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Discussion Starter #1
Any reason why this couldn't be done? I understand that we'd be into serious drive-shaft issues territory, which maybe a Quaife LSD would mitigate. Maybe not. Anyways - can a 156 2.4 JTD M-Jet 20V be mapped this far?
 

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No, not without some hardware modifications first. You'd need a lot more boost, maybe more than the turbo could provide at the higher revs required to achieve this power. If you did manage to get this much boost the intake temperatures would be very high, you'd definitely need an FMIC. Probably a full exhaust system too, just to free up the turbo and let it spin.

That being said, we have a 1.9 16v JTD on the forum with over 250bhp, so it is do-able.
 

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It is actually do able but bang on the limit, if you went the re map route alone the new code would take variables outside the safety limits introduced by ALFA for this engine in 2003, it is very likely you would introduce a Torque spike at around 1800rpm, driving through this on a regular basis would wreck the clutch beacuse there is no way of limiting the torque with these parameters to less than 320flbs, at above 3500rpm the standard Turbo cannot produce enough `air` so we have an issue once again with limiting over fuelling which will probuce a smoke screen, this is a totally different issue to improving air filters etc.

An upgraded Turbo and Clutch is the only way of producing a drivable car with this power, a much more sensible upgrade is 225BHP and 305flbs which i have driven and helped code, very driveable great between 2000-3500rpm and not too `smokey` please remember you cannot eliminate all the smoke after a remap there are just not enough options within the code to optimize every eventuality
 

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It is actually do able but bang on the limit, if you went the re map route alone the new code would take variables outside the safety limits introduced by ALFA for this engine in 2003, it is very likely you would introduce a Torque spike at around 1800rpm, driving through this on a regular basis would wreck the clutch beacuse there is no way of limiting the torque with these parameters to less than 320flbs, at above 3500rpm the standard Turbo cannot produce enough `air` so we have an issue once again with limiting over fuelling which will probuce a smoke screen, this is a totally different issue to improving air filters etc.

An upgraded Turbo and Clutch is the only way of producing a drivable car with this power, a much more sensible upgrade is 225BHP and 305flbs which i have driven and helped code, very driveable great between 2000-3500rpm and not too `smokey` please remember you cannot eliminate all the smoke after a remap there are just not enough options within the code to optimize every eventuality
That's quite an answer, I have spent the last 2 years mucking about with my old 2.4jtd 140 to get more power, and its took this long to learn what you have summed up so well in a few words!

Who do you work for? What do you do?
 

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Hi jasons

I worked for David Sutton Motorsport in the 80`s working on the Quattro A2, Sport Quattro and eventually the S1 E2 (the group B car with all the spoilers and 620BHP) for the British Rally Championship

I worked through an interesting stage in engine electronics, the 1st quattro in 83 (A2) had mechanical Bosch Injection and a very simple ECU with no scope as such for programming so we relied on a turbo the size of a waterwheel to produce power, things improved as the years went on.

We also developed the 1st anti lag systems - very crude but effective! an enrichment valve fired fuel into the exhaust on the over run which was ignited in the hot exhaust, the resulting explosion kept the turbo spinning and ready for action, this is now done with a chip the size of your finger nail, i was also at the 1985 RAC when we ran an S1 for Walter Rohrl which had a development twin clutch gearbox called PDK, you will see it on many VW`s now called DSG, again in 1985 the software carried in this car for this gearbox weighed 45kg and was the size of a 28 inch TV!

Things have changed!!

I now work in construction as Audi pulled out of Motorsport in 1989, i went to Seat Sport for a year etc but rallying is not what it was, the days of having a beer with Hannu Mikkola and a beer with Colin are long gone, all the `stars` are now wrapped up in cotton wool, its getting more like Formula 1.

Looks like you have a good JTD there with sensible mods - good luck with the 240BHP - hope you make it, the engine is strong and the internals can cope easily if in good fettle, its just clutch, driveshafts and turbo

Regards

Regards
 

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I did hear that the 20V has a GM gearbox and will probably not cope with that much power and torque.

Does anyone know if it's just a bolt on job to use the earlier box fron the 10v models?
 

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Hi not sure about the boxes as ALFA hardware not my bag, would think unlikely as a direct fix and ratios final drive should be considered, just spoke with a mate in the Vauxhall trade and 250BHP and 330fLbs is the verbal upper limit with 10% safety factor on top, what should also be considered is full throttle regularily in 1st gear and from very low revs causes huge torsional vibration in the box and driveshafts full thottle from low revs in the higher gears has the same effect on the clutch
 

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Discussion Starter #8
My experience (having a 20V) is that, yes, it's the GM F40 gearbox. Not Alfa. And yes, it's not spec-ed to handle the MAX torque after a re-map (Celtic quotes 285->342lbft). And yes, you (ask Mark_JTD) will probably be wearing out the drive shafts, clutch, etc. faster. This is the point of specifications after all. And no, the Q2 doesn't fit the 20V. Instead you're probably looking at a Quaife GM F40 LSD (they list it under Saab LSDs). But the standard remap on the 20V (I used the EXCELLENT Adie Hawkins at AHM) is truly worth it. Different car. More torque from lower revs, a much greater willingness to accelerate after 3k rpm and (for me) no smoke under 4k. Having had a remapped 10V (150) I can say that the mpg on the unmapped 20V is worse than a mapped 10V. But the mapped mpg is significantly worse (if infinitely more fun).
 

