NightRider

First of all, I have 5AT with no major modifications. A major question I had was - is there a standard or recognized equation for elevation factors? I live in Denver here and the elvation of that track is >5800 feet. Granted, this was my first time ever going to the track, but I got in 8 runs so I started to get the hang of it.

BOTTOM LINE: Best time: 16.2/Best 60 ft: 2.1

This was acheived with VSA off of course, Brake torqueing the start, and staying in SS all the way. I never broke out of 88 mph. One thing I noticed is that starting out, no matter if it was in L, D, or SS1, 1st gear never seemed to shift North of 6500. This is strange as I have seen it go to 6800 on countless instances. Another possible factor is that it had rained approximately 1 hr before runs started, so humidity was very high. Temperature was right around 75-80.

The reason I belive it could have been environmental factors is the other cars as well:

Mustang Cobra (sc) - ran 14.7
Trans AM (00-04) - ran 16.3, 15.9
Ford Lightning - ran 13.9 with an almost perfect start

Any comments, suggestions, explanations, etc?

SlntSam

So you're not happy with the car anymore?

Sometimes when I drive to work I can get there in 30 mins, sometimes it takes 45 cuz there's traffic. What can you do?

screaming

Everyone knows that you only need 88 MPH for the flux capacitor to kick in. Geesh man, it's not a Delorian!

-Steve

AcuraVic

Were you able to get a top speed run at this track ? Also, my experience with the sport shift is it does not perform better than the regular automatic. When you go back try a run with the tranny in full auto and compare the results. THe climate was definatly a factor, expecially with the TL because the computer is tied into everything.

VQ35DE

Sounds about right given your elevation. Assuming 5800ft elev, you being 175lbs? and 5AT, I figured it'd be something like 15.9 sec @ 86mph in stock trim. So that seems to translate to upper 14s @ sea level. $.02

IIRC:
whp loss @ elevation = (elevation/1000) * .03 * whp@sea level
where, Net whp = whp@sea level - whp loss @ elevation

1/4 mile trnslation -
ET = ((car weight/Net whp)^.333)*5.825
MPH = ((Net whp/car weight)^.333)*234

**Math experts here, check me if I'm wrong; I'm def no math wiz. **

leeherman

Did you remember to shut off your climate control completely?

I ran my '93 Camry V6 a number of years ago. It was a ridiculously hot and humid day, and I was only running low 17s (probably should have run low to mid 16s on a better day). I was leaving my fan on and hitting the "A/C" button as I returned on pit row.

I forgot to shut off the compressor for one run and lost a full second!.

I may be wrong, but I suspect elevation is a bit less of a factor with modern fuel injected and computerized vehicles than it is with older, carbureted vehicles like my Dart. Temperature and air quality, however, will impact performance significantly.

Regards,

TireSmoke

EWWW... 16.3 in a Trans Am? My '02 (last year they made them) ran mid 13's at 106mph the very first day I ever went to a track. And if you compare that trap speed to the ET, you'll see I suck at launching the car.

Based on that, I would concur with the others in saying that elevation must have totally tied down your car.

GreatWhiteNorth

Elevation may be less of a factor with modern fuel injection only with respects to drivability (the mixture will remain optimized, rather than go lean or rich). Altitude, however, still saps power because there's less oxygen "up there". Taken to extremes, it's why climbers near the peak of Everest require Oxygen bottles to continue.

The effects of altitude are less of an issue for forced induction vehicles, especially turbocharged cars that can "keep adding" air to make up for the lower ambient pressure. They still lose some power, but not to the extent a normally-aspirated car like the TL will.

1SICKLEX

NightRider good work 1st of all going to the track. 2nd, you'll get better as you practice. Third, when did u get your best time, what run?

I know the pros don't even start their car until they get ready to race. They push the car down! Heat saps engine power.
Remember, magazine times are taken at optimum conditions and the best times published. Then they are proffesionals.

