Tuning advice

M

m4matteo

New member
Points
11
Location
isle of wight
Car
Zafira Gsi turbo
Hi all,


I have recently purchased a 54' plate Zafira Gsi Turbo and as this is the first time I have spent a reasonable amount of money on a car I am looking at what I can do with it :)


I am looking at places to start or even a process (i.e. do this first this second etc).


I have started simple by getting HID bulbs and nice mats lol. I will also be getting the grill changed (if anyone has any recommendations on picking one, great).


So from what I can tell maybe a new intake and a remap would be a great place to start right?


many thanks
 
Turbos can be very addictive and you can get hooked on boost.
Wouldn't get a remap until you start mods.
IMO the first engine mod should be a turbo back 2&1/2 inch mandrel bent exhaust with resonator type mufflers and a hi flow cat if needed as that will open up the system and allow the turbo work better with zero back pressure which allows them to spool/come on positive boost pressures faster.

Would also recommend upgrading the brake pads as well along with a full bleed of the lines and Motul RBF 600 fluid.
 
Although you are unlikely to be prosecuted, fitting HID bulbs to non-HID headlamp units is not legal, as far as I am aware. This is because the non-HID units have lenses designed for standard bulbs so the light spread when HIDs are fitted is different and can cause unwanted glare.

Party pooper? Me? Surely not :)
 
Greetings m4matteo and a Warm Welcome to our TorqueCars Forum my Friend!

Good to have you along with us :)

A remap for the GSI turbo would be the way to go forward. Replace the air filter with a performance version, and seek further recommendations for some hotter running iridium sparkplugs. Give the car a full service before you have it remapped.

You would also benefit from replacing the exhaust downpipe with a 3" version to help keep the exhaust temperatures lower. This ideally would need to be done BEFORE you have the car remapped. Not sure if the downpipes are readily available for your car as Vauxhalls are not my thing, but any decent specialist exhaust centre will be able to make one for you quite easily. The new downpipe can then be made to reduce down at the section where it couples up to your current exhaust system.
 
old-git said:
That's a new one on me T9. How does that work?
Click to expand...

Acknowledged by a lot of the big tuning houses and FACT for turbocharged engines. From what I gather the larger downpipe allows the heat to dissipate more quickly therefore allowing the exhaust gas temperatures to be lower and therefore allowing more scope when increasing the BHP developed. This is tried and tested on many BTCC cars to which Simpson Race Exhausts make systems for teams based around the world. The size is prevalent to the space that is available for the downpipe increase. The very first time I had a proper remap done to the car it was held back due to the very high exhaust gas temperatures recorded. It was Viezu (based in Bromsgrove) who explained to me what the issue was and how to resolve it. Needless to say a visit and a chat was booked with Simpsons for advice. This was delayed due to the engine dying and my having to have a race engine built for the beast, then I had to wait nearly 3 months for a slot to become available to have an exhaust system built by the gurus.
 
When I had my 3inch system installed app 18 years ago I had a before and after dyno power runs performed the same day and if my memory serves me correctly the power went up app 15% and it allowed faster spooling and boost increase so I found the boost cut for the first time and had to have a "boost cut defender" installed.

In those days dynos were not as sophisticated as current models and there were no print outs.

T9 My understanding is that one needs to retain exhaust heat before the turbo to keep the gas speed high to drive the turbine wheel and post turbo the lower temps reduce the gas volume thereby making for less back pressure which in turn allows the turbo to spin faster.
 
Well TC I as I understand it, the high exhaust temperature attained can be detrimental to the performance of the rest of the system if the flow rates involved act to slow the rate of exhaust emission required to keep the turbo running at it's optimum. If it is a more in depth explanation that you seek then Google or a chat with Simpsons might be better for you.

