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2.5" vs 3" hoodpipe for b230ft

Sorry, forgot to mention I am building up the engine with an eventual goal of 300hp. I posted a list of mods in another thread, so I'll try to find it. I guess it's not completely ZFG but like it's just meant to be a fun car, bought it for $500 CAD to learn about cars. Also I don't know what FWIW means sorry. I also just had the idea of running one of those electric butterfly valves between a hoodpipe and a downpipe with a muffler for residential driving or if I see a cop lol.

Edit: found the list:

- 60 A/R intake, 63 A/R exhaust T3/T4 turbo (externally wategated using adapter plate)
- Ebay stainless header (with flange flipped and supported)
- 13mm rods from 90+ b230ft
- new piston rings
- new rod bearings
- replacing all gaskets/seals in the head.
- re lapping valves
- porting head ???
- 2.5" hoodpipe
- new spark plug wires
- electronic boost controller
- wideband gauge
- boost gauge
- upgraded injectors (low impedance brown-top equivalent)(setup using the guide forum)
- removal of stock air box for cone filter.
- possible ebay intercooler if I can find another $200 CAD

I think that's it but I'm probably missing something lol. Ill jut edit as I remember things.

I endorse this plan, but there are issues with your layout. Namely... you'll spend lots of money making that motor right and still end up at 200hp.

It'd be easiest to start with a basic +t setup. Even with a 15g you might be pushing the skinny rods. Regardless... with a 300hp Volvo run a hood dump. Until then... my vote is still point it down.

Look at it this way. If you do it... and you don't like it/can't afford the tickets... you need a new hood AND exhaust. If you turn it down and don't like it... you need a muffler.

FWIW = for what it's worth.
LMGTFY = let me google that for you
YMMV = your mileage may vary
 
Well I've already bought 90% of the parts so there's no going back now. I'm also wondering how I would get pulled over, like is it the sound that would get me? But for me it would likely cost $300 for the exhaust parts here in Canada with a hood pipe costing next to nothing so that's the main selling point for me. Also I wouldn't need a new hood, just weld the plate cut out back on haha. And thanks for the info on the acronyms.
 
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You'll get pulled over because they'll see your ****ing exhaust pipe sticking straight up out of your hood as you do a 10km/h fly by.

BC and Alberta have different rules. Your buddy that does inspections probably does insurance inspections, which is different than a safety dot inspection. Seriously, I'm not making this **** up- I'm a tech up in Edmonton.

Fly under the radar man. A ticket and inspection is way more than a proper exhaust costs
 
Don't worry about anyone's opinions, they are entitled to make them. Just do you, 'Full tilt diva' the **** out of it! lol. ;-)
 
That piece is nice! great work.


It will be over 96dbz.

1. I ran the wastegate on my Evo external dump (though... not out the hood because I think it's ridiculous ESPECIALLY if you're trying to save money) this is mine actually lol
Toxic_Dump.jpg


It sounded GREAT until WOT. It sounded like a McLaren Mercedes as the WG was flapping about... after that, it sounded like tractor. It was also WAY too loud. And that's with a turbo in the way.

2. I ran the Volvo with both "some" exhaust and "no" exhaust. While I generally like the tractor motor sound it makes, and with the "some" exhaust once you got onto the revs you could definitely hear the neat grpA sounds (regardless of how different the motor is) it was LOUD. Like... you won't be able to have a conversation loud. This was with no turbo.

3. I ran turbo and downpipe (15g) and it was quiet enough, but it sounded like a semi truck. Too whistley. I added a HF cat and a muffler (straight through) and exited out the side and it sounds quite good now... but it's definitely too quiet. I'll probably experiment with some other choices.


Toxicfab also makes that O2 housing in a hood dump. Cutting a hole in your hood to save money is like fighting for peace or screwing for virginity. You can run it down and have the same exact thing. But my real point is... it will be loud. Unless I'm missing something silly.

You also need a plan for water.
 
That piece is nice! great work.

Heh... it's not mine. It's toxicfab... it's all super nice. I have one of his manifolds on my Evo now.

Regarding getting pulled over... don't be foolish. Cops pull people over for anything. Including but not limited to whatever they feel they can fit into the definition of probable cause. I'll say this. I felt like I was able to get away with a LOT more loud exhaust crap in the Volvo because the cops probably just assumed it was some pile of crap. If you have a pipe coming out of your hood... flush or not you're going to get noticed. Especially if you're driving like a jackass (queue the classic teen response of... I never do that, and then queue the classic adult response of... then why does it matter so much to put a pipe through your hood).

Obviously your mind is made up. You're completely correct... you might not get pulled over... but if you do it's going to become a problem.

Regarding your turbo build... read more. Be conservative with boost to start. You have skinny rod motor and youthful indiscretion. Try not to die.

Re gross polluter... ignore them... they say that in pretty much every post that doesn't meet their standards.
 
build a normal downpipe, run it open for a few weeks and hate life, run the rest of the exhaust.

hood exit is loud AF. open downpipe under the car is loud AF.

You will get a lot of attention, and you will get pulled over.
 
Well considering everyone's concern, I'm genuinely considering picking up one of those $50 Ebay butterfly valves and some how setting it up so I can choose between a muffled downpipe (not built all the way back) and a hoodpipe. The only problem is I cant seem to find a valve that switches between two pipes, they are all just open or closed (meaning I would need 2 to actually switch between exhaust options). Also I'd have to find a place to put the O2 sensor bung so that it works for either configuration. Anyone ever done anything similar?
 
Well considering everyone's concern, I'm genuinely considering picking up one of those $50 Ebay butterfly valves and some how setting it up so I can choose between a muffled downpipe (not built all the way back) and a hoodpipe. The only problem is I cant seem to find a valve that switches between two pipes, they are all just open or closed (meaning I would need 2 to actually switch between exhaust options). Also I'd have to find a place to put the O2 sensor bung so that it works for either configuration. Anyone ever done anything similar?

:rofl: really? After the beating you're taking in this thread, you're asking if anyone here has ever done something similar to an even crazier idea you just had?

The answer is no, and please...build an exhaust or run an open dump facing downwards. There's absolutely NO reason to cut a hole in the hood, except for a futile attempt at what passes for 'street cred' now...thanks to a million stupid ricer youtube channels.
 
Guys please understand that this is not for "street cred" its for saving money, that's it and that's all.

No. It isn't for saving money. Because turning it down is less linear feet of pipe than up and could be easily used as the front of a downpipe later.

That's why people are flaming you. There is no argument you can make that cutting a hole in your hood was the cheapest option. It's not. You're doing this because you want to see fire shoot out of your hood. Fine. But don't be a rube and talk about it saves money blah blah blah. :roll:
 
Oh I didn't realize it was the same amount of piping. I thought it would be much longer to do a downpipe. Will there be a big difference between a 3" open downpipe and a 2.5" ? I have much better access to 2.5" at the moment but I'll work out how to get 3" if it shows significant performance gains.
 
Guys please understand that this is not for "street cred" its for saving money, that's it and that's all.

I learned this lesson a looooooong time ago: If you can't afford to do it right, don't do it.

A hood pipe is far from the best/cheapest answer. If you're hell bent on an open exhaust, get a 90* mandrel bend, the same bend you'd use to make the hood pipe, and point it down instead of up. That way, you'll still have the extreme loudness, and will only get pulled over for noise violations and not safety/emissions violations.

A 3" open vs. a 2.5" open isn't a big deal, IMO. I'd go with the cheaper of the two, depending on what they charge to adapt the piping to the turbo.
 
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