V-10 Killer

iTrader: (22)

What can I say, I'm bored at work and daydreaming about working on my car...
Out of pure curiousity, what's the most power you've seen from a 402 at ~14-15 psi, and on what fuel. Unless I commit to a different PCM, I'm limited by the MAP table. Having an idea where the limit is will help. Then I could size the fuel system appropriately.
I'm sure it boils down to efficiency BSFC and compressor efficiency, but this is more fun

Please help me fight of the post lunch nap attack.

slowlsx

iTrader: (28)

I just lol out loud. How the hell can we even guesstamate with you just telling us its a 402? With a 70mm you might make 500... with an 88mm you might make 1k. With stock 317s you might make 600... with a set of 3k dollar heads you might make 800... get where im going with this.

V-10 Killer

iTrader: (22)

Sorry, don't look that far into it. This isn't so much about what I might see, it's more that I'm curious what others have seen. I'm not shooting for a "this is my parts list" kind of thread. I only mention a 402 because it's a fixed point for me. I get where you're coming from and have seen a few threads with numbers. I just would like to see a broader range.
For example Killer-LS1's build thread. His first run made 750ish, second made 1020ish. But there's no way for me to see what it made at 14-15 psi. See what I'm getting at?

123quattro

Saying 14-15 psi is irrelevant. The boost on a 70mm vs 90mm will give you a difference in power of 2 like slowlsx mentioned.

I wouldn't be happy with less than 800whp if that helps.

PUNISHER TA

iTrader: (13)

Please explain how the same amount of air provided by two different sized turbos would give you different power. That isnt physics.

Unreal

14-15psi at 200F because one turbo is out of efficiency range is different than 14-15psi at 80F. Cooler air, more dense, more power.

TNTramair

iTrader: (15)

I made 633rwhp and 657rwtq on a 402 with stock l92 heads on only 8psi...with the base APS twin turbo kit. it would however run out of steam near 5300 rpms...turbos just couldnt handle the big cubes but i allways thought it was pretty respectable for only 8psi and such small turbos.

VIPERSLYR

Mines not a turbo car but ysi with a break in tune 15 psi with no timing Kurt urban 402 trick flow 235 heads not ported, ls6 intake made 900 rw on 94 pump gas and dual nozzle meth kit. Tuned by Arun at dasilva motorsports

NicD

iTrader: (7)

smokeshow

iTrader: (17)

Because science.





That's how.

stevieturbo

It's magic ! It cannot be explained by mere mortals....it just happens....otherwise everyone would just use tiny turbos

redtan

iTrader: (5)

Who said anything about the same amount of air? Are you one of those people that thing psi is a measure of how much air is moved?

On the same exact engine, an 88mm turbo making 14psi is moving a HELLUVA lot more air than a 70mm turbo making 14 psi.

TNTramair

iTrader: (15)

SPRAYED 01

iTrader: (22)

I think punisher was just messing around with that one

rotary1307cc

iTrader: (5)

LOL??

ah no, the engine combo sets sets volume consumption

the difference in power is the compressor thermal efficiency

PUNISHER TA

iTrader: (13)

No, Im just some shmuck graduating with a degree in mechanical engineering. Now, I didn't study airflow as much as I would have liked, but I think I understand the concepts well enough.


For the record, my orignial statement was focusing on the engine as a system. not the turbo.


I clearly do not mistake psi for airflow. but you are incorrect. and this is the misconception I was trying to get at. I just had this talk with a buddy of mine.

but pressure with a displacment and we get airflow.

Looking at the engine as a system. a set displacement filled to a certain pressure. which is what we are reading at the MAP... a 6.0L filled with 15psi from a 75mm turbo has the same exhaust output as a 6.0L filled with 15psi from a 90mm turbo. (not moving more air through the system) yes, heat MAY be an issue, but lets say that can be disregarded as the system is pump with enough meth to negate the issue. and also, lets remember I am talking about real data, where a turbo was able to provide the amount of air I am talking about. I am not an idiot saying put a 25mm turbo on it.

If people would hop off the high horse for a second. Think about it. and let me know.


Also, I am not claiming that they will make equal power, but it sure isn't a factor of 2...


No...



haha exactly.

This is what I was trying to get at. Thank you.

PUNISHER TA

iTrader: (13)

Those are pictures, not science... ahole.

V-10 Killer

iTrader: (22)

Thanks for playing along, that's all I was asking for

soundengineer

iTrader: (16)

same CFM...yes...you should see the same amount of power(as long as all other variables are exactly identical....)
however, same boost, is not the same amount of air.
BOOST is just a measure of restriction....
so if you see 20 psi, you might see xxx horsepower..but you can get there the same with less PSI on a more efficient Motor....

people like to say that one turbo is more or less efficient than another...and in reality... they need to understand the amount of air it can flow in a CFM value is more or less than another.

its why some guys say I can make xxx power with a big turbo, or a can take a smaller one and make more PSI and make the same amount of power....
what they really said was....I just want xxx power and I can do it by doing it "this way"

they usually dont understand why it works that way.

its also why Big cubes, make big power, with less boost than a smaller motor....typically bigger cubes can flow more air before restriction happens..

less restriction = more power at the same "boost" values

mike13

iTrader: (27)

I would like to add that the turbine side of the turbo is many times not factored in. a TC78 with a 68mm turbine wheel is not going to make the same power as a borg warner 75 with a 87mm turbine. At any boost level.