NightRider

Because of the postings, let me elaborate. I drove to the track straight from work (~25 miles). I weigh 215, but I also had as much out of the car as possible such as spare tire and such. I waited at least 5 minutes with engine off between each run, waiting about 15 or 20 minutes on one, which suprisingly was not my best time. In my opinion, probably 6 out of 8 runs I didn't get a great start. It was one of the starters opinions that elevation and the weather and other factors affected most cars times 1-2 seconds. Also, Yes I was running the worst tires in the world aka EL42's, which had previously been setup with the dealer to look at vibration and stability issues. Could be part of the tire equation, but for the trap my tires with vsa off spun for about 5 seconds before connecting. That is alot for an automatic and never happens on the street, just a chirp here and there. Even my 0-60 by my estimate seems almost a second quicker on the road compared to at the track, and I live at roughly the same elevation. I also had around 8th tank o gas

Aegir

Hey, the 2.1 60ft is not bad for this car. Nice job. Sounds like just a bad day weather-wise. With an 88mph trap speed, clearly your TL did not like the weather conditions. Since the car modifies its state of tune based on MAP, the lower pressure could alter performance significantly more than traditional thumbrules and correction factors account for. If you are getting 2.1 60ft times, seems like you just need good conditions and to hit your shifts right to post some pretty good numbers.

Others have posted that the 5AT won't go past 6500 in 1st in SS - that it should be in low or drive through 1st and then shifted to SS once in second.

JetJock

At the elevation you are at, I'd guess you probably only made 75% or less of the maximum power the engine was cabable of...just my .02cents!

NightRider

Granted, the 60 ft was a 2.19 and that was my best, I was still surprised about that. The other 60ft were 2.3-2.6. Last night I was driving through my neighborhood fairly late and decided to give it a little juice in 1st. With the houses around for some echoing, you could definitely hear a difference from when it was stock. Compared to how it is now with the loopty induction tubing taken out and K&N, it sounds like there is a shop vac attached to the motor! You can definitely hear a whoosh, almost sounds like a shreaking when into higher rpms. Sounds very nice though. Still, down low power sucks. I actually kept up the the Cobra to about 20-25 because I got a great start, but even one run with a 200sx(zx?) it was a mid or late 90's one kept up with me off the line...

curtis_127

Which track did you go to? I live down in the springs and would be interested in getting a few runs in before I take the car up to Minneapolis next month(visiting brother, planning on going to a local track up there to go head to head against him in his 94 integra which is slightly mod'd ) It would be nice to actually see what the difference is from this elevation to almost sea level.

chazy777

I would love to bring my car to an official track where they let you try and get your best time.. Anybody know where I can go within the Northern Bay Area where people can enter in their car to get time results? I wouldn't care about racing (losing or winning) .. I would want to just see if I can hit 0 to 60 under 6 seconds and get 1/4 mile in less than 15 seconds..I would like to see how good I can race the gears to their max and see how good I am with a manual.. I feel I'm good, but I may surprise myself by not getting good times each try.. would be good learning experience!

Also what is best weather condition to test this at? overcast? humidity? temperature? etc..

How much does it cost per run? or how does pricing go?

Course I would take my 100lb woofer out of the trunk and spare tire, hit the VSA button, windows shut tight, fold in mirrors, everything turned off in car (stereo climate control, NAV, etc) make sure I have everything out of the car .. I'm 220 lbs unfortunately .. I would probably go to the gym for a while before hand

any other hints?

lindros2

which tires were you running?

I found a tremendous gain in traction and a bump in cornering by moving to the Pilot Sports.

RAdams

Elevation definitely kills performance. When my buddy runs his car out at Bandimere the difference is night and day versus our nice, sea-level track.

KilroyR1

Racing is dangerous and any advice is given w/o assumption of liability...having said that...

If you want to get serious, get a portable air compressor that runs off the cigarette lighter. Pump the rear tires up to the max pressure listed on the tire sidewall, then take the fronts down to 20 PSI and take one pound of air out each run until you get no wheelspin or hit 15 PSI - that should be the lowest you go.

Have 1/4 tank of gas or less.

