Guess my quarter mile time/trap speed!
03-28-2017, 10:54 PM
#1
Guess my quarter mile time/trap speed! Going to be letting my 96 z28 m6 rip at the strip this year.
Guess my trap speed and E.T!!!
MODS:
K&N CAI, 1LE intake elbow, Air foil, TB Bypass.
1.6 roller rockers, 112lsa, 215/224 .533/.533 lift cam.
Stock Heads with a 3 angle valve job, Pac 1218 Springs
Solomon Mail Tune with LT4 knock module, tuned for SLP 160 stat, Meziere ewp. Car runs around 180 degrees.
1 5/8 Mac Mid Headers & Catless y-pipe into a magnaflow catback.
Stock 100k Short Block with MSD super conductor wires and ngk tr55 plugs.
Six speed trans, stock clutch, 342 gears. UMI LCA's, Relo brackets, panhard bar, Bilstein shocks.
Plan on launching with sticky tires but at maybe 1500-2000rpm to save the weak 10 bolt rear.
Temps hopefully between 50-65 degrees at 800ft elevation.
Guess my trap speed and E.T!!!
MODS:
K&N CAI, 1LE intake elbow, Air foil, TB Bypass.
1.6 roller rockers, 112lsa, 215/224 .533/.533 lift cam.
Stock Heads with a 3 angle valve job, Pac 1218 Springs
Solomon Mail Tune with LT4 knock module, tuned for SLP 160 stat, Meziere ewp. Car runs around 180 degrees.
1 5/8 Mac Mid Headers & Catless y-pipe into a magnaflow catback.
Stock 100k Short Block with MSD super conductor wires and ngk tr55 plugs.
Six speed trans, stock clutch, 342 gears. UMI LCA's, Relo brackets, panhard bar, Bilstein shocks.
Plan on launching with sticky tires but at maybe 1500-2000rpm to save the weak 10 bolt rear.
Temps hopefully between 50-65 degrees at 800ft elevation.
03-29-2017, 04:39 AM
#2
Is this the first time you've ever taken this car down the track/first time with a 6 speed down a track??
Is this the first time you have ever been down a track?
Those 2 answers will dictate a lot.
Other factor is what tires are you using? And what RPM are you going to shift at? Track prep? Race weight? If it's a well prepped track with bias ply tires or ET street radials, and this isn't your first rodeo, and you shift at 6500 rpm and power shift/speed shift/no lift shift however you want to phrase it, and your race weight is 3600 or less, I think the car has 12.0 - 12.3 in it at 110-112. If this is your first time down a track, I would honestly be happy with 13.5 at 106. From some of your previous posts about not spinning it high, I think if you only shift at 5800 and haven't mastered power shifting, you'll be mid to high 13s.
Launching a 6 speed on a 10 bolt is almost an art, it's a delicate line between a 1.8 60', a 2.5 60', and a however long it takes them to tow you off the track because you broke your 10 bolt 60'. You want to use the motors torque to pull you out, start at 2000rpm and don't feather or slip the clutch, it will take a lot of passes to get your feel right. You want to end up basically releasing the clutch while pressing the throttle the whole way down, it should bog to about 1500rpm without the rpm rising over that 2000 starting point and then the clutch should be out and your foot should be on the floor and the motor should pull you out. If you are feathering the clutch at all, you won't get linear power delivery to the tires and you'll spin. It's 1 fluid motion, and extremely hard to do on your first few passes ever with butterflies in your stomach and your heart racing. Bias ply tires or real drag radials can mask it a little, but put more stress on the 10 bolt. You need to preload the pinion and ring gear and let the motor pull you, if you shock the ring and pinion by retracting the clutch too fast without letting it bog, you'll break the 10 bolt.
Street tires = don't go through the water box if there is standing water, like a puddle at all, only go through the water box with street tires if it's just a wet surface, otherwise go around. Standing water and street tire grooves will pick up the water and drop it from your tires onto the track and cause you to spin. Street tires only need a 2-3 second burnout in 1st gear to clean the dust and rocks off, side step it in 1st gear at 4000-5000 and hold a 4500ish rpm burnout for 2-3 seconds then roll out as you push in the clutch.
