hybrid turbo experience - small exhaust & large compressor
Compressor to turbine match is the key and these intentionally mismatched setups usually don't work out too well.
The undersized turbine usually performs poorly when it comes to transient response. I would assume this is due to the smaller turbine wheel having a poor mechanical advantage on the compressor wheel. Basically, the smaller turbine wheel can not get the torque needed to accelerate the rotating assembly quickly.
Small turbine/large compressor usually has a lower boost threshold on the dyno compared to the properly matched turbine to the same size compressor. On the street though, that properly match turbo drives better and has stronger response in every situation but lagging the car in fourth from 2000 RPM.
The undersized turbine usually performs poorly when it comes to transient response. I would assume this is due to the smaller turbine wheel having a poor mechanical advantage on the compressor wheel. Basically, the smaller turbine wheel can not get the torque needed to accelerate the rotating assembly quickly.
Small turbine/large compressor usually has a lower boost threshold on the dyno compared to the properly matched turbine to the same size compressor. On the street though, that properly match turbo drives better and has stronger response in every situation but lagging the car in fourth from 2000 RPM.
Evolving Member
Joined: Feb 2007
Posts: 491
Likes: 1
From: Redmond Washington
Check out these crazy guys running a 50 trim .48 a/r stage 3 hotside with the turbonetics "Super 50" compressor wheel. This compressor wheel has the same size inducer as a regular 50 trim, but the exducer is almost 82 mm. This combined with the small turbine housing gives what most people would call a "missmatched" turbo. But they are making lots of hp at low revs and note their comments about how it compares to the .63 a/r.
http://www.srtforums.com/forums/f24/...f-dyno-409314/
Funny thing is, the vendor that builds this turbo (AGP) doesn't really recommend it because "it can't max out the compressor". I say who gives a rip that it can't max out the compressor. It's the overall performance through the rev band I'm looking for, not max out this or that.
When you look at their dynos which are chopped off in the pic, remember hp and tq cross each other at 5250 rpm, also they are shutting off at about 6200 rpm - stock SRT4 rev limit! Also it's FWD, the AWHP would be a little less. You can figure out the rest.
Gary
http://www.srtforums.com/forums/f24/...f-dyno-409314/
Funny thing is, the vendor that builds this turbo (AGP) doesn't really recommend it because "it can't max out the compressor". I say who gives a rip that it can't max out the compressor. It's the overall performance through the rev band I'm looking for, not max out this or that.
When you look at their dynos which are chopped off in the pic, remember hp and tq cross each other at 5250 rpm, also they are shutting off at about 6200 rpm - stock SRT4 rev limit! Also it's FWD, the AWHP would be a little less. You can figure out the rest.
Gary
Check out these crazy guys running a 50 trim .48 a/r stage 3 hotside with the turbonetics "Super 50" compressor wheel. This compressor wheel has the same size inducer as a regular 50 trim, but the exducer is almost 82 mm. This combined with the small turbine housing gives what most people would call a "missmatched" turbo. But they are making lots of hp at low revs and note their comments about how it compares to the .63 a/r.
http://www.srtforums.com/forums/f24/...f-dyno-409314/
Funny thing is, the vendor that builds this turbo (AGP) doesn't really recommend it because "it can't max out the compressor". I say who gives a rip that it can't max out the compressor. It's the overall performance through the rev band I'm looking for, not max out this or that.
When you look at their dynos which are chopped off in the pic, remember hp and tq cross each other at 5250 rpm, also they are shutting off at about 6200 rpm - stock SRT4 rev limit! Also it's FWD, the AWHP would be a little less. You can figure out the rest.
Gary
http://www.srtforums.com/forums/f24/...f-dyno-409314/
Funny thing is, the vendor that builds this turbo (AGP) doesn't really recommend it because "it can't max out the compressor". I say who gives a rip that it can't max out the compressor. It's the overall performance through the rev band I'm looking for, not max out this or that.
When you look at their dynos which are chopped off in the pic, remember hp and tq cross each other at 5250 rpm, also they are shutting off at about 6200 rpm - stock SRT4 rev limit! Also it's FWD, the AWHP would be a little less. You can figure out the rest.
Gary
This was completed on a 2.4L, which is going to give completely different results compared to our stock 2.0. Spool time, Tq, etc..everything is completely different
.
Evolving Member
Joined: Feb 2007
Posts: 491
Likes: 1
From: Redmond Washington
Not all mismatches are made in heaven but I think this 50 trim is one of the good ones.
Torque and spool event numbers won't translate to our motors because of the difference in engine size. But top end hp should be about the same once you account for the difference between FWD and AWD. Their comparisons to the other 2 turbos should come out about the same on our motors. The "S3" is kinda their "spool king" turbo, but this 50 wails ahead of it at only 3300 rpm on the SRT. It's a good "area under the curve" turbo.
A cool thing about it is that the wheels are not mismatch. The only thing "mismatch" about it is the turbine housing. So for the cost of an extra turbine housing, $200 or whatever, you don't have to take anybody's word for it. You can find out for yourself which a/r you like best. You could buy a .48 housing and a .63 housing and swap them back and forth all you want. Almost like having 2 turbos for the price of 1, plus a little. Daily driver duty? - put on the .48 housing. Cranking up the boost and taking it to the Texas mile? - put on the bigger housing, for sure!
Gary
Torque and spool event numbers won't translate to our motors because of the difference in engine size. But top end hp should be about the same once you account for the difference between FWD and AWD. Their comparisons to the other 2 turbos should come out about the same on our motors. The "S3" is kinda their "spool king" turbo, but this 50 wails ahead of it at only 3300 rpm on the SRT. It's a good "area under the curve" turbo.
A cool thing about it is that the wheels are not mismatch. The only thing "mismatch" about it is the turbine housing. So for the cost of an extra turbine housing, $200 or whatever, you don't have to take anybody's word for it. You can find out for yourself which a/r you like best. You could buy a .48 housing and a .63 housing and swap them back and forth all you want. Almost like having 2 turbos for the price of 1, plus a little. Daily driver duty? - put on the .48 housing. Cranking up the boost and taking it to the Texas mile? - put on the bigger housing, for sure!
Gary
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