Downsize the turbo to boost earlier.

[Stephen John Dauncey]

Hi,
I'm fed up with having to change down to make progress at normal traffic speeds.
Has anyone tried installing a turbo from a 140bhp TDI onto a 170bhp car?
I'm wondering if it is possible as it seems the obvious way to improve drivability at lower revs. I've had the car remapped and this has helped but its still no where near as responsive as the lower hp model.
Please share any related information.

 

[SootySport]

That’s what turbo powered cars do. Keep the revs up for less lag. If you put on a smaller turbo, it will always be under stress.

 

[nluk100]

Have you got a custom map on the car or a generic one? It might be possible for a tuner to reduce the boost back to near std but add more fuel to help it pick up earlier. Are you sure you don't have the stuck vanes issue that these cars suffer with as they are usually pretty responsive (for a derv!)

 

[Stephen John Dauncey]

That’s what turbo powered cars do. Keep the revs up for less lag. If you put on a smaller turbo, it will always be under stress.

Okay, thanks for the comment.

 

[Stephen John Dauncey]

Have you got a custom map on the car or a generic one? It might be possible for a tuner to reduce the boost back to near std but add more fuel to help it pick up earlier. Are you sure you don't have the stuck vanes issue that these cars suffer with as they are usually pretty responsive (for a derv!)

No I think it's running fine it'll get to 60 in under 8 seconds.
It was Elite Remaps, stage one giving 200bhp and 300nm - it improved the situation and is great above 2k rpm but having recently driven a standard 140bhp TDI, I found myself haveing a better all round driving experience, at least at legal speed limits!
I could change the car for a 140 but I've gotten a bit attached to it, so wonder if I can just change turbos instead.

 

[ab1702]

No I think it's running fine it'll get to 60 in under 8 seconds.
It was Elite Remaps, stage one giving 200bhp and 300nm - it improved the situation and is great above 2k rpm but having recently driven a standard 140bhp TDI, I found myself haveing a better all round driving experience, at least at legal speed limits!
I could change the car for a 140 but I've gotten a bit attached to it, so wonder if I can just change turbos instead.

You want to get it remapped again, no need to mess around changing the turbo. If it’s someone that knows what they’re doing when remapping then they’ll be able to fetch the turbo in earlier and give you a bit more torque earlier in the Rev range. Whereabouts in the country are you and people might be able to recommend a good tuner for you?
Or even go back to the place you had it remapped and see if they can change it for you.

 

[Stephen John Dauncey]

You want to get it remapped again, no need to mess around changing the turbo. If it’s someone that knows what they’re doing when remapping then they’ll be able to fetch the turbo in earlier and give you a bit more torque earlier in the Rev range. Whereabouts in the country are you and people might be able to recommend a good tuner for you?
Or even go back to the place you had it remapped and see if they can change it for you.

Okay then, thanks for the suggestion. I'll ask about custom remapping.

 

[ab1702]

Okay then, thanks for the suggestion. I'll ask about custom remapping.

Mine is a 170 and is remapped to 212 hp and about 430 nm, it’s a dream to drive and never had any problems with clutch or anything. Power is there whenever I need it.

 

[Stephen John Dauncey]

Mine is a 170 and is remapped to 212 hp and about 430 nm, it’s a dream to drive and never had any problems with clutch or anything. Power is there whenever I need it.

Nice one! Was it done purely with software?

 

[ab1702]

Nice one! Was it done purely with software?

Yes.
You’ve got to have a good look around for things like remapping because there are a lot of cowboys doing remaps these days that don’t know the first thing about actually properly tuning an ecu and will just randomly increase a few things like fuelling etc and hope for the best.

 

[Stephen John Dauncey]

Yes.
You’ve got to have a good look around for things like remapping because there are a lot of cowboys doing remaps these days that don’t know the first thing about actually properly tuning an ecu and will just randomly increase a few things like fuelling etc and hope for the best.

Wow! Oh well I will certainly enquire further on this front.

 

[SootySport]

Nice one! Was it done purely with software?

Ah well, you never mentioned the important bit. Just having a software download doesn’t trim the mapping to suit you. Needs to go on a rolling road to customize the mapping. Try your original tuner to get it just as you want it if he has the rolling road. It will be cheaper than starting all over again. You need to tell him what you want from the remap, don’t just let him guess. In the end you should end up with a smoother, quieter, more mpg map.
Also make sure he doesn’t lock the ECU with a password, that will cause big problems at a later date.

 

[Stephen John Dauncey]

Ah well, you never mentioned the important bit. Just having a software download doesn’t trim the mapping to suit you. Needs to go on a rolling road to customize the mapping. Try your original tuner to get it just as you want it if he has the rolling road. It will be cheaper than starting all over again. You need to tell him what you want from the remap, don’t just let him guess. In the end you should end up with a smoother, quieter, more mpg map.
Also make sure he doesn’t lock the ECU with a password, that will cause big problems at a later date.

