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How loud is R1 + mnr exhaust -- Marc??
bitsilly - 22/6/07 at 12:16 PM

Marc, or anyone if you can help.. Does anyone know how loud the old orange demonstrator car I bought is, it is the orange R1 on carbs powered with the exhaust made by MNR. I think it has been to brands hatch before!

TimC, the exhaust is the same as yours I think!
ps is it an option to bring wire wool and chicken wire to keep it in? I have to get it below 100db.
Cheers


chockymonster - 22/6/07 at 12:33 PM

Mine (on a FI engine) went through SVA at 94db!

That's with a panel filter, not an airbox.


amalyos - 22/6/07 at 02:29 PM

That must have been with the CAT on.
Mine was low with the CAT but once it came off, it will go up.
I have a 5" X 30" MNR exhaust. and it measures around 102db @ 7500rpm, on a cheap EBAY noise meter.

Steve

[Edited on 22/6/07 by amalyos]


smart51 - 22/6/07 at 02:40 PM

I was getting 108 dB(A) with my MNR can and carbed R1 engine. see this thread

http://www.locostbuilders.co.uk/viewthread.php?tid=39899&page=2

I fitted a bigger can from The Kit Car Workshop which was measured at elvington at 102 or 103. I fitted and extra 130mm long 6" can which brought that down from 105 dB (on my noise meter) to 100 dB.

http://www.locostbuilders.co.uk/viewthread.php?tid=63423

The MNR can was measured by Procomp and the others by my uncalibrated noise meter from Maplin. Marc has always said he got lower readings with calibrated meters.


bitsilly - 22/6/07 at 03:42 PM

Cheers gents. I hope to pop out to Llandow, smile nicely and see if I can get a free check.
Have also been told I can calibrate the revs lower than they are but I'm sure a scrutineer would be on the lookout for that.
New can is an option if all else fails, or is the MNR can repackable?
100db seems a bit tight!


bitsilly - 22/6/07 at 03:56 PM

Smart, thanks for the links. Seems I may well have to spend more money.
What has happened with yours now, does it pass at 100db?
How much did the bolt on bit cost? What would you do if you were me???
Much appreciated.


TimC - 22/6/07 at 04:21 PM

Ed

Ring me over the weekend and I'll pop down with my can. I think we'll find that it's longer. If it is, I'm sure that we can sort out a temporary swap.

TC


marc n - 22/6/07 at 07:12 PM

think last time i used it was donnington, cant remember what their noise limit was but im sure its pretty low, and it passed no worries, might be worth checking the packing in the exhaust if you are worried as it doesnt take much for it to get hot and collapse, one thing i have found is that the packing lasts no time if it is running and not moving with airflow, last sva had this problem

best regards

marc


smart51 - 22/6/07 at 07:35 PM

quote:
Originally posted by bitsilly
What has happened with yours now, does it pass at 100db?
How much did the bolt on bit cost? What would you do if you were me???


I made the small silencer. The end plates came from Miliner off road and I had a friend weld in the pipes. I got a guy off eBay to sell me a bit of 6" tube but fireplace companies will sell you 6" stainless flue pipe.

Will mine pass 100 dB? maybe. I measure it at 100 - 101 dB but I suspect that my meter reads high by 1 or 2 dB.


rjbrookes - 22/6/07 at 08:59 PM

i seem to get random results...depends on the day the weather and the noise meter!!!

had - 92@4000 102@4500 101@6000- and 103@8500!!!!!! mine leaks so dont help but the 92 was without leaks....

make sure your panels and seat harnness etc are all "tight"/not rattling

russ


bitsilly - 24/6/07 at 07:06 PM

Thanks everyone.
Tim, I've been away for w/e, will ring asap.