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Wow, elevation does matter. 1/4 mile times inside

 
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Old 04-26-2003 | 01:03 AM
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Default Wow, elevation does matter. 1/4 mile times inside


Look at that timeslip and tell me I did something wrong. Btw, I'm number 118. My reaction time was near perfect and my 60 foot wasn't too bad. It could've been better if the track wasn't so coated with rubber and water. I guess it's time for me to get an aftermarket lsd. My car's got close to 1700 miles on it and was broken in pretty well. Oh, I forgot to mention that this is LACR in Palmdale, CA where it's 2600 feet above sea level. I never knew that a N/A motor would suffer this much from elevation.
I did meet up with M Powered and he ran some good times. 13.7 I believe. G Rated was there too and he got 14.8 in his track model and that was his best as far as I saw. My best was 14.9, but this is the one I scanned first. Anyway, I stopped after a while cuz it was too embarrassing pulling 15's 8 outta 10 times of my run. Can someone share info on if N/A's suffer THIS much in such high elevation?
Old 04-26-2003 | 09:20 AM
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Did you really think elevation didn't matter? There are a lot of experienced racers on this board including myself and raceboy and it seems that this has been discussed. Maybe I dreamed about it. Of course elevation matters on any vehicle. The only thing that it does not affect is something like a Top Fuel car since they have the power to spin all the way down the track at 300 MPH if they want to. They just dial in a little more fuel/power at the higher alt. tracks like Denver and get after it. We don't have that luxury. Import guys seem too tied up and enfatuated with FI that they can't comprehend a NA motor and how it works.

Get to know the basics before you start analyzing the cool stuff. Like, why does a motor slow down at high alt? How does each part of a motor affect the next part and thereby make power? What touches what and moves what inside? What does a change to any of those parts mean to power changes and why? What is octane and how does it affect performance at different alt? Gearing, tire size, geometry, and other components of a regular old car. When you know that stuff and how it ties into all the other aspects of driving, making power, etc. then start worrying about turbos, SC's, etc. Know what you are doing before you do it. There are millions of ways to self educate. What ever happened to howstuffworks.com or the old race books that teach you about setting up suspension and building your own race motor. These are invaluable tools that, if not help you build a motor, can teach you all of the above mentioned things. Then we can discuss things like theory on ideal setting for given situations, etc. instead of what is octane? What is altitude? What is offset? Why not just google it if you are lazy or actually go check out a book at the library if you are industrious?

This is just a rant and not directed at the topic starter. But it applies to many people who get excited about modding their car and racing, etc. They have no idea what they are doing.

I was the same way when I was 15. My dad got so annoyed with my incessent stupid questions that he had me figure it out myself. I am grateful because I can build motors, set up suspensions, etc. I think this is something we should all learn so that we are not like the typical honda owner or whatever just BS'ing our automotive lives away.
Old 04-26-2003 | 10:51 AM
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When your car runs at high elevation the air up top is a lot thiner than the air down here. Why do you think all the people who live up in Lancaster and Palmdale are retarded?

Anyways, the thiner the air, the more air your car needs to run. Well question is, where is your car going to get that air? If you are N/A the answer is, "pull it out of your ***." If you are FI, your wastegate has the capabilities to compensate for this by keeping the wastegate closed until it makes requested boost level. The only down side is the turbo lag is increased.

My best so far is a 13.7 @ 102 mph in Palmdale in cool climate. Now... my best at sea level in HOT climate was a 14.0 @ 106 Mph The reason why I got such a shitting ET was due to traction. In cool climate at sea level my car should see upwards of 106-108 mph. E.T. would depend on how much traction of the track. So with that said, my car just like your car suffers A LOT. It just so happens I dont have to worry about a 15 sec timeslip j/k
Old 04-26-2003 | 12:00 PM
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Yeah, I just made a trip from Phoenix (900 ft.) to Cheyenne Wyoming (6000 ft.).....big difference in power...glad I don't live there anymore.
Old 04-26-2003 | 12:16 PM
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...well, elevation DOES matter, but I have pulled a 14.79 on my completely stock Base model at 5400 feet (I am in Albq, NM), so you should really be in the mid to low 14's I would think. On top of that the track up here is really hard to launch at (It's not in the best of shape so everyone other that AWD and slicks gets horrible 60' times...the best I've been able to pull has been a 2.97s) So, I would imagine you should be able to lower those times drastically. My first time at the track the best I could pull was a 15.3s and on my third trip I got the 14.79, but I now consistently run 14.9s and 14.8s.
Old 04-26-2003 | 01:22 PM
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Your correction is 14.4

