assasinator

all right i give up. was trying to use reason. obviously i dont know what im talking about and need to shut up.

sw07gt

iTrader: (10)

He may not be being completely honest about his mods but there is no way that car is making mid 300's wheel to have come around me like that.

assasinator

his car IS making more power than that, but using more boost than he is saying.



a MP70 compressor map.


look at the map, and 6 psi(1.4pressure ratio) the flow max is really about 42lb/minute(420crank hp). it just is what it is. he is using more boost.

R6cowboy

iTrader: (3)

Whatever formula and numbers you are talking, I for one certainly can't disagree or say you're wrong. But the point I was getting at is that there's no telling exactly what power level the motor is at just by knowing its a 2v modular with a turbo at 6psi or 9psi or whatever. The motor can have one type of blower (roots, centrifugal, turbo, etc) at 9psi, swap it out for a different type of blower at the same 9psi, and the motor can be at a different power.

A local guy I know with a MK4 Supra made 650+whp with a Precision 61mm turbo @30psi. Swapping out the 61mm turbo for a Precision GT45 76R turbo and it still makes 650+whp but at lower boost, around 18psi. Serious question. Does this make sense when using the formula you are using? That this guys motor will make more power with LESS boost using a different turbo. I don't know why it works, it just does.

For anyone to make assumptions and say that the mentioned 2v Mustang in this race couldn't make a certain amount of power without knowing any specifics about the motor, well that's just idiotic. I'm also being reasonable, not making assumptions like some others.

assasinator

yes i can answer why a larger turbo makes more power or same power with less boost.

a smaller turbo needs a higher pressure ratio to flow its max.
here is a smaller turbo, a 63 garrett..



simply note the highest flow on the map....its in the 2.25 pressure ratio range... and is 68 lb/minute.


here is a larger turbo....




to simple MATCH the smaller turbo's 68 lb/minute it only needs about 6psi.


now at 18 (2.3 pressure ratio)psi the turbo flows...35 pounds per minute to 110 pounds per minute. he simply doesnt use the extra poer that bigger turbo in my example flows.


realistically the supra need more boost to make that power, it does take a Fixed Map level for any given engine to flow air for HP. the supra probably doesnt use the bigger turbos potential thats all.



a really good example is MY turbo setup. that big turbo in my car is good for 1100 crank hp using race gas.

but for the street i can boost it low(8psi ) and spin my motor to the moon and still make great street hp from much lower boost than i'll need at the track. at 8 psi it flows around 70 lb-minute or 700ish crank hp. big turbos can be great. MY MOTOR WILL NOT FLOW ENOUGH TO MAKE 700HP AT 8PSI. that should take in the 15psi range.


efficiency really matters when a small turbo is pushed to its limits. its one reason twins make so much power. they are making COOL boost compared to a "at the limit" turbo. a big single run in its efficiency sweet spot will generate a lot less heat. turbos are just like blowers that way. push them to hard and the heat the air and kill power.


all of the formulas for turbo power are at www.turbobygarrett.com


im not trying to sound like a guru. i do the best i can. i do come on kinda strong.

i do submit to the school of thought that there is middle ground between the map calculations and real world differences in motors. a lot of that is optimization of modded motors, not stock bolt ons. ie racing gas, ported heads, great exhausts, etc.

regal3.4

F8L BYT

Bring the 2011 there! It would still be a fun time as I'm sure you know! We are bringing a bunch of guys down this year

Heater

2V Mustangs suck


/thread

assasinator

tracy ripped the flooring of the motorhome up. she doesnt want to use it with no flooring. shes gonna tile it. next year.