quiet efficient exhaust

[little_pete]

Hi, I'm going to be fitting a 12g940 head to a 1098 with a hif 38 on an alloy manifold. I'll hopefully be using the car to tour places (first stop germany) so I want the engine to run well but not be too loud. Whats the best route to go down? (planning ahead, will not do this for some time) I want usable power. I've heard switching to a tubular manifold rather than cast adds alot of noise? I've seen there is a metro cast manifold with twin exit but can you not get downpipes for this? can you mate say a twin box maniflow to the standard cast manifold without doing any fabrication? or would that just be pointless waste of money. Should I just stick with the standard (relatively new looking) stainless system? (would have to hack the manifold to add the hif38)

[bmcecosse]

I would stick with the newish stainless system. When I changed away from that to a 3 branch (not LCB) manifold and straight through larger bore exhaust - I got a LOT more noise, and negligible (if any!) increase in performance. An LCB exhaust is definitely not advised unless going to quite a high state of modification on the engine - it can actually lose power on a low tune engine.

[little_pete]

Cheers that'll save a bit of money, It's already quite tiring on the ears long distance. I guess the best thing is to change to 3.9 diff with the money saved from the exhaust ;-) or will that state of tune not cope with that diff?

[bmcecosse]

Of course it will - I have a 3.7 final drive and it pulls that very well. But if you are going to be heavily laden - the 3.9 may be the better bet - and more affordable too.....

[little_pete]

What is the most economical way of obtaining a 3.7 or 3.9 diff? are you running 3.7 on a 1098? My diff leaks quite alot at the moment from the front where the axle goes in. I'm not keen on 'touching' something twice, and think I'd leave a diff change to a garage so would make the change when the leak gets sorted if I decide to swap the diff

[bmcecosse]

You just have to search around for a suitable final drive unit (note the 'diff' is just the bit inside which allows one wheel to run faster than the other) - and hope to get one at a good price. It's a VERY easy job to swap one for the other. Not at all a 'garage' job. Yes - my 1098 with 940 and 38HIF pulls the 3.7 very well - but I rarely have more than '2 up' (and a large box of spares) in the car...

[little_pete]

sounds good to me

would this be an easy enough fix? or best looking out for a known good one?

http://www.ebay.co.uk/itm/MIDGET-SPRITE ... 0974782036

[bmcecosse]

Up to you if willing to have a 'hum'.... Mine does whine a bit - but hardly noticeable above the general din!

[little_pete]

I notice mine every now and again more a whirr whoosh, it's a slight humm or buying one untested at that price? or best to plonk for a known good one looking closer to 4 times that money

[bmcecosse]

I would go with it........

[David W.]

Doesn't the sprite/midget axle fill from the rear? Morris fills from the front. If you put a sprite/midget unit in a Morris axle, will you have a fill port?
David

[bmcecosse]

Easily sorted.......just fill through the breather or via an 'uphill' half shaft if no fill point in the axle. I ended up with TWO fill points........

[little_pete]

Mine is a late model, I have a plug at the back which is accessed under car about half way up the diff, so I would understand that would be OK. the price is going up on that item, and I understand from reading around that there should be some washer/shims between the bearings or a collapsible washer which 'preloads' the bearings I would guess either the incorrect shims have been used or the washer has been collapsed too much. I don't think I'd be able to remedy the stiffness/humming myself, will keep an eye out for others perhaps a 3.7

[bmcecosse]

There are no 'bargains' - too many eyes watching these days - and 3.7 seem to get > £150 these days....

[MarkyB]

Fast, Good and Cheap, pick any two.
Quiet and efficient is a bit like that.
If efficient = quiet, no problem though.

[little_pete]

I know everything is a compromise. Unless you just go all out for one thing. I want it all ;-). but a better designed exhaust could potentially be quiet whilst providing a performance increase over the original, just appears the companies opt for all out sports exhausts. I guess it's supply and demand. At the moment my biggest performance increase will just be getting the engine running correctly.

[MarkyB]

Maximum profit and forget the punter seems to be modern business practice, that and not paying any tax