Help Reduce Turbo Lag

[Matt]

So i’m getting an Opel Corsa C Facelift 2005 1.3 CDTI and noticed some quite noticable turbo lag.

Are there any methods to reduce this? So far I’ve heard of:
– Heat sleve
– Stainless steel 2.5″ exhaust pipe (and maybe a muffler although that’s another question)
– ECU Remap

The cheapest and (looks) efficient is the exhaust pipe.
Would this make any noticable difference?
Thanks 🙂

Topic

[Third Gear]

I’m really not familiar with small diesel engine, but generally a hot turbo will work better than a cold one.

Ball bearing turbos are better than standard bearing turbos.

The turbo itself creates back pressure, so any additional restrictions after the turbo can slow down the spooling.

Tuning will help any modern engine.

I would start with the exhaust first – maybe a down pipe and a muffler. Anything to help get the exhaust out more efficiently should work well.

[TexasCoder]

It may not hurt to also check that the waste gate is also properly set, according to manufacturer specs. Also, check the tubing that comes off the turbo to the turbo control valve, and the control valve itself. Sometimes the tubing can develop cracks and pin holes, which will effect its operation/vacuum. If you can find the schematic on your turbo control valve, you may be able to simulate it “actuating” and time its performce to get a better understanding if it is opening/closing the waste gate at the proper intervals.

As a side note, I felt the same thing with my 2004 Volvo XC90 2.5L Turbo. I found that the waste gate was off by 4 PSI (out of recommended factory spec), along with two of the three hoses having cracks. After replacing these hoses, with silicon hoses, and adjusting the waste gate, I could tell a noticeble spool time difference. One other thing I am thinking about doing is buying an aftermarket heavy duty turbo control valve, as the stock one has almost 150,000 miles on it, and are known to be problematic.

Just keep in mind, be careful and take your time when tuning your turbo. The engine components are designed to a tight specification, and too much boost can damage the engine, and vise versa, too little boost and your performace and economy are shot. As long as you stick to factory recommendations, you should be ok, but if you start to play outside those guides, make sure you take your time and test test test everything.

Hope this helps!

[Matt]

thanks for the reply. yes I was looking to change that as its the cheapest.

Did some research and found out that the heatwrap doesn’t really do anything in reality so i’ve put that idea away.

I’ll see about the exhaust downpipe (not the exhaust manifold, right?)

is

[Third Gear]

I agree with TexasCoder. The wastegate is also very important to turbo function. It might be a good idea to make sure it is working correctly. It may be a good idea to look into a boost controller as well.

Most people with turbos will put on a better flowing exhaust and a downpipe (after turbo). Usually the exhaust manifold isn’t an issue, although sometimes it can be. Some people also remove their catalytic converters, but I don’t recommend that unless it is race car because it is illegal pretty much everywhere.

I’m not sure how big the pipe is, or where it is located but 100 Euros doesn’t sound bad for parts and labor, especially if the pipe looks to be good quality.

[Matt]

I’m not planning on increassing the turbo pressure.

Is the catalytic converter and a particle filter the same? as it doesn’t have a particle filter (as the emmissions are so low, that it doesn’t need it).

So I should check these:
– Waste gate (is it the same as a BOV?)
– Exhaust pipe

also, where is a stock turbo usually located? And how do I check the Waste gate?

Thanks alot guys. I owe you!

[TexasCoder]

Quoted From Matt:

I’m not planning on increassing the turbo pressure.

Is the catalytic converter and a particle filter the same? as it doesn’t have a particle filter (as the emmissions are so low, that it doesn’t need it).

So I should check these:
– Waste gate (is it the same as a BOV?)
– Exhaust pipe

also, where is a stock turbo usually located? And how do I check the Waste gate?

Thanks alot guys. I owe you!

I am not familiar with the term particle filter, unless you mean the engine air filter?

As for the items you are going to check, that is a good start. There are two ways your Blow Off Valve (BOV) engages – A Boost Control Solenoid (BCS) is the same as (in all intents and purposes) as a Turbo Control Valve (TCV). Some minor differences between the two are how they are actuated, the TCV are both vacuum and electrical, where as your older model BOV are mainly vacuum actuated.

The Blow Off Valve is used within the turbo to vented over pressure from the exhaust, without it, your tubo would “explode”, as too much pressure would damage the engine and the turbo turbine(s). That is why checking your waste gate operation is important, if it is not actuating properly your BOV may open to soon and vent the turbo pressure the engine needs, and vise versa, if it stays closed to long, your engine could suffer damage.

The turbo is located on the exhaust side of the engine, usually in line or connected to the exhaust manifold. If you can, try and purchase a factory service manual for your vehicle, this will give you all the information and parts locations for your vehicle. You should be able to contact your local dealership and order one.

