[Mk2] [Turbo] Japspeed exhaust plus bung fitting and DB readings

[Phill P]

Hi peeps

Thought I'd just put a post up about fitting some ebay bungs to my 4.5 inch Japspeed tailspipes.

Once fitted will also get DB readings for a normal car (wifes Rover 600 2.0 petrol) and a friends mucho modded Skyline GTS,with and without bungs

At the mo the mr2 at tickover 800 or so revs the DB reading is 80.5 from 1 metre and 45 degrees (taken between the pipes) with no bungs fitted.

Will update as and when.

Paul

[loudandproud205]

what db meter will you be conducting research with?

[Phill P]

Don't know make as its a friends,but it was used at a company that did pa's systems and rental of large screens to conferences so it should be accurate and will give a reference point to what can be done with a simple bung.

paul

[Phill P]

Tis this one

http://cpc.farnell.com/_/st-805/sound-l ... dp/IN04453

Paul

[loudandproud205]

thats pretty much what they use at track days but with extended mic so should be intresting to read results.

i tried to do mine with a friends RTA that we used to use for db drag but so far are mics havnt proved to be sucessfull, since phase out of old mics its now bloody hard to anything with them other than stick them in the window and use them for spl tests

[Steve-O 2007]

are these the £25 each ones?

[Phill P]

Yes they are,turned in a couple of days and will try to fir tommorrow depending on weather.

http://cgi.ebay.co.uk/TUNABLE-EXHAUST-B ... 5d280ec916

Paul

[lockys96]

track days will do 0.5m at 3/4 revs

make sure your rev limit is 7,ooorpm lol

its a shame there is more mechanical noise from the mr2

[Phill P]

Ok bungs fitted,didn't get to position them further in the exhaust due to Japspeed fibs,when they say 4.5 inch tailpipess they mean external. Also chopped around and 1.5 inches off the end as its running flush with the slash cut which was badly off centre the 3 inch curve of the exhaust.

Anyways,performance wise it boosts a little slower and up tp .85,whereas before it was around .91.

Noise wise,its like a standard exhaust,all the noise now is the Apexi doing its thing

Will do DB tests at weekend.

Paul

[loudandproud205]

looks positive then may have to get myself one pending noise on the 5zeigen exhaust am getting as it dont look like its silenced very well :p

[Phill P]

Oky dokey

Slight booboo in that I got me maths wrong and couldn't remember if it was 3/4 or not of max revs so did it to 4500,if I can will re do at 3/4 revs.

MR2 with bungs in

Tickover 76.8 db

At 4500 92.5 db


With bungs out (although cat still fitted)

Tickover 81.1

At 4500 98.6

At 7000 108.8

Did the Skyline gts with no cat and bung in...... build thread here http://www.skyline-owners-club.com/foru ... e-mk2.html

Tickover 78.2
4500 94.5
6000 106.5

Bung out

Tickover 86.6
4500 102.1
6000 107.1

And up the side of the car the screamer pipe was starting to come in to the party at 109.8.

Although boost was low at this point as not loading the engine.

Hope this helps.

Also got to hear mine for the first time from behind

[loudandproud205]

interesting read, yours didnt seem as loud as i expected tbh

[Phill P]

I was surprised myself after hearing all about the legendary Japspeed exhaust and how your hearing will fail in 2 minutes.

Didn't get to test the wifes normal rover 600 for db reading but I suspect that with the bungs fitted plod would pay you no attention at all over your exhaust.

Infact most of the noise at least from in the cabin is mechanical.

However the downside is that although I got to follow my car and hear the exhaust for the first time from behind,and it did sound nice,.......it will never sound as nice as 6 cylinders


Paul

[lockys96]

well if you can get a fujitsubo legalis r you can get 96db at 5,000rpm on a stroked engine and with wild cams and have 480hp no bungs

[Rob]

Interesting thread - I have these waiting to go in, although I believe mine are a different make.

With the restriction to the exhaust flow, is this likely to cause more back pressure and damage the Turbo?

[Phill P]

http://www.imoc.co.uk/forums/viewtopic. ... highlight=

[BiGWiLlYsTyLe]

I need some bungs for my Japspeed too.

Why wont the fit right into the pipe? Would you need smaller ones bud?

[Phill P]

Diameter of the bung is 4.5 inches,however Japspeed exhaust internal diameter is less by a few mm.

[Rob]

http://www.imoc.co.uk/forums/viewtopic. ... highlight=

Thanks mate, although i am not sure on just 1 persons opinion. With the stock exhaust the gasses go straight out of the pipe and not bounce back off the solid wall of the inner faces of the bungs which could cause a pressure trap.....

[Phill P]

Unfortunatly no one else commented

Paul