Welcome to the SR20 Community Forum - The Dash.
Register
SR20 forum logo

Thread: VE-T blogger, dynos, movies, and pics.

+ Reply To Thread
Posts: 261-270 of 277
2008-10-29 20:03:24
#261
Originally Posted by Coheed
You are wrong sir. Here's why. You may live at sea level and don't understand. So let me clarify it for you. The atmospheric pressure at this altitude is 12.8 psi right now. Sea level is around 14.7. That is almost 2psi right there. Your wastegate opens based on an atmospheric reference/pressure differential. If you don't know what this means, learn how a wastegate works.

Not only is pressure vastly different, but oxygen concentrations at this altitude are a lot less as well. Because Oxygen is heavy! Take a trip on pike's peak if you don't believe me. That 600whp Nx will have maybe 350whp by the time you reach the top. But elevation doesn't matter? Your argument makes no sense.

There is no tricking a dynojet. It bases its numbers on acceleration. I may only have 375whp, but I accelerate like a 440whp car? lmao. The corrections are correct! That's why dynojet rules! I can redyno in florida and get the same numbers. Or anywhere else in the country.


WOW ARE YOU SERIOUS!!!!!!!!!!!!!!!!!!!!! You my friend need to learn how a wastegate works! if you are running a bleeder boost controller, you have boost going into one port and the other going to the bottom of the wastegate, the top port should be open. Which means that say you have a 1bar (14.7) spring in that gate, no matter what the atmospheric pressure is you WILL make 14.7 psi of boost!.. all it does is over come the spring. Also get with the times and get a good boost controller, if you want I can send you one, I have them for $35! Yes the oxygen is less I agree there. but you should not be using a higher correction, because as you say my 600whp NX would only be 350 by you! so your 375whp should only be 375 there not corrected to 475!

I think your lack of oxygen is getting to you!
2008-10-29 23:54:39
#262
.......
2008-10-30 04:59:03
#263
Originally Posted by boostin50
WOW ARE YOU SERIOUS!!!!!!!!!!!!!!!!!!!!! You my friend need to learn how a wastegate works! if you are running a bleeder boost controller, you have boost going into one port and the other going to the bottom of the wastegate, the top port should be open. Which means that say you have a 1bar (14.7) spring in that gate, no matter what the atmospheric pressure is you WILL make 14.7 psi of boost!.. all it does is over come the spring. Also get with the times and get a good boost controller, if you want I can send you one, I have them for $35! Yes the oxygen is less I agree there. but you should not be using a higher correction, because as you say my 600whp NX would only be 350 by you! so your 375whp should only be 375 there not corrected to 475!

I think your lack of oxygen is getting to you!


You are correct, the spring pressure is what determines when the wastegate will open, but spring pressure is affected by pressures on the diaphram. If I put pressure on the top port by 2psi then I would be adding 2psi to the spring. This will affect boost pressures. Don't believe me? Put a cap on the top port and drive to a higher altitude. Congrats, you will be pushing MORE boost. You have to look at the atmospheric reference. It is pure physics. If I add 2psi to the top port to get 14.7psi of atmospheric pressure, the diaphram will have to fight the pressure of the spring as well as the atmospheric pressure. There are two forces acting on the wastegate, not just spring pressure. They are designed specifically that way to prevent boost from adjusting due to pressure differences.

So try this. Put the wastegate in a pressurized environment of 43psi or 3 bar. You now have 3 bar of pressure pressing against the diaphram on both ports. So the spring is still going to open when the boost port hits 14.7psi MORE pressure than atmosphere. It has to have more pressure than the atmospheric reference in order to open.

Obviously running an engine in an environment where the atmospheric pressure is 3 bar would cause problems right? That is how atmospheric pressure affects wastegate pressure.

As far as the boost controller goes, you are right. I need a better one. This one is inconsistent and fluctuates wildly with temp changes. I want an electronic one, but that has to wait til next year. I have a ton of things planned

The motor may only put out 375whp up here, but take it to sea level and it will see more power. Elevation makes a huge difference! Don't believe me? Look at the times people run up here. STIs run mid 13 at sea level. They barely break mid 13s with a ton of mods and more boost up here. How about that beloved c6 zo6? Only 12.5 up here. Sad but true. Cars up here are usually a full second slower in the 1/4, it doesn't matter if if is forced induction or NA. That's why the hardcore guys go to Vegas every season to see what they will run closer to sea level.
2008-10-30 05:07:15
#264
he has a valid point and you guys need to get off his back about it. There wouldnt be a correction factor in the NHRA section if it didnt make a difference, Its different for both n/a and forced induction. Not much difference but slight. Get off the mans back and stop arguing. The correction factor when i looked at it for where he is at is .9XX basicly a full second and ADD 7 mph on to his trap speed.