I agree with “Third Gear” about the booster controller and also look into getting a boost guage (if you haven’t already gotten one), although most of the boost controllers do have built in guages so you can monitor your PSI Boost.

Here is a video that got me started in turbos, it may help to explain it a little more: http://youtu.be/ShldMVI2_cI

Keep us posted on what you find.

[Matt]

I just have just recieved Haynes Opel Corsa Owners Workshop Manual. but it doens’t really say anything about the turbo.

[TexasCoder]

Quoted From Matt:

I just have just recieved Haynes Opel Corsa Owners Workshop Manual. but it doens’t really say anything about the turbo.

The Haynes manual is a good start, but the factory service manual that I refer to is the actual book produced by your vehicle’s manufacturer. I think the Opel is/was produced by General Motors. Do you have a local GM dealer that you can contact and ask them if they can order a Factory Service manual for you? These books are the same books that the service technicians use in the dealer service bays…they cover everything from lug nuts to welding points on the chasis…a much more in-depth repair manual than the consumer grade Chilton and Haynes manuals.

[3SheetsDiesel]

Since you’re working on a diesel engine, rather than a gasoline engine, don’t bother buying an blow-off valve (BOV). Those are only used on turbocharged gasoline engines, to allow air out of the intake tract when the throttle plate closes, such as during a gear change. As you’ve got a diesel engine, you don’t have a throttle plate, ergo no need for a BOV. The wastegate is used to route exhaust gas around the turbine wheel (the side of the turbo that the exhaust blows on) to keep it from spinning too fast and creating too much boost.

The exhaust manifold is very rarely a restriction on a diesel engine, so as long as it’s not cracked, it should be just fine for your purposes. The downpipe you were asking about bolts to the back of the turbo and has the rest of the exhaust system attached to it. Since you’re complaining of poor boost response, I’d make sure that there aren’t any restrictions on the “cold side” of the turbo (meaning from the engine air filter to the compressor wheel, to the intercooler, to the throttle body) and repairing any restrictions you find. I’d also check for exhaust leaks anywhere upstream of the downpipe, including the wastegate (which may be internal to your particular turbocharger, I don’t have any specific experience with Opel, but diesel is diesel, the same concepts apply). Don’t bother looking for vacuum lines that are leaking on your engine. Your engine doesn’t make vacuum, so nothing is vacuum powered on it unless you have a belt driven vacuum pump.

The particle filter is a piece in the exhaust designed to catch the soot that a diesel creates when you stomp the throttle. It has to be regenerated from time to time, which the car should do automatically. Provided that the particle filter on your car works the same as the one on the Ford diesel, it regenerates the filter by dumping raw fuel into the exhaust stream and essentially shooting fire out of the exhaust ports, through the turbo, down the downpipe to the particle filter to burn the soot out of it in much the same way that a self-cleaning oven works. Your car may have a catalytic converter, but most diesels that I’m familiar with don’t have them.

As to exactly how you check a wastegate, I’m not really sure. I imagine google would have the answer to that question.

[Matt]

Thanks for answering EXACTLY the questions I asked. and all the others. I should get my car tomorrow (i’ll be driving it home). I’ll let you know how it feels 🙂

How can I make sure there is nothing restricting air in my Intercooler?
Also, is checking the wastegate a DIY job or should I take it to a professional?

My dad has expersiance with cars but he known nothing about diesel (at all). He has a Skoda 120L which in Malta is considered a DIY car since ALL owners fiddle with it them selfs.

[3SheetsDiesel]

The easiest way to check for restrictions in the intercooler is to remove it and physically look inside. If there’s a restriction, you should be able to see it. I’m presuming that your car has an air-to-air intercooler. If it’s air-to-water, just make sure that the outside of it is free of debris and you’ve got clean coolant in the engine’s cooling system.

On the air-to-air intercoolers, make sure that the fins on the outside are free of debris, and when you remove the tubes leading to it to look inside, make sure that there is no oil in there. Oil in the intercooler is indicative of, at best, failed turbo seals, and at worst a turbo that has completely failed. Regardless, if there is oil in the intercooler, the turbo will need to come off, and the intercooler will also need to be removed and either replaced, or professionally cleaned to get all of the oil out of it. The reason I mention this is because of the fact that a diesel engine can and will use regular oil as fuel, so if it’s breathing oily air, you could go into what’s called a runaway condition, which is where the engine will act as if you’re holding the gas pedal down and there will be very little you can do about it short of blocking off the air intake with a piece of wood or something similar.

As far as checking the wastegate goes, I imagine you can do that yourself, but I can’t tell you how, as I don’t know myself. You may need to take it to a professional for that.

