turbo sizing help
#31
Going with the pack
is quite monotonous.
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is quite monotonous.
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I have seen one of those quoted numbers on the dyno.
Not sure I would blindly trust dyno numbers without seeing them yourself.....
Not sure I would blindly trust dyno numbers without seeing them yourself.....
#32
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this is true i just think if they were trying to pimp their products or something with these dyno charts they would put more of their products in the info lol.
#33
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I don't think anyone's questioning the integrity of Lindsey's runs or the good faith with which they no doubt ran those sessions - but there are so many variables - with variation between different brands of dynos, individual dynos, gear selection for the runs, atmospheric conditions, transmission loss factors, traction etc.
If you run some of the calcs on the Garrett site you'll find that the rpm & boost requirements for a 2.5 to make 500 bhp are an extreme stretch for even the most highly stressed & well built 951 motor.
If you run some of the calcs on the Garrett site you'll find that the rpm & boost requirements for a 2.5 to make 500 bhp are an extreme stretch for even the most highly stressed & well built 951 motor.
#34
Rennlist Member
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I don't think anyone's questioning the integrity of Lindsey's runs or the good faith with which they no doubt ran those sessions - but there are so many variables - with variation between different brands of dynos, individual dynos, gear selection for the runs, atmospheric conditions, transmission loss factors, traction etc.
If you run some of the calcs on the Garrett site you'll find that the rpm & boost requirements for a 2.5 to make 500 bhp are an extreme stretch for even the most highly stressed & well built 951 motor.
If you run some of the calcs on the Garrett site you'll find that the rpm & boost requirements for a 2.5 to make 500 bhp are an extreme stretch for even the most highly stressed & well built 951 motor.
#36
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most of those dyno runs also show they are only revving to 6.5k like i was wanting to.
heres a link for if anyone wants to take a look at what im talking about here.
http://www.lindseyracing.com/LR/Parts/DYNO.html
heres a link for if anyone wants to take a look at what im talking about here.
http://www.lindseyracing.com/LR/Parts/DYNO.html
#37
Burning Brakes
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One of the trends I've seen in numerous 951 dyno charts is that once you get to a certain size turbo it adds more lag than it makes up for in top end power. In other words, turbos with 51 to 58mm inducers seem to be the sweet spot for balancing peak power with response and area under the curve. Going bigger might yield more peak power but at the expense of much greater lag. And the 951 seems to have an rpm cap on the powerband so it's tough to increase power above 6500 unless you get into custom intake manifolds, exhaust headers, cams and headwork.
#38
Race Car
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One of the trends I've seen in numerous 951 dyno charts is that once you get to a certain size turbo it adds more lag than it makes up for in top end power. In other words, turbos with 51 to 58mm inducers seem to be the sweet spot for balancing peak power with response and area under the curve. Going bigger might yield more peak power but at the expense of much greater lag. And the 951 seems to have an rpm cap on the powerband so it's tough to increase power above 6500 unless you get into custom intake manifolds, exhaust headers, cams and headwork.
I would fully agree with this. I oftern forget that I'm running at a much higher elevation and have to use a larger turbo to overcome the losses. Generally speaking a gt30 is about the perfect turbo for a 2.5. But' it would fall short up here. I would either need a gtx3076 or a gt35.
I think the 58 58 woudl also fall short up here hence the 6262. And for 500 hp I think it would be necessary even at lower elevations.
However, with all that said. I'd still side on teh smaller turbo side if you are only looking for 400ish hp. How oftern are you planning on running it like that.
Myself, I race mine weekly and NEED a larger compressor.
I know for a fact mine makes over 500 hp (not dyno either) daily and a smaller turbo would just not last long.
Set some realistic goals ie: trap speed, driveability(a 2.5 drives much different than a 3.0) and then maybe we could give a much more accurate recommendation.
Also, if e85 is available. you may want to use it. It really helps these engines live.