Question for those with 3" exhaust and lowered

[--Wolf--]

How do you have a 3" pipe and have your car sacked on coilovers while staying legal?

Had a thread on this a while back but now need to get onto it for cert and wof. Basically the back of my exhaust sits slightly under the dif so is roughly 50mm off the ground and needs to be 100mm for legal. Car is lower than display pic, and don't really want to raise it up (But might have to). Exhaust place said would probably need to go 2 1/2" because with 3" they could only remake it and move it so it sits about 20mm higher (so it clears the dif) (has to have 10mm clearance between pipe and body also)

Any ideas? Want to stay low and 3" and legal if possible.

(attached is pic of how exhaust sits, but when the car was higher, was told in previous thread it was just missing a hanger but it physically can't be held up any higher the way it is and $300 to have it redone 3" and only 20mm higher seems a bit much)

 

[Scruggs86.5T]

Guessing your lowered on springs. Why not replace your rear springs with the old stockers and then go get it inspected. After your inspection just drop it back down.

Sent from my DROIDX using Tapatalk

 

[--Wolf--]

Lowered on coilovers.

For cert they put the height of the car on the cert place and then you only have +/- 5% to change.

 

[mecevans]

oval shaped 3in pipe crammed as high as possible or if you really have to then cut the subframe.

 

[te72]

I don't like scraping the shit out of my exhaust and front lip, so I keep the ride height high enough for the area I live in... but if I were to live in a place with smoother roads I'd have mine lower. Even at this height I doubt my exhaust is 100mm off the ground in all places, and my car is pretty high, considering how others and my old car with Eibach's used to be. Are they really that strict about your undercarriage?

 

[harojake]

ive got a 50 merc lowered and to clear the exhaust from shitty michigan roads i got some rectangle pipe, it sits high enough off the ground and far enough from the car and still sounds and performs like a 3 inch exhaust, i also used the same kind of pipe on a 32 ford show car sittin 2 inchis from the ground

 

[whitemike]

Cutting the subframe so you can keep the car lower is probably the stupidest thing I've heard in a great while.

 

[te72]

Cutting the subframe so you can keep the car lower is probably the stupidest thing I've heard in a great while.

Could always JB Weld it back together if you screw it up, right? Right?

 

[OfnaRcR4]

Cutting the subframe so you can keep the car lower is probably the stupidest thing I've heard in a great while.

+1

 

[hvyman]

Lowered on coilovers.

For cert they put the height of the car on the cert place and then you only have +/- 5% to change.

How are they going to know if you changed it? Raise it up, inspect it, lower it back down. Ive never heard of this before tho.

 

[mecevans]

Not talking about a hack job here. I have seen a couple mk3's with the exhaust hump notched slightly so that the exhaust tucks better. But, they have reinforced subframes.

 

[Poodles]

How are they going to know if you changed it? Raise it up, inspect it, lower it back down. Ive never heard of this before tho.

More than likely it's listed on the registration so if he gets pulled over the cop can look at it and compare.

IIRC Japan had some of these ruls as well, might explain some of the odd exhaust systems they made back in the day for our cars. I remember a few that went down to 2 smaller piped to pass under the humps in the subframe and then joined back up at the muffler. Would give you more ground clearance there.

 

[--Wolf--]

Cert plate goes on the car itself. Need cert for coilovers among other things. And lowest point of the undercarriage has to be 100mm off the ground for any car/suspension.

I've never had that part of the exhaust scrape and it probably never will unless something goes under the car because of where the wheels are in relation to it.

How would 3" to say 2 or 2 1/2 at the low point then back to 3" perform? Exhaust system isn't 3" straight through, just the back, but definitely want to finish it off something. Otherwise I'd probably have to go 2 1/2" for the whole thing. And would it need to go back to 3" at the muffler or could it just stay 2" and whatever for that last couple of feet?

 

[Poodles]

You could either hunt for the rare systems that did it, or make one of your own that splits off to 2 smaller pipes to keep the same flow...

I think lilmiss had one of those systems, I'll have to look...

EDIT: found it, shamelessly stolen from LilMissMKIII

 

[--Wolf--]

Ah read your first post wrong... So 2 smaller pipes would give the same flow, but how much difference would having 1 smaller pipe at the back make if the rest of the system was say 3"? Seems a lot easier and I only have until 5th Aug to get it done. Will see if I can find that system tho

 

[GrimJack]

Have a look at how mine is run...

Now that's twin 3 inch pipes, but I don't see why it can't be done with smaller pipe. One 3 inch pipe is 7.1 in[sup]2[/sup]. Two x 2 inch pipes is 6.6 in[sup]2[/sup]. Two x 2.5 inch pipes is 9.8 in[sup]2[/sup]. So 2" pipes would be a small restriction, 2.5 inch pipes would be none at all.

 

[Poodles]

I updated my post

Oh, and Grim, those pics load like their being beamed from some guy with a telegraph...

 

[GrimJack]

And +/- 5%? That's freaking ridiculous. You get more than that filling up the fuel tank. What happens if I have a full tank and two fatties in the back seat? When people make up stupid rules that can't work in the real world, I find a way around them, rather than try to conform. Like install an electric exhaust cutout for when I want performance, and use a stock exhaust the rest of the time. Or get it certified with the tank dead empty... or if that doesn't work, lift the car back up, then drop it as soon as it passes to whatever height I want. If I get caught on it, I'd go before the judge and say it was the extra fuel ... or that I was carrying cinderblocks in the hatch ... or dispute the police ruler. Or something.

 

[GrimJack]

I updated my post

Oh, and Grim, those pics load like their being beamed from some guy with a telegraph...

Ya ya ya... they are hosted on my machine at home, which has only so much upload bandwidth, and they aren't small. It's just so damn convenient posting stuff when you get to copy it to a network drive rather than try to upload to photobucket.

 

[--Wolf--]

Looks like a very nice system, probably very expensive as well. Not only would I need the extra piping but they told me each bend was $30. I couldn't even go twin 3" because even a single 3" fitted properly and as high as possible would still be way to low. Mine would be lucky to be 50mm off the ground under that subframe.

The only way would be the twin 2.5" for the same performance but for the money I think I might as well just go single 2.5" since the rest of my exhaust is only that atm anyway. Should also quieten it down a bit as well since I got picked up on noise.

Would love to be able to get around the rules but they're pretty strict on the car lowering. If anything underneath is not 100mm off the ground, or I have coilovers and no cert then car is instantly required to be off the road with a nice fine until it's fixed.