What parts do you think qualify as "bolt-ons"?
 

Seriously. Some guys in the Strictly Scion Facebook group jumped on me for saying a turbo kit isn't a bolt on. This is the engine section so the focus is on the engine part obviously.

Engine
pulleys

Intake
filter
CAI

Exhaust
header
overpipe
frontpipe/downpipe
cat-back

Suspension
coilovers
springs?
sways
LCA

Fuel (or is this engine?)

Drivetrain

Because a turbo requires a lot more than just stringing up some bolts. Need to tune it, wastegate, BOV, intercooler, oil lines...

To me, a bolt on is an easy part that can be completed in an hour or two with some wrenches and ratchets. I consider a turbo a project, or a wallet denter.

I've always understood the term "bolt on" to refer to engine performance mods (not suspension, chassis rigidity, etc), more specifically those that don't require the engine itself to be disassembled or removed (valve covers, heads, block, etc). A bolt on mod may even require a day or two (such as a turbo kit) but simply doesn't require the engine itself to be cracked open. An intake, exhaust, catch can, etc.

Many other parts are technically "bolt on" as well, such as a chassis rigidity mod or coilovers, etc, but this is typically a given, unless the part states some modification is necessary for fitment.

I wouldn't call a turbo a bolt on either but I also wouldn't jump on for saying that.

I installed a jackson racing supercharger in my civic in just an afternoon is that a bolt-on?

In my opinion, it's a bolt-on until you crack open an engine to replace a part with something stronger/better performance potential. Because then it becomes a bolt-in, as you are fundamentally changing the property of the engine itself and won't run with stock tune.

What about "Lick-um-Stick-um" parts?
Those are useless and tacky most of the time.

That's the exact same argument I made. I can't just install it and drive. You have to go through a tuning process.

I'd still call a turbo kit a bolt on, if it's a kit. If fabrication is required etc. It is no longer a bolt on IMHO.
If the engine needs to be cracked open it's no longer a bolt in either. if the sump needs drilling, no longer bolt in. If the sump needs replacing, borderline but I'd still call it bolt in.

Tuning has little to do with it IMHO. Coilovers are bolt in but should have a wheel alignment done. Same thing.

Exactly what I would define it as too - a simple installation that can be *completed* by anyone with basic tools.

The second you have to strap your car to a dyno or put it up on a lift it's no longer a bolt on. Note that some FI kits would qualify if they come with a canned tune because a re-flash is something an average person can do at home.

But tuning is a form of fabrication - you are building (fabricating) a custom software map to match the modifications. Without a re-map your car either won't run at all, or can run badly enough to pop the motor.

Coilovers are a bad example because:
A) you can put it together and get a pretty safe alignment just eyeballing it
B) you can do your own alignment in a garage using tape measures and the string method.

If you didn't crack open the block/head, it is a bolt on...turbo kits can be installed in my garage on a pair of jackstands or at the hobbyshop on a lift...unbolted the old bolted on the new. Just because you have to have a tune doesn't make it not a bolt on

A turbo kit is most definitely a bolt on. A custom turbo is not a bolt on. Disassembling the engine is not a bolt on.

Bolt ons are anything that doesn't involve disassemble of the internal workings of the engine. Greddy has been selling "bolt on" kits for decades. Personally I feel cams are bolt ons on any inline or v engine. On a boxer, they are more involved so I would shy away from the term when referring to them

This thread should have been a poll... lol.

I don't care what it is, if someone wants to pay for a turbo for me, I'll be your BFF.

Pretty sure its basically slang for an parts that fits up directly with the vehicle that don't require altering the part or the car itself. Such as fabrication work or cutting of any sort. It just "fits".