Topic: Straight thru' exhausts, are they.... (Read 4030 times)

landraver · « **on:** December 27, 2005, 21:06:18 »

legal? i.e. will it pass an M.O.T.?
I've built one for the 90 but will it pass? The 90 is an '87 with a 300tdi engine. The exhaust exits between the passenger door & the rear wheel arch. Your thoughts would be appreciated!
Cheers fellas
Jeff

Xtremeteam · « **Reply #1 on:** December 27, 2005, 21:09:02 »

mines is straight thru,only has the diddy wee silencer at the back & is made up of about 4/5 different bits o landy exhaust welded together,on a diesel its ok to have no silencers as the turbo kills nearly all o the noise

Paul · « **Reply #2 on:** December 27, 2005, 21:12:56 »

Depends on the noise emitted from the vehicle...

If it is clearly unreasonably above the level expected from a similar vehicle with a silencer then it can be failed.

There is also no requirement for a diesel to have a silencer.

HTH

Canada Al · « **Reply #3 on:** December 27, 2005, 22:42:23 »

my SIII SWB 2 1/4 petrol has a staight thru and I have never had any trouble at MOT time ......Al

drmike · « **Reply #4 on:** December 28, 2005, 07:11:59 »

Is there any benefit to a turbo diesel having a straight through exhaust?

rollazuki · « **Reply #5 on:** December 28, 2005, 09:47:17 »

The zook(diesel) has a straight thru exhaust and to be honest, it is soooo quiet. Passed MOT no probs, Id like to make it a little louder if anything.

V8MoneyPit · « **Reply #6 on:** December 28, 2005, 15:03:22 »

I'm about to build the system onto the V8. One silencer 23" long and 4" diameter using 2.5" pipes. Will exit above the jackable sill through the body side ahead of the rear wheel arch. Should sound 'bootiful' as they say in these parts :D

Oh, and I have Land Rover enthusiast as an MOT tester :D

johnniep · « **Reply #7 on:** December 28, 2005, 21:02:17 »

i have a rangerover v8 on open pipe, home made, but i have just welded in a stainless absorbtion box, which keeps it nice and burbley low down, but plant it and your on a rocket ship and its soounds soo nice!! if youwant it to be quiet, jsut change gear nicely at low revs but if you want boot it, and it also mean evri one knows where im 2 at a trial!!!

cheers
johnniep

landraver · « **Reply #8 on:** December 30, 2005, 13:14:06 »

Thanks for the replies fellas.
Now you've put my mind at rest I'll carry on with cutting the hole in the bodywork :D
Jeff

drum · « **Reply #9 on:** December 30, 2005, 15:16:50 »

Quote from: "landylover"

Thanks for the replies fellas.
Now you've put my mind at rest I'll carry on with cutting the hole in the bodywork :D

That was restrained of you, I'd have cut the hole then asked the questions :D

robbie · « **Reply #10 on:** December 30, 2005, 17:48:58 »

Me too.... but only when the weather warms up a bit :)

Eeyore · « **Reply #11 on:** December 31, 2005, 11:38:14 »

As an interesting aside, a good friend of mine (in OEM powertrain*) did some calcs regarding the ideal exhaust bores for tubular systems. Apperently, as a quick and dirty, the ideal is about 1" of bore per 100 hp output from the engine. But this only works for petrol, apperently!

I didn't ask him about twin pipe systems.

Just a little snippet that might be helpfull for all our budding pipe benders out there!

cheers
8)
Eeyore

*He developed a cracker for Bentley that cranked out 800 ft/lb 'o' torque at tickover :twisted:

V8MoneyPit · « **Reply #12 on:** January 03, 2006, 17:47:45 »

With due respect, I would suggest that this rule is a little over simplified. The system length, silencer size/design, bends in the system, head porting design, etc. all have significant effect on power output. The bore must vary depending on the other factors.

Results of tests on the classic Mini found a 1.75" bore system worked best for outputs from mildy tuned (say 50bhp) right though to over 100bhp. This is with a long centre branch manifold off the 3 port standard head (the middle port is siamesed). Once you get above about 110bhp, a 2" system flows better.

If 1" per 100bhp was standard for the OEM's, why do they all use bigger systems? Even a Polo develops near to 100bhp these days and it certainly uses a system bigger than 1". Equally, an 800bhp Bugatti would require an 8" system!!! Now that would REALLY like to see :lol:

Eeyore · « **Reply #13 on:** January 03, 2006, 20:03:08 »

Ah, but with all due respect....

Ever wondered why really powerfull engines have mulitple exhausts?

:lol:

cheers
8)
Eeyore

drum · « **Reply #14 on:** January 03, 2006, 21:42:39 »

Anybody know how it effect a turbo diesel??

Presumably you want as little resistance as possible after the diesel??

Thrasher · « **Reply #15 on:** January 03, 2006, 21:50:55 »

Interestingly the Rover V8 runs better when the branches join before a multiple exit. If you take an exhaust from each side it causes some issue ... if only I could remember what it was!

muddyweb · « **Reply #16 on:** January 03, 2006, 21:54:39 »

Quote from: "Thrasher"

Interestingly the Rover V8 runs better when the branches join before a multiple exit. If you take an exhaust from each side it causes some issue ... if only I could remember what it was!

Without getting *very* dull, the Rover V8 runs better with a bit of cross-pressure :-) I've also found that you can 'tune' the torque of the V8 quite well with the exhaust system... nothing especially scientific... but it's a fun exercise :-)

Xtremeteam · « **Reply #17 on:** January 03, 2006, 21:57:15 »

Quote

nothing especially scientific... but it's a fun exercise

bet that went like"lets see what noise a V8 can make" ??

landraver · « **Reply #18 on:** January 07, 2006, 15:19:05 »

Finished it today :D

landraver · « **Reply #19 on:** January 07, 2006, 20:19:05 »

is it any good?
I've never done (or seen) one before

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AuthorTopic: Straight thru' exhausts, are they.... (Read 4030 times)