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:D Sigma I've been telling everyone they can expect ANY Mazda 6 5 seped to run mid 15's in the 1/4 mile. Most folks look at me like I am an ass clown. Similar to what you said when I was questioning the performance of the cars I sell.

But you're right about 9.8 something 1/8 mile yielding a mid 15 second 1/4 mile. I was looking at some old truck et's I ran with the 03 5.3 auto Silverado I had.

2.249 60'
6.455 330'
9.288 594'
9.915 1/8 mile @71.76
15.538 1/4 mile @85.91

I do understand there are great drivers found in many areas of the USA. I love :love: the Mazda line so much I sell the cars. 99% of all FWD cars have wheel hop. The first 60' is the most important time for any car on street tires. Especially a car with a 3.0 engine That's only 180 cuin. I don't care how many RPM past red line you take the car to shift. Wt. Hp. and Cuin always come back and limit the cars performance.

I still am waiting to see it happen. A 14 second pass out of a Mazda 6. I'll guess I go to Kil Kare again tonight for another session of Test aand Tune. I'll watch, drink a couple, and beat on the dog a little.
 

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Again, not trying to rile you up, but I ran 14.90 in my friends M6 5 speed with a CAI on it, but I've never seen another one run personally. Most people that I've watched run in these slower cars (ie slower than low 14's) slip the clutch way too excessively and either shift slower than my mother or miss gears. YOU need to get in a 5 speed and make 4-5 passes before you decide what they run. JMHO
 

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Im going to be racing my friend at Atco later in the summer most likely and I have a question about power braking. What would be a good launch rpm for the 5sp atx? While not being too tough on the tranny?
 

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Originally posted by smokeU6s@Jul 12 2005, 03:42 PM
Im going to be racing my friend at Atco later in the summer most likely and I have a question about power braking.  What would be a good launch rpm for the 5sp atx?  While not being too tough on the tranny?
[snapback]453950[/snapback]​
Eh...... Anything you do isnt going to be good on the tranny. I would say 1500 rpm's as a safe bet. Some people might tell you 1.6-2k. I would try to keep it on the lower end... rather safe than sorry and ANY powerbreaking, even if its mild, should help your start and your time.
 

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Ok guys thanx for the tips, i will keep them in mind when I do go to Atco
 

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so if i do power braking, do i rev it up to around exact 3k then let go of the brake right there... or if i rev it up a little higher and then when it drops down to 3k i let go of the brake?? and if i use the "M" at whens a good time to shift? i usually do around 5.5k to 6k no higher than that b/c 6.5k is the redline.....
 

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well let me know next time your gonna go ive wanted to get my six out there havent had the chance would be nice to see another six out there.

so if i do power braking, do i rev it up to around exact 3k then let go of the brake right there... or if i rev it up a little higher and then when it drops down to 3k i let go of the brake?? and if i use the "M" at whens a good time to shift? i usually do around 5.5k to 6k no higher than that b/c 6.5k is the redline.....[/b]
to power brake properly apply brake and apply as much gas as possible without the engine lugging or over powering the brakes.let it shift at 6.5 or around there. shifting earlier your gonna be slower. redline is where to shift. you wont hurt anything bringing the duratec to 6.5 it can handle alot more.
 

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Dang, I must be really horrible it seems. 16.49 @ 83+ mph at Bandimere Speedway in Denver. RT .574, 60' @ 2.2. Launched at 5k rpm, dumped the clutch (cringed as my rear diff slammed), and the whole drivetrain just bogged down (prob from too much gas). It was my first time, I guess I should take it out and practice.
 

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Dang, I must be really horrible it seems. 16.49 @ 83+ mph at Bandimere Speedway in Denver. RT .574, 60' @ 2.2. Launched at 5k rpm, dumped the clutch (cringed as my rear diff slammed), and the whole drivetrain just bogged down (prob from too much gas). It was my first time, I guess I should take it out and practice.[/b]
You just need some practice, plus altitude doesn't help. Is yours stock? What fuel were you running? How many miles on the car? How many miles since last oil change? Track temps?

