[Automaton]

So I hope it doesnt get ot it. But its possible that my player's chars are going to climb into a van soon (normal non armored civillian big van) that has a bunch of explosives stuck to the bottom and will be remotely detonated.

I hope they dont, but they might.

My question is, (since I still find the explosive rules perplexing) how much is needed and what type to blow up a van.
They are placed to kill the team by a rival runner who wants them out of the way. I want it to be seriously dangerous, but I don't want to simply have to tell them, you blew up and died.

Any suggestions/help?

[Omnibobatron]

 Is there any way they could figure it out, or is it too late for that? Are the explosives visible with a perception test? Is the rival team smart enough/have access to enough explosives to be sure to kill them? Perhaps an edge test to reduce damage? Cuz the way it sounds is chunky salsa. Bring chips.

[Automaton]

Yeah they will get a chance to figure it out. But just in time so they won't catch the full blast probably. Unless they're really smart.

I want there to be eoungh explosives to blow up the van and possibly kill pc's if they are in it. But not a 100% certainty of death.

[Michael Chandra]

Well are we talking huge-armor PCs or people with 3 Body and 8/6 armor?

[StarManta]

Well, first off, chunky salsa totally applies. But even if it doesn't....Explosion in an enclosed space? A standard HE grenade would probably  kill the team.

1. It does 10P damage to everyone, which will probably kill one or two outright.
2. It bounces off of each wall, all 6 (top and bottom as well), and each bounce will do 8P damage.
3. It bounces again, for another 6 x 6P damage. Repeat until it's down to zero.

The only way to survive that is to be in armor that can get 8 hits every time. A fully built out troll with Heavy Military Armor (14 Impact + 10 Body) can average 8 hits each time, but it only has to fall short a few times for the reflected DV to knock him out (since it'll be converted to Stun). And remember, that's with a single HE grenade. Add 2 or 3 more and even that troll is a dead man. And you could easily hide a dozen HE grenades in the van with methods that are nigh undetectable.

....but really, just save yourself the trouble and chunky salsa it.

[Michael Chandra]

If the explosion is at the bottom, it would reflect from the roof and the floor would make it shrapnel. Afterwards, on its bounce back you could let it flow out through the ground (and let the car get blown into the air) so it's just a double-hit with the chunky salsa rule.

[Automaton]

We are talking a full team who can take some damage and is wearing good armor.

The explosive is underneath the car, not in the car so it doesn't bounce around XX times.

The idea is that either the party notices before they get into the van themselves, or they will get a call that near the end might give them the clue they are about to be blown up and so jump out of the van split second reaction with taking the blast in their backs, or they are inside the van it gets blown skyhigh and they need to pick themselves and the pieces off the road having been blown from the exploding van or having crashed into an obstacle with the wreck.

I have seen them survive hits of 10 damage before, so...

[Michael Chandra]

Biggest question: Can they take 20 DV damage as Stun, or would it be Physical? I doubt it so let's go easy on them.

Let's assume the explosion smashes up, then onto the roof, then back down. Roof is ~1.5m above the floor, so let's just say the blast hits the player at 1m distance, then again at 2m distance. It's a directional blast which means -1 per meter, but halved due to shrapnel from the floor, so it's then -1 per 2 meters. Meaning we got 2X-1 as the total damage value.

However, the armor value of the barrier is added to the resistance. A bulldog has 8 Armor without modifications. Let's assume the players have 4 Body and 12 Impact Armor, with the Bulldog Armor added they're at 24. I assume they'll edge this with a reroll afterwards. They got well over 75% to score 12+ hits, let's assume 10 hits for now. On top of that they can survive 15+ damage, though they'd be in overflow. So 25P total damage is the max you want to aim for. Of course you might just make it even riskier.

25 as 2X-1 means X is 13. X = 15 would mean 29P vs Impact. If you make the roof 2m high for easy calculating, you could say it's -1 for the first and -2 for the second hit, so 27P.  As non-directional blast we're talking 15->14->12 = 26P.

So a single kilo Rating 15 plastic explosives (so less than 1 liter in size) as directional blast would translate to 29P. As circular blast it'd be 26P. The players would add the Bulldog's Armor to their resistance rolls and got a fair chance, with an Edge reroll, to not all go K.O. and likely not have any deaths, if they face that 26P.

[farothel]

also depends on where exactly you put the explosives.  If you put them around the fuel tank, you can use less explosives.

I would just write down: the explosives to X DV, and leave the exact amount a bit vague.

[ZeConster]

The explosive is underneath the car, not in the car so it doesn't bounce around XX times.

Considering you're talking about a "normal non armored civillian big van", it might not even have mattered unless the enemies were to fine-tune the explosive's DV to aim for the chunky salsa effect, or just use a grenade - any explosive strong enough to seriously injure the party members on its own is likely to also blow the van's walls, floor and roof off (not sure what the Structure rating of a vehicle is, but with car walls being thinner than 10cm, I figure any explosive with a DV of over 12 will easily break through), meaning no barriers remain to reflect the blast aside from the pavement.

Anyway, regarding how much DV to go for: if you want just the right amount of tension, you could retcon the damage - pick something between 20 and 30 DV as the 'default' which you can use if the players detect the explosives (assuming 4 hits on the Demolitions+Logic test to place the stuff, 2 kilos of R15 Foam/Plastic Explosives will give you a DV of 26.87 pre-rounding, while 3 kilos gives you a DV of 32.91 pre-rounding), but if they don't find the explosives, just give them a cinematic description of the explosion tearing the van to shreds, and make them do a damage resistance roll - then, fine-tune the actual damage so 1 or 2 of them are about halfway between KO and Dead from the damage.

[Automaton]

Thank you all for the great input!

Its interesting to see the different aproaches to this problem.
But you have given me enough to play with and make sure that it doesnt have to be an end of campaign event.

[All4BigGuns]

You really shouldn't be doing this in the first place. If they've already gotten into the vehicle, this would generally mean they have no reason to believe that it has explosives attached, and since I saw a quote from you stating that the explosive device is underneath the vehicle, there is no way that they could get a Perception check to notice it--this basically turns it into a nigh-unavoidable damage resistance against what is likely to be a rather high Damage Value.

[Michael Chandra]

Of course they could notice it with Perception as they approach the vehicle. Only a bad GM would't allow players to notice things that they clearly might notice, and he made clear he's not a bad GM like that, giving them multiple shots to notice/realize and not aiming to kill.

[All4BigGuns]

Not really, they couldn't. The only way that they would be able to really stand a snowball's chance in hell of noticing an explosive in the undercarriage is if they were underneath the vehicle, and I find it unlikely that any of them would be paranoid enough (this would be getting to the point of mental illness in paranoia) to look underneath every vehicle they get into.

[Michael Chandra]

So it's a -2 for not paying attention and glancing the bump underneath the car by accident. Intuition 4, Perception 4, Vision Enhancement 3, -2 penalty, threshold 4, 4 players getting a check, 82% chance at least one notices the device.