I was toying with the idea of an HKS Hiper backbox and centre, along with my ScoobySport downpipe.

I like the idea of the extra noise, but I would like the ability to make it quieter! (For those late night/early morning returns!!)

I've been told that there is 'bung' you can get to make it quieter!

Does this 'bung' have a great effort on the amount of power or noise?

With the bung in, how does it compare noise wise to say a full ScoobySport system??

How much does it cost?

Cheers
Andy

 

Hi Andy,

Take a look at this link

 

And disappoint all your neighbours?

Scotty.

PS: I'll do a swap for my SS backbox if it bothers you that much

 

Andy

I think they sell the bung that you are looking for in Amsterdam

Sorry couldnt resist

Ian

 

Andy,

Totally unrelated to this thread. Was at Cheam at lunch time... When are they starting work on your car ? Thought things would be underway by now..

Scott.

 

Andy,

It is very easy to make the HKS Hiper backbox much quieter by using the original HKS silencer which slots inside the tailpipe and does the job admirably at a very low cost.

According to those who are using it as and when needed it preserves the performance in most parts of the rpm range, except for the very top end where it is a bit reduced.

Also, HKS not loud at all when used in conjunction with a proper downpipe and without the JECS ecu. Once the fuelling is optimised there is a 6-8dB reduction in noise just from there.

Call me or email of you need further assistance.

regards
q.

 

Thanks for the offer Scooty, but maybe not yet!!

Ian, What you do in the privacy of your own bedroom is your own business

Thanks Nito, I did a search but couldn't find anything!!!

Scott, some minor work will be done on Monday, and it goes down to the bodyshop after. I should have it back around about the 7th!! Sooner than I thought!!

Thanks q, I'm sure we'll chat about it as soon as I get my car back!

Cheers
Andy

 

T8NGO!

I have experience of this and agree with q to an extent.

I have an HKS Hiper which is groovy - however once I fitted the BPM downpipe things went a bit awry.

The car seemed quieter inside, especially at easy cruise, however on full bore and outside it was noisier. At Castle Combe with this set up I was turfed off, measured at 105-107 db at 4,500. This was with what I would regard as a fairly good non-Jecs map in the car (btw, q is correct a good non-Jecs map is quieter and smoother).

Anyway, I do have the HKS 'bung'. On the road datalogging would suggest that using the bung did not 'significantly' reduce gas flow and the car felt as if it performed very close to the original. On track, however, removing the bung made a much more significant difference, with the care requiring significantly extra fuel in all zones from 5000rpm upwards. The car was also boosting more readily.

In terms of noise I would suspect that inside the car is MUCH quieter and although I have not had it measured, I feel that it would be around 90-95db with bung. It is definately quieter than the a full SS system.

Technically it is interesting as the bung has the same internal diameter as the exit pipe from the HIPER backbox (although smaller than the tailpipe ).

If you are coming to the next Fleet Meet (Sunday 11th) then I can take you out to demonstrate - although not around the Bends

Cheers,

R

 

Rannoch,

Thanks for the advise, and my car should be there!!

Although I won't be going through the Pirbright Bends!! I'd love to hear the difference it makes!!

It might be all academic, as I might be swapping my exhaust for Ronnies Super Drager! I've been told that it's quieter than the Hiper!!

We'll see I guess!! I can't make any decision until I get the car back!!

Cheers
Andy

 

Andy,

you don't want that puffy thing that Ronnie has, and if you take it, we'll set Penni on you.

See you soon mate - hope your car is on the mend!

Cheers,

David

 

Try looking for a little device called a "Super Trap" Used to be very popular with the Rally Cross boys. You can add baffles easily to suit the occasion - ie totally remove the thing on the road coz it looks a bit strange on the end of the pipe or play about with the number of baffles to get the required dB(a) SPL for the track etc. And don't worry too much about the "perceived" loss of gas flow - if a 600 HP monster Rally Cross engine works fine with it ???????