Okay thanks, I'm sure that makes sense.
But looking online at Celtec Tuning maps I can see there is no substitute for having the smaller turbo if you want to have power at lower revs. The 140 TDI produces way more power and torque at 2000rpm than a 170 TDI. The bigger turbo just needs more revs to come into power. I'm looking for power lower down so to go back to my original question - Is it possible to fit a 140 turbo onto a 170 car? Anyone?

 

[abmat]

I don’t think fitting a smaller turbo would change anything as it’s the map that decided when the turbo boosts.

Get it properly mapped to drive how you want it.

 

[Stephen John Dauncey]

I don’t think fitting a smaller turbo would change anything as it’s the map that decided when the trunk boosts.

Get it properly mapped to drive how you want it.

Thanks for your comment but the turbo size also plays a part. That's why the 140 and 170 diesel engines have different characteristics. I haven't seen a map of a 170 that can match the 140 below 2000rpm.
If it was a supercharger in question it would be straight forward as you suggest.
It may be that no one has attempted fitting a smaller turbo to the 170 or perhaps its not physically possible.

 

[SootySport]

If you have limitless funds, you could try all options to see what suits you. For myself I always go for tried and tested mods.

 

[samuelh_888]

Sell your car and get a 140.
Don't use Celtic Tuning

 

[Stephen John Dauncey]

If you have limitless funds, you could try all options to see what suits you. For myself I always go for tried and tested mods.[/QUOTE

Sell your car and get a 140.
Don't use Celtic Tuning

Okay, thanks.

 

[Daveyonthemove]

I do know what you mean about the smaller turbo and lower down power, this is true from my own experience.
I used to have the one of the last run of the MK1 Leon FR TDI (run out with the Cupra R body kit and alloys) which had 150bhp stock, and mapped to 206bhp with Custom Code. Loved that car.
I then got hit with the 2008 recession and changed to a Skoda Fabia VRS which had the same engine but was 130bhp (mapped to 180bhp).
The smaller turbo did make this car much quicker to pick up speed, but it ran out of puff much sooner.

You would be trading one benefit for another, and ultimately a good map would reduce the lag and give you a better mix of the two characteristics of each turbo with what you already have.
I think it would be more complicated than simply changing the turbo, but I could be wrong. I do know that a decent map from a reputable company would be able to fine tune your power delivery for less than the cost of a replacement turbo, fitting and a further remap.

 

[ab1702]

Thanks for your comment but the turbo size also plays a part. That's why the 140 and 170 diesel engines have different characteristics. I haven't seen a map of a 170 that can match the 140 below 2000rpm.
If it was a supercharger in question it would be straight forward as you suggest.
It may be that no one has attempted fitting a smaller turbo to the 170 or perhaps its not physically possible.

Like I said to you before it’s down to the remap on your car. All you need is a remap that gives you more torque earlier in the Rev range and fetches the turbo in earlier. If you’ve got Facebook then look at West Yorkshire Tuning where I had my 170 done. The guy puts most of the dyno graphs on there from the cars he tunes so find some 170’s on there and see what you think.

Edit. Just found one. Look at the difference in torque at 1500 rpm.

 

[Stephen John Dauncey]

I do know what you mean about the smaller turbo and lower down power, this is true from my own experience.
I used to have the one of the last run of the MK1 Leon FR TDI (run out with the Cupra R body kit and alloys) which had 150bhp stock, and mapped to 206bhp with Custom Code. Loved that car.
I then got hit with the 2008 recession and changed to a Skoda Fabia VRS which had the same engine but was 130bhp (mapped to 180bhp).
The smaller turbo did make this car much quicker to pick up speed, but it ran out of puff much sooner.

You would be trading one benefit for another, and ultimately a good map would reduce the lag and give you a better mix of the two characteristics of each turbo with what you already have.
I think it would be more complicated than simply changing the turbo, but I could be wrong. I do know that a decent map from a reputable company would be able to fine tune your power delivery for less than the cost of a replacement turbo, fitting and a further remap.

Thank you, yes it's probably not straight forward to change turbos but I would like to know.
My previous car was a mk 4 golf 115tdi. It had really nice torque from low down and like you say ran out of puff by about 3000rpm. This audi 170tdi is the opposite really. Ive had it for four years now and I like it very much but I'm aware that I'm driving a lot faster than I would like in order to get a better response from it. I think the map I had from 'Elite' was reputable and it has improved the lag but having driven a standard 140 the other day I would be happy to give up some topend rush for a bit more low down grunt.
Hopefully someone on here has tried to do what I'm suggesting.

 

[Stephen John Dauncey]

Like I said to you before it’s down to the remap on your car. All you need is a remap that gives you more torque earlier in the Rev range and fetches the turbo in earlier. If you’ve got Facebook then look at West Yorkshire Tuning where I had my 170 done. The guy puts most of the dyno graphs on there from the cars he tunes so find some 170’s on there and see what you think.

Edit. Just found one. Look at the difference in torque at 1500 rpm.

Thank you for the info and advice. I had a look online, the site looks interesting and I will speak to them when they get back from their holidays.
It would be good if they can get my car to pull like that 140 I tried as I would prefer not to give up the topend power of the 170.

