Can induction Mods improve power in a Smart?

[bus_ter]

I'll talk specifically about the Roadster, because that's what I have.

It's been said the maximum reliable power you can run the Smart Suprex engine at with reasonable reliability is 120-125bhp. Above this they like to throw a rod or fail in some spectacular way. The standard Roadster engine has all the hardware necessary to run it's engine to the limit. All you need to do is turn up the boost with a remap (commercial remaps only sell up to about 115bhp for reliability reasons, but there are 120+bhp maps available). Forget everything you've heard about induction mods and silicone pipes etc. Personally I believe they are largely a waste of money and only introduce possible problems (there are plenty of blown off pipe stories around). If you take a 100% standard Roadster, with original airbox, intake, exhaust etc exactly as it left the factory and install a 115bhp remap, what do you get? You get a 115bhp Roadster. What does this mean? It means when you turn up the turbo boost the car, as it is, is quite capable of taking in all the extra air, and blowing it all out again through the exhaust. This demonstrates quite nicely how the standard induction system, and exhaust system do not limit the power of the engine. So what happens if you take a standard 80bhp Roadster and install all the intake mods under the sun, and a nice sports exhaust to boot? The result is a very noisy 80bhp Roadster! Look at it this way. A standard Roadster boosts to 1.0Bar. After doing all those mods it will still boost to 1.0Bar (look at the Turbo gauge if you don't believe me!) The car's ECU tells the Turbo to open until 1.0Bar of air pressure is reached, and then hold it there. So the air entering the engine is completely controlled by the turbo. Doesn't matter what intake modifications you have done, no more air is allowed in to the engine! And if no more air is allowed in, then no more can come out. So there's no point having a less restrictive exhaust (from a performance point of view at least).

So does anyone disagree with this theory? If so, which parts are flawed and why?

Let the debate begin!

(You might guess I have nothing to do at work today! )

[darrpen]

Re: Can induction Mods improve power in a Smart?

That may or may not be the case, but the intake mods do smooth out the gear change. Well they did on my roadster.

What map do you have?

[Messerschmitt Owner]

Re: Can induction Mods improve power in a Smart?

have you moved from 'all fur coats and nae nickers' city?

The bigger pipes do make a difference - they don't increase the power (they can't - after all the restrictions at the turbo and the intercooler ultimately limit the maximum volume of air going into the engine and therefore the power). A lot of the time, the engine is sucking in air too, rather than having it blown in - there's no ram effect on a smart car!

However, what the bigger pipes do do is increase the flow of air, i.e. more air can flow more quickly, up to the maximum. Why else would Brabus have fitted a larger tik pipe, and why else would the roadster have had a bigger tik than the fortwos if there was not a benefit to be had.

WHat increases is volume and flow of air at all engine speeds and power output up to the maximum, although the maximum power output is determined by the maximum amount of air that can be flowed into the engine and that is limited by the size of the turbo intake.

You also have to remember that the manufacturer designs the original parts for a multitude of driving styles, climates and conditions and to meet regulatory factors such as CO2 emissions rather than go for out and out power - otherwise our cars would leave the factory with big turbos, more power and go faster bits already fitted.

[bus_ter]

Re: Can induction Mods improve power in a Smart?

That may or may not be the case, but the intake mods do smooth out the gear change. Well they did on my roadster.

What map do you have?

I have an SW-Exclusive remap which I find excellent. I believe remaps are THE way to improve performance from these little turbo engines.

Induction mods may improve gearchanges, but why do they? In any case that's a sub topic. I mainly thinking about Engine Power levels.

[bus_ter]

Re: Can induction Mods improve power in a Smart?

have you moved from 'all fur coats and nae nickers' city?

The bigger pipes do make a difference - they don't increase the power (they can't - after all the restrictions at the turbo and the intercooler ultimately limit the maximum volume of air going into the engine and therefore the power). A lot of the time, the engine is sucking in air too, rather than having it blown in - there's no ram effect on a smart car!

However, what the bigger pipes do do is increase the flow of air, i.e. more air can flow more quickly, up to the maximum. Why else would Brabus have fitted a larger tik pipe, and why else would the roadster have had a bigger tik than the fortwos if there was not a benefit to be had.

WHat increases is volume and flow of air at all engine speeds and power output up to the maximum, although the maximum power output is determined by the maximum amount of air that can be flowed into the engine and that is limited by the size of the turbo intake.

