2.5 NA into a Series 3: Exhaust ideas

[xmod109]

So I finally got the 2.5na started up in my series and it made some noise....lots of noise and lots of smoke... so now I need to figure out the exhaust on it.
I used the 2.5na down pipe so there wasn't any restriction form the smaller 2.25 petrol system. I'm thinking of building the new exhaust to follow the old rout but it might make more sense to push it straight out the back with a hump over the rear axle.
Thoughts?
Also, if anyone has an old defender exhaust lying around off a 110?

[Alex C]

Del you should come over for a visit, i have a bunch of exhaust pipes, boxes etc

[xmod109]

Sounds like a plan.

[camo388]

From my experience there are 2 styles of down pipe.  Either a bell or a flat face going against the manifold.  If your engine had the down pipe and matching manifold then you will be alright.  I have the complete exhaust system from a 90 and so I know it will be too long for my 88" Lightweight.  I know there will some chopping and welding to get it to fit.  With the LWT's smaller exhaust, the exhaust still had to go under the crossmember at the bellhousing.  It will need to be the same for the larger 2.5 exhaust which I don't like.  But there is no way around that unless I take the exhaust straight up through the bonnet!  The LWT had it's muffler crosswise behind the rear axle and I will likely have to put the 90's muffler same way to include it in the system.  If your is a 109 then you may have room to have muffler lengthwise the same as the 90/ 100's are.  If it wasn't for the restriction in the smaller 2.25 system, I would be very tempted to attach it to the 2.5 down pipe and the job would be done with 1 flange fitting.
Good luck!

[Moose]

.......  If it wasn't for the restriction in the smaller 2.25 system, I would be very tempted to attach it to the 2.5 down pipe and the job would be done with 1 flange fitting.
Good luck!

When I put the 2.5NA into my Series 3 88, we just grafted the 2.5 down pipe into the 2.25 exhaust system and it has been running fine for over 7 years and many thousands of kms.  I don't know if a full 2.5 system would improve things any but I'm happy with the way it runs with this set up.

Brett

[xmod109]

Hi Brett

Thanks for the info, I know a few people that have done that or just swapped over to the 2.25 petrol manifold with no issues but I like doing things the hard way I guess. that and my 2.25 exhaust was totally destroyed, between being rested out and death by sawzall during the removal  ;D.

I think i'm going to do a mix, follow the old path through the PTO hole and over the rear axle but then hide the muffler ( or maybe a second muffler ) under the deck and come out cross side.
That way I'll get more protection of the pipe off-road  as well. 

That's how I've got it planned in my mind anyway. How it works out will probably be different.

[binch]

Document this process well Del!   Could be a learning experience for all  ;D

[camo388]

.......  If it wasn't for the restriction in the smaller 2.25 system, I would be very tempted to attach it to the 2.5 down pipe and the job would be done with 1 flange fitting.
Good luck!

When I put the 2.5NA into my Series 3 88, we just grafted the 2.5 down pipe into the 2.25 exhaust system and it has been running fine for over 7 years and many thousands of kms.  I don't know if a full 2.5 system would improve things any but I'm happy with the way it runs with this set up.

Brett

I came across this reply on another LR forum and it gives me food for thought.  Second reply, No. 22

https://www.lrukforums.com/threads/series-3-2-5n-a-exhaust.80804/page-2

I live in Alberta where I can see the mountains from my house and at a higher altitude I expect the engine would normally be working harder to stay cool.  As I have the complete 90 exhaust system on hand, I'm probably better off using it.

[Red90]

What a strange theory.  I can't imagine how he is connecting exhaust size to engine cooling.

Anywho, for the NA, it can't hurt, but you probably won't notice much.  Getting the timing set perfectly and enough fueling is the big thing to make sure you are getting as many ponies as possible.