These guys Simpsons, Viezu, MapTun, SpeedParts, Trollspeed, SaabNoob, to name but a few, have an enviable reputation when it comes to performance enhancements. If they recommend a 3" downpipe as a minimum then I am not in a position to say that they don't know what they are talking about just because I don't understand the in's and out's of this enhancement. A guy on a Vauxhall forum has a GSI turbo engine modified with the pipe and that has gone into a kit car for his track day toy. If a 3" downpipe is specified as a preferred essential performance enhancement then so be it. Currently, on the Saab 9-3, 9-5 and the 9000 when it comes to taking a car from Stage one to the next levels of Stage 3 and above then a 3" downpipe has to be installed.
 
old-git said:
Although you are unlikely to be prosecuted, fitting HID bulbs to non-HID headlamp units is not legal, as far as I am aware. This is because the non-HID units have lenses designed for standard bulbs so the light spread when HIDs are fitted is different and can cause unwanted glare.

Party pooper? Me? Surely not :)
Click to expand...

It's a much discussed subject and over the last 5-6 years it;s become more and more of a grey area.

The DfT has published a paper on the subject but it's full of opinions only. Even it (DfT) suggest seeking legal advice for the definitive answer. Fact is that there is no definitive answer until something is tested in a high court and appealed subsequently. Opinions form no part of law.

There are some problems with aftermarket HIDs yes, these are addressed by the DfT in its paper.

And technically you COULD potentially (by a long shot) be prosecuted for using HID burners in light units that are not appropriately marked.

Given DfT's on the fence stance I'd be happy to fit aftermarket HIDs if the beam pattern and alignment are appropriate and sufficient to pass an MoT inspection. Washers and self levelling (if fitted) are required to work correctly,whether or not the light source is Metal Halide or Tungsten halogen.

Sadly though soime people think that the purpose of headlights is to dazzle and blind other road users. Those people should be taken off the road on account of their clinical stupidity, regardless of vehicle lighting
 
Thanks T9, interesting reading. Something I will have to look into (Not for modding the Elan as my pipe is already 3", just for knowledge).
 
old-git said:
Thanks T9, interesting reading. Something I will have to look into (Not for modding the Elan as my pipe is already 3", just for knowledge).
Click to expand...
.

That goes for me too as one is never too old to learn new things:)

T9 hope we can meet to chat and check out the Saab when we are in London on our trip in August.
 
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Struggling with this pipe size thingy.

A larger pipe will equate to less surface area for a given volume of gas thereby slowing the heat loss not increasing it.

Gas speeds will be reduced in line with Bernoulli's principle, thereby increasing backpressure (never a good thing).

My system is as insulated as possible in order to keep the gasses as hot as possible so they flow quicker helping to evacuate the gases, reduce back pressure and improve turbo spool up thereby reducing lag.
 
Having just asked this very question to othe exhaust guru that made the stageas new exhaust before he started i wiill give his 2ps worth. ( he does build and design exhausts for racing skylines )
I was told it depends Completely on the engine and to some extent both the above veiws could be considered correct in certain cases
In all cases the exhaust gases operate the turbos . Before the turbos the gases need to move as fast as possible. Smaller pipes are better as long as the gas flow is not restricted. Here the design of the manifolds are important. Some can flow double the stock bhp some cant. The number of downpipes also makes a difference. A 6 cylinder engine like mine with two 3 into one manifolds and two downpipes may need less improvement that say a 4 cylinder with a 4 into 1 .
It also depends where the gases go after the turbo . If they join the exhaust again then from there back pressure doest matter so much ( as explained to me ) so size of pipe should be as large as needed so as to not restrict flow.
It isnt power but volume of gas here so if mine is 2.8 litres revving to 9k it will theoretically need a larger diameter than t 9s or ogs which will not produce as much volume of gas even if they produce more power.
Some exhausts have a screamer pipe direct into the atmosphere . Then the main exhaust after turbo becomes less important.
Its when the turbo "exhaust" goes back into the main exhaust that larger bore pipes come more into their own.

The main thing is to rememBer is that some stock systems are much better than others so need less initial impovement.
 
Like a lot of things in like, often more then one way of doing something, usually more opinions than there are people and every set up is different :)

I guess that is why it is so much fun :)
 
Don't you love it when we go off topic?

The gsi turbo has a Z20let in it I think... A decent turbo back exhaust from the likes of mongoose or maybe even a powerflow dealership will see decent gains, a decent enclosed filter or a good branded replacement element will see nice gains even before the car is remapped. These cars are about 190bhp as standard and from the stated mods I cannot see why 220 to 240bhp isn't attainable.
 
