Help - Too noisy post upgrade

[Brad Tipp]

Having upgraded a 1.6 Superlight with roller barrels ,amongst other mods, I’m now a little noisy. Autocar evening at Jonathan Palmer's site at Bedford produced 104.2Db (Yes don't ask me where the .2 came from) from the exhaust and 88Db on drive by.

I need to find an airbox that will fir the roller barrels and that doesn't cost £1000.00 !!

I could also do with changing the standard exhaust box for a larger one, that again doesn't cost too much.

Ideas.

 

P.S. I know these subjects have been raised before, but I couldn't find succinct answers for them, apologies for going over old ground. blush.gif

Maybe we need some FAQ's for Regularly asked things ? idea.gif

 

[ashaughnessy]

Sorry, I don't have any answers for you, just want to add to your questions with my own.

In Low Flying about two months ago, there was an article about a new airbox thing that Caterham have introduced specifically for the roller barrel throttles. How come the roller barrels are so much noisier?

Anthony

[Brad Tipp]

I'm sure someone will give the technically correct answer, but my understanding is that it's only on full throttle that they are much nosier. At that point there is nothing in the way of the inlet tract and thus the resonance buildup is greater.

[CHRIS CLARK]

Yes, you are right about the 999 UKP air box from Caterham to fit the roller barrel TB's fitted to the R500. Nice bit of light weight carbon etc., but worth it? UUmmm. Depends on the depth of your pocket I guess.

 

This set-up is the one mentioned in LF.

 

No easy answers for you I'm afraid.

[murph7355]

Mail Oilyhands. He has the contact details for someone (Bernard Scouse?) who has sorted an air box for Jenvey TB's which can't be a million miles off what you want. Cost was half that of the Caterham Heath Robinson cast off and included trumpets, filter etc etc I think.

 

As for your noise, doesn't sound (excuse the pun) like just TBs have caused this much? What other mods have you made? How old's your exhaust? How was it being measured (revs, dist. from car, angle etc)...

 

Mine's not exactly quiet (and is on TBs with the Caterham race exhaust) but was only at 96dB or so when measured at the RR day, which shows method can be as big a factor as anything if nothing else...

 

PS Am looking at an FAQ with Barry. I often talk sh*te but plenty of people on here don't so condensed wisdom would seem like a good idea! Anyone wants to input, mail me (or Barry I guess - check out the 'Suggestions' link on the Blatchat front page).

 

Edited by - Andy Murphy on 29 Jun 2001 02:22:30

[Brad Tipp]

Exhaust is 2 yrs old with 6000 miles on it.It's the race exhaust 4 into 1 . Other mods include gas flowed head and uprated cams as you would expect.

The rate was measured 0.5 mtr from the exhaust 1t 45 degrees.

 

Yep it seemed load to me, but mine was 98Db before any mods, so maybe you had a really low reading?

 

I'm going to try to make up an airbox and see how that goes, and change out the exhaust box for a larger cross section one.

[EFA]

The company who make the airbox for Caterham have shown interest in making one for the 48mm Jenvery tapered bodies in that there are quite a lot of them around.

 

I offered my car to be the mule, but I would suggest that the air intake still be outside the car behind the headlamp "pointing forwards"

 

This would maintain the ram air effect without the risk of hydraulicing your engine should you hit a big puddle. As the filter is forward facing, this would certainly mute the drive by levels, and hopefully have an effect on static.

 

Circuits know that the static reading is often inaccurate due to reflection and surface on shich the car is tested, and as the objective is to reduce drive by noise I think getting this down to a sensible level will get you on the circuit.

 

Anyone interested in getting a low noise ram air filter box for a VX made up in carbon contact me and we'll do a "lets buy it..."

 

I do have contacts that would also make the tools and components for us directly if there are any draughting types out there want to design them.

 

 

 

Arnie Webb

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