555 replies to this topic

[Muncher]

Both readings were 96dB

He's now extending the silencer by about 5 inches, so up to ~32 inches long

if it is 96db now, why is he adding an extra 5"s?

As a safety margin, remember I am also only running ~220bhp at the moment but with the LSJ engine will be running 375bhp+ which will make it a lot louder.

[The Batman]

and 375

[alanoo]

I guess the delay for a 4/2/1 will be too long unfortunately...

I'll ask Chris but I wouldn't have thought it'd be too long, maybe a week or two?

Well why not...
I'll have to have it adapted to my 2bular cat next, but I could have this done locally by our welder

The 4/1 would be plug and play on my 2bular cat section but of course still not optimal at all on my N/A build

[Muncher]

I guess the delay for a 4/2/1 will be too long unfortunately...

I'll ask Chris but I wouldn't have thought it'd be too long, maybe a week or two?

Well why not...
I'll have to have it adapted to my 2bular cat next, but I could have this done locally by our welder

The 4/1 would be plug and play on my 2bular cat section but of course still not optimal at all on my N/A build

So you'd want a 4-2-1 which would have a similar flange position to my 4-1 on my 3" system, i.e. further down to the primaries are longer?

[alanoo]

To make a good 4/2/1 you'll have to have a flange close to the cat I don't really care, I just need at least an interim solution, I noticed the plug&play OE flanged position 4/1 has unequal lengths btw, cyl 2 appox 3.5cm shorter, not sure at all something better is doable but if this proto is for sale at a good price, I may be interested

[Muncher]

It's probablky easier if you give him a call on 01296 483777 and have a chat with Chris

[NickB787]

Got measured at Snetts yesterday at 5200rpm it was about 94, about because I wasn't a steady as I should have been good though I am pleased. Off to Bedford to check it there.

[Muncher]

Got measured at Snetts yesterday at 5200rpm it was about 94, about because I wasn't a steady as I should have been good though I am pleased.
Off to Bedford to check it there.

That's good. I don't think mine gets much louder past 4,500rpm actually.

[Muncher]

Picking it up tomorrow, it's been made repackable and the silencer has been extended by 4 inches. No packing had been lost since it was built and the heat colouration suggests it's not getting too hot leading to a breakdown in packing, which is a good sign.

[The Batman]

when will you be running 375? as once this is done then get a sound tested as me and probably many others will be wanting this information!

[Muncher]

Once I can get the new engine built. I have every part aside from the pistons, new injectors and the fuel pump arrangement, plus a few odd bolts etc. The Harrop and my porting kit will be with me next week so I can start working on the head, the endplate is coming off so Pro Alloy can do the dual pass mod to it, adjust the oil filter housing on the LSJ block and plug a couple of oil paths in the head. Anything over 350bhp I will be happy with really. Being realistic I think we are looking at Autumn time perhaps.

[techieboy]

What injectors do you need Muncher? I've got an almost brand new set of LSJ (green) injectors that have only seen some action on a dyno whilst TMS were trying to remap for them as part of the 2.4 inlet conversion.

[The Batman]

i have 2 lsj injectors that are brand new

[Muncher]

What injectors do you need Muncher? I've got an almost brand new set of LSJ (green) injectors that have only seen some action on a dyno whilst TMS were trying to remap for them as part of the 2.4 inlet conversion.

Not sure, I will check. I think they're Bosch ones, possibly the VXR ones?

[alanoo]

I think he'll need some bigger stuff than LSJ injectors

[Muncher]

I have it back now, with an extra 4 inches It is certainly quieter, noticeably so, I'd say it was just perfect now. 3,000 rpm = 89dB 3,500 rpm = 91dB 4,000 rpm = 91dB 4,500 rpm = 92.4dB 5,000 rpm = 95.5dB 5,250rpm = 96dB Very pleased

[The Batman]

oooo only leaving a couple of dbs for an extra 150bhp

[Muncher]

oooo only leaving a couple of dbs for an extra 150bhp

More than a couple, with a 105db limit @ 4,000rpm that's a whole 14db off. Plus I don't think the volume will alter THAT much with the extra power, it's more about resonance and tone at various rpm rather than volume of gas I think.

[The Batman]

oooo only leaving a couple of dbs for an extra 150bhp

More than a couple, with a 105db limit @ 4,000rpm that's a whole 14db off. Plus I don't think the volume will alter THAT much with the extra power, it's more about resonance and tone at various rpm rather than volume of gas I think.

bedford has a db limit off 98db at 3/4 revs thats what most places test at as this is the peak loudest otherwise they wouldnt test at this!

i imagine that an extra 150bhp would make a fair bit more noise but i dunno im no specialist!

[Muncher]

How do they determine the rev limit? It will quieten slighly if anything as it beds in. It is also repackable so more stuffing can be added as required.