Kranz Posted April 5, 2007 Share Posted April 5, 2007 that must have cost stupid money! I was quoted £5k+ per turbo £200 per turbo mate New!!! Quote Link to comment Share on other sites More sharing options...
Thorin Posted April 5, 2007 Share Posted April 5, 2007 Now this should be interesting. Quote Link to comment Share on other sites More sharing options...
Kranz Posted May 11, 2007 Share Posted May 11, 2007 Thread resurection time number 2 I now have the turbos, and they're absolutely mint!! Compressor is 42.8mm minor and 59.4 major, which makes it a 52 trim 0.42 A/R GT2259 compressor wheel. I've checked it out and its capable of 500hp between the pair.... Spot on for what I want. Turbine is quite small at 43.2mm and 48.4mm, but you've got to remember that the VNT vanes can make the turbine act like a big or small one. I'll see how this goes. If the turbine is too small and the VNT actuation can't keep the boost down when fully 'open' I'll have to fit an external wastegate. Luckily I have one or two hanging about I have the basic mechanical control system, which will plug into the pre & post throttle pressure tappings. I'll use an electronic boost controller to control the boost on the VNT actuators, but if the turbines are too small (as mentioned above) I'll need another means of boost control for the wastegate.... probably another electronic boost controller to be on the safe side. Watch this space Quote Link to comment Share on other sites More sharing options...
Wez Posted May 11, 2007 Share Posted May 11, 2007 Make sure these dont work on vacume like the ones I have been playing with recently, should be able to test the vane working with a compressor and gauges. VNT are also prone to surging in low revs which you will need to counter/prevent. Quote Link to comment Share on other sites More sharing options...
JustGav Posted May 11, 2007 Share Posted May 11, 2007 Hmmmm, now I would be tempted to try one of these on an a series engine... Do you know if your source can do small T3 versions... Quote Link to comment Share on other sites More sharing options...
Kranz Posted May 11, 2007 Share Posted May 11, 2007 Make sure these dont work on vacume like the ones I have been playing with recently, should be able to test the vane working with a compressor and gauges. VNT are also prone to surging in low revs which you will need to counter/prevent. Wez, the actuator works on pressure/pressure and pressure/vacuum depending if the engine is on boost and if the throttle is causing a vacuum. It'll work ok. Low rev surging can be controlled by using vacuum to open the vanes and fitting a restrictor on the vacuum signal to dampen the presure/vacuum waves... plus a one way valve. Theory of operation is that there are two tappings into the actuator capsule. The actuator is sprung to hold the vanes closed to spin the turbine up. The top connection to the top of the actuator capsule is pressure pre throttle. The bottom connection goes to post throttle (inlet manifold) pressure/vacuum. The theory is that at idle and part throttle (off boost) the vacuum will pull the vanes open, reducing the restriction on the exhaust. When the loud pedal is floored there is no vacuum, so the actuator closes the vanes and the turbo spools up. As pressure builds up the pressure is fed to each side of the actuator. To control the boost, the pressure on the 'vacuum' side of the actuator is bled off by the boost controller through a one way valve (required to prevent vacuum being lost when running part throttle). As full boost is being fed to the top of the capsule, and boost pressure being bled off the bottom connection of the capsule, the pressure difference causes the actuator to open the vanes when there is sufficient pressure difference to overcome the spring pressure.... so the more that is bled off the lower the boost setting. Sounds easy eh??? Quote Link to comment Share on other sites More sharing options...
Kranz Posted May 11, 2007 Share Posted May 11, 2007 Do you know if your source can do small T3 versions... No, sorry mate. These were a one off I believe. Look like they are development turbos I'll ask where he got them from though. Garrett themselves will do you a GT series turbo with a VNT option for £££££. Quote Link to comment Share on other sites More sharing options...
mikeyb10supra Posted May 11, 2007 Share Posted May 11, 2007 something I have been thinking about doing something like this for a long time, would be very interested to see how this works out, I was planning a conversion using hks small speced twins on the stock setup but was very concerned about the manifold properties! and heat issues how do you think the stock manifold will hold up to the garrett jobies?? Quote Link to comment Share on other sites More sharing options...
Kranz Posted May 11, 2007 Share Posted May 11, 2007 how do you think the stock manifold will hold up to the garrett jobies?? Not too bad I think, as the Garretts are about the same weight as the J specs along with all their cast pipework, cast downpipes etc. I'll be using some supports to brace it all up. The fabrication required is a pair of adaptor plates to go from the J spec 3 stud flange to the T25 inlet of the turbines....... and some downpipes of course! Quote Link to comment Share on other sites More sharing options...
mikeyb10supra Posted May 11, 2007 Share Posted May 11, 2007 Not too bad I think, as the Garretts are about the same weight as the J specs along with all their cast pipework, cast downpipes etc. I'll be using some supports to brace it all up. The fabrication required is a pair of adaptor plates to go from the J spec 3 stud flange to the T25 inlet of the turbines....... and some downpipes of course! and there will be no flow restrictions associated with the narrow runners on the j-spec manifold? only thing I was worried about with going down this route was the added heat element and the manifold physically not being able to flow enough given the size of the turbos, I will certainly be watching this thread with great interest keep us updated ps where did you pick the garretts up out of interest:cool: Quote Link to comment Share on other sites More sharing options...
Wez Posted May 11, 2007 Share Posted May 11, 2007 The stock manifold should flow enough as some budget turbo kits use an adapter on the stock manifold to mount a single which is good for 500hp. Quote Link to comment Share on other sites More sharing options...
