Has anyone ever put a larger turbo into a 450 CDI?

[Jon]

Hi everyone, I am new to the site and as a smart car owner. I have a 2005 CDI fortwo and I am curious to see if anyone has or if its even possible to put a larger turbo into one of these units to significantly increase the horsepower?. maybe a TD04 turbo like what can be found in a 4D56 1.8 litre mitsubishi 4 cylinder diesel engine. I have one of these turbos lying around and thought maybe I could mod it into the smart car. I have not done any research on this so if it seems like a dumb question / idea I will apologize in advance. Any thoughts, comments or feedback regarding this is appreciated. I realize that there would be a lot of modifications needed but I am always up for a challenge. Thanks again! I look forward to hearing your thoughts and opinions on this topic!

[lebikerboy]

The bigger the turbo the more lag...

[Francesco]

Lack of air isn't the problem with the smart OM660 engine, and it peaks at over 17 psi. A remap adds significantly more fuel than stoich beyond 2500 rpm, which increases power and torque by as much as 30%. Unlike all the headroom in, say, a 1.9 TDI, there isn't much more to be done here; 799 cc will never be a drag strip monster.

[Alex]

It has been looked at many times, and it just doesn't make sense. The stock unit has more than enough capacity for even an aggressively remapped engine, and more than that would just mean such lag and lack of low-end power that I don't think it has ever been done. It's not just lag, a bigger turbo isn't able to produce the boost you need at lower RPMs.

Turbodiesels are very different than gas engines. Too much so to go into details here, but gas engine turbo principles don't apply.

[Jon]

Thank you very much for the info! I guess the best place to start is with a remap!

[houseofdiesel]

If you are thinking of doing this, you can but it will cost a large amount of R&D, making an exhaust manifold and oil lines, mounting it and supporting it so the manifold doesn't crack, attaching the exhaust, then the issue of controlling it and remapping the engine management.

A couple of interesting thoughts, as engines get better with each generation so do the turbos, more efficient and better designs. For example the turbo on VW tdi engines are now on the 4th generation in 10 years, there is power to be found just upgrading to a current generation turbo (not necessarily larger). Turbos get better design with each new model, but it is extremely important to have the right mapping and sizing for your application.

VNT turbos are great, they provide instant boost and far superior boost control vs a common waste gate design. You can run a bigger turbo without lag, for example a VNT15 GT 1538 should be fine on 0.8 cdi, it was installed on the VW 1.2 tdi (3 cyl). Now comes the hard part, controlling the vnt and having it added to the engine management. These turbos do have a tendency to gum up or warp over time as they have rotating parts that are internal to them, but this is a problem after 200-300k kms or several years-acceptable service life.

I have done some research, there is so much to understand you could spend several months of spare time looking into it and still have questions, this is just selecting the turbo itself! Finding an engine management system or person that can program is going to be tough if not impossible.

I have the said GT1538 turbo new sitting around waiting, but kids keep me busy and it is not a priority in life to have more power out of my smart, the Jetta is there for that. It will eventually happen, took me 3 years to get a new turbo on the Renault diesel motorhome...

The point to spend some time researching before you jump in and start making a manifold only to find out it runs poorly/ruins the drivability.

[Tcheno]

I did

https://www.facebook.com/GreenMonster42

[dmoonen]

On a 450 diesel? Never mind yes he did. What are the specs on the turbo?

Edited January 6, 2015 by dmoonen

[Tcheno]

Don't know exactly since I took the car to a specialist shop and they did all the work for me

Here is the comparison between stock turbo+remap and big turbo+remap

BIG Turbo + Remap

Stock Turbo + Remap

Edited January 7, 2015 by Tcheno

[tolsen]

I see stock is much better up to 3100 rpm. Big turbo gives substantially more power at very high revs but who drives a Smart like that?

[dmoonen]

So a 12.4hp increase at the wheels based if the dynos being the same. Not bad but how much did that set you back lol

[Tcheno]

You be the judge on how goot it is.

