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Too loud for trackdays!


turbobungle
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My UK Spec TT is (way) too loud for most track days, I have a Nur Spec exhaust and no cats, standard manifold, Blitz Induction kit, I went to a track day with a limit of 99db, they told me to hold the revs at three quarters of max. revs and they took their reading. 109db! I put in the Nur Spec insert which took it down to 106db, then the track sold me a load of fibreglass matting to suff in the exhaust with the insert. Eventually it got down to 100db with them being lenient on the revs but then every straight i got to my mate in his Skyline pissed all over me!! I was well down on power. Anyone got any ideas for a quieter track friendly exhaust without compromising on power?? Please help!

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As said, not a good idea to track a car with all that in the exhaust!

 

I'm getting a Blitz Nur spec RX one soon from Nic and i'm hoping that will be quiet enough for my car... I'm aiming for 95db.

 

My exhaust is 3" from the turbo back.

 

I'll report on it next month when it's on the car and I'm back from the Nurburgring.

 

EDIT: woo 4000 posts

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the nur spec is renouned as a loud exhaust due to its straight through design and stainless construction, if you must keep it i would look at having maybe a couple of 3" silencer boxs welded in (magnaflow, borla, etc) and wrapping the whole exhaust, i run a mild steel superdragger which are one of the quietest "big bore" types

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the nur spec is renouned as a loud exhaust due to its straight through design and stainless construction, if you must keep it i would look at having maybe a couple of 3" silencer boxs welded in (magnaflow, borla, etc) and wrapping the whole exhaust, i run a mild steel superdragger which are one of the quietest "big bore" types

 

 

Does the Superdragger keep it quiet enough for track days? Has yours had the cats removed etc.?

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Bugger, I was hoping that inserting the baffle would let me run at Goodwood:(

 

No chance. I had just a cat back exhaust and induction kit and only just got on that track. They don't like loud cars there. Fantastic track though.

 

I've got a noise tester if you reckon yours is quiet enough

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Bugger, I was hoping that inserting the baffle would let me run at Goodwood:(

 

these baffles as far as i can figure are designed for going to work at 7 in the morning and not unduly p*****g your neighbours off, they should never be used when driving the car hard, you are effectively strangling the engine, your egt's will be definately be in the turbo melt down zone

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these baffles as far as i can figure are designed for going to work at 7 in the morning and not unduly p*****g your neighbours off, they should never be used when driving the car hard, you are effectively strangling the engine, your egt's will be definately be in the turbo melt down zone

 

Am confused by this. Why should a baffle be any different to fitting a restrictor ring on a J-spec car and raising the boost with an EBC?

 

I'm surprised by the quoted db in the first post here. I had no problems at the Ring with double decat and a Nur Spec (no baffle), while my pals F355 was thrown off at 103db. The Ferrari is much louder than my Supra TT. I may have to have it checked to confirm the noise level however.

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Am confused by this. Why should a baffle be any different to fitting a restrictor ring on a J-spec car and raising the boost with an EBC?

 

it is the level of restriction, i used to run a restrictor ring and hole is a lot bigger than the tail pipe bung that some exhausts use, i have not seen a bung in the flesh but they seem to me to be around 1", 300 hp through a tailpipe that is smaller than a Ford Fiestas exhaust :(, the car would be better with a stock exhaust on

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Stock cat pipe back system, custom 3 box system, or a Tanabe Medallion Touring. Goodwood are VERY noise intolerant, I'd stick a stock system on it for there.

 

oops ive booked up there 105db day,

 

external wastegate yet to be plumed back into the downpipe

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it is the level of restriction, i used to run a restrictor ring and hole is a lot bigger than the tail pipe bung that some exhausts use, i have not seen a bung in the flesh but they seem to me to be around 1", 300 hp through a tailpipe that is smaller than a Ford Fiestas exhaust :(, the car would be better with a stock exhaust on

 

Don't have the bung to hand to measure atm, but its nothing like 1" on the Nur Spec. I'm pretty sure it's larger than the restrictor ring. I have a dyno plot to prove that running ~1.2bar with appropriate restriction (No EBC), the bung dropped the rhhp by less than 4% so it's not a significant restriction.

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Don't have the bung to hand to measure atm, but its nothing like 1" on the Nur Spec. I'm pretty sure it's larger than the restrictor ring. I have a dyno plot to prove that running ~1.2bar with appropriate restriction (No EBC), the bung dropped the rhhp by less than 4% so it's not a significant restriction.

 

so whats the point of fitting a nur spec in the first place, you would probably have a free'er flowing system using stock

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so whats the point of fitting a nur spec in the first place, you would probably have a free'er flowing system using stock

 

Not sure how my comments suggest that a Nur Spec is more of a restriction than a stock system? I'm merely comparing a Nur Spec with or without the baffle (the difference being less than 4% at BPU). The baffle only appears small compared with the Japanese insistance of making a tail pipe the size of a dustbin! The car came with the exhaust so I haven't spent any time researching the best system for the car. I would have preferred a smaller bore that had more clearance around the diff.

 

On a J-spec TT you need to have a restriction in the system so nobody can claim to fitting a 'performance' exhaust because they need it more free flowing (and then stick in a restrictor ring!). The exhaust gets changed because the original has either rotted away or the owner wants it to be louder. Weight is no doubt improved also.

 

With regards to the adjustable valve Jody, they have drive by noise meters as well. In a previous car I've passed the static and failed the drive by.

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90% of proper circuits do drive by testing throughout the day. Why not just NOT follow the sheep and fit a sensibly quiet system in the first place. Job done :) There is NO WAY an externally vented wastegate will pass any on circuit noise testing.

Chris, what do you think to adding a baffle to the wastegate, as a quick & dirty fix Vs plumbing it back into the exhaust? Someone suggested this to me recently and claims it works fine on his single Supe.

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