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According to Celtic Tuning a remap alone will achieve over 250bhp along with a very useable 276lbft. That's gotta be stretching the Zafira chassis far enough anyway
 
C20 I can see near 250bhp with. The Z20 I cannot, mainly about 230bhp I reckon with a healthy engine. Yugguy is right though, a decent intercooler will really help with cooling and a bigger turbo. I believe the one from an Astra VXR will fit.
 
Thanks for all the replys guys. I think I am leaning towards maybe getting the boost back exhaust system done and a remap later in the year.
 
I have been looking into exhaust and there is a lot to learn so wanted to be clear and check I was right :)
I am right in saying the system will go..


Turbo>>>> downpipe with precat in it>>>> cat>>>>> silencer>>>> backbox/muffler.


I have read that I could get a downpipe without the precat in it and also get rid of the silencer part and replace with a pipe. Which im guessing would be a cheaper option if fully replacing the system. This sound right to you? What sort of differences would this make?
 
The ideal exhaust for me would fail the current MOT and that is what you need to think about while creating your own system. I am sure someone far more knowledgeable on these things will pipe up (No pun intended) as to what can be and to what can't be done. Some guys have their CAT fitted with a V-band setup on either side of the CAT. So come MOT time they fit the CAT with just a few tweaks of a bolt then straight after the MOT test swap it for a straight piece of pipe.
 
Os is right to be honest. If you want to stay legal, keep with the cat.

You can get turbo back systems with incorporate a sports cat but you don't need any silencers. Back box/muffler is a legal requirement and you will get pulled if its a straight pipe.

Here is a brief picture... lol

Turbo------Cat--------------------backbox.
 
Excellent thats everything I thought. So other questions would be.....can I keep he standard cat and fit new everything else? As the cats are really expensive. Also what is the standard bore size for my car because if I keep the cat I guess I would have to get the correct bore size to connect it all. Also would the cat to back box essentially just be a piece of pipe?
 
You can, but it will seriously bottleneck the set up. You can decat the exhaust but again, tis illegal and will fail the MOT. You can alwys refit the cat when MOT time comes.

Or... :)

Get a decat pipe, weld a gutless cat onto the pipe, then fit a MIL eliminator cable, so the MIL light doesn't come on.

Of course that isn't what I expect you to do at all! Because its naughty...
 
davalav said:
Get a decat pipe, weld a gutless cat onto the pipe, then fit a MIL eliminator cable, so the MIL light doesn't come on.

Of course that isn't what I expect you to do at all! Because its naughty...
Click to expand...


It is truly frightening the things you know Dave :lol:

I think if your skills were used for good instead of evil, the world would be a much better place :lol::lol:
 
Does the cat have a noise cancelling effect? I dont really wanna mess about with replacing the cat every mot to be honest so is it worth doing the rest of the system or should I spend the money else where?
 
Hopefully I got this right, but will bow down to superior members knowledge here. CATS do not reduce noise per se but merely effect a cleaner emission into the atmosphere.
Depending on your CAT manufacturer it is usually a more straight forward entry through the MOT if you have a 200 cell CAT fitted as opposed to a 100 cell CAT. Your exhaust chap will be the best person to talk too with regards to any emissions issues in your neck of the woods.

Bottom line, I would suggest that you stick with a performance filter upgrade and a remap proceeded by a good full service to the engine. Enjoy the car for what it is for a while after the works have been completed and then you will be able to make an informed judgement as to if the power is sufficient or not.
 
T9 man said:
Hopefully I got this right, but will bow down to superior members knowledge here. CATS do not reduce noise per se but merely effect a cleaner emission into the atmosphere.
Depending on your CAT manufacturer it is usually a more straight forward entry through the MOT if you have a 200 cell CAT fitted as opposed to a 100 cell CAT. Your exhaust chap will be the best person to talk too with regards to any emissions issues in your neck of the woods.

Bottom line, I would suggest that you stick with a performance filter upgrade and a remap proceeded by a good full service to the engine. Enjoy the car for what it is for a while after the works have been completed and then you will be able to make an informed judgement as to if the power is sufficient or not.
Click to expand...


Wise words. :)


Does the car have a FSH?
 
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