 

[Ike]

In theory it does make sense that a smaller turbo would spool-up quicker. The car would need to be custom mapped in addition though plus you’d need to undo it all again when selling-on, that or try to sell what most people will find a somewhat confusing proposition.

Seems that most remaps are made for maximum gain. Mine barely moves <2.5k rpm, then comes on, at about 3.5k or so it really takes off... The other thing you may wish to consider would be an alteration of your gearbox ratios?

 

[Stephen John Dauncey]

In theory it does make sense that a smaller turbo would spool-up quicker. The car would need to be custom mapped in addition though plus you’d need to undo it all again when selling-on, that or try to sell what most people will find a somewhat confusing proposition.

Seems that most remaps are made for maximum gain. Mine barely moves <2.5k rpm, then comes on, at about 3.5k or so it really takes off... The other thing you may wish to consider would be an alteration of your gearbox ratios?

Thank you, is yours a 170tdi?
Yes I think you're right about the need for a new remap as well as a different turbo. In the end it all comes down to money I guess.
My car is rapidly running out of much value anyway as its on 181k and I do about 20k a year so the selling on issue is not of so much account.
My idea of fitting a turbo from a 140 was because they are readily available at a relatively low price.
If the job runs into too much money it starts to make sense to just change the car.

 

[Ike]

Thank you, is yours a 170tdi?
Yes I think you're right about the need for a new remap as well as a different turbo. In the end it all comes down to money I guess.
My car is rapidly running out of much value anyway as its on 181k and I do about 20k a year so the selling on issue is not of so much account.
My idea of fitting a turbo from a 140 was because they are readily available at a relatively low price.
If the job runs into too much money it starts to make sense to just change the car.

No, I have an S3...
<————————

181k, 20k/yr, my advice would be drive 1 gear down.

Otherwise, there are much more efficient cars if spending some money. I used to do 40k/yr. Probably not what you want to hear, but if I we’re you, and head governed heart then I’d probably get nearly new Astras, rinse whilst in warranty then switch.

 

[Daveyonthemove]

In theory it does make sense that a smaller turbo would spool-up quicker. The car would need to be custom mapped in addition though plus you’d need to undo it all again when selling-on, that or try to sell what most people will find a somewhat confusing proposition.

Not really.
It would be a 170bhp with a 140bhp turbo, remapped to roughly 170bhp. A potential buyer probably wouldn't know any different.

 

[Ike]

Not really.
It would be a 170bhp with a 140bhp turbo, remapped to roughly 170bhp. A potential buyer probably wouldn't know any different.

maybe, but once it goes to the garage they’ll have a couple of hours of wtf...

 

[samuelh_888]

How would you change gearbox ratios? Honestly...


See Post 3: https://www.audi-sport.net/xf/threads/how-do-audi-do-it-2-0d-engine-140bhp-or-170bhp.87762/

 

[smurfworth]

Just a few points,

1, the 140 turbos are like chocolate and blow up frequently, stick with the 170 one as it’s the better one

2, driving a remapped car using the low down torque puts a huge amount of stress on the duel mass flywheel.

My advise, change your driving style to rev it a bit more, have it remapped by a decent company like revo apr or r tech etc or buy something faster to start with

 

[desertstorm]

As above, you need to change your driving style slightly. If you want the car to accelerate faster change down a gear. If you fit a 140 turbo you will miss all the top end performance. There really shouldn't be that much difference in the spool of a 140 and a 170 turbo.

 

[Sayam]

The 140 and 170 turbos aren't that different, there is something else at play here. I don't want to play blame game but get yourself a decent map first and foremost.

Not sure where you are but Rick @ Unicorn Motor Dev. has a great reputation over here, speak to him?

 

[Ike]

How would you change gearbox ratios? Honestly...


See Post 3: https://www.audi-sport.net/xf/threads/how-do-audi-do-it-2-0d-engine-140bhp-or-170bhp.87762/

just swap cogs with those from another gearbox of the same type made for a different engine. obviously the maths would need to be done but that is it.

 

[nluk100]

No I think it's running fine it'll get to 60 in under 8 seconds.
It was Elite Remaps, stage one giving 200bhp and 300nm - it improved the situation and is great above 2k rpm but having recently driven a standard 140bhp TDI, I found myself haveing a better all round driving experience, at least at legal speed limits!
I could change the car for a 140 but I've gotten a bit attached to it, so wonder if I can just change turbos instead.

Your 0-60 won't be affected by sticking vanes mate - it only affects low down torque / pick-up. When does your boost kick in? Take a read of this ... https://www.audi-sport.net/xf/threa...an-sticky-vane-which-causes-overboost.149599/

 

[JimS3]

You can move the power band a few hundred RPM up or down the Rev range on the twin cam TDI engines by rotating the inlet camshaft a few degrees in relation to the crank.

If you have access to VCDS then check the torsion value, a value of 0 is standard factory setting, the more minus you go the more the powerband is shifted up (less low down torque, more turbo lag, but stronger near redline) a positive figure increases low down torque at the expense of top end power.

I set one up recently with a -2.7 figure that was gutless under 2300rpm, with the cam moved back to 0 degrees it pulled hard from 1900rpm.