Full exhaust system on 2.2 HDi

[406loon]

My car is booked in on friday 5th august to have a full system priced up. I have discussed the following spec with the fabricators:-

3'' downpipe, cat left in place, 2.5 defap pipe going to a 2.5 middle pipe with a mildly packed silencer and then the a 2.5'' backbox - all T304 and utilising mandrel bends.
At a later date I will get a 2.5'' 100 cell sports cat but that will do for now.

I have read a bit about exhaust diameter etc but am wandering if 3'' downpipe is excessive? but from what I have been reading 2.5'' system is about right for the engine type/size and power. I have just fitted a BMC-CDA carbon induction kit with cold air feed which seems to aid turbo spool a few hundred rpm earlier and theres quite a nice induction roar if sounding a bit boomy.

Sometime later after the exhaust system is finished I am hoping for a full rolling road tune at the DervDoctor diesel tuners to see if she can get close to the 200bhp barrier and near 400nm torque. Realistically im not sure if the injectors/fuel pump/turbo will cope with those increases and dont know how good the stock intercooler is - or how easy it would be to DIY a FMIC setup. There seems to be a lack of tuning info for the 2.2 and HDis in general.

Just looking for ideas and opinions from people on HDi tuning really


Alex

[Doggy]

If you're keeping the std cat, I think you've no option but to use the existing downpipe - or am I missing something?
(This bit is of real interest to me as I need to replace mine - flexi's been changed once & I dont think there's enough metal to do it again).

Why bother with a defap pipe - the empty chamber works fine & may help you with future MOT's as it'll look std. - it has a 66mm clamp at the outlet, so more or less 2.5" anyway.

The only silencing mine has is the OEM back box, if there's any increase in noise, it's barely detectable, so I don't think you need a middle box.

If you take the downpipe / cat off during a defap - (not really necessary, but almost as quick to do it that way), you can see & see through the cat element. Mine looked pretty free flowing and was perfectly clear & pretty clean, after 142k & 5k without a FAP / regen. I suggest comparing this with whatever's in the 'sports cat' before you decide.

The std injectors /turbo / pump set up can handle at least 178 bhp / 295 lbft / 398 Nm. - with std induction & exhaust including FAP.

If I can get someone to monitor the live data on mine while driving, I'm pretty sure you can see the fuel pressure, boost, post-i/c charge temp etc. which would answer most of your questions. Subjectively, mine pulls hard from about 1800 rpm to the red line, which implies it's OK on the std bits.

I have no doubt you can probably get more from a 'custom map' / rolling road session, but most people don't bother as the price tag for the generic map is impossible to ignore. (You have a generic engine, after all).

I think a few of the guys on the coupe forum have dabbled a bit further - worth checking over there too.

[OdinEidolon]

I have just fitted a BMC-CDA carbon induction kit with cold air feed which seems to aid turbo spool a few hundred rpm earlier

wait, what? If so thats a huge improvement. You can feel (and hear! Hisssssssssssssssssssssssssssss! Will it break?) the turbo pushing at around 1400 on mine, what's on yours?

[Bailes1992]

You don't need a CAT on a diesel to pass an MOT ;)
Although the law is changing in January where as you have to have a cat, weather ot not ir passes emmisions. Have a word with the exhaust place about getting your old CAT welded over a straight piece of pipe ;)

[omega]

to prove it all works you would be best haveing it on the rolling road before modification and then after the work is done.as sometimes we fall into the trap that it "sounds nicer/louder so it must be faster,or ive spent so much on it it must be faster".

[Doggy]

Next best thing.....

with characteristic self restraint, it's off to my private test track to establish some baseline performance data, before downloading the 180 Bhp no-FAP map file.
Another test run and the difference is amazing. 4th/5th gear pull wasn't exactly slow as standard, but this something else.

I'll do some more details later, but how about 40-60 in 3rd 5.0 sec., 70-90 in 4th 10.1 sec., 80-100 in 5th 13.2? (that's standard).

Now we have 40-60 in 3rd 3.5 sec., 70-90 in 4th 7.0 sec., 80-100 in 5th 9.7

[OdinEidolon]

Next best thing.....

with characteristic self restraint, it's off to my private test track to establish some baseline performance data, before downloading the 180 Bhp no-FAP map file.
Another test run and the difference is amazing. 4th/5th gear pull wasn't exactly slow as standard, but this something else.

I'll do some more details later, but how about 40-60 in 3rd 5.0 sec., 70-90 in 4th 10.1 sec., 80-100 in 5th 13.2? (that's standard).

Now we have 40-60 in 3rd 3.5 sec., 70-90 in 4th 7.0 sec., 80-100 in 5th 9.7

That's huge improvement Eric, can't wait to remap my car too. But what i love of this engine is the sub 2000-2500rpm pull (which won't be heavily improved by the remap I guess), much better than competing engines (JTD, MJT, TDI). That' why PSA are the best at diesels.

