Team-BHP - Sluggish Pick Up at Hot Engine

Hello,

I own 3.3 yrs old 68000 kms run indigo TDI.

I feel a very sluggish pick-up when the engine is hot during these summer days. At this particular time the engine temperature needle remain at the Center mark. I commute daily for around 60 km from Noida to Delhi . When in the morning when engine is not hot it feel really very light and compete with even petrol car well. but after say an hour from start up when engine get hot it become a bit sluggish and looks like have to pull forcefully and almost you will feel that the engine loosing power and coming to a halt. even noise level is not as smooth as in morning .

it become more sluggish with AC on especially in afternoon when outside temperature is high. with respect to when AC on at cold engine like in morning time.

Is it happen with All Indigos ? I use premium diesel normally Hi Speed

Any suggestions on the same.

Regds,

Virender

My Indica TDI faces the same after being driven around in the city at high temperatures. this effect is less if you are on the highway at high speeds.

I drive more in the morning/evening, so it affects me less, but I do face it too. If the issue gets worse with the AC on, you might want to check the EGR. It is deactivated when the AC is turned on to compensate for the drop in power

Quote:

Originally Posted by greenhorn (Post 1280094)

What is EGR and how it function ?

Same here, I have noticed nearly 20 kmph drop in top speed when it's really hot, apart from the drop in pickup. It's a common issue with all intercooled engines, with a rise in intercooler core temp, power drops noticeably. This is the reason why the new WRX STi comes with a system to spray water on the I/C core (manual in lower end versions and auto on the top end version).

@greenhorn EGR in the 475 TCIC is disabled after 3000 RPM, not when the AC is switched on.

Do the wheel rims get very hot (i.e. difficult to touch) when the car is sluggish ?

I has this problem in my V2 DLS 2004 (75K) and it turned out to be brake drag. Some work on the master cylinder for 400 fixed it.

Quote:

Originally Posted by adityamunshi (Post 1280265)

I have not check the wheel rims but what is the relation of hot engine with wheel rims

Nothing new, Virender. It's most definitely the hot air working against the engine & intercooler.

BTW, I've always felt my cars being *faster* at night. Slim margin but definitely noticeable. Colder / denser air? Probably.

Quote:

Originally Posted by GTO

BTW, I've always felt my cars being *faster* at night. Slim margin but definitely noticeable. Colder / denser air? Probably.

Yes, the colder air passing through the IAT sensor advances the timing through the ECU.

It happens because the calipers arent completely released and the brakes are applied (partly) even when the car is moving.

Quote:

Originally Posted by virender (Post 1281276)

I have not check the wheel rims but what is the relation of hot engine with wheel rims

The point from GTO regarding temperature is spot on. All internal combustion engines work in the principle of constant volume. What happens is, as temperature rises, the density falls. As a result of this, when you keep the volume of charge constant, the amount of air, or the weight of the charge that is actually reaching the cylinder falls, resulting in the drop in power. Coupled with this is the turbocharger/supercharger in which, because of compression, the temperature of the air/air-fuel mix also rises,and that too by upto 200C depending on the compression, thus nesessiating the intercooler.
It therefore stands to reason that in a hot day, where the temperature of the air itself is high, there is a noticeable fall in power output. Incidentally, the air intake design can also make a huge difference in the temperature of the air coming in. While free flow air filters increase power output by allowing more air into the engine, the lesser drag of these filters also reduce the temperature rise of the incoming air due to friction.

What I see about my uncle's indica (2004, diesel) when he parked his vehicle in garage, he used to open then bonnet, in that way the engine cools fast and in monring, it is not as hot as closed bonnet car. the car is used for rental and cross over 1,41,000+ KMs in April 2009 and now running with an avg of 12 with AC on. So, I suggest people with good garage facility, please open your car's bonnets all the time when it is in garage. :thumbs up

Also as the temperature raises, the coolant is getting hotter. So, the cooling effect of the engine is lesser. At higher temperatures, the newer engines are also derated for torque (also power) i.e., the maximum torque output from the engine is restricted as it would be difficult to cool the engine at higher torque outputs. If the engine temperature goes really high (for e.g., above 105 C or so) the torque could be dearted by as much as 40%.