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My experience (having a 20V) is that, yes, it's the GM F40 gearbox. Not Alfa. And yes, it's not spec-ed to handle the MAX torque after a re-map (Celtic quotes 285->342lbft). And yes, you (ask Mark_JTD) will probably be wearing out the drive shafts, clutch, etc. faster. This is the point of specifications after all. And no, the Q2 doesn't fit the 20V. Instead you're probably looking at a Quaife GM F40 LSD (they list it under Saab LSDs). But the standard remap on the 20V (I used the EXCELLENT Adie Hawkins at AHM) is truly worth it. Different car. More torque from lower revs, a much greater willingness to accelerate after 3k rpm and (for me) no smoke under 4k. Having had a remapped 10V (150) I can say that the mpg on the unmapped 20V is worse than a mapped 10V. But the mapped mpg is significantly worse (if infinitely more fun).
Unless of course you do what I did. See my thread " Life with a 156 " Pud knows what I did, No to 250 Bhp. Read..
 

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Hi jasons
Looks like you have a good JTD there with sensible mods - good luck with the 240BHP - hope you make it, the engine is strong and the internals can cope easily if in good fettle, its just clutch, driveshafts and turbo

Regards

Regards
Its up to 230bhp, but still needs fine tuning, next step is trying the ecu with overboost set to zero, in an attemp to keep control of the boost at the same level all the time, rather than high, then dropping, then creeping back up.

I was relying on putting back on the methanol injection for the last 10bhp, it should be easily acheivable now, and if luck is on our side, maybe a couple more bhp?
 

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Best of luck with it Jason..

Personally if I was buying another diesel Alfa it would be the 16v. For the reasons of lighter front end, and the Alfa gearbox & driveshafts, I would pick it over the 2.4 20v. Such a shame the 1.9 makes a horrible noise.. :(
 

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Best of luck with it Jason..

Personally if I was buying another diesel Alfa it would be the 16v. For the reasons of lighter front end, and the Alfa gearbox & driveshafts, I would pick it over the 2.4 20v. Such a shame the 1.9 makes a horrible noise.. :(
I agree about the noise but since using BP Ultimate in mine performance is not only better but the top end seems to have opened up a bit sound-wise as well - a bit more 'rorty' (if that's possible for a diesel:lol:).
 

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I agree about the noise but since using BP Ultimate in mine performance is not only better but the top end seems to have opened up a bit sound-wise as well - a bit more 'rorty' (if that's possible for a diesel:lol:).
I know what you mean.

It's bad, but not that bad. :lol:
 

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When I get one, its going to get a full exhaust system, no silencers or cats, not even a backbox. Then it will sound something like rorty :lol:
 

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Best of luck with it Jason..

Personally if I was buying another diesel Alfa it would be the 16v. For the reasons of lighter front end, and the Alfa gearbox & driveshafts, I would pick it over the 2.4 20v. Such a shame the 1.9 makes a horrible noise.. :(
the 1.9 doesn't have the same sound as the old 5pot 2.4, but when you really tune the 2.4, you tend to loose the nice noise and now all I hear is massive induction roar and the high pitched whistle of the turbo.
The 1.9 is a more advanced unit than the old 2.4, I loved it in the 147 Ti I had.

For me, there will be no next Alfa, this is only on the road on a shoe string budget, the only reason the bigger turbo went on was because it was cheaper than fitted a standard one!

unless alfa bring out a really radical new diesel, big engine, twin turbo, I'll be tempted into pink shirts, bluetooth earpieces, white socks (if any), dark shades and a shaved head - yes a BMW! 335d/535d
 

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Its up to 230bhp, but still needs fine tuning, next step is trying the ecu with overboost set to zero, in an attemp to keep control of the boost at the same level all the time, rather than high, then dropping, then creeping back up.

I was relying on putting back on the methanol injection for the last 10bhp, it should be easily acheivable now, and if luck is on our side, maybe a couple more bhp?

Excellent (although at what point is it time to stop spending the money :lol:) ... getting my uprated clutch, Q2 and Eibach ARBs fitted later this year ... I hear what tatt's is saying about the airflow, my car reachs 200bhp by 3000 rpm, and then doesn't really get any higher ... looking at the rolling road graphs it does seem like the power hits a brick wall ...


... I'll be hot on your heals next year with the FMIC :thumbs: (if I can justify it to myself :lol:)
 

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I think any suspension mod worth it apart from springs/dampers must be the ARBs. My front bushes have just gone 'ping' (literally) and it was replaced under warranty. The dealer said that the ARBs on the 147/156/GT JTDs just go with monotonous regularity. Another superb example of Alfa scimping on the OE spec (together with all the others:lol:) Definitely Eibach front and rear next time!
 
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