Diy turbo swap help
Discussion
So, my crap turbo (kp35) has packed up. not sure what's up with it but it's not boosting much. I'm wanting to upgrade rather than replace as these units are weak anyway.
How do I fit a not stock turbo to my manifold? I can weld but I don't think I can weld cast iron/steel (something about thermal expansion cracks cast stuff). Thinking maybe some sort of adapter but I must be able to make it myself. I'll be using a used turbo to replace, probably a garrett off a volvo. I don't need to worry about the air side as I'm doing a top mount conversion.
How do I fit a not stock turbo to my manifold? I can weld but I don't think I can weld cast iron/steel (something about thermal expansion cracks cast stuff). Thinking maybe some sort of adapter but I must be able to make it myself. I'll be using a used turbo to replace, probably a garrett off a volvo. I don't need to worry about the air side as I'm doing a top mount conversion.
Are you sure it's the turbo? I spent f
king ages working on a mates car when we thought the turbo was stuffed - turned out to be a faulty MAF. (It was a new one but a cheapo Ebay jobbie). May be worth checking - would have saved me a load of work, swearing, skinned knuckles and drinking time! 
king ages working on a mates car when we thought the turbo was stuffed - turned out to be a faulty MAF. (It was a new one but a cheapo Ebay jobbie). May be worth checking - would have saved me a load of work, swearing, skinned knuckles and drinking time! sunbeam alpine said:
Are you sure it's the turbo? I spent fking ages working on a mates car when we thought the turbo was stuffed - turned out to be a faulty MAF. (It was a new one but a cheapo Ebay jobbie). May be worth checking - would have saved me a load of work, swearing, skinned knuckles and drinking time!
It's chucking out black smoke and barely boosts to 5psi, it should be 19psi. Could the maf cause these problems. Also how do I check a mafking ages working on a mates car when we thought the turbo was stuffed - turned out to be a faulty MAF. (It was a new one but a cheapo Ebay jobbie). May be worth checking - would have saved me a load of work, swearing, skinned knuckles and drinking time! Afghanwarrior said:
Also how do I check a maf
Simplest way to check the MAF is to unplug the cable running to it. This should force the car to deault to a "safe" map as it's not getting a signal from the MAF. If the car runs better (not perfect, but better) with the MAF unlugged, it's probably faulty. Afghanwarrior said:
It's chucking out black smoke and barely boosts to 5psi, it should be 19psi. Could the maf cause these problems. Also how do I check a maf
Boost is a measure of resistance not flow. Where are you measuring this from? Could just be a boost leak. What engine/vehicle is it? And what do you want to achieve with a bigger turbo?
sunbeam alpine said:
Simplest way to check the MAF is to unplug the cable running to it. This should force the car to deault to a "safe" map as it's not getting a signal from the MAF. If the car runs better (not perfect, but better) with the MAF unlugged, it's probably faulty.
This doesn’t work 100% of the time although sometimes it is a simple test. Depends on the programming in the ECU. Better to plug it in and read the live data from the sensor, specifically voltages and flow then compare it to either the data sheet or a vehicle with a known working MAF sensor.
sunbeam alpine said:
Afghanwarrior said:
Also how do I check a maf
Simplest way to check the MAF is to unplug the cable running to it. This should force the car to deault to a "safe" map as it's not getting a signal from the MAF. If the car runs better (not perfect, but better) with the MAF unlugged, it's probably faulty. 300bhp/ton said:
Afghanwarrior said:
It's chucking out black smoke and barely boosts to 5psi, it should be 19psi. Could the maf cause these problems. Also how do I check a maf
Boost is a measure of resistance not flow. Where are you measuring this from? Could just be a boost leak. What engine/vehicle is it? And what do you want to achieve with a bigger turbo?
It's a 1.3 cdti corsa and Im going to make it twin turbo to get more air without to lag of a big turbo. Then get some more fuel mapped in.
Afghanwarrior said:
300bhp/ton said:
Afghanwarrior said:
It's chucking out black smoke and barely boosts to 5psi, it should be 19psi. Could the maf cause these problems. Also how do I check a maf
Boost is a measure of resistance not flow. Where are you measuring this from? Could just be a boost leak. What engine/vehicle is it? And what do you want to achieve with a bigger turbo?
It's a 1.3 cdti corsa and Im going to make it twin turbo to get more air without to lag of a big turbo. Then get some more fuel mapped in.
Did you plumb the boost gauge in? If it’s downstream of the turbo such as reading at the intake manifold or inter cooler. Then a boost leak may well show as low boost at that point. Even if the turbo is still working perfectly.
And there are other things that could cause a turbo not to boost correctly. I’d want to get to bottom of what is wrong, before wanting to change anything. As you won’t know if you are actually addressing the problem or not.
300bhp/ton said:
I’m sure you could sink a fortune into upgrades on your diesel Corsa only to end up with a slow diesel Corsa. Only one that nobody will want to buy.
