Crossflow noise experience

[Gridgway]

I have finally got my refurbed crossflow car running properly.  It's gone from 1600-1700 with Kent 244 cams and quite a high compression ratio (higher than I was expecting, but that's a different story).

As I have posted in other tech questions threads, I've had to faff with getting the carbs set up properly and then the new Pertronix electronic ignition was all over the shop (aka broken).  But it's running now (and even quite fast while still running in).

Anyway, now to the question, it is really rather loud - much much louder than it was as a wheezy 1600.  Sounds equally to be the intakes as the exhaust.

I hadn't anticipated a "make it quieter" phase to the project, but are there any experiences out there with regard to this spec of crossflow and noise?

Thanks

Graham

PS this is not my BDR project - yes I know, how many projects does a sane person need at any one time?

[Mcalvert]

I have a similar 1700 Crossflow (244 cam on twin Webers and electronic ignition).  I have a (fantastic but now rather aged) Raceco silencer that the talented Mike Riley made for me which gets the static noise down to around 95/96db, so have never had any noise problems on track.  

 

[Andrew Gilbert]

you talking specifically about intake or exhaust (or both) noise?

The cam and the current tune will create a different set of intake noises on tick over and whilst running through the rev range, have you had the carbs balanced and set up on a rolling road to harmonise those? The exhaust side, as Michael says, a decent can such as a raceco will do wonders

[Gridgway]

Thanks both.  I am slowly coming round to the idea that a new silencer will be needed as I can't see how to do much on the induction side unless an airbox helps.  Yes it has been set up on a rolling road with the carbs balanced and jetted.

It's a good job I'm not keeping a log of costs on this one.  Looking at the Raceco site, I hope the stainless ones are cheaper than the £750 for the titanium ones!

[Iamscotticus]

Did you upgrade the 4>2>1 1.75" exhaust to 4>1 2"

[Gridgway]

It's 4 into 1 although not at home to check the dimensions, but think it's 2"

[rkeywood]

I wouldn't have thought you'd have an issue with a static test. I've used various 1700 and 1600 race engines with 234 and 244s and std exhaust over the years without a problem. 3/4 'max' revs is not that high.

[Terry Field]

I did the same with my last car. 1600 to 1700, 244 cams and electronic ignition, and a 4:2:1 exhaust, probably 2".

It was fast and VERY loud, a real 'bark'! I loved it!

I did several track days at Brands Hatch and Castle Combe with no noise problems either on the static test or the drive past reading. I think most of the noise was induction based.