Drifto

iTrader: (6)

NASCAR makes 700hp through a 390cfm restrictor. That shouldn't be possible, but it is. I've never seen that kind of power on a turbo that small either ,but I'm not about to call BS on a person who engineers them. I bet you think the world is flat too.

sonicnofadz

iTrader: (4)

Looking at today's materials and turbo design, it seems like it would be difficult to obtain that much power through that type of restriction, however turbo efficiencies keep going up all the time (using lighter/stronger materials, more sophisticated compressor/turbine blades, etc.) so who knows. Maybe this type of power will be easy to obtain in a few years.

Jason Siebels

Who says they shouldn't be able to make 700hp through a 390cfm restrictor? 390cfm will deliver 802.28hp on a standard day, so depending upon the altitude correction for that particular moment... 700 is a no brainer!

Jason Siebels

Absolutely, turbo's are getting better...let's take a quick look at what that means.

a 67mm turbo at the end of it's efficiency will move around 70lbs of air/minute...this is good for around 700hp (depending upon the efficiency of the setup..... at the END of it's efficiency. So if you had an INCREDIBLY efficient setup, I could see mid 700's (I have made 720 to the tires with that turbo with everything optimized, and ALL in....nothing left!) and a serious strech would be around 800.... a FAR cry from 1100. Not to mention the fact that to move an additional 30 to 40 lbs of air the other issues that you are going to run into...incredible compressor/turbine speeds, backpressure will continue to climb at an alarming rate (choking off flow through the engine...reducing power) . The only way you get more flow through a certain size opening is with pressure pushing it, or vacum drawing on it. Even IF the compressor was capable of drawing enough air through a 67mm opening to prodcue that kind of power, the turbo would probably have exploded long before it could move any where near that much air due to rotational speeds, and loads. Remember 67mm is just under 2.68inches....think about it....2.68 inches.

EFIxMR

iTrader: (10)

hmm maybe the 66mm turbo hes talking about is attached to an ECOtec

Drifto

iTrader: (6)

I'm curious where you are getting that. Based on a very simple equation, 390/1.45= 268.9hp. By your estimate the 600cfm stock turbo should make 1241.4 hp. I guess we are all wasting our time putting bigger turbo on when the stock one is so capable

shiv@vishnu

iTrader: (20)

In the case of Jay, he does. He's just not one to talk about it on evom. If you took the time to ask him off-line or via PM, you may get the info you are looking for.

Shiv

Ted B

iTrader: (6)

But if we keep dropping the backpressure with larger hotsides . . . Wait a minute, suddenly I'm having serious deja vu!


I am curious as well.


I broke it out like this:

One cubic foot of air at STP = 0.0807 lbs.

390cfm = 23,400 cfh of air

23,400 cfh = 1888 lb/hr of air

(1888 lb/hr) / (12.5 AFR) = 151 lb/hr fuel (estimates)

(151 lb/hr) / (0.45 lb/hr/bhp) = 335bhp (and one can see this is a highly liberal estimate)


Apparently, the 390cfm figure is only a rating at a standard pressure drop. The engine can create a much larger vacuum than what was used to calculate the rating, and therefore, the orifice will flow much more air than 390cfm.

Jason Siebels

Turbos are lbs/min...not cfm.

sonicnofadz

iTrader: (4)

I believe that you can measure the flow of air with either unit, it doesn't really matter. Although when using CFM (cubic feet per minute) you have to specify the temperature and pressure since the volume of air is dependent on these variables. With PPM (pounds per minute) there isn't any need for variables to be specified because the weight of air is always the same regardless of the temperature or pressure. Alot of engineers use both of these units when specifying turbo parameters.

HPF Tom

iTrader: (8)

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AIM: HPF Tom