I know that it is now much nicer to drive on the track (dropped 2 seconds) and fun on the road:

Edited January 7, 2015 by Tcheno

[Alex]

Interesting project. Any more data?

Especially the boost pressure, why isn't that on the charts? Gotta see what the turbo is doing under different conditions to understand. Is the wastegate still controlled mechanically, and at the same level as stock? What speed does the new turbo hit full boost? Is the new remap substantially different from the old one? Curious where the big top-end gains come from, the stock turbo makes full boost right up to the top. I know that when my car was overboosting into a limp it would handle full throttle up to about 3300 RPM, and only then trigger limp mode.

This could get interesting. And make Coast Steve want another smart all over again...

[Tcheno]

Interesting project. Any more data?

Especially the boost pressure, why isn't that on the charts? Gotta see what the turbo is doing under different conditions to understand. Is the wastegate still controlled mechanically, and at the same level as stock? What speed does the new turbo hit full boost? Is the new remap substantially different from the old one? Curious where the big top-end gains come from, the stock turbo makes full boost right up to the top. I know that when my car was overboosting into a limp it would handle full throttle up to about 3300 RPM, and only then trigger limp mode.

This could get interesting. And make Coast Steve want another smart all over again...

Have a look at the facebook page, there is a foto album with all sorts of logs of the turbo upgrade

https://www.facebook.com/media/set/?set=a.763380777026406.1073741830.501151679915985&type=3

[tolsen]

OK for the track but I can't see the point for public roads. Speed limit is 120 Km/hour and the standard Cdi does that comfortably.

[Alex]

OK, I see a maximum MAP of 248, attaining that at about 3400 RPM then mechanically operated wastegate controlled. Nice and flat boost, wastegate and actuator are well matched for the engine and turbo. I take it that MAP reading means a maximum boost of 1.5 bar. I believe the the stock setup is supposed to be set for 1 bar maximum, and members have confirmed through trial that the ECU will limp at 1.2 or a tad below. The stock map and the remaps I've heard of use the same overboost level.

I have to go, later...

[Tcheno]

OK, I see a maximum MAP of 248, attaining that at about 3400 RPM then mechanically operated wastegate controlled. Nice and flat boost, wastegate and actuator are well matched for the engine and turbo. I take it that MAP reading means a maximum boost of 1.5 bar. I believe the the stock setup is supposed to be set for 1 bar maximum, and members have confirmed through trial that the ECU will limp at 1.2 or a tad below. The stock map and the remaps I've heard of use the same overboost level.

I have to go, later...

Yes max boost is 1.5Bar. I was actually already running it a 1.5Bar with stock turbo.

[MikeT]

1.15 bar is stock boost at maximum.

Impressive work.

Why not do this to a petrol engine, starting to with a BRABUS? It would be faster. In Canada we only have the cdi in the 450 models, but in Portugal you had them all.

[Tcheno]

1.15 bar is stock boost at maximum.

Impressive work.

Why not do this to a petrol engine, starting to with a BRABUS? It would be faster. In Canada we only have the cdi in the 450 models, but in Portugal you had them all.

Me and my mechanic are working on prepping his 82HP Roadster for the track and a big turbo mod is on the list

[Alex]

I was actually already running it a 1.5Bar with stock turbo.

Is that the "stock turbo + remap" chart showing 45.1 wheel hp? Why only 45 hp if boost level has been raised? There are three different remaps used here in Canada, all with pretty much the same hp and sticking with stock boost setting. With a higher boost thus more air, more fuel can be added for more power.

More data, please! I'm not at all doubting the figures, just trying to understand the role the bigger turbo plays. If you already had 1.5 bar boost from stock turbo, how does a bigger turbo running at the same boost do anything but hurt low-end power and cause lag? Was the stock turbo not able to maintain 1.5 bar at 4000 RPM?

Edit: Let's leave out any discussion of potential engine destruction at higher boost levels. Understood that this is a toy car project, no confusion with my reliable long-lived practical daily driver car with 268,000 km of fuel-saving (wallet sparing) use on it, and running strong although starting to puff a lot of blue upon start-up.

