2 callers, I make it $55 into a $65 pot, he makes it $110, others fold & I make it $275. He said he might have called if he had a set of 4s instead of 2s. But that's what he said.

However, I had been card dead for some time & had not made a substantial bet like this in the 2 hours he had been there.

It is impossible to compute EV even rough estimate is difficult. It is possible to compute FE needed for breakeven when you have 8 clean outs.
As for implied odds the chance you get c/r complicates estimation, also we dont know what is your plan otr - you can give up missed draw but can finish bluff otr too.

Actually better way is look at your value range and select good bluffs acordingly. Or play explo and always check to suspected station.