I'll race in 1/4 Mile Guatemala's National Championship. I need some Advices to do my best, there's a new 1/4 mile raceway park here and it's at 240feet over sea level. Im in the Twin Cam Category and in this category there are cars like Toyota MR2, Honda Twincam w/o VTEC, etc etc, any car with Twincam Engines. The tree works in semipro (Prestage/stage, 1st light 0.5seg, 2nd light 0.5 seg, 3rd light 05.seg, launch)
Theres the mods i have in my 96 Z24 Manual Trans:
Pacesetter 4-1 Headers
2 1/4" exhaust pipe
Borla Proxs Muffler
Catalyzer removed
Detonator Removed
Rksport Upper & Lower Mounts
Rksport Boots Inserts
Front Upper Strut Bar
1.7" Lowering Springs
Stock 16" Alloy Wheels
225/50-16 Kumho Tires
My questions are:
At what rpm's do i have to launch?
Do I low the tires pressure?
at what rpm's do i switch de gears 1-2, 2-3, 3-4?
I dont know what is my ET's because is the first time ill be run the 1/4, but in the 1/8 at 6500feet altitude im in 10.80's
Thanks for the advices..
Quote:
At what rpm's do i have to launch?
i've grown used to going to 2400 or so rpms and just dumpin it. this season i'm going to try the "feather" approach where you take it up to 3k and run it out til you start to break out then just let her have it when you gain complete traction.
Quote:
Do I low the tires pressure?
i lower mine to 25psi or so, the more surface area you get on the track the better... kind of a no brainer.
Quote:
at what rpm's do i switch de gears 1-2, 2-3, 3-4?
take it right to redline
and that 1/8th mile seems quite high.... but then again so is the altitude
have fun
i thought we were supposed to shift right at or around the peak hp curve or something because at redline its already dropped off
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98' Pontiac Sunfire SE
lowering the tire pressure creates more drag and you start to lose surface contact because the center of the tires starts to pull of the pavement
id go w/ about 32 psi for stockers
a little less than recommended is fine
sappyL61 wrote:lowering the tire pressure creates more drag and you start to lose surface contact because the center of the tires starts to pull of the pavement
id go w/ about 32 psi for stockers
a little less than recommended is fine
I've never heard that before. As a rule of thumb you always want to lower the air pressure in the front tires so the side wall can flex and to increase your contact patch with the ground. You also want to raise the rear tire pressure to reduce roll resistance. When I use to run stock wheels I would run around 25psi and then play with it (+/-) depending on conditions. When I run drag radials I start at 18psi and go from there.
Quoth the Raven 'Nevermore
raven@accesswave.ca
Raven Autosports
55 McQuade Lake Cres,
Halifax, Nova Scotia, Canada
(902) 850-3330
10.82@132
I was told that the peak HP is where you want to shift and on some car that is anywhere from 5600-6100 RPM. I still have practicing to do.
2004 Grand Prix GTP (Competition Group)
SOLD-->1999 Z24 5M-#30 to register on JBO
"You can please some of the people some of the time but you can't please all the people'
all the time
going from 1-2 i switch at 5700 and hit the gas so that i let go of the clutch at 6500 and as its going from the 6500 to 4000 hold the pedal down as hard as possible
when i do it my speedometer shoots from 28 to 43 mph
if you do it too good you can get the cdplayer to skip from the tires loosing there grip
and i never hold the acelerator pedal all they way down during the entire shift sequence
thats known as a powershift and is really bad on your transmission
^^^^What your doing anyways is still bad and if you shift quick enough between 1st and 2nd if you hold the pedal all the way down it should never get far past redline.
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Madjack wrote:Like I said before, building an engine like ours (2.2 or 2200) is a painstaking chore , since there is so few custom made parts. It's frustrating to me too, but that's what I like about doing this engine, it's the challenge.
and making the tires lose traction is what you want to happen too.... ?
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98' Pontiac Sunfire SE
^^^ thats why i said too good
when done right i get about 6-7 feet ahead of them instead of loosing distance from shifting
uhm
if you deflate the tires the center cups up
thats why you would have exceive wear on the outer sides but the inner part will be normal tread
like if you overinflate the center section wears and the outer retains more tread
You would have to deflate you tire below 25 to get that happening, also the brand of tire can make a difference.
2004 Grand Prix GTP (Competition Group)
SOLD-->1999 Z24 5M-#30 to register on JBO
"You can please some of the people some of the time but you can't please all the people'
all the time
I always used the feather approach compined with a speed shifting.I launched at 5,000 rpm's and rode the clutch pretty hard.Then the instant I got traction I let off the clutch and got ready to grab 2nd gear.I never let right foot leave the floor.It will hurt your syncro's if not done properly.
With lots of practise I was able to pull a few 15.20's out of my 03 Sunfire,5 speed.My only mods were intake and a welded on muffler.I also got good enough to pull 2.0 60ft times occassionally.
I ain't callin u a gold digga,but you ain't messin wit a broke cracka
eCOfIRE .cOM wrote:I always used the feather approach compined with a speed shifting.I launched at 5,000 rpm's and rode the clutch pretty hard.Then the instant I got traction I let off the clutch and got ready to grab 2nd gear.I never let right foot leave the floor.It will hurt your syncro's if not done properly.
With lots of practise I was able to pull a few 15.20's out of my 03 Sunfire,5 speed.My only mods were intake and a welded on muffler.I also got good enough to pull 2.0 60ft times occassionally.
If taking this approach you'll probably want to keep a coin jar labelled "new clutch fund" somewhere handy.
Of course, racing isn't about extending clutch life and he's right in that you can definitely improve your times like that if you're good at it.
you are sooo true sir.......I went a transmission in the first 8,000 miles and I was one my second clutch by the time I hit 38,000 miles.
but you gotta pay to play.
I ain't callin u a gold digga,but you ain't messin wit a broke cracka