If it's your first time at the track, don't focus on the numbers, focus on having fun and feeling out your car. Every moment is time to learn and practice, if you **** up the launch, focus on your shifts the rest of the way. If you are spinning, don't ride it out, retract the throttle until it stops spinning, then ease back in and keep going, don't ride a burnout or you can crash or blow the motor letting it spin at high rpm with no load. Nobody looks cool holding a burnout down the track, those guys are idiots and dangerous to themselves and the guy in the next lane, I've seen too many crashes because people did this.
Have fun! It's a blast! Before you go you should practice your 1-2 and 2-3 shift on every on ramp and every stop light, and work on power shifting. You start by putting a tiny bit of force on your hand on the shifter in the direction you want to go, not enough to move it while you are still accelerating, but a little. When you go to shift, kick the clutch as fast as you can and you'll feel the shifter start to move in your hand and as soon as it starts moving/releases, throw it the rest of the way to the next gear. By the time your hand starts to move towards the next gear and tells your brain to tell your foot to release the clutch, do it, don't wait to tell your foot to release the clutch until your hand makes it the whole way, your hand should make it just in time as the clutch releases and you are back in the throttle. Do it first at 0% throttle, then 25%, then 50%, 75%, then 100%, eventually shifting without lifting the throttle. It should happen so fast that the rpms don't rise while shifting at full throttle and the nose doesn't dive at all. Every time the nose dives, you are transferring weight off the rear tires and increasing your chance of spinning the next gear, especially on the 1-2 shift. Powershifting alone can drop 0.5 seconds from your ET. Also shifting at 6500 with your setup vs 5500-5800 can drop another 0.5 seconds, which is why my guess ranges from a 12.0 to a 13.5, that last 0.5 can come from a good 1.8 60' vs a 2.3 60'.
Is this the first time you have ever been down a track?
Those 2 answers will dictate a lot.
Other factor is what tires are you using? And what RPM are you going to shift at? Track prep? Race weight? If it's a well prepped track with bias ply tires or ET street radials, and this isn't your first rodeo, and you shift at 6500 rpm and power shift/speed shift/no lift shift however you want to phrase it, and your race weight is 3600 or less, I think the car has 12.0 - 12.3 in it at 110-112. If this is your first time down a track, I would honestly be happy with 13.5 at 106. From some of your previous posts about not spinning it high, I think if you only shift at 5800 and haven't mastered power shifting, you'll be mid to high 13s.
Launching a 6 speed on a 10 bolt is almost an art, it's a delicate line between a 1.8 60', a 2.5 60', and a however long it takes them to tow you off the track because you broke your 10 bolt 60'. You want to use the motors torque to pull you out, start at 2000rpm and don't feather or slip the clutch, it will take a lot of passes to get your feel right. You want to end up basically releasing the clutch while pressing the throttle the whole way down, it should bog to about 1500rpm without the rpm rising over that 2000 starting point and then the clutch should be out and your foot should be on the floor and the motor should pull you out. If you are feathering the clutch at all, you won't get linear power delivery to the tires and you'll spin. It's 1 fluid motion, and extremely hard to do on your first few passes ever with butterflies in your stomach and your heart racing. Bias ply tires or real drag radials can mask it a little, but put more stress on the 10 bolt. You need to preload the pinion and ring gear and let the motor pull you, if you shock the ring and pinion by retracting the clutch too fast without letting it bog, you'll break the 10 bolt.
Street tires = don't go through the water box if there is standing water, like a puddle at all, only go through the water box with street tires if it's just a wet surface, otherwise go around. Standing water and street tire grooves will pick up the water and drop it from your tires onto the track and cause you to spin. Street tires only need a 2-3 second burnout in 1st gear to clean the dust and rocks off, side step it in 1st gear at 4000-5000 and hold a 4500ish rpm burnout for 2-3 seconds then roll out as you push in the clutch.
