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Discussion Starter #1
I am looking at possibilities for remaping my 2.4. I know a fair bit about it, but find myself wanting an answer to this question.

1) If i leave the DPF in as well as EGR, it only maps to 235 Bhp,instead of 250 (Qtronic)
Why does it not go as high? I know DPF removal gives a bit better turbo behaviour, but should not affect .max boost by enough to warrant 15 bhp. So where has the 15Bhp gone?

I am not fussed about taking out the DPF and EGR for a couple of reasons. First being i can easily take off my EGR valve to clean (have done it once already and wasnt to dirty), second being i know when its doing a regen so it wont get blocked and if required i can force one, third being i can see new MOT regs getting tougher on this and dont want to pay to put it back in and forth i like the clean exhaust tips :D
 

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remap a car with dpf on, will increase the regens, because the richer mixture. more smoke more regens.
After talking with some specialists regarding the dpf, they warned me that forced regen should only be done in extreme cases or not done at all ,due to the heat that passes to the turbo. if the car is parked and running over 2500 rpm and if you heat the exhaust to over 700 ^degrees c ,the smoke that passes into the turbo will damage the turbo in a longer period of time(not healthy in my opinion),remember that there is no air passing trough the inter-cooler!! Avoid forced regens.(In my opinion). I think you loose some hp because of the engine compression, as more clogged it is as more compression you have. if you run a car with high millage and delay the injection time , and increase exhaust pressure you can start getting diesel dilution in engine oil , due to delayed injection and higher fuel pressure.
I think remapping is ok but combine with increasing compression because of the dpf is not that ok for me.
I did that and ruined the dpf (it was so clogged,was running 11 bar pressure),provoked dilution due to back pressure.
So I took it out.
I do feel bad because of the pollution. But dpf and egr is a bad idea, it decreases engine durability.
don´t know if you agree...
 

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Discussion Starter #6
remap a car with dpf on, will increase the regens, because the richer mixture. more smoke more regens.
After talking with some specialists regarding the dpf, they warned me that forced regen should only be done in extreme cases or not done at all ,due to the heat that passes to the turbo. if the car is parked and running over 2500 rpm and if you heat the exhaust to over 700 ^degrees c ,the smoke that passes into the turbo will damage the turbo in a longer period of time(not healthy in my opinion),remember that there is no air passing
It shouldnt be any richer if remaped correctly and a forced regen is a last resort. As said, i know when it is doing a regen so would not interupt it. Are you thinking of chip boxes that plug into the fuel rail only?
 

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It shouldnt be any richer if remaped correctly and a forced regen is a last resort. As said, i know when it is doing a regen so would not interupt it. Are you thinking of chip boxes that plug into the fuel rail only?
no ... i did a good remap.. only 300gr into turbo and delayed the injetion time... almost no fuel pressure change... did a soft remap , I did it for economy.
the problem was the dpf backpressure was to high and forced fuel trough the piston rings .
it was all ok after taking the dpf and close the egr to 4%.
no more dilution.
I thing even if you dont increase the fuel pressure , you will get more fuel into the engine do to delay tne injection time, and the dpf backpressure doesnt help at all.
I do believe it should be better on yours 2.4 , I have a 1.9 8v eco 115hp and gave only more 15-20hp.

What I don t understand is why you don´t use a pipe instead of the the dpf
and put it if you need to pass mot one day.
the other thing is the egr .you are using exaust smoke into your engine .
if the egr gets dirty , so the engine gets more carbon residue.
and you will get more 15 hp by redusing the backpressure
the 15 hp you are missing you use them as energie against the backpressure produced by the dpf.I think, do you agree?
 

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I think you will have a regen increase 20 % more(normaly did 4 regens per fuel upno remap,with remapand dpf 6-7regens). that means more fuel to do regens.
 

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Discussion Starter #9
the problem was the dpf backpressure was to high and forced fuel trough the piston rings .
it was all ok after taking the dpf and close the egr to 4%.


What I don t understand is why you don´t use a pipe instead of the the dpf
and put it if you need to pass mot one day.
I dont see how DPF causing backpressure will cause fuel through the piston rings as backpressure shouldnt affect the ignition cycle :confused:

And if i had to pay to have the DPF installed and removed every year, with the hassle as well, really would make the gains worthless compared to a straight remap
 

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I dont see how DPF causing backpressure will cause fuel through the piston rings as backpressure shouldnt affect the ignition cycle :confused:

And if i had to pay to have the DPF installed and removed every year, with the hassle as well, really would make the gains worthless compared to a straight remap
more smoke more clogging higher pressure , more pressure inside the cylinders with more fuel,specially when car is cold (I do a lot of small trips ,but did my regens right)
can eventualy produce dilution. my car has allready 85k (and you do have a much better engine)
You do see dilution on the jtdm1.3.


alltough people here do not have problems with dilution, I had because of the dpf..
took the dpf out and no more problems..

perhaps a faulty dpf in my case...

You are 100% right not wanting to change to dpf every mot
but people do not have problems in mot know.

are they going to change the rules soon?
 

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the loss of 15 bhp is probably because the map can't be as optimal oweing to it still having a large obstruction in the exhaust (the DPF) :).

Re:the EGR valve, yes you can clean the valve easily enough, but what about your inlet manifold ie where it's "recirculating" all that nice exhaust gas to?

I have a 2.4 with DPF delete and EGR disabled and it has improved my mpg from 34ish to 40ish. You might want to factor that into your thoughts as well.

For me the lack of worry about EGR valves and blocked DPF, plus the improved consumption were enough of a reason to do it.

Not trying to tell you what to do, just offering my experiences.
BTW it shifts pretty well now too :)
 

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DPF removal

Just a thought but other forums suggest taking off the DPF and cutting it open on the top side,removing the innards then rewelding.I hardly think the MOT tester is going to scrutinize the DPF.By the way,mine has passed 2 MOT'S without the DPF.Emmisions were up a bit but nowhere near fail levels.My 2.4 159 is doing oever 10mpg better than it did before and 60-70 bhp more in conjunction with a full remap plus is much more driveable now.Best thing I ever did to my old girl
 

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Discussion Starter #14
How would a DPF/EGR remove & remaped 2.4 compare in acceleration to a 3.2? Given the Bhp would be similar but the 2.4 having more torque. Deciding wether to get a 3.2 or remap the 2.4
 

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How would a DPF/EGR remove & remaped 2.4 compare in acceleration to a 3.2? Given the Bhp would be similar but the 2.4 having more torque. Deciding wether to get a 3.2 or remap the 2.4
Cracking question!

I've only got a mild remap, having opted to keep the DPF until the warranty is up. Whilst the acceleration isn't bad, I drove a Vectra VXR before, and the Alfa is nowhere near that grunt-wise. I'm hoping that when I get the DPF removed / EGR thingy sorted and a more aggressive remap that I get something approaching the g-forces I was getting out of the VXR.
 
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