[DiscoPol]

all this talk of bigger this and faster that, remap this, tweak that, it all makes me sad that i have a while to wait before i can start playing, the 2.2 Bi-turbo is a lovely engine and the power delivery is fantastic with the two turbos no lag all the way up to the red line.

I have a local place that will remap me to 210bhp and 440nm ish without touching anything mechanical ie faps and cats etc etc etc but im going to wait until the warranty is up and then de-cat de-fap and re-map all in one go, i reckon the results will be very pleasing indeed, for now i will have to put up with the 180 it comes with as standard

[Doggy]

I'm sure most of us would agree your Sinclair hardly needs it, I'd be amazed if it isn't quicker in real terms in completely std form. Still, I understand the urge to tweak......


What really appeals to me is low or no-cost modifications that work.

I've just lowered the lawnmower.

[406loon]

Looks like this is a grey area, probably why the exhaust place wants to have a look at the car's individual exhaust sections before they quote me. When I get an idea of prices and options I will post them on the forum.

The problem is I have not played with exhaust systems on any of the diesel cars I have owned but have had full turbo back systems before - my S40 T4 had a full 2.5'' turbo back with decat and I can tell you it made a huge difference, no drawbacks whatsoever and it wasnt unbearingly loud either. I bought a 3'' downpipe with decat for my Fabia vRS but sadly sold the car before I had a chance to fit it to see the results. Most tuning companies supply 3'' downpipes and on alot of cars the common pipe diameter is 3'' for downpipe then either going to a 2.5'' cat back or if its got a uprated turbo/big bhp 3''. I know the downpipe is where it all matters and that once the gases have left there they have slowed down to a point where pipe diameter thereafter doesnt matter as much, but to most of us who use our 406s as daily drivers noise is an issue. Also If the diameter is too large the gases can be slowed down because of the larger diameter so going from a 3'' down to 2.5 can help exhaust gas velocity.

Eric, I will at least have some if not the whole system done by the 20th for Gaydon. You are more than welcome to take her for a spin to see how she drives. From what you said about the downpipe though - I take it the cat although it is bolted to the FAP chamber its welded onto the downpipe? I read somewhere that only the early 2.2s had unboltable FAPs. Just hoping mine has same exhaust as yours. I cant see them changing the exhaust between an 02 and 03 but who knows.

[Doggy]

It looks like this:


Item 11 is the CAT c/w downpipe & flexy section: 12 is the DPF

On the car, it looks like this:


You can just about see the end of the flexi part of the downpipe joining onto the cat half of the chamber at the extreme right of the picture above. The FAP is in the longer, downstream section of the chamber.

AKAIK all 2.2 406's have the same arrangement - it's bolted together in the middle, perhaps that's they meant?

Be interesting to compare notes in a few weeks, Alex.

[406loon]

Thanks for the info Eric. When you gutted the cat did you notice a lambda sensor(s) in the system? I am thinking of having a downpipe made up that would cover the length of the old downpipe/cat (3'') and then bolt to a universal 100 cell cat in 2.5'' then bolt to a 2.5'' middle section (no silencer) and then a backbox.So basically the cat will sit where the DPF would be. This way it will remain legal regarding the future MOT test while not being restrictive and hopefully not too loud either - The only thing which might be an issue is dealing with the lambda sensor(s).

Alex

[OdinEidolon]

[OT] Alex, do you think the BMC CDA airfilter makes much of a difference? [/OT]

[406loon]

Alex, do you think the BMC CDA airfilter makes much of a difference?


Thats a tough one. The turbo does spool earlier and more easily. I wouldnt say to anyone to pay the price premium for a brand new one - I dont believe they are worth £180 odd, but I got mine off ebay for £95. At the moment its not running a cold air feed. I am getting a pipe fabricated to fit on friday when the car goes in to have the exhaust done which I am hoping will make the car feel more responsive.

I have heard good things about these filters. Alot of people with type-r/VAG 1.8Ts engines have produced dyno charts claiming bewteen 6-9bhp increase with just the CDA added. I like to take any sort of claims with a pinch of salt though. I will be adding a cylindrical heat shield to further reduce the effect of engine bay heat effecting the filter housing. I might also make my own heat shield out of ceramic coated sheeting that acts as a heat barrier on the engine side and has a rubber lip at the top so when the bonnet is closed it will stop heat soak from engine. Also I am removing the engine cover to prevent further heat soak.

[Bailes1992]

Really don't bother with a CAT your wasting your money! Diesels don't get emmisions tested. Get the exhaust place to gut your old cat and weld it over a straight bit of pipe.