Exhaust effect performance?

[Anonymous]

Hi,

i've got an aftermarket, wider bore than usual, stainless exhaust system on my 16v. it is also blowing a bit..

the performance of the car generally seems down, could the exhaust effect it badly? ie are valvers known to suffer performance loss from these systems?

i'd like to replace it with standard if there is a chance of performance being reduced.

thanks!
james

[Mike P]

James,

The downpipe on a Bx16v has a centre baffle till it levels out under the car to increase touque from the engine amd most aftermarket downpipes either don't have one or only a 4" one at the manifold joint.

A standard downpipe with aftermarket centre pipe, cross box and back box is better.

Mike P.

[Mike E (uk)]

The exhaust design on these cars is considered by many (who know more about these things than me) to be of an excellent design and therefore very hard to improve upon.

The end pipe is unlikely to have any effect on performance, the critical bit is the front 2 sections.

Most common engine power problem is distributor/HT problems.

Start with the simple HT stuff 1st, new plugs,|HT leads rotor arm & cap.
It may take a while to sort, but well worth it.

If you don't know when the cam belt was last changed, get it done quickly.
Like on many OHC engines, cam belt failure is an expensive and time consuming business.

Mike

[Mike P]

I learnt this week from reading the original Citroen workshop manauls that the downpipe is described as a Siamese design

Mike P.

[Timmo]

do you know where the blow is?? (easy way to find it at the mo is fire it up stick it in high and have a look aunder in the mornings on a cold engine as you can see the gasses escaping! )
obviously any blow is goign to cause a performance loss! the std system is very good but can be improved on with some subtle changes! Luke knows more about this as i know he looked deeply into gass flow's etc when sorting his sytem out!

the std system wise, back box is about £25, crossbox is around £20 intermediate pipe is around £15, the down pipe its the expensive one! citroen still want £200ish for one!

if its blowing up front then a sealing ring is less than a tenner! but you wil need the shorter spirngs for it too as the long ones are too long on a new ring! - can be a real pita to do though as one bolt always seizes!

[Anonymous]

the exhaust fitted is a Scorpion one. it is cracked where the pipe leaves the middle silencer. At the weld.

it is also blowing at the join to the back box.

so its blowing quite badly.

Scorpion are happy to look at it but want me to post the item to them

[Toddman]

Sadly the scorpion system is renowned for being poor due to the fact it has no "siamesed" or split downpipe.

Best plan is to source a genuine downpipe and graft that onto the ss system.

Good thing about scorpion is that they retain the std joints so you can easily make up a new system.

I would go for a std downpipe with split then straight through to the ss cross box and back box will work very well and sound sporty but not loud.
I run this but have a Devil rear box instead of the scorpion rear box.

Cheers
Luke

[Mike E (uk)]

Perhaps you could get it welded up?

[jonsgot]

Yep I have the same full SS system and have had to have it welded in the past. The performance did improve but I still need to get the front down pipe changed.

[iain a]

... my dad had a ss sytem put into his jag by 'top gear' in st albans, on london road, by the old cinema(opposite esso petrol statiion)...if your from watford you'll prolly know it, he reccomends them... as said before, keep the downpipe...change the rest... £300 for the whole system, probably less if original downpipe used.. you could also enquire if they do an exact ss copy of the downpipe....

[Anonymous]

I contacted Scorpion and they said send it to them. it should be covered under a lifetime warranty. i wold but i sold the car now

[RichL]

Purely from memory (the BX is currently boxed in the garage since the local pikeys expressed interest when picking up a scrap cooker from my place), the downpipe and manifold are seperate and join at the back of the engine bay, dont they?
If so, how hard would it be to get a custom exhaust maker to run two, smaller diamater downpipes off the manifold (half-round pipes even) and rejoin the single section exhaust lower down?

[Toddman]

Purely from memory (the BX is currently boxed in the garage since the local pikeys expressed interest when picking up a scrap cooker from my place), the downpipe and manifold are seperate and join at the back of the engine bay, dont they?
If so, how hard would it be to get a custom exhaust maker to run two, smaller diamater downpipes off the manifold (half-round pipes even) and rejoin the single section exhaust lower down?

That's right Rich the downpipe is like two back to back D shaped tubes welded together down the length of them.
Trouble is there is an inner and outer curve so not every ehaust place will have the knowledge or tooling as a lot of the ss exhaust makers are just franchises.
Would be nice to have a proper fil ss system though

Cheers
Luke

[Mike P]

The gauge of the metal used in the downpipe is so thick they will last longer than the rest of the car.

Consider that the youngest original downpipe is now 14 years and how little they have corroded, if you discount the front resonator box joints that should be chopped out and replaced anyway by now.

I looked at a decent one off stainles downpipe and came to the same conclusion as Luke.

Mike P.

[Vanny]

i've got a few contacts in north wales that do fabrication and in Sandy Way there is a tyre place that does SS exhausts which bought an extruder and roller so i'm moping that once i find an original down pipe and some money that they will be able to make one up! If they can't i'll have to spend some time learning how to use the steel roller and make one myself

THough i understand what your saying Mike, i have never seen one getting near to rusty before, i guess being twin skinned helps quite a bit!