Exhaust fabrication to meet Track Day regs.

[petbeemer]

Currently 109.8db, tested last week at Brands.

Would like to get it < 100 ideally.

Well ive looked for the Dep2Pro back box to give me an idea but can't seem to find any, presumably its a big empty tin can on the end? silenced tail pipe will bring it down 2db's or so and take the rasp out of it but i think you'd be looking to replace the silencer with something that actualy works, a decent back box working on absorption shouln't be that loud if it is then theres certain tricks you can do to make it quieten down still further that loose very little in power

[cantfindausername]

This is the exhaust...

http://www.car13.net/images/project/rebuild/113.jpg

The rest of the system is custom stainless jobbies. Is that likely to increase the db somewhat?

[petbeemer]

This is the exhaust...

http://www.car13.net/images/project/rebuild/113.jpg

The rest of the system is custom stainless jobbies. Is that likely to increase the db somewhat?

Ah...they look to be absorbtion type boxes i.e perforated tube running straight through with sound deadening material around the edges, length is the problem 2x short cans don't equal 1x long can your only hope is to get someone close to make you silenced tail pipes, im guessing.... but the pipe size looks to be around 2.5" entering the boxes with tail pipes 4.5"? that should give you something to work with, the only other thing would be to place perf sheet in stages 'slots' in the perf that runs through the box, that will make the noise travel into the material inside more without killing power.

Peter

[cantfindausername]

Thanks Peter. A few places have questioned fitting a large single silencer as these reduce noise better. I'm more looking for a redesign than an adaptive solution to this exhaust.

[petbeemer]

Thanks Peter. A few places have questioned fitting a large single silencer as these reduce noise better. I'm more looking for a redesign than an adaptive solution to this exhaust.

Personaly i'd plump for a single box, where the stock one was but just have a single tail on the right, presumably your on 3" for the system so should get a nice size box underneath, make sure the stainless is grade 3 or better and at least 1.6mm that should give it a nice deep burble

[cantfindausername]

Thanks again for the advice. I think the silencer would need to be more towards the cross member due to the boot mounted i/c, but generally you've summed up what i'm looking for. How much would a you be able to do a piece of work like this for, and what sort of turn around times would be involved?

Thanks,
Ant

[Bender Unit]

BALLBAGS!

Got the bits I needed to modify my drop in bung, only to find that its missing - it must have falled out at the last trackday - cant understand how as it was nearly impossible to fit / femove it was that tight and also bolted!

Does anyone know where I can get drop in bung inserts with a 3.75 dia? No one does one that size or at leats that I can find.

[Bender Unit]

OK found a company that sold me some exhaust spares! Total bargain, £15 for 2 meters of stainless perforated tube and 4 end plates - will be using them again as they sell it all!

So I did some measuring cut what I needed



Then some weld to hold it all together.



The bung slots down into the tail pipe - had to run a flap disc around the end flanges as it was a bit too snug. Drilled a hole so it can be bolted into place. Just need to wrap it with some wadding now.

A quick check even as it is, has dropped the dB by 1, so the wadding should help further.


Annoyingly having a clear out in the garage I found my other exhaust bung! DOH!

[cantfindausername]

Cool, good to see the idea coming together. Would be great to see some vid footage of it with and without the homemade silencer.

[Yas]

Any joy on this guys? Not had mine tested but I reckon it's around the 120db mark It's way too loud for town driving and my neighbours have already given me an earfull!

[lockys96]

fujitsubo legalis r on 272 cam, big turbo 480hp is 96db at 3/4 revs

[Yas]

Sweet! Did you find any restrictions on the legalis whilst mapping? I take it 480 isn't on full boost? I'm off to Simpson Race Exhausts in the morning to go through some options on silencing my current 5Zigen or making up a new system.

[lockys96]

480 is full boost at 1.5bsr

[cantfindausername]

Sweet! Did you find any restrictions on the legalis whilst mapping? I take it 480 isn't on full boost? I'm off to Simpson Race Exhausts in the morning to go through some options on silencing my current 5Zigen or making up a new system.

Look forward to seeing what they come up with. Still toying with the idea of getting them to fab me something, but will have to be a bit down the road for me I think as there is just too much other stuff to do.

[Yas]

Just got back, they said it's not even worth trying to silence the 5zigen cos it's too bloody loud

Spoke to Matt and he reckons the best option is for them to make a new system from the downpipe, so mid-section with flexi over subframe 90degree bend right.. 180deg follows into a massive box then exits out the left/rear.. something like this I imagine but the other way round



Price £700+vat

Tbh with a design like that i'd rather track down a legalis/hks hiper or similar, will be cheaper to My main concern with a big box is heat transfer into my bmic and airflow issues with a massive silencer in the way, but if that's the only way to go I guess I can work something out.

[lockys96]

the fujitsubo is at its limits at 480hp if you want to track, its a good option.

i wont go into details about H&S exhaust, but that thing was such bad heat build up.

the fujitsubo is a good exhaust. i have a sheet of reflective metal stuff under the boot floor to desperse heat, its is expensive stuff, but works, as i too have a boot intercooler

[lockys96]

oh and there are 2 of them for sale on ebay now, absolute bargain

£150 and then $262 to ship to UK.

that will be about £350 with tax/duty, so bargain

[Yas]

I'm on a GT3076 and i'm hoping to see more track action than dragging so I think i'll be on a look out for a legalis, anyone know how loud/quiet the HKS Hi-power or Hiper is?

Edit: on my way to ebay, cheers pal

[cantfindausername]

Yas, that design is what all the places I've spoken to about the MR2 have suggested. The big single silencer is the best way to get an decent sound deadening. I too am in the BMIC/Heatsoak boat. Its not a great boat to be in to be honest as it massively restricts the exhaust possibilities. I'm wondering if the silencer could be moved nearer the subframe though rather than the bumper. I think I'm still going to visit a few places when my car rears its head again. There is a place in Lincoln that I've been recommended by my tuner and its just round the corner from him, so no doubt I'll be paying him a visit to discuss when I'm next up that way.

[cantfindausername]

ok now I'm just thinking of stupid ideas. What about a silencer in the down pipe area? Would that see too much heat you think? Guess it would just burn up the matting inside pretty quick eh?