You also have to remember that the manufacturer designs the original parts for a multitude of driving styles, climates and conditions and to meet regulatory factors such as CO2 emissions rather than go for out and out power - otherwise our cars would leave the factory with big turbos, more power and go faster bits already fitted.

Alnwick(I've being stationed at Boulmer to keep an eye on the Ruskies!- any roadster owners nearby?)

So you agree with me that they don't improve Max power. This is something then that is largely misunderstood. I think the average person modifying their Smart believe they're getting an increase in power from these mods.

When the engine is just sucking (as in not producing positive boost) your throttle is low and I would imagine the demand for air is also very low. At this point the air going through the engine must be like you pissing into the Nile basin. Much more capacity available than being used, so improved intake I wouldn't of thought would make much difference?

I do think improved induction could help pickup of the Turbo. But I wonder how much real world performance there is to be gained here. On full throttle gear changes it takes forever for the gears to be changed around, but a fraction of a second for the boost to hit max once the power is back on.

Aren't there three types of TIK pipes to match the 3 Turbos? Each sized to match the intake size of the Turbo. So the Brabus has a TIK that matches up with a 74kW Turbo. The standard Roadster TIK matches with a 60kW Turbo etc. Is there any benefit having the TIK go wider than Turbo? Someone a while back suggested this might create a lip and add turbulence.

[T33NEY]

Re: Can induction Mods improve power in a Smart?

Buster, you have a point... What you are saying is largely true, but as is often the case, there is more to it..

Induction mods wont always increase ultimate power on a turbo engine. As you rightly said, the power is largely limited by boost which will be the same regardless of induction mods.
However, engine response can improve quite noticeably. Why? The engine can get the air it needs much quicker due to better breathing. I found on my own Fortwo, before I started modding it properly, I only added a 80bhp roadster tik pipe, better airfilter and did the delip mod (No remap). As I expected, peak boost figures didn't change one iota (Thats limited by the ecu, so why would it change). Peak performance was also largely the same. The difference was the time it took for the engine to deliver maximum boost. Pre induction mods I had to wring the arse off it, and by 4500rpm's or so, it just about scraped its way to 11psi of max boost. With induction mods it reached 11psi a good 1500rpm earlier. So its the same max boost, but you have it for more of the time. = Faster car (Or less slow in our case) So mods like this are definitely still beneficial, remap or not.
But yes, i don't think they truly give the gains many folk think they will... (forget faster gear changes for a start)
Also, induction mods if done properly help to deliver colder air than the stock system gives. 11psi of cold air is much better than 11psi of hot air.

Intercooler hoses is also an interesting one. Im not so sure about these. Certainly the top one doesn't benefit from being changed, in my opinion. However the bottom one certainly looks a bit restrictive. So maybe] there are some gains from changing that. But I couldn't be sure.

Having said all that. There is definitely a lot of bollox in the tuning world for just about all brands of car. Maybe its a placebo thing.. "I've spent £100 on this! So my car must be faster for it" Even more so if its a shiny blingy mod.. The folks that make and sell this stuff know it too.
I see people doing mods which I can be pretty certain do not make their car any faster at all, and may even be making it perform worse instead. But you try explaining it to them! They wont have any of it

You raise a good point with the tik pipes diameter being matched to the turbo too. This was a point I raised a few months ago on here. But im not sure anyone really grasped what I was getting at (And maybe they still dont :p ). But the point was, much like a chain is only as strong as its weakest link, you can only flow as much as the narrowest point will allow for, which is the turbo inlet. You can add all the fancy induction parts in the world, but the restricting part is still going to be that tiny turbo inlet (A whopping 23mm! for the standard turbo, right?)
Mismatched tik size to turbo causing turbulence may be true.. I couldn't be certain of this either. But I expect the effect on our engines is minimal. By the very nature of how turbo engines work, air flow tends to be very turbulent anyway so the lip may be of little consequence. On a non turbo car however, something like this could potentially have more of a negative effect.

Just my 2rpms worth!

Paul

[bus_ter]

Re: Can induction Mods improve power in a Smart?

Some great posts here. Very informative! Thanks

[smart-eddy]

Re: Can induction Mods improve power in a Smart?

This is a very interesting read and what t33ney said about the induction size vs the size of turbo inlet make sense too. but anyway are we then saying that to get the best out of the roady the re-map is all we need but it would be better for the car in any way to get all the induction stuff like new tik pipes etc? or would these have little or not noticable differences in performance or engine durablity therefore making them pointless if a re-map is to be done on the car?