I took my '07 6s ATX out for the first time in July and had a best run out of 4 with a [email protected], .687 RT (Best RT I got that night was .256), 60'@2.519. I brake torqued to about 1800-1900RPMs. And I know the car can do better since I probably was still suffering from heat soak, albeit not as much as earlier that night since my times improved and the outside temps were going down from mid 80s from my first run to mid 70s on my 4th and best run. Plus my last run I was able to let my car sit in the staging lane turned off for an extra 30-40 minutes before I had to turn her on, so that aided in cooling. Elevation at the track I went to, Maryland International Raceway sits around a paltry 80ft :p .

Since then I have installed a tranny cooler which should help the transmission under brake torquing and keeping shifts crisp run after run. I plan to go again soon, maybe after I get the MAFci 2nd Gen installed.

Practice makes perfect! ;)

Paul
 

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Altitude is around 5700 ft. Fuel was 91 octane. Track temps were low 90's, raining, pretty humid. Mobile 1 full synthetic oil only, last done maybe 2k miles. 14k+ on the car at that time. Running a CP-E CAI and Magnaflow cat-back, no tune. In comparison, I was there with a couple other friends. One guy was running 16.1 sec in his Charger R/T (automatic) and another guy 16.1 in his Impala SS (automatic). I'm thinking the altitude has alot to do with it, but I know I need alot more practice. Hopefully I can get more runs in come Sept/Oct/Nov.
 

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Altitude does have an effect, especially since you are in the mile high region. But since you have a turbo it shouldn't effect you as much as the NA cars, aka Charger R/T and Impala SS. I think the rule goes for every 1,000 ft above sea level expect about 3-4%% loss in HP on NA models (Technically it's not altitude but air pressure, but they tend to go hand in hand in our world). Below is the SAE correction factor for Horsepower dependent upon intake temperature and air pressure.

The SAE correction factor can be approximated using this equation:
CF = 1.18 * (29.235 / Bdo) * ((square root (To + 460) / 537) - 0.153)

where CF = the correction factor, Bdo = the dry ambient barometric pressure in inches of mercury (in/Hg), and To = the intake air temperature in degrees Fahrenheit

Sea Level barometric pressure is about 29.235 in/Hg. So if a engine makes 100HP at sea level on a 77 degree day, it would make 95.96HP at a 1000ft elevation (1 in/Hg drop in barometric pressure), or a 4.04% loss in power just for 1000 ft.

Other factors that will cause power loss are high temps and high humidity. Now although a turbo shouldn't be as effected by elevation/air pressure as NA cars, it can still lose power (close to the amount a NA car can too!) if the turbos efficiency for boost is already tapped at sea level. In other words if the turbo is making 16PSI of boost at sea level and the turbo and controller are only capable of doing 18PSI consistently and under control then at high altitudes you will probably be losing almost as much power as an NA car since the turbo is unable to overcompensate enough for the lower air pressure (of course I may have read that wrong).

Below is a website to do power conversions based on altitude, humidity, ambient temp, abient barometric pressure, etc. :
Horsepower Altitude Conversion

Based on your info, I did two calculations on the site (one at 24 in/Hg based on altitude, one at 29 in/Hg based on weather channel reading). Since you said it was raining I set the humidity high at about 90% and temp at 90 degrees. Based on those numbers, HP loss on a NA car would range anywhere from 28.2% to 43.2%. So a 345HP Hemi would have been running at the equivalent of a 196HP to 247HP car. That's quite a loss! And judging by the times they ran and the heavy weight of their car, that sounds about right. Also their runs should be fairly consistent being automatics.

Paul
 

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Altitude does have an effect, especially since you are in the mile high region. But since you have a turbo it shouldn't effect you as much as the NA cars, aka Charger R/T and Impala SS. I think the rule goes for every 1,000 ft above sea level expect about 3-4%% loss in HP on NA models (Technically it's not altitude but air pressure, but they tend to go hand in hand in our world). Below is the SAE correction factor for Horsepower dependent upon intake temperature and air pressure.

