156 2.4 JTD 20v "tweaks"

Hi all,

Had the car for over a week now and already thinking of "tweaks", nothing to major though as it's primary use is long range transport (will be doing around 40k miles this year).

I'd like to perhaps change exhaust with maybe an air filter change to improve airflow. I'll be doing a remap but would only do that after the aformentioned. Remap will be a balance of power\mpg mainly just to improve the drivability. I would look into an uprated clutch if needed (i.e. more power can be gained for not a lot of mpg loss). Stiffer shocks with the standard springs might be an option to help with the grounding problems at the front? Also maybe replace the plastic sump guard with an alu one as this might provide a bit more clearance?

I'm divided over the exhaust upgrade, I have searched on here and there are plenty of people wanting to see someone else do it, but not many who have! What else is worth doing to the car?

1. Remap

2. Koni-FSD

3. Powerflex

4. BMC-CDA

5. De-cat

6. Sport back box

7. A license to speed

My order would be:

1. Koni-FSDs

2. BMC-CDA

3. De-cat

4. Sport back box

5. Red Dot custom remap

6. A license to speed

And do the Powerflex bushes as and when the old ones wear out.

Cheers

Brakes, brakes and brakes chaps.

No point having all that go if you can't stop it.

My remapped, fettled big nose 156 20v was a beast, but the brakes were awful. I actually turned them a nice shade of blue with smoke pouring off them with one lucky AOer a few years back...

BTW, all the above tips are well worth doing

front mount intercooler

3.5bar map sensor

enlarge and straighten intake to 3 1/4"

that'll get the breathing sorted...

...then remap it, should get 225-250bhp.

LSD

17" rims with 225's

KONI sport kit or FSD's

Brakes

Cheers all, thanks for the options!

Koni FSD's do seem to be flavour of the month and look pretty good to me, so I'll be getting them ordered shortly.

De-cat and possibly a supersprint back box are also on the to-do list.

BMC-CDA was a thing I was unsure about, seemed a "nice" thing to do not essential?...

Powerflex I will do, I had that done all round on the GTV and it was like a new car! At the moment the 156 feels pretty tight, but they will go in when needed.

Brakes are also short listed, currently looking at the Red-Dot offerings. Just putting stock rear discs on but will be looking at something better for the fronts. They're not going to last too long, that I can see already....

Jasons, I've already got 17" wheels with 215's, 225's might overhang a bit too much. I'll have to look into that. I have looked at the front mount intercooler setups, might be a bit too far for me and what I have in mind. Also living in Gloucester I noy sure I want to make it soooo easy for the water\floods! to get where I don't want it! The LSD I haven't looked into too much, what benefit would I get for that, would that only really be required for a big increase in bhp\torque? Going 225-250 I asume would need an uprated clutch, I've seen Pud's use of the CG (from memory) motorsportsw offering on ebay. Is that a pretty solid unit?

Originally Posted by jj_glos

I asume would need an uprated clutch, I've seen Pud's use of the CG (from memory) motorsportsw offering on ebay. Is that a pretty solid unit?

Its no different in design, I don't think the friction plate is stronger/harder wearing but the release bearing is different. I think the mechanic who fitted it said the 'arms' are stronger/bigger, or something

I don't really know how it all works..

Anyway, it does its job, and cost not much more than a standard clutch kit..

Originally Posted by Pud237

I don't really know how it all works..

Anyway, it does its job, and cost not much more than a standard clutch kit..

You and me both

I think they're currently doing them for £163 @ buy it now. I'll probably have a chat when I get the remap done and go from there.

225's sit perfect on the rims, don't touch arms or arches.

The LSD just makes pulling out of corners, driving on a slippy wet road and hard into/out of corners much better.

It stops the car from spinning the inside wheel.

Keeps the power and the car planted on the road.

Have a chat with Augusto from Red Dot about a remap, at the same time mention 156 with Limited slip Diff and that your thinking of having one fitted, he drove my car with one and was more impressed with the lSD than he was with his own remap which took the car from 140 - 202bhp!

Pushing the power out of a remap can put all the power on the tip of the throttle, an LSD can help transfer all this torque to the road, the best way is to enlarge the air mass housing, this makes it all linear again and makes the car drive like it should.