Keep your junk (spare tire, jack kit) in a box and leave it at home or with a friend at the track.

Don't manually shift; you take away your consistency.

Get an adjustable suspension (I love to run bikes at the strip). You want to keep weight from transferring to the rear - so run the spring preload soft at the front and hard at the rear. Min compression damping at the front and max at the rear. Max rebound damping at the front and min at the rear.

Move the seat up as far as you are comfortable and lean forward (the same amount each run) - every little bit helps in front wheel drive.

Make one change at a time and see what happens.

Don

NightRider

I ran at Bandimere in Morrison. I may try and goto PPIR down there to see if there is any elevation difference and how that could affect times, along with weather of course. I must say, the TL was the best overall car there all things considered, although definitely not the fastest. A lot of people checked out my car in and out, even after they saw the damn times! If your brother has a turbo he will beat you for sure.

NightRider

I did say it before, but I was running the worst tires ever created (EL42's). Once these wear down, (I have 9900 miles and back ones that were switched from front are nearly bald) I will probably get the Falken Ziex. I have heard good things about these, and I had low profile 18 inch wheels with Falkens on my MB and really liked them.

2K2SilverTL-S

Check your IMRC actuator!!!!!! This is a known problem in some Type S models AND IT ABSOLUTELY KILLS the secondary butterfly valve and hence VTEC power. There is another member on this forum that didnt realize that his was broken till he ran at the track (this was a type S). I would DEFINITELY look into that.

VQ35DE

Ziex 512s worked miracles on my torque steer happy Maxima.

350z6413

I’ve been to Bandimere a couple times and the altitude and lack of oxygen is a bitch. Expect a couple seconds slower than what people at sea level are getting and what the testing from magazines and manufactures say. With my last car, CL type S, my ¼ mile time was around 15.8. And with my current car, 350Z, my last time was 14.2. My brother has a new TL and it seems way faster than my old CL.

Just to let you know how much a loss we are experiencing in Colorado, a stock 350z with the manufacture listed crank HP of 287 produces about 230 hp at the wheels at sea level. A 350z that was dynoed in Ft. Collins was at 199 hp at the wheels.

So in general, don’t feel bad about your time as compared to others. Just take it as a sacrifice to live in the beautiful Rockies.
DK

3PUTT

aren't cars in Colordao area have their oxygen sensors adjusted to compensate for the elevation?

KilroyR1

They compensate to produce the desired air/fuel ratio in the exhaust. This compensation; however, cannot add power, only minimize the power loss.

Don

kazuaki

First off, don't feel bad. There are a lot of factors at work here...

First, the actual elevation of 5800 ft is not necessarily the elevation your engine "sees". What I mean is that the Density Altitude is what matters. The density altitude is a corrected "effective altitude" based on the altitude, temperature, humidity, and barometric pressure. I regularly race at a 2800 ft track that sees DA's of over 5500 ft. So, your DA could have easily been over 5800 ft.

Second, let's assume your DA was actually 5800 ft. Given that, the NHRA correction factors for that are .9276 for ET and 1.0773 for trap speed. That means your 16.2 @ 88 MPH is roughly equivalent to a 15.0 @ 94.8 at sea level. See, not so bad after all...

Remember, these are only formulas which give approximations. However, in my experience racing a low-11 second car, they are fairly good estimates.

NightRider

I guess that I just don't understand the car magazines. I remember seeing a best time of 14.7 for a 5AT, how was this possible? You figure the engine gets a little better when broken in, mine has 10K miles on it. You would assume the car testers get a "new" car to test, which means the engine may not have been broken in yet. Even with the applied logic of elevation disparity, I had fairly minimal amount of weight in the car and still could not make that time even with an adjustment. Do they just make up those numbers? I know that with the MT's the magazines dump the clutch at 4K and such, but there is no way to really get a great start of the line with the 5AT.

VQ35DE

There are SO MANY factors to consider (as previously posted by others), it's anyone's guess as to what can be done to improve your stock ETs. However, your elevation is a BIG factor working against you.