I'm no stranger to Garrett's GT ball bearing range of turbochargers and I think the GT2854R would make a good unit for an EA82T engine .
The compressor map shows its good for about 27 lbs/min airflow which conservatively means its good for 270 odd engine Hp .
The turbine map shows approx 16 lb/min corrected gas flow in a 0.64 AR turbine housing .
I use GCG in Sydney and they can put together one off compressor/turbine combinations if the parts can be found .
I prefer the higher performance version of the GT28BB turbine (NS111) so I'll be asking if they can build it up the way I want it .
http://www.turbobygarrett.com/turbobyga ... 1171_9.htm
The better turbine's map looks like this .
http://www.turbobygarrett.com/turbobyga ... turb_e.jpg
Cheers A .
Garrett GT2854R for EA82 ?
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discopotato03
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twilightprotege
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discopotato03
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I wouldn't waste Bretts time with stickers , I'm oblivious to that kind of thing .
Twilight I've spent quite some years researching this kind of thing and I know enough to look at a turbochargers specifications a tell whether its suitable for the task or not , more specifically Garrett ones .
Anyway from the top .
Garretts GT (Garrett Technology) ball bearing series starts with their GT2554R at the smallest end . This means their smallest GT turbine in its smallest 62 trim size .
I don't follow the usual guff where people look at a compressor wheel and housing and base the whole units performance around it . I look first at the turbine and its housing combination because that's what drives the thing and if you get it wrong it doesn't matter what spins on the other end .
Compressor and turbine flow need to be in a certain ratio or you get a very biased pressure "balance" across your engine , OEM turbo systems are often like this but the problem usually doesn't get out of hand until someone screws the boost up .
In very basic terms if you can get the turbine inlet pressure (exhaust manifold pressure if you like) close to inlet manifold pressure under boost the engine should scavenge properly and make good power .
So , if you get it right and size it so the turbine response is where you want it to be in the engines rev range you end up with reasonably linear larger NA like engine performance .
The trouble is that everyone tries to follow the manufacturers fetish of boost at cranking revs and choke it all up in the hot side .
I prefer to try and make the engine stand on its own feet and let the turbo enhance what it has to start with .
All top notch turbos have annular contact ball bearings because they have a lot less resistance to rotation particularly from low revs (turbos rotating group) so it takes less exhaust gas energy to zip, them up to speed (better transient response) .
The usual practise with bush bearing turbos is to size them fairly small because small passages mean higher gas speed - with which to overcome the higher friction bearings . The result is they get up to speed ok but the small passages become a restriction at higher revs so the exhaust manifold pressure gets higher which neither the engine or turbo likes very much .
I have been down this road with larger 2L TC 16v engines that had huge breathing abilities compared to an EA82 , that led to the first batch of Garrett GT2860RSs being ordered into Australia and no guesses who got the first one . Ask Brett .
What I want them (GCG) to build up is a toned down version of that GT2860RS because I'm not chasing 300-350 chp this time .
I want the same 53.8mm 76 trim GT28 NS111 turbine but this time in the smaller 0.64 A/R turbine housing (vs the 0.86 A/R one last time ) .
The jury is still out on the compressor size which can be either 54.3mm 60T or 60mm 60T , the lower inertia of the smaller one is a plus on that score and is more than good enough to move the 20 odd lbs/min airflow I could possibly use .
The real bonus is that NS111 turbine because it has a low blade count (9) and is very light and open bladed .
It's major diameter is 53.84mm which is not too far behind the compressors 54.3mm which means the blades tip speeds are similar - won't get one side reaching its mechanical limits before the other
So low exhaust restriction , important in a low tech Siamese port engine , light weight free flowing turbine and an appropriately sized compressor to move enough air at reliable rotating group revs .
I my experience a well speced BB turbo has a faster "idle" speed than bush bearing turbos and at very light engine loads they can windmill fast enough to push a little more air down the engines throat than it would get on its own . Inlet manifold pressure doesn't have to go positive to get more air into the cylinders than the atmosphere can supply and you can feel it when you drive cars that can do this .
If you've never tried it you probably wouldn't believe it but I offer this challenge . Get two turbos with the same wheels in them , one bush one BB , spin them over by hand at the same speed and see which one stops first .
I reckon the the rotating group in my GT2860RS used to spin for 20 odd seconds after a hot idling shut down , you could hear it on a quiet night .
Anyway no stock of these turbos for a month or so and Brett will be back in a couple of days .
Cheers A .
Twilight I've spent quite some years researching this kind of thing and I know enough to look at a turbochargers specifications a tell whether its suitable for the task or not , more specifically Garrett ones .
Anyway from the top .
Garretts GT (Garrett Technology) ball bearing series starts with their GT2554R at the smallest end . This means their smallest GT turbine in its smallest 62 trim size .
I don't follow the usual guff where people look at a compressor wheel and housing and base the whole units performance around it . I look first at the turbine and its housing combination because that's what drives the thing and if you get it wrong it doesn't matter what spins on the other end .
Compressor and turbine flow need to be in a certain ratio or you get a very biased pressure "balance" across your engine , OEM turbo systems are often like this but the problem usually doesn't get out of hand until someone screws the boost up .
In very basic terms if you can get the turbine inlet pressure (exhaust manifold pressure if you like) close to inlet manifold pressure under boost the engine should scavenge properly and make good power .
So , if you get it right and size it so the turbine response is where you want it to be in the engines rev range you end up with reasonably linear larger NA like engine performance .
The trouble is that everyone tries to follow the manufacturers fetish of boost at cranking revs and choke it all up in the hot side .
I prefer to try and make the engine stand on its own feet and let the turbo enhance what it has to start with .