The SAE correction factor can be approximated using this equation:
CF = 1.18 * (29.235 / Bdo) * ((square root (To + 460) / 537) - 0.153)

where CF = the correction factor, Bdo = the dry ambient barometric pressure in inches of mercury (in/Hg), and To = the intake air temperature in degrees Fahrenheit

Sea Level barometric pressure is about 29.235 in/Hg. So if a engine makes 100HP at sea level on a 77 degree day, it would make 95.96HP at a 1000ft elevation (1 in/Hg drop in barometric pressure), or a 4.04% loss in power just for 1000 ft.

Other factors that will cause power loss are high temps and high humidity. Now although a turbo shouldn't be as effected by elevation/air pressure as NA cars, it can still lose power (close to the amount a NA car can too!) if the turbos efficiency for boost is already tapped at sea level. In other words if the turbo is making 16PSI of boost at sea level and the turbo and controller are only capable of doing 18PSI consistently and under control then at high altitudes you will probably be losing almost as much power as an NA car since the turbo is unable to overcompensate enough for the lower air pressure (of course I may have read that wrong).

Below is a website to do power conversions based on altitude, humidity, ambient temp, abient barometric pressure, etc. :
Horsepower Altitude Conversion

Based on your info, I did two calculations on the site (one at 24 in/Hg based on altitude, one at 29 in/Hg based on weather channel reading). Since you said it was raining I set the humidity high at about 90% and temp at 90 degrees. Based on those numbers, HP loss on a NA car would range anywhere from 28.2% to 43.2%. So a 345HP Hemi would have been running at the equivalent of a 196HP to 247HP car. That's quite a loss! And judging by the times they ran and the heavy weight of their car, that sounds about right. Also their runs should be fairly consistent being automatics.

Paul[/b]
Here is a link to the current SAE standard http://www.mazda6tech.com/images/dyno/sae.pdf

Your formula is not quite right, corrected:

CF = 1.18 * (29.235 / Bdo) * square root [(To + 460) / 537)] - 0.18

You can't broad brush a turbo like that, assuming all turbo's are at limits of back pressure and efficiency at sea level. Best to just add boost pressure to top and bottom of the dry pressure ratio ... close enough.

When I use that calculator (by Whadil?), I get about 22-25% power loss in this case. You can't enter a low ambient (24") and a high elevation. If you enter 5700 ft, you then enter the local station barometric pressure from weatherchanel, which is an adjusted equivelant sea level pressure.
 

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Wow, thanks to both for your indepth explanations. Seems like a combination of my noob driving, the high temps, and the altitude. I'll be going more, and likely during cooler parts of the year. Shooting for below the 15.5 mark at least.
 

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Here is a link to the current SAE standard http://www.mazda6tech.com/images/dyno/sae.pdf

Your formula is not quite right, corrected:

CF = 1.18 * (29.235 / Bdo) * square root [(To + 460) / 537)] - 0.18

You can't broad brush a turbo like that, assuming all turbo's are at limits of back pressure and efficiency at sea level. Best to just add boost pressure to top and bottom of the dry pressure ratio ... close enough.

When I use that calculator (by Whadil?), I get about 22-25% power loss in this case. You can't enter a low ambient (24") and a high elevation. If you enter 5700 ft, you then enter the local station barometric pressure from weatherchanel, which is an adjusted equivelant sea level pressure.[/b]
Sorry about the incorrect calculation. That was a cut and paste directly from Neuspeed's site that was explaining SAE adjustments and formulas. So if there is an error, it's on Neuspeed's part.

As for the turbo, I wasn't intentionally trying to "broad brush" it. Turbos are complex devices that really throw a curve ball into the adjustments mix. I wasn't pretending to know all, just added the little I do know and researched on. It's people like you who have more experience with turbos, that I rely upon to correct or add to my response to help paint the bigger picture. :p

Thanks on the barometric pressure response. It request an ambient and wasn't sure if that implied weather channel adjusted values or for the unadjusted value that's typically based on altitude alone. That's why I posted both responses so as to give the driver an idea of what possible range to expect, even though one side maybe more realistic than the other (which is more along the ~25-28% range from what I have seen.

Thanks for the corrections!

Paul
 
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