Edited January 8, 2015 by Alex

[Tcheno]

I was actually already running it a 1.5Bar with stock turbo.

Is that the "stock turbo + remap" chart showing 45.1 wheel hp? Why only 45 hp if boost level has been raised? There are three different remaps used here in Canada, all with pretty much the same hp and sticking with stock boost setting. With a higher boost thus more air, more fuel can be added for more power.

More data, please! I'm not at all doubting the figures, just trying to understand the role the bigger turbo plays. If you already had 1.5 bar boost from stock turbo, how does a bigger turbo running at the same boost do anything but hurt low-end power and cause lag? Was the stock turbo not able to maintain 1.5 bar at 4000 RPM?

Edit: Let's leave out any discussion of potential engine destruction at higher boost levels. Understood that this is a toy car project, no confusion with my reliable long-lived practical daily driver car with 268,000 km of fuel-saving (wallet sparing) use on it, and running strong although starting to puff a lot of blue upon start-up.

its quite simple to understand. pressure does not mean volume.

So the same pressure on a bigger turbo means more volume and most importantly lower IAT and EGT

[Alex]

Sorry, I guess I skipped over "Don't know exactly since I took the car to a specialist shop and they did all the work for me ".

I see you don't know the difference between pressure, volume and that interesting little dynamic called flow.

Edit: That sounds a lot grumpier than I meant to be. Blame lack of coffee. I said it, won't edit it out but I didn't mean it in that way.

Edited January 9, 2015 by Alex

[Tcheno]

Sorry, meant to say more flow not volume on my previous post (the word did not came to my mind)

Final result is basically something like this:

Edited January 8, 2015 by Tcheno

[Alex]

OK, but all that marvelous performance above 1.5 bar and above whatever flow level our 800 cc engine takes can't be utilized. The wastegate opens and limits the pressure. The engine removes .8 liters 2000 times a minute at 4000 RPM, the turbine replaces it and that is all the turbo makes. Pre-turbo intake restrictions reduce maximum turbo performance but as long as the maximum turbo flow and pressure is not reached the turbo just works ever so slightly harder and all you get is ever so slightly more exhaust restriction. A shorter straighter less restrictive intake post-turbo is good, less pressure drop on the way to the cylinder. Bigger valves and intake ports are used for the same reason, the mass of fresh air in the cylinder is fractionally greater.

Less exhaust restriction helps get fractionally more exhaust out of the cylinder, leaving room for more fresh charge. Although that one is really tricky, I'm not sure a smaller turbine spooled up faster with a lot of wastegate bypassing isn't less restrictive than a bigger turbine struggling to get up to speed with the wastegate full closed.

Let's not confuse the issue with any talk of the very real factor of resonance.

In any case, typically you see only small gains through intake and exhaust work, not the 25% you have.

Do you know more about any map changes concurrent with the project? If the wastegate on the stock turbo was set from 1.17 up to 1.5 bar and the ECU told that 1.5 was fine, then you can give more fuel in proportion. Was the previous map using the 1.5 bar boost to full effect? I don't think so, because all the remapped cars here are producing in that 45 Whp range at stock boost. I think that's the big jump in power, the rest is shiny fun expensive nicely crafted eye candy. Not knocking it in the context of a unique fun car, it does look very nice. I just still don't see the turbo itself doing anything except hurting the low-end.

Ideas?

[Tcheno]

I have a BMC CDA installed for intake, EGR is out and I have put on a decat sports exhaust.

Also, the wastegate does not need to be adjusted in any way to get to 1.5Bar, you just need the remap to put more fuel in and remove the ecu boost limit.

As for the Dyno tests, they were all done on the same place.

To date there was only one other car (nation wide) that could be on the same performance level as mine and that's my mechanic's car, and that changed when we swapped my turbo and did a new remap to account for it.

We do not take remaps as a one size fits all but as a custom and time consuming per car job and that has always been the key for success.