All top notch turbos have annular contact ball bearings because they have a lot less resistance to rotation particularly from low revs (turbos rotating group) so it takes less exhaust gas energy to zip, them up to speed (better transient response) .
The usual practise with bush bearing turbos is to size them fairly small because small passages mean higher gas speed - with which to overcome the higher friction bearings . The result is they get up to speed ok but the small passages become a restriction at higher revs so the exhaust manifold pressure gets higher which neither the engine or turbo likes very much .
I have been down this road with larger 2L TC 16v engines that had huge breathing abilities compared to an EA82 , that led to the first batch of Garrett GT2860RSs being ordered into Australia and no guesses who got the first one . Ask Brett .
What I want them (GCG) to build up is a toned down version of that GT2860RS because I'm not chasing 300-350 chp this time .
I want the same 53.8mm 76 trim GT28 NS111 turbine but this time in the smaller 0.64 A/R turbine housing (vs the 0.86 A/R one last time ) .
The jury is still out on the compressor size which can be either 54.3mm 60T or 60mm 60T , the lower inertia of the smaller one is a plus on that score and is more than good enough to move the 20 odd lbs/min airflow I could possibly use .
The real bonus is that NS111 turbine because it has a low blade count (9) and is very light and open bladed .
It's major diameter is 53.84mm which is not too far behind the compressors 54.3mm which means the blades tip speeds are similar - won't get one side reaching its mechanical limits before the other
So low exhaust restriction , important in a low tech Siamese port engine , light weight free flowing turbine and an appropriately sized compressor to move enough air at reliable rotating group revs .
I my experience a well speced BB turbo has a faster "idle" speed than bush bearing turbos and at very light engine loads they can windmill fast enough to push a little more air down the engines throat than it would get on its own . Inlet manifold pressure doesn't have to go positive to get more air into the cylinders than the atmosphere can supply and you can feel it when you drive cars that can do this .
If you've never tried it you probably wouldn't believe it but I offer this challenge . Get two turbos with the same wheels in them , one bush one BB , spin them over by hand at the same speed and see which one stops first .
I reckon the the rotating group in my GT2860RS used to spin for 20 odd seconds after a hot idling shut down , you could hear it on a quiet night .
Anyway no stock of these turbos for a month or so and Brett will be back in a couple of days .
Cheers A .
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discopotato03
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discopotato03
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I finally got to speak to Brett today and he thinks the alternate turbine idea should work quite well .
All they've got to do is dig out the right turbine and wait for stock of these turbos to arrive in the next 6-8 weeks .
Then swap the turbine in the cartridge and profile machine the housing to suit the NS111 turbine .
I can see a bit of mucking around with wastegate actuator brackets because the housings are going to have to be clocked to suit a flat four .
Also I think the std actuators on these turbos are 10 lb where a 7-8 would probably suit me better .
Because this will be an altered spec turbo like the GT2860RS , that's what the "S" means , I think I'll christen this one GT2854RS .
Ah just for the record whats the usual fix for an early (86) Rx's over-boost switch , just remove the manifold pressure signal line ?
Cheers , A .
All they've got to do is dig out the right turbine and wait for stock of these turbos to arrive in the next 6-8 weeks .
Then swap the turbine in the cartridge and profile machine the housing to suit the NS111 turbine .
I can see a bit of mucking around with wastegate actuator brackets because the housings are going to have to be clocked to suit a flat four .
Also I think the std actuators on these turbos are 10 lb where a 7-8 would probably suit me better .
Because this will be an altered spec turbo like the GT2860RS , that's what the "S" means , I think I'll christen this one GT2854RS .
Ah just for the record whats the usual fix for an early (86) Rx's over-boost switch , just remove the manifold pressure signal line ?
Cheers , A .
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discopotato03
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- Location: Sydney
Part of the reason I went looking for that GT2854R is that it is compact like the std IHI though understandably light years ahead aero and bearing wise . wise .
Where it will be interesting is that it should be able to pump significantly more air , and pass more exhaust with less restriction , and I should be able to a degree regulate airflow via the waste gate actuators spring rating .
If I can get a Garrett one of a similar value to the std IHI one the turbo will still handle more air/exhaust at that pressure and it remains to be seen how the air flow meter and injectors cope with the extra air .
Boost controllers can always raise the regulated pressure but they can't reduce the base setting of the actuator .
OT but may have to look around for a generic 1 to 1 adjustable fuel pressure reg , I think HKS do one .
If may be possible to play with the computers head , depending on how good its close loop function is at light load , by using a different fuel rail pressure and slightly larger electrically compatible injectors - and altering the TPS's open throttle contacts switch point . From memory the 3P NA TPS open throttle contacts switch slightly later in the throttles arc so maybe a factory solution .
Fun and games , cheers A .
Where it will be interesting is that it should be able to pump significantly more air , and pass more exhaust with less restriction , and I should be able to a degree regulate airflow via the waste gate actuators spring rating .
If I can get a Garrett one of a similar value to the std IHI one the turbo will still handle more air/exhaust at that pressure and it remains to be seen how the air flow meter and injectors cope with the extra air .
Boost controllers can always raise the regulated pressure but they can't reduce the base setting of the actuator .
OT but may have to look around for a generic 1 to 1 adjustable fuel pressure reg , I think HKS do one .
If may be possible to play with the computers head , depending on how good its close loop function is at light load , by using a different fuel rail pressure and slightly larger electrically compatible injectors - and altering the TPS's open throttle contacts switch point . From memory the 3P NA TPS open throttle contacts switch slightly later in the throttles arc so maybe a factory solution .
Fun and games , cheers A .