This ^^^.You also have to deal with insuring a modified car, and if you do manage to raise the output torque significantly you will probably find the engine and transmission are no longer reliable.
The best way to get a faster car is to buy a faster standard car.
If that isn't possible, the next best is to buy a car that somebody else has wasted time and money upgrading.
The last option is to try to DIY. Really, the only time that is a good idea is when you have time and money to burn and are interested in the experience, not the end result.
GreenV8S said:
300bhp/ton said:
I’m sure you could sink a fortune into upgrades on your diesel Corsa only to end up with a slow diesel Corsa. Only one that nobody will want to buy.
This ^^^.You also have to deal with insuring a modified car, and if you do manage to raise the output torque significantly you will probably find the engine and transmission are no longer reliable.
The best way to get a faster car is to buy a faster standard car.
If that isn't possible, the next best is to buy a car that somebody else has wasted time and money upgrading.
The last option is to try to DIY. Really, the only time that is a good idea is when you have time and money to burn and are interested in the experience, not the end result.
Edited by Afghanwarrior on Wednesday 4th October 16:48
Afghanwarrior said:
I am interested in the journey. I'm not chasing numbers and I don't want to go fast as such, I just really enjoy molding my car. I like to be different and try new things. I don't care how much it costs or how long it takes or how many components I destroy it's just for my own fun. I love my little corsa and this is the car I chose to modify. If I wanted a fast car I would have bought one. Who else has even tried to make a twin turbo 1.3 cdti? No one. Also I'm not building a car for someone else to but I'll scrap it when I'm done coz that's all it will be worth and if I can't get insured coz its too extreme (lol) then it will be a track only car.
Go for it, good luck, I hope you will let us know how you get on. 
Afghanwarrior said:
GreenV8S said:
300bhp/ton said:
I’m sure you could sink a fortune into upgrades on your diesel Corsa only to end up with a slow diesel Corsa. Only one that nobody will want to buy.
This ^^^.You also have to deal with insuring a modified car, and if you do manage to raise the output torque significantly you will probably find the engine and transmission are no longer reliable.
The best way to get a faster car is to buy a faster standard car.
If that isn't possible, the next best is to buy a car that somebody else has wasted time and money upgrading.
The last option is to try to DIY. Really, the only time that is a good idea is when you have time and money to burn and are interested in the experience, not the end result.
Edited by Afghanwarrior on Wednesday 4th October 16:48
But I do wonder. Is this your first car? Do you still live at home?
If yes to these. Then I suspect the reality of life. As in needing time, money and usually transport. Will likely put pay to your plans. People who say “I love my little Corsa”, especially when it’s a diesel. Strike me as being 17-18 and have never really driven much else.
But happy if you prove me wrong
maybe keep this thread as a bit of a build thread. 300bhp/ton said:
Well I won’t stop you. Go for it.
But I do wonder. Is this your first car? Do you still live at home?
If yes to these. Then I suspect the reality of life. As in needing time, money and usually transport. Will likely put pay to your plans. People who say “I love my little Corsa”, especially when it’s a diesel. Strike me as being 17-18 and have never really driven much else.
But happy if you prove me wrong maybe keep this thread as a bit of a build thread.
I know what you mean but I'm 26, married with 2 kids, own my own home and I've had about 12 carsBut I do wonder. Is this your first car? Do you still live at home?
If yes to these. Then I suspect the reality of life. As in needing time, money and usually transport. Will likely put pay to your plans. People who say “I love my little Corsa”, especially when it’s a diesel. Strike me as being 17-18 and have never really driven much else.
But happy if you prove me wrong
maybe keep this thread as a bit of a build thread. Afghanwarrior said:
300bhp/ton said:
Well I won’t stop you. Go for it.
But I do wonder. Is this your first car? Do you still live at home?
If yes to these. Then I suspect the reality of life. As in needing time, money and usually transport. Will likely put pay to your plans. People who say “I love my little Corsa”, especially when it’s a diesel. Strike me as being 17-18 and have never really driven much else.
But happy if you prove me wrong maybe keep this thread as a bit of a build thread.
I know what you mean but I'm 26, married with 2 kids, own my own home and I've had about 12 carsBut I do wonder. Is this your first car? Do you still live at home?
If yes to these. Then I suspect the reality of life. As in needing time, money and usually transport. Will likely put pay to your plans. People who say “I love my little Corsa”, especially when it’s a diesel. Strike me as being 17-18 and have never really driven much else.
But happy if you prove me wrong
maybe keep this thread as a bit of a build thread. I assume you're thinking a pair of small parallel turbos, rather than sequential assymetric, with a small one covering low revs, and a larger one for the top end?
OK, first off - can you even get two small enough turbos? What are you thinking, something off a Kei?
You're going to have to fabricate an exhaust manifold from scratch. Where are the turbos going to sit? Heat implications?
Have you actually done the sums to see if this is going to give any benefit?
Wouldn't it just be so much easier (and more effective) to look at swapping in a 1.9CDTi from an Astra?
Hell, why not just get an Astra?
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