https://my350z.com/forum/showthread....threadid=27329

Last edited by Maximam; 04-26-2003 at 01:32 PM.
Old 04-26-2003 | 10:37 PM
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Hrm... alright, I guess I was asking for flaming when I asked something like this. I'm sure it wasn't meant directly to me, but I just have to say that when it comes to most stuff, I do know what I'm doing. Yes I know how engines work and what happens when etc etc does this, but my main question was with N/A cars cuz I haven't really had too much experience with them in the past. Mostly, I've had some sort of F/I and never really suffered a second off of my times. Maybe I wouldn't have run a 14 flat at sea level, but I'm pretty sure it should've been low 14s. With that said, I'm going to try again after racking up a couple more thousand miles like some have suggested. Thanks for the replies.
Btw, newmexicoz33... was there anything you learned to get from 15.3 to 14.8 or did you just keep doing it and just got better?
Old 04-27-2003 | 06:21 PM
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Originally posted by Mr B

Btw, newmexicoz33... was there anything you learned to get from 15.3 to 14.8 or did you just keep doing it and just got better?
...funny you should ask, I actually have some really good advice after going to the track yesterday at around 3pm. First of all, it was HOT ( I was cooking inside the car) and I went with over half a tank of gas so the car was running about .2 seconds slower than usual (I am really consistent with my times). I usually go with only a 1/4 tank of gas (an extra 1/4 will add noticeable weight) and before noon (so the air isn't so HOT).
As far as driving techniques go, it is really mostly about getting a good launch, and quick shifts. As I got more and more practice I found that the best way for me to launch is to rev up to around 2900rpms and to feather the clutch gently until you feel the tires get traction then dumping the clutch and flooring it. I suspect that you should be able to launch at a little higher rpms (since I have no LSD and this track sucks to launch at), but the whole trick is feathering the clutch until you feel the tires hook up, then going all out. Otherwise you'll just sit there peeling out and your 60' will suck. Also, remember that the reaction time doesn't affect you actual ET, so just ignore the other car and focus on getting a good launch, and experimenting on different rpms to launch at until you get your technique down. Once you figured out the best way to launch your car (just look at your 60' times) then you can focus on good RTs. Also, don't let up until you are completely clear of the 1/4 mile point.
Old 04-27-2003 | 06:30 PM
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...oh yeah, and I also lower my rear tires to 27psi.

BTW: I just noticed there should be an edit to my first post when I said the best 60' I have been able to get is 2.97....It's supposed to be 2.297s.
Old 04-27-2003 | 10:36 PM
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Originally posted by newmexicoZ33
...oh yeah, and I also lower my rear tires to 27psi.

BTW: I just noticed there should be an edit to my first post when I said the best 60' I have been able to get is 2.97....It's supposed to be 2.297s.
2.2 is not to bad on street tires.
Old 04-28-2003 | 09:31 AM
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Hrm... so you got that 14.79 with 2.2 60' times? I got all 2.2 60' that day until I just didn't care and tried new things. Ah well... I'll just break in my car's engine some more and try again another day. Thanks for the help though.
Old 04-28-2003 | 03:51 PM
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...2.297s is really a 2.3s 60' time, and it is BAD even for street tires (also most of my times are around 2.35s 60'). And as I stated, this is because the track sucks and we are at such high altitude. Perfect example is a Mustang GT and a Mustang Cobra that I was talking to (both on street tires). They both go to the track in Roswell, which is in much better shape and is at around 3400' I believe. They both get down to 2.1X and 2.0Xs 60' times whereas they are still only able to pull around 2.3Xs 60' times up here.
Also Mr B, there can be "variations" in two 60' runs with the same time. Meaning that even though you cross the 60' mark at two equal times, you can still have a higer acceleration rate going on one over the other, which means that your car will cross the 1/4 point faster. That's what I mean about trying to launch at the highest RPMs possible without compromissing your 60' time too much. So just because you get a 2.2 60' it doesn't mean that you can't necessarily get a better 2.2 60' launch. Also, I pulled my 14.79s run with less than 2500 miles on the car.
Old 04-28-2003 | 06:52 PM
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Hrm, interesting. I guess I'll keep practicing and seeing how high of a rpm I can launch before I get too much wheelspin. Thanks for clearing that up.
 
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