Yes this is fact. Go look it up if you dont believe us. This thread has turned to shi* all because somone doesnt believe in correction factor. Go ahead and argue and your point will be shot away like it never existed. Great job with the build and with the mods and turbo your running there is no reason why you wouldnt put down 442whp easily at sea level. Cars here in southwest az run a hell of a lot better being we are basicly at sea level. I mean hell i ran a 12.4@110 on a t25 and when the t28 went on at 9psi it was faster than the t25 setup. So yeah we know what we are talking about
2008-10-30 05:48:35
#265
You just stated the same thing i did coheed?????? that is my point if you run 1 bar at sea level you will still run one bar at altitude, atmospheric pressure has no effect on it.. because where ever you are atmospheric pressure will be the same on the top and bottom under no boost. you don't cap the top port on a waste gate it won't work unless you have an electronic boost controller, so how that comment has anything to do with this is dumb. All I am saying is your car makes 375 hp not 442.. you can't put a correction in for HP because of altitude.. yeah if you brought it here it would make more power but how much you don't know for sure. Also that NHRA correction is for class ranking for ppl that run in higher elevation because obviously they will be slower.
2008-10-30 13:25:28
#266
which is my point, he is at 5k feet of elevation. The correction factor for that elevation is .9 faster in the 1/4 and 7mph faster trap speed. So how the hell does that not equate for making more power at sea level. How much more hp does it take to run .9 seconds faster in a 1/4 mile. almost 100whp more thats what. Your 1/4 mile time and trap is a direct reflection of horsepower so again how the hell can you say that you cant put in a correction factor in for horsepower. bull crap.

Plain and simple he comes here to phoenix and dyno's his car will make that 442whp easily and run almost a second faster in the 1/4 and trap probably well well over 120mph every run. Directly reflected back on making more power. Your car doesnt travel slower because of elevation, it travels slower due to the fact its making less power up there. Done deal man. Drop if
2008-10-30 13:35:54
#267
Originally Posted by boostin50
You just stated the same thing i did coheed?????? that is my point if you run 1 bar at sea level you will still run one bar at altitude, atmospheric pressure has no effect on it.. because where ever you are atmospheric pressure will be the same on the top and bottom under no boost. you don't cap the top port on a waste gate it won't work unless you have an electronic boost controller, so how that comment has anything to do with this is dumb. All I am saying is your car makes 375 hp not 442.. you can't put a correction in for HP because of altitude.. yeah if you brought it here it would make more power but how much you don't know for sure. Also that NHRA correction is for class ranking for ppl that run in higher elevation because obviously they will be slower.


You are right, one bar spring is one bar of pressure. But the total pressure is going to be different. If you have 1 bar of atmospheric pressure, and a 1 bar spring, it will take 2 bar TOTAL pressure to open the wastegate. But if you have only .5 bar atmospheric pressure and a 1 bar spring, the wastegate will open at 1.5 bar of total pressure. That .5 bar less pressure makes a difference in both power, and the total pressure you are forcing into the engine. Make sense now? The wastegate spring pressure is always fighting atmospheric pressure.

The comment about capping the top line is just for reference, but if you did the experiment you would know what I mean. If I put pressure on that port to mimic the different atmospheric pressure from here to sea level I would be running an extra 2psi of boost, even though the spring pressure is 1.1 bar. It would go to 1.25 bar. The boost gauge also gets a reference to atmosphere. If you don't understand what I am talking about then take a physics class.

As far as the correction factor goes, it makes perfect sense. ZO6 power to weight ratio is about 7.11 lbs/hp. I beat one on a roll when I was running only 19psi of boost. That puts me around 395 whp. If my car weighs 2800lbs that is the same power/weight ratio, but my car weighs only 2717 factory curb weight and the AC equip has been removed.

But apparently the correction factor makes no difference? It is impossible for a car with a power/weight ratio of over 7.11 to accelerate faster, gearing aside. Trust me there, I would rather have the ZO6 gearing. If I only made 7.2lbs/hp (375whp) I would not accelerate faster than a 450whp NA car with a power weight ratio of 7.11. Altitude affects turbo and NA cars the same, the only difference is you can make it up on a turbo car with more boost. I would argue the point that turbo engine are actually affected more by altitude than an NA engine and I can prove my point there as well.
2008-10-30 22:09:29
#268
I think all that is being said is that your car makes 375 whp currently not 442whp which would explain the slower times to an extent. The MPH is still high though, so i am assuming you were spinning done the track.

But I am really not sure what the point of all this arguing was. Someone needs to clean this thread up.
2008-10-31 05:11:35
#269
The 1/4 mile times suck because of the crap tires I am running. If I can give full throttle through 1st, 2nd, and 3rd I will hit mid 11s on high boost and trap around 120. Next season I will get slicks and you all will see that mid 11s is possible on this power level, even at this elevation.

More boost made the tires spin worse and didn't improve trap speed or et at all, tires are the weakest link. Seen sense, you are right. The engine at this altitude is only making 375whp to the ground on high boost. It sounds really low for my setup but that is what happens. I would love to drive her to sea level and feel what it's like. Even my wife's GA16 had power to chirp tires at sea level in Washington. It's an automatic too haha.

up here it is so slow it is rediculous. 0-60 in prob 20 seconds.
2008-10-31 18:32:55
#270
......Nice set-up, no ones trying to start anything. Why can't there be any technical arguing anyway? Get an EQ mani, make some more power and have some fun.
+ Reply To Thread
  • [Type to search users.]
  • Quick Reply
    Thread Information
    There are currently ? users browsing this thread. (? members & ? guests)
    StubUserName

    Back to top