The problem with the LSD is that his is the 20V unit, so the Q2 will not fit...

Originally Posted by kgb

The problem with the LSD is that his is the 20V unit, so the Q2 will not fit...

I know, shame that is..

Ah, nuts. I'd only skimmed the " Retrofitting a Q2 to an existing Alfa" thread so far and hadn't picked up on that.

Has anyone fitted the Autodelta under tray? Supposed to give 40mm more clearance over the standard plastic?

Autodelta Shop

thanks for those tips upthere!

...but...

...where can you find 3.5bar map to 20v JTD?

The JTDm already has the 3.5bar one as far as I can make out. Also, looking on EB Spares it says the Q2 can be fitted to all 6spd manuals.... Q2 diff for 6 speed manual cars

Cheers,

Mark

Originally Posted by Mark_JTD

The JTDm already has the 3.5bar one as far as I can make out. Also, looking on EB Spares it says the Q2 can be fitted to all 6spd manuals.... Q2 diff for 6 speed manual cars

Cheers,

Mark

Unfortunately it doesn't fit the 2.4 20v though as that doesn't use an Alfa 6 speed gearbox, it uses the Vauxhall F40 gearbox..

Sorry to be the bearer of bad news

Originally Posted by Mark_JTD

The JTDm already has the 3.5bar one as far as I can make out. Also, looking on EB Spares it says the Q2 can be fitted to all 6spd manuals.... Q2 diff for 6 speed manual cars

Cheers,

Mark

3 bar I think. 1bar atmospheric, to it should measure up to 1.8bar reliably.
You have to take into account overboost.

I can find the bosch part no for the 3.5 bar if you like, but it works from a base voltage of 1volt, unlike the standard 2.5/3bar sensors that work on a base voltage of 2volts, so it will need chipping in, it will not work just by fitting.
There is also a 4bar version, but little point as the turbo can't sustain that kind of boost.

Jason, it will be nice of you if you can look up the bosch part number for the 3.5Bar sensor.

probably don't have it anymore to hand,

but look at the bosch australian website, the motorsport section, you will find downloadable tech sheets there for map sensors and air mass, such as the 80mm intake!

the 3.5 bar map sensor is used on the 270cdi merc, you can always call bosch and talk to a techie, which I didi also, but they can only refer to limited documentation.

Have to consider that intake and 3.5bar map case later...now I know where I can ask the parts, thanks to you Jason

My project is know in situation where we have dynoted the car a couple of times (original, and a stg1 map).
This weeks mission is to work the new ss-exhaust (decat) inc. downpipe
and install the bmc cda. Then rolling road sessions to tune the stg2 map and see is there any difference between stg1 and stg2.
Stg3 comes later and contains at least fmic...

Can you do a run with the BMC-CDA....with and without...

Originally Posted by kgb

Can you do a run with the BMC-CDA....with and without...

Yes, I think I can. The rolling road session might be in next week (end of the week) if we get the exhaust done.

do the fmic, not so much for the gains of fmic, but more so to allow a decent - straight, free flowing route - for the intake to the turbo.
Do this, and the fmic is a bi-product are what really count.
If the car has a particulate filter, remove it, exhausts don't make a huge difference, on a turbo deisel you could remove the exhaust after the turbo and it will drive very similar.
An enlarged 80mm intake is really only of use after the fmic and straight intake to a large filter.
Then, get the fuel in, get the boost up, a 3/3.5bar map sensor will aid this. The large intake will kepp the throttle linear and progressive.
16/20 valves will rev anyway, 8/10 will need more boost, maybe a bit of water/meth injection to help clear up the smoke at higher revs.

Sorry for delay.
The new exhaust is now installed and the car runs much smoother.
The throttle repsond is much much better and I just have to say that the different is smashing
You wanna know the dyno results?
We have now dynoted the original car, stg1 remap, stg1 remap+exhaust, stg2 remap for new exhaust (still original ic and original airfilter box).
original ~130kw/307ft
stg1 map ~150kw/326ft
stg1 map+exhaust ~152kw/340ft (much more power/torque from 1800-3800rpm)
stg2 map for new exhaust ~165kw/370ft
the turbo runs 1.5bar pressure (original map sensor)

next project is to install fmic and bmc cda (done when the filter finally arrives ).