If it's your first time at the track, don't focus on the numbers, focus on having fun and feeling out your car. Every moment is time to learn and practice, if you **** up the launch, focus on your shifts the rest of the way. If you are spinning, don't ride it out, retract the throttle until it stops spinning, then ease back in and keep going, don't ride a burnout or you can crash or blow the motor letting it spin at high rpm with no load. Nobody looks cool holding a burnout down the track, those guys are idiots and dangerous to themselves and the guy in the next lane, I've seen too many crashes because people did this.
Have fun! It's a blast! Before you go you should practice your 1-2 and 2-3 shift on every on ramp and every stop light, and work on power shifting. You start by putting a tiny bit of force on your hand on the shifter in the direction you want to go, not enough to move it while you are still accelerating, but a little. When you go to shift, kick the clutch as fast as you can and you'll feel the shifter start to move in your hand and as soon as it starts moving/releases, throw it the rest of the way to the next gear. By the time your hand starts to move towards the next gear and tells your brain to tell your foot to release the clutch, do it, don't wait to tell your foot to release the clutch until your hand makes it the whole way, your hand should make it just in time as the clutch releases and you are back in the throttle. Do it first at 0% throttle, then 25%, then 50%, 75%, then 100%, eventually shifting without lifting the throttle. It should happen so fast that the rpms don't rise while shifting at full throttle and the nose doesn't dive at all. Every time the nose dives, you are transferring weight off the rear tires and increasing your chance of spinning the next gear, especially on the 1-2 shift. Powershifting alone can drop 0.5 seconds from your ET. Also shifting at 6500 with your setup vs 5500-5800 can drop another 0.5 seconds, which is why my guess ranges from a 12.0 to a 13.5, that last 0.5 can come from a good 1.8 60' vs a 2.3 60'.
Last edited by bufmatmuslepants; 03-29-2017 at 04:57 AM.
03-29-2017, 09:24 AM
#5
Bufmat.......Ran it at the track in stockish form and got a 14.2 @ 101. I have about 6 passes under my belt. 2.2 60ft without my new rear end mods and was on crappy tires. Full weight car, power windows, seat.
I like 5500-5800 for engine longevity but i will rev her out to about 6k tops at the strip. I really wouldn't feel safe past 6k with my self alligning roller rockers and tight stock bearing clearances dont like revs over 6200 is what i read. Whats your guess with this new info!
I like 5500-5800 for engine longevity but i will rev her out to about 6k tops at the strip. I really wouldn't feel safe past 6k with my self alligning roller rockers and tight stock bearing clearances dont like revs over 6200 is what i read. Whats your guess with this new info!
03-29-2017, 10:29 AM
#6
Village Troll 
iTrader: (2)
Your bearings are fine at that RPM. You need to find out where power peak is. Those gears aren't doing you a whole lot of good for 1/4 times. With that mild a cam you may consider 3.73's over 4.10's if you are going to do gears. Experiment with different shift points. My 211/219 cam peaked at 5800rpm and I shifted at 6200rpm which is where I had the best results. Won't say what kind of time you'll run because of your gearing.
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03-29-2017, 11:05 AM
#8
Bufmat.......Ran it at the track in stockish form and got a 14.2 @ 101. I have about 6 passes under my belt. 2.2 60ft without my new rear end mods and was on crappy tires. Full weight car, power windows, seat.
I like 5500-5800 for engine longevity but i will rev her out to about 6k tops at the strip. I really wouldn't feel safe past 6k with my self alligning roller rockers and tight stock bearing clearances dont like revs over 6200 is what i read. Whats your guess with this new info!
I like 5500-5800 for engine longevity but i will rev her out to about 6k tops at the strip. I really wouldn't feel safe past 6k with my self alligning roller rockers and tight stock bearing clearances dont like revs over 6200 is what i read. Whats your guess with this new info!
