Old Turbo HP Comparison Chart Question.

[Turbo6Smackdown]

On the old gn/ttype.org site there was a chart there that layed out some of the more common turbo upgrades and their horsepower. When one says "this turbo is good for 600 horse", what's that based off of? Which heads? Doesn't that very WILDLY per combo? Does anyone know what baseline assumption was for the old gn/ttype chart?

 

[Turbo6Smackdown]

No one? Someone's gotta know

 

[pacecarta]

600hp is based on the turbos ability to flow air ...how much boost youll need to get there varies with your engines efficiency .. better heads will need less boost ..how fast youll go with 600hp varies with 60 foot and your weight ..but at 600 hp that TA61 in your sig is pretty much all in and will need good air to get there

 

[bison]

Turbos support mass flow. They don't make power. If they made power you could just use larger and larger turbos and make more power. There needs to be a balance between the compressor and the turbine and they need to fit the engines potential and operating range. It takes a certain amount of mass flow to actually drive the compressor. The design of the wheels can have some effect on the type of boost that will be generated. Tall compressor wheels typically flow less but will work better at higher pressures. Shorter wheels typically flow more at lower pressures. More blade surface area for a given inducer will usually have more potential mass flow. The compressor covers diffuser plays a huge role in extracting all the power out of a compressor. Likewise the exhaust housing plays a huge role in what the turbine can flow. When you compromise any of these and want to get as much as possible you have to change the dynamics of the engine. Turbos are usually rated in mass flow such as lbs/min. At 3600lbs It takes about 40lbs/min to run mid 11's, 50lbs/min will get you in the 10's, 60 will get you mid 10's, 70 will get you to 10.0, 80 9.60's, 90 low 9's, 100 high 8's


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[Turbo6Smackdown]

I get all that but, does anyone know the baseline assumption on the original chart? Was it based on a bone stock gn engine?

 

[pacecarta]

you didnt listen , the motor doesnt matter , the turbo can only move so much air before its maxed out and thats the chart ..bolt it to a ls , ford or supra and it wont change that hp limit ..
the expected ets were based off a 3700lb regal as weight affects ET that can be achieved with x HP
you need air to make hp and that air has to go through the turbo which is basically a fan ...fans have cfm ratings at a set speed and a turbo has a max speed at which it can move so many cfm or lbs of air , with the air known you can only burn so much fuel so you know how much hp it can support , basically 40lb min will support 400hp , 50lb/min will support 500hp 60lb will support 600hp
for 600 lbs per min you need 300lb hr of fuel (thats at a .5 bsfc),
easy to calculate fuel needs is 600hp divide by 2 (BSFC 0.5) then divided by 6 (6 injectors) is 50lb /hr per injector. thats about 85% duty cycle on a 60# injector .. thats the fuel needed for the horsepower and adding methanol gets you a little further .

stock unported 8445 head engine wont make much over 500hp due to the head restriction which will work a turbo harder (and limit its max air flow) so throwing a bigger turbo on wont make it go much faster as it can make a turbo less efficient by asking it to operate off the center (sweet spot) of the compressor map where efficiency is poorer . most turbos have compressor maps to see this to help choose correctly

 

[Pronto]

There's excellent technical information here on turbos!

 

[V6sleeper]

Good info here.. That should explain everything to everyone

 

[Turbo6Smackdown]

Ah ok, I'm trackin' now. Thank you. I need to separate things in my head first. I get it.

 

[Mr.Spool]

When one says "this turbo is good for 600 horse", what's that based off of?

not running 20psi

 

[Turbo6Smackdown]

Lol. Oh don't worry, I rarely run that little boost. Car ran great at 25 Friday night.

 

[1952ray]

There's excellent technical information here on turbos!

Yes, and we have two of the best there is in the same thread