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New Member
CDTI 150 Turbo / Fueling modifications
Good afternoon Everyone.
This is my first time creating a thread / discussion so please, be gentle...
I've owned my virtually stock engined CDTI 150 Vec for a couple of years now, the only power boosting mods I've done thus far consist of removing and blanking the swirl flaps, EGR delete and a remap. The car has been run like this for about 18 months and now its starting to smoke under load, so I believe its time to take things to the next level...
I'm particularly interested in hybridizing the turbo but fancy going down a slightly different route to the more traditional 1756 turbo; using a 60mm compressor housing from a gt2260v (bmw 330/530), having a 360 thrust bearing or a a ball-bearing... bearing, a billet 60mm compressor wheel and a billet 17mm turbine wheel (rather than the cast units) for faster spool.
Has anyone had a go at a 1760 before?
I appreciate the turbo is only as successful as its accompanying counterparts such as cooling an fueling; I've already invested in an upgraded inter-cooler, 80mm MAF and associated pipework, and a 4 bar MAP sensor which leads me onto my next idea - fueling.
I've researched the possibilities of installing Insgnia CDTI 160 (327) injectors for better flow, but was wondering whether installing a high pressure fuel pump from an Alfa 2.4 jtdm would aid the fuel side of things.
Has anyone done this? Can anyone see of any benefits? Is it likely to directly replace the 1.9's unit due to the similarities of the engines?
I'm open to suggestions/comments/abuse (within reason) as I am a man with a little knowledge, and can therefore be considered dangerous...
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10th March 2017, 00:29
#2
Regular Member
Hi Dannay,
like you im picking things up as i go and also have a 150 cdti vectra that i would like abit more poke from. I just wanted to add my 2 pence and say you are along the right lines for faster spooling regarding ball bearing turbo's, journal bearings arent as efficient at getting the compressor mass moving as quick as it could and can contribute to lag. As im sure you know, theres a balance where smaller turbos run out of puff (compression power) and big turbos in which the propellar/impellar can take longer to spool up due to its greater size and mass. You can get ceramic ball bearing turbos, but im not sure what they cost. Have you considered a port and polish? My cylinder head is nearly off and its tempting. Extremely labour intensive but can give a more efficient burn and release some ponies, and its free, kind of. As for fueling i have no idea sorry, im just learning but i know there are guys here who get some decent power from their cars.
If you do ever get a more powerful turbo dont forget the waste gate actuator, you could end up realeasing quite a few horsepower into the atmosphere due to having a spring still installed thats meant to cope with lower pressure and will not be able to hold the boost if it overpowers the mechanism.
There was one particular post where a guy was reaching 300bhp, but that guy was on a mission, clearly....
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26th March 2017, 09:13
#3
Lmao!!! Waster gate actuator!?! You better leave that engine alone Bacon as you have no idea what is in there ��
All of the answers to the above are on the site already but I'm in bed and I have time so we'll do this again.
360 deg thrust bearing: you already have one, they are standard on the GT1749MV.
Using a 60mm wheel has been done, using it with a larger housing from another turbo has already been done. The traditional 44.5/60.0mm wheels spool very late on a GT17 and you will limit your torque because of this and make it a dog to drive low down. A guy called Harvey tried it and managed 280bhp but he went back to a 41.6/56.0 compressor because it spooled too late. I had different compressors produced with smaller inducers and an 8 blade design rather than 6/6, they are running 2.5 bar of boost on several cars, enough for 250+bhp. Still later to spool than a standard turbo obviously but they spool fast enough to see peak torque in the right place.
Standard injectors are capable of about 230bhp before the injection durations are too long for the effective injection window (30 deg BTDC - 12 deg ATDC). 327s are capable of 300+bhp but the fuel pump is not, so an R80 pump is required above about 125mm^3/stroke or 280bhp on 327s. Obviously there are variations in injector flow and pump capacity, so as a rule of thumb you can pusn the pump until the achieved rail pressure starts lagging demand, at which point it needs changing.
Best option but most complex is to fit a modern GTB turbo as it will spool faster and support more boost. I went for a GTB2056 water cooled unit and then hybrided that with a 44.5/60.0 billet compressor with extended tip to 65mm. With all the other supporting mods, 140mm^3/stk and 40psi produced 295bhp/427lbft and I have since lifted it to 145mm^3/stk and 44psi but can't be bothered to re-dyno at this time. I know from my Racelogic Performance Box that is has gained 10bhp on the road, so that puts it around 305bhp obviously.
Back to my first comments, modern diesels use VNT turbos that don't have wastegates. The angle of air onto the turbine and the entry volume is varried by guide vanes during operation to provide much better spool and to control boost pressure. This system has the same effect as varrying the AR of the exhaust housing during operation. A GT17 turbine will run away beyond control if you just keep putting in more flow from higher boost and fueling, resulting in huge boost spikes and overspeeding the shaft. It is possible to fit an EXTERNAL waste gate to the system via the EGR port, something I myself did. This can release upto15bhp according to my road tests with the box but it is a complicated setup.
Last edited by nutron; 26th March 2017 at 09:19.
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26th March 2017, 09:35
#4
There speaks a Man who knows
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On the wastegate option, you can fit a very small turbine if you are going to use an external wastegate. The complicated bit is getting the waste gate plumbed into the exhaust system, it just needs a standard boost feed to activate it and I used a 24psi spring as that was the highest they had. The ECU will automatically vary VNT to match the exhuast flow, so there is no real need to change mapping when you fit one.
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12th March 2019, 14:56
#6
Originally Posted by
nutron
On the wastegate option, you can fit a very small turbine if you are going to use an external wastegate. The complicated bit is getting the waste gate plumbed into the exhaust system, it just needs a standard boost feed to activate it and I used a 24psi spring as that was the highest they had. The ECU will automatically vary VNT to match the exhuast flow, so there is no real need to change mapping when you fit one.
Just out of interest I assume you wanted to bypass the exhaust turbine as this causes a flow restriction when at high RPM?
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17th March 2019, 17:06
#7
It allows some bypass if done right yes but still retains enough flow through the turbine for the ECU to control boost.
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18th March 2019, 11:19
#8
Originally Posted by
nutron
It allows some bypass if done right yes but still retains enough flow through the turbine for the ECU to control boost.
Is this something worthwhile on a standard turbo running 26ish psi or is it more for higher boost levels on a hybrid etc?
I assume the boost is then re-introduced into the down pipe after the turbo?
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18th March 2019, 19:22
#9
No there is no point in it for that application.
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