Kranz Posted May 11, 2007 Share Posted May 11, 2007 and there will be no flow restrictions associated with the narrow runners on the j-spec manifold? Ideally I'd like a shiny new HKS twin manifold with the T25 flanges, but at over £1K its not in the budget at the moment I think some 3/4 inch plate made into adapters for around £10 is more like it! Eventually I'll be looking for the HKS manifold though. only thing I was worried about with going down this route was the added heat element TBH I think the heat should be less than with stock ot hybrid turbos as the VNT's are less of a restriction, even though it may be making more power. ps where did you pick the garretts up out of interest:cool: Good old ebay! Just kept searching for VNT. Won the one and bought the second at the same price. Quite a result. Quote Link to comment Share on other sites More sharing options...
JustGav Posted May 12, 2007 Share Posted May 12, 2007 No, sorry mate. These were a one off I believe. Look like they are development turbos I'll ask where he got them from though. Garrett themselves will do you a GT series turbo with a VNT option for £££££. You appear to have a very good understanding of these units, what sort of size would you recommend for a metro turbo a-series 1275cc? Quote Link to comment Share on other sites More sharing options...
Kranz Posted May 12, 2007 Share Posted May 12, 2007 You appear to have a very good understanding of these units, what sort of size would you recommend for a metro turbo a-series 1275cc? I'd go for one based on the VW Golf 110hp (VNT17) or Ford Focus TDci VNT, as its a VNT15 (Garrett GT15 with VNT). The Golf one I believe is going to be easier to fit as it isn't integral with the manifold. Here's a new one for only £166!!!! http://cgi.ebay.co.uk/Turbo-Garrett-VNT-15-nieuw_W0QQitemZ140115046882QQihZ004QQcategoryZ61372QQssPageNameZWDVWQQrdZ1QQcmdZViewItem It'll need a new twin port actuator capsule, but I'm sure these are available.... or the current one can be modified. It'll have a compressor wheel size of either 32.9mm or 34.7mm minor and 49 major, making it a 45 or 50 trim wheel respectively. Quote Link to comment Share on other sites More sharing options...
JustGav Posted May 12, 2007 Share Posted May 12, 2007 I'd go for one based on the VW Golf 110hp (VNT17) or Ford Focus TDci VNT, as its a VNT15 (Garrett GT15 with VNT). The Golf one I believe is going to be easier to fit as it isn't integral with the manifold. Here's a new one for only £166!!!! http://cgi.ebay.co.uk/Turbo-Garrett-VNT-15-nieuw_W0QQitemZ140115046882QQihZ004QQcategoryZ61372QQssPageNameZWDVWQQrdZ1QQcmdZViewItem It'll need a new twin port actuator capsule, but I'm sure these are available.... or the current one can be modified. It'll have a compressor wheel size of either 32.9mm or 34.7mm minor and 49 major, making it a 45 or 50 trim wheel respectively. Cheers muchly, going to look into it now, only prob I forsee is getting it to fit next to the bulkhead... Quote Link to comment Share on other sites More sharing options...
TLicense Posted May 12, 2007 Share Posted May 12, 2007 This looks like a very interesting project. Keep us all updated with how you get on. Quote Link to comment Share on other sites More sharing options...
Wez Posted May 12, 2007 Share Posted May 12, 2007 What EGT range are these designed to work with as I read earlier VNT units didnt work to well at high EGT. Quote Link to comment Share on other sites More sharing options...
Kranz Posted May 12, 2007 Share Posted May 12, 2007 What EGT range are these designed to work with as I read earlier VNT units didnt work to well at high EGT. I'm looking at 800 deg C pre-turbine to start with and see how it goes. If its alright I'll increment up until I reach the limit for the power I'm at People that have adapted diesel VNT's to gasoline engines haven't reported any temperature problems that I can find, but more carbon formation problems. I think its important to fully exercise the vanes once in a while to keep the crud off them, otherwise they stick in one position. Quote Link to comment Share on other sites More sharing options...
Wez Posted May 12, 2007 Share Posted May 12, 2007 I read on another forum of VNT working ok at 900degC To reduce the carbon output could you run them with some methonal and pull some fuel, that would also give you a lower EGT too. Quote Link to comment Share on other sites More sharing options...
Kranz Posted May 12, 2007 Share Posted May 12, 2007 I read on another forum of VNT working ok at 900degC Cool! Linky???? Quote Link to comment Share on other sites More sharing options...
Gazboy Posted May 27, 2007 Share Posted May 27, 2007 You're a pioneer! Even the Porsche tuners are baffled by VNT! Quote Link to comment Share on other sites More sharing options...
Fusi Posted June 30, 2007 Share Posted June 30, 2007 Any updates? Quote Link to comment Share on other sites More sharing options...
BASHTHEBISHOP Posted July 1, 2007 Share Posted July 1, 2007 Any updates? Quote Link to comment Share on other sites More sharing options...
JohnA Posted July 2, 2007 Share Posted July 2, 2007 ... I think its important to fully exercise the vanes once in a while to keep the crud off them, otherwise they stick in one position. that's what I've heard too. I've just seen this thread, very interesting project Quote Link to comment Share on other sites More sharing options...
Guest jiggersplat Posted July 5, 2007 Share Posted July 5, 2007 status? Quote Link to comment Share on other sites More sharing options...
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