Back when I didn't know better, I revved a cam-only stock bottom end LT1 up around 6,900 rpm (at least according to crappy factory tach) with SA rockers for several passes down the strip. I was a stupid teenager, would not do it now nor recommend it but the point I'm trying to make is that I think you are being too conservative. I'm willing to bet you'll leave ET and MPH on the table if you don't shift it a little beyond 6k. I'm guessing low 13's in ET with 10x trap speed. 
03-29-2017, 11:12 PM
#10
TECH Resident
03-31-2017, 05:29 AM
#15
I have probably 250 passes shifting at 6300 rpm by the factory tach on a Craigslist 120k mile stock bottom end. 6300 is the safe rule of thumb limit for SA rockers. On a low turnout day at the track I got to play with shift rpm and found 6300 got the best results. With your cam it would want more rpm, so shifting anywhere lower than 6300 will be leaving quite a bit on the table. A 14.2 at 101 is a little slow for a stockish car, so you either are at high elevation or are "granny shifting, not double clutching like you should". 2.2 60' on old street tires isn't bad, but I'll say 13.2 at 106 given the new info, but I bet the car has 12.3 at 111 in it if you can get a near 0 DA day and some more passes under your belt.
03-31-2017, 07:38 AM
#16
Bufmat, elevation is 800ft. I had crappy tires that spun pretty easily and no rear end mods done yet. I feel the car was capable of high 13s easy in stock form. Just had to bog off the line at 1500rpm so it didn't spin.
With my rear mods which helped considerably, eliminated all wheel hop and keeps the car tracking straight i feel i should get at least a 2.0-2.1 60ft with some better tires even with my little experience. I will practice powershifting but i want to be careful because it is kind of a daily driver from april-november. I think trap speed will tell me a lot about the power i gained. 101mph stock. Im thinking it should trap somewhere in the 107-110 range.
In stock form it was kind of doggish getting up to 60mph. I think it needed a tune and a tune up. Now with cam, tune, ewp, headers it absolutely flys in 2nd gear and gets to 60mph quickly. I always had pretty slow 1/8 mile times in stock form but my "big end" times seemed on par with a mid 13 sec car. It always felt fast in 3rd and 4th gear.
My guess is i will run a 13.3 @107 without powershifting and launching with a 2.1 60ft. I would be pretty excited to get a high 12 with traction though.
Its all in good fun, idc what it runs really, its a street cruiser first and foremost! Sees the strip once or twice a year and about 10k street miles.
With my rear mods which helped considerably, eliminated all wheel hop and keeps the car tracking straight i feel i should get at least a 2.0-2.1 60ft with some better tires even with my little experience. I will practice powershifting but i want to be careful because it is kind of a daily driver from april-november. I think trap speed will tell me a lot about the power i gained. 101mph stock. Im thinking it should trap somewhere in the 107-110 range.
In stock form it was kind of doggish getting up to 60mph. I think it needed a tune and a tune up. Now with cam, tune, ewp, headers it absolutely flys in 2nd gear and gets to 60mph quickly. I always had pretty slow 1/8 mile times in stock form but my "big end" times seemed on par with a mid 13 sec car. It always felt fast in 3rd and 4th gear.
My guess is i will run a 13.3 @107 without powershifting and launching with a 2.1 60ft. I would be pretty excited to get a high 12 with traction though.
Its all in good fun, idc what it runs really, its a street cruiser first and foremost! Sees the strip once or twice a year and about 10k street miles.
03-31-2017, 11:07 AM
#17
Bench racing....anyone's guess....and mine was high 13's @ 102....which was based more on the 2.xxx 60' time.
run it at the track and find out.
Good DA and 1.8xx 60' would lower the ET and increase MPH greatly....if that happens.
run it at the track and find out.
Good DA and 1.8xx 60' would lower the ET and increase MPH greatly....if that happens.
10-06-2017, 05:47 PM
#19
Well, gonna run it this Sunday the 8th. Supp to be about 70 degrees. Got a trailor on call in case the 10 bolt snaps lol!! I have 255 50 16 M/T drag radials so it doesnt spin to 50mph like with my street tires. Time to see what the old white turd can do!
Last edited by 350 groundpounder; 10-06-2017 at 06:30 PM.