[Matt]

I have no idea what type of intercooler it has. the problem with a stock turbo is that they decided to put it almost underneth the engine and quite difficult to mess arund with. wasn’t able to locate it even with a torch light lol.

[3SheetsDiesel]

Air-to-air is the most common type of intercooling. Air-to-water is typically only used on mid-engined turbo cars, like the Toyota MR2, or on rear engine cars, such as the Porsche 911 Turbo.

For intercooler identification, an air-to-air intercooler will be somewhere in the front bumper, either centered under the grill, or on one side or the other, beneath the headlights. If the intercooler is mounted in the center of the bumper, it’s commonly referred to as a front mount intercooler, or FMIC. Take a look at the front of a Mitsubishi Lancer Evolution to see what I mean. The intercooler is the shiny thing between the headlights. If the intercooler is mounted directly below the headlights, it’s called a side mount intercooler. VW uses this type of intercooler on the 1.8T powered cars.

There is a third type of air-to-air intercooler, called a top mount, but I’ve only ever seen them on turbo Subarus.

It’s probably going to be tricky to find regardless. You may want to find a shop that will check it for you, but ask if you can watch how it’s done so you’ll know for next time.

[SpawnedX]

Alright, I hate to step on anyone’s toes or upset people, but there is a lot of bad information in this thread. I mean A LOT of bad information. When it comes to turbochargers, I highly recommend inquiring with people very familiar with the systems, as in own them, they are a whole different breed.

First and foremost, we need to figure out if what you are referring to as turbo lag, is actually turbo lag, or is a boost leak. This would be the basic way to understand the two. Turbo lag is the period of time it takes for the engine to enter boost, not necessarily reach full boost, once the turbo starts making a slight amount of boost, it should continue to build boost at a rapid pace. So if what you are referring to as turbo lag is it is taking a long time for the car to actually get out of vacuum and into boost, than you are correct. If what you are referring to is it feels like it is bogging down or is taking a very long time to go from low boost to full boost, you are experiencing a boost leak and a boost leak test is in order (you should do this anyway on a regular basis with a turbocharged vehicle).

Now let’s talk a few other things.

Wastegates: Not really going to benefit turbo lag, even if it isn’t being actuated properly as mentioned above with being “4 PSI off.” The wastegate does not open or actuate until the car has already reached and begins to exceed the maximum boost pressure the spring in the wastagate/actuator is designed to handle. Now if that wastegate was stuck open it could create “turbo lag,” but that would be better defined as a pre-turbo leak, which is the same thing as a cracked turbine housing or exhaust manifold. This is a simplistic view on these things, but it is sufficient to get you to where you need to be.

BOV: Most vehicles don’t come with “blow off valves” and most aftermarket valves are not “blow off valves” they are compressor bypass valves. The real purpose of them is not to divert anything related to gas and it’s not to avoid damaging the engine, not really. It is actually for when the vehicle’s throttle plate is slammed shut, such as coming off the accelerator. There is still charged air in the intake with nowhere to go, so pressure builds up and backs up towards the compressor housing. This effect causes the compressor wheel to have opposing forces, air coming in from two sides, which may reverse the direction of the wheel itself. This is very bad for the turbo, not really the engine, and it results in the death of your turbo. This effect is known as “compressor surge.” As such, replacing it is not going to help you with turbo lag either.

The most simplistic way of explaining this is, anything not exhaust related is going to provide marginal, at best, if any, improvements to spool. Exhaust is where you need to start. Porting your exhaust manifold and turbine housing would help, but could also be detrimental depending on where you are at. However, removing as much restriction from the exhaust flow to allow the turbine housing to exhaust cooling exhaust gases for the new hot gases from the last exhaust stroke will help the most. I will avoid the science and leave it at, the expansion of heated gases helps spin the turbine wheel faster.

This means your benefits would come from a larger diameter downpipe and exhaust, removing or gutting the catalytic converter. The truth is, the catalytic converter being removed would actually get you the most gains. It is also usually illegal. Do at your own risk.

As far as your intercooler goes, you probably have an air-to-air intercooler, not many, if any, stock cars come with water-to-air intercoolers. Air-to-air is more efficient for constant use on the vehicle. Performance based systems, like purpose built drag racing cars, are better off using water-to-air, and most of them actually use a blow through setup, as in no intercooler system at all. Upgrading this will not really help with your lag either. In fact it could be detrimental to your performance, as it could account for more pressure drop.

Boost controller also won’t really do you much.

[Matt]

Reading your comment and taking into account everything you said, will Cleaning the EGR valve help? I heard something from a friend of mine but I think I’ll better ask someone else for a second opinion

[Author]

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