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Discussion Starter · #1 ·
All/.
Gone down this road before about CAT removal, but having it off( ooer) Weds/Thurs.
It has been mentioned that once the CAT is off, other than obvious problems with emissions, the car should have better MPG and Throttle response etc... We all know this.?
However, my local MOT garage has offered what they reckon to be sound advice, and that is that the engine Management system may not be able to cope with changes, and will have to be re-tuned or adjusted. In simple terms performance without CAT would have potential, but car may initialy run like a bag of shite !! Not knowing any better, any second opinions please.
( When I suggested CAT removal to Abbotts, they quoted £200 plus VAT, and only mentioned advantages in removal). I am having pipe made up for me locally, and fitted for TOTAL of less than 40 quid.
I know one or two of you have had CAT removed, Electronics however not brought up before. If it make difference, 3000 miles ago, had trionic done, I though ECU had a brain, and re-adjusted itself?
Thankyou,
Andy
1994, 2.3T CSE
 

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Andy,
Removing the cat will have no bad effects.
In fact having a cat(less) car is a plus cos all cars with cats have lamda sensors, the lamda sensor is there to protect the cat (amongst other things) by monitoring the exhaust gasses and sending this info to the ecu.
If you remove the cat the lamda sensor will still be in place and carry on monitoring the gasses.
All that will happen with cat removed is better air flow (less back pressure).
I have been told by a reliable source the the trionic systems has an error margin of 30%, so it's well capable of dealing with these sort of changes.

What you might have to do is re-set the trionic system by unplugging it for 2 mins and then letting the engine idle for 5 mins and then take the car out on a steady drive for 10 - 15 mins and then give er some stick (ooh err!)

Damian
 

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removing cat wil only improve performance,lambda is positioned before cat in exhaust line/anything that happens after lambda has no effect on electronics. lambda only analyses gasses before cat and adjusts accordingly.
 

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But surely the ECU will be setting the fuel fix to provide enough HC in the exhaust gases for the cat to work. If you take the cat out wont you simply end up pumping more unburned HC into the atmosphere?

Steve
 

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Discussion Starter · #7 ·
Thanks Guys/. bit of reasurance!!

Damian, I am completely useless when it comes to engines, need instructions to raise hood ( or bonnet - see what I mean) !. Can you explain very simply where is ECU, and how to disconnect, or shall I take it to Local Saab Specialist and bung then a few quid for pointing me in right direction ??.
Cheers,
Andy..
 

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Hi Andy,

No prob mate, allways happy to try and help someone!

The trionic ecu is on the RHS of the engine bay (looking from the front of the car) at the top under the plastic bulk head cover.
You will need to remove the 5 (i think) torx screws all the way along from left to right.
Disconect the washer pipe from under the bonnet, then remove the plastic cover.
the ecu is silver and will be upright against the bulkhead, there should be a lever that will release it, there's not a lot of room to pull it all the way up cos the cable that connects it is at the bottom.
Just unplug the cable and leave it for 5 mins.

as they say in the trade ... replacement is in reverse of removal, he he!

In respect of ksowden1 question .. yes. anything like head work, cams, L&B and air intake / flow will affect the engines breathing and characteristics, the ECU should re-learn after any of these to get the best performance.

BTW Andy is this bypass pipe your having made, is it mild steel or stainless?

Also, Just in case any ones interested, I have fitted the dawes devices boost controler on my 2.3 CSE '96 and it rocks!! not as good as my old hybrid turbo / ecu mod, but still a major improvement in boost spinup and sustained boost level.

C ya.
Damian
 

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stuartph,

Yes the boost controller disables the apc/trionic ability to open and close the wastegate that controls boost pressure.

You still have overboost protection and knock detection so it's still fairly safe.

The difference between the boost controller and the bleed valve is that the bleed valve just takes the output vacuum from the apc solenoid and bleeds some of the pressure off, hence the apc thinks its running at X pressure where in actual fact your running at X + a bit (very technical !!)
What also happens is that the wastegate is always slightly open or closed and therefore you have a gradual boost increase.

Where as the boost controller bypasses the apc solenoid, and keeps the wastegate shut until it reaches the boost pressure you set.
What this does is allow the turbo to spin up faster so that you reach a good boost level faster.(less lag)
It also maintains that boost level much better than the apc will.

You've got to make sure that your head gasket is up to the extra boost else things will end in tears!!

Damo
 

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Discussion Starter · #12 ·
Damian / all.

Thanks again, cat removal now off till next monday, will have a go at finding Trionic unit etc.. Will post again next week on this thread.

Neil/
Pipe is mild steel, a good thick american grade, same diameter as my Abbot back box.pipe wall looks reasonable thick too.

Bought pipe and flanges from local exhaust centre for 20 quid, and the local oddball(but genius welder)putting on for a tenner( I always give him more than he asks for work, feel guilty at his prices. Im sure every towns got one...
 

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ksowden1,

No need to disconect batery terminal to reset trionic, its double earthed with a herkin great earth strap.

No i don't own a company that repairs trionic !! he he , Im just and IT / electronics engineer who likes to fiddle with things that go buzz!
I can modify the old apc moduals so that you get silly boost pressure and long boost cycle tho!

Damian
 

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Hi Blower,

Theres two ways of doing it.
The fist is the easiest but doesn't give the best response times.

Disconect the pipe from the apc solenoid to the wastegate, Block the pipe with a bolt and tie it up.
Then take a pipe from the inlet manifold (there should be a spare nipple on the LHS of the manifold , just pull the cap off).
Run that parallel with the pipe to the dump valve and leave about 4 inces spare from the DV and cut.
The dawes device will have a pipe allready atatched, but I found it too short.
So using a coupler add an extra length to it, enough to reach fron the dump valve to the waste gate nipple (the one you just removed the pipe from).

What I did was to strap the Dawes device to the dump valve.
You then connect the bottom most pipe (the one you extended) to the waste gate and tie wrap it.

Then attatch the pipe from the inlet manifold to the top nipple on the Boost controller, but dont tie it yet.

That's about it,apart from setting it up!
I found onece it was installed the boost on the in car gauge was well down.
All you do is undo the large lock nut and turn the body of the boost controller clockwise (making it shorter)
I found on mine that i had to turn it about 6 times to get the boost I wante, But I would do it a few turns at a time.

Take 'er out and see how it goes.
when youv'e got the right boost level pull off the top pipe and undo the twists in the pipe, put it on again and tie wrap it.

The second way (I have not done yet cos the kit i got would not match the internal diameter of the saab pipes)
Is to take the top pipe of the boost controller and put a T piece just off the output pipe on the turbo, this is under the air intake pipe from the filter.
Its a real git to get to, and the pipe diameter is bigger that that of the pipe supplied with the Dawes job, youll need a down sizer to do it.
B cos its closer to the turbo vacuum output it is quicker to react.
Like I said I haven't done that yet,was going to get the bits and do it last weekend, but i managed to loose my wallet somewhere and have spent the last two days cancelling all my cards :) [expletive deleted]!
BTW what version are you getting? I ended up getting the race deluxe one, it's a bit faster to react than the standard one.
I also ordered a load of the pipe that comes with it to replace all the vacuum hoses under the bonnet cos it's a cool silver colour (yeah vain I know!!)

Blower if you want more info /help e-mail me if you want (I don't want to take over this thread ,you know what I mean !!)
[email protected]

Cheers

Damian
 

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cheers damian, much appreciated.

going to order the dawes devise 2moro.

im replacing my vaccum pipes aswell, havent decided on red (to match di unit).
or blue (to match hose to my twin piston dv)
guess im vein too???
 
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