Quote John Banks:

"In the UK it is accepted to put a downpipe on your Prodrived car except on the new shape where an up-pipe was also found to be necessary by Scoobysport to avoid going quite close to ignition retard limits of the Prodrive modified ECU. "

So it is not suggested to fit just a downpipe on a Wrx 01. But what exactly is this phenomenon called ignition retard limit?

Are there different cures for it (instead of fitting also an up pipe), like fittig a 1,35 mm restrictor?

Your help would be appreciated.

Cheers

Caronte

 

The engine control unit (ECU) has a limit on how much it can retard ignition advance, running stock boost it won't be an issue really....it's when boost is upped beyond reasonable limits that things will go **** up.

/J

 

J

I'm not sure that that is correct. Pete Croney commented in an earlier thread (sorry, I can't find it without search ) that he was unhappy fitting a de-cat downpipe to a PPP'd MY01 as he found that it was running 8-11 degrees retard on a rolling road. He commented that this was too close to the maximum of 12 degrees that the standard ECU is capable of. This problem was reduced by 3-4 degrees by fitting a de-cat uppipe, with the additional benefit of lower EGTs.

Hope that helps.

Duncan

PS. By all accounts fitting an uppipe is a b1tch and requires removal of the downpipe and the turbo, hence people generally do both together to save on the labour.

 

Umm...rolling roads are another thing altogether...I reckon my "hot" map will be quite dangerous on a RR.

/J

 

BUT!

Getting rid of that pesky uppipe cat (which has been known to fail in some circumstances and end up in the turbo), can't be a Bad Thing (TM of Pat's?).

/J

 

J

Agreed - RR's are VERY hard on a car, but tuning on them leaves a margin for the road, a hot day, or even a dodgy batch of fuel. Getting rid of a potentially very expensive failure is a Good Thing.

To answer the original point - I don't think you can achieve the same effect as the removal of the uppipe cat without retarding the ignition by other means such as a programmable ECU or an extra device such as an Apexi ITR.

Duncan

 

Cheers all,

so can you recomend a good place to remap the Ecu. Someone that has rally car preparation exxperience?

Cheers

 

And, does an up pipe cat is likely to fail more without a catted downpipe, (e.g higher internal temperatures???)

C.

 

I've just re-read my last post, and realise that I forgot to add perhaps the most important point.

Retarding the ignition is a band aid to cover up for the problems caused by the restrictive exhaust. It is a much better idea to remove the restriction (ie the cat in the uppipe, resulting in more power and lower emissions) than retard the ignition (which will lower the power and increase emissions).

In terms of changing your map - it depends on who produced your map in the first place. If it is a standard (or PPP) ECU this cannot be done easily, and you will need to consider a replacement. If it is a replacement, then get it redone by the person that sold it to you!

Duncan

PS In answer to your latest question - yes, the higher exhaust temperatures will increase the stress on your cat and increase the chances of this failing - with potentially very expensive results.

[Edited by BugEyed - 2/27/2002 4:24:35 PM]

 

Thanks Duncan,

Yes I do own a ppp 01. But I am a little bit in concern of co emission. That's why I thought that replacing just the down pipe would have let me replace in a second occasion the OE downpipe for an eventual emission test quicker. By replacing both this operation will be much longer, more expensive and not so good for the turbo seals.

Caronte

 

Caronte

I'm in the same situation with the cats. Currently I'm running without the 3rd cat, but want to remove the first two. However, I'm not sure whether to

• risk failing a roadside test by running without any
• replace the 3rd
• buy a downpipe with a "sports cat" - such as the GGR one

Duncan

[Edited by BugEyed - 2/27/2002 4:48:57 PM]

 

I thought about a sport cat in dp too.

Does it provide enough counter-pressure in order to avoid overboost issues? and do you think that the power/torque gain would be appreciable as well?
(GGR stands for?)

C.

 

Graham Goode Racing http://www.grahamgoode.com/

 

The point of lowering the back pressure / resistance is to increase the power! Yes it does mean you have to adjust the restrictor for the solenoid, or you can do what I'm doing which is to ditch the factory boost control and add a separate electronic boost controller!

GGR = Graham Goode Racing]

Duncan

 

Ok, really stupid question maybe, but what/where is an up-pipe?

Cheers.

 

The uppipe is the pipe that connects the exhaust manifolds (headers to out American friends) to the turbo. On the MY01+ this contains a catalyst, hence the comments.

Duncan