Page 1 of 1

Perhaps, a new drag launch

PostPosted:Sun May 11, 2014 9:51 am
by yogib777
Caution
serious damage to motor, tranny and axles may occur if you engage in this activity


racers only, who understand and are prepared for the risks
only works on slicks to my knowledge

stock flywheel has been used to 5000 rpm BUT
stock clutch will fail rapidly used this way

best done on clutch and flywheel chosen for this activity


my clutch is multiple times harder than the stocker, utilizes a cf disk and a solid steel, 14 lb flywheel

[one of 2js rare drag clutches]



been playing with the idea of using a flywheel motor assisted launch

sit at the line, spin the motor to rev limit
using the rev limiter as a two step

launch, just pop the clutch, yes sidestep it
and BACK OFF the gas, [about 3/4 throttle]

let the slicks wrinkle and catch as the rpms fall
nail the gas

seems to work on both sets of slicks
car is burnout capable now

jumps off the line
no clutch slipping at all

note
preload car to take the slack out of the axles
hold with parking brake
and return clutch to the floor
then launch

saves on axle breakage


looks like at least 2 weeks before vids
rained out this week

photo crew working next week


btw
the use of the flywheel to control the launch is very consistant
it behaves the same way, every time
the inertial spin down is pure mathematical physics

Re: Perhaps, a new drag launch

PostPosted:Sun May 11, 2014 9:59 am
by yogib777
on the big slicks
no hop at all [back on solid mounts]

the littles can hop, but not often

the small hard 15" rivals are still the most hop prone
but hop is way better than the shock mounted engine setup

comparative hop vids when the rain stops

Re: Perhaps, a new drag launch

PostPosted:Sun Sep 20, 2015 8:16 am
by yogib777
update
the launch vids are long up

and the real world results were this

the 14lb fltwheel is still lightweight
and does not store enough energy to do a pure flywheel launch

so clutch slipping is still very necessary

as a result the clutch and flywheel ended like this after 3/4 of a season's runs
Image

and thats with the upgraded cf disk and stage 3 pressure plate
[replaced with stage 4 clutch and drag only 6 puck clutch plate]

did survive several high hp nitrous shots
at least it got me home


the flywheel was also replaced with the same 14lb 2jr unit
but a different launch system is now employed
anticipating slipping the clutch

Re: Perhaps, a new drag launch

PostPosted:Sun Sep 20, 2015 8:18 am
by yogib777
the car never reached my expectations NA
but was super on nitrous

turning faster mph in the 1/8 [91]
than the present turbo [88]

Re: Perhaps, a new drag launch

PostPosted:Sun Sep 20, 2015 8:21 am
by yogib777
can't find the launch vid on site

so i will repeat it here
no hop whatsoever
but omg slow [NA]
Image

Re: Perhaps, a new drag launch

PostPosted:Sun Sep 20, 2015 8:31 am
by yogib777
Launch or burn out

on 24.5x8x15 slicks
6500 rpm slip the clutch
Image

on 245/45/16 r-comps, 9.6" wide [tread]
4500 rpm, slip the clutch
Image

22x8x15 slicks
6500 rpm more sudden clutch release, less slip
Image


no hop, on any tire pictured
car ran and launched at high rpm, straight down the strip

Re: Perhaps, a new drag launch

PostPosted:Sun Sep 20, 2015 8:35 am
by yogib777
however on these
it was a bunny

great in the mountains
fair in the rain
but terrible on the drag strip

bfg rivals 225/40/15
Image

Re: Perhaps, a new drag launch

PostPosted:Sun Sep 20, 2015 8:42 am
by yogib777
now it's time to learn new techniques

we doubled the power
added 2" wider tires
Image

please excuse dirty car
Image82 by Barry Belgard, on Flickr

Re: Perhaps, a new drag launch

PostPosted:Fri Oct 09, 2015 11:07 am
by yogib777
update
10" tires are too much for the subframe and unibody

at above 300 ft lbs tq

on launch the unibody twists
and the k frame moves

distorting everything

once 0-60 ft times drop to 1.8 or below

a roll cage will help the unibody

but the k frame mounts above 400 hp
imo will be a problem

presently my temp fix
is slipperier tracks and limited to 8" slicks

will try again in late oct

with new heim joints
replacing my 4 year old orig prototypes with the better production items
ImageDSCN0947 by Barry, on Flickr

note new windshield banner

Re: Perhaps, a new drag launch

PostPosted:Wed Oct 21, 2015 8:38 am
by yogib777
problem disappeared on the track
the g-tech 0-60ft times were accurate

was able, on one run, to duplicate the 1.8 sec run
fastestest it ran was 7.9s in the 1/8
beating the vq record here by .6 in the 1/8

but i could not duplicate it
ran some mid 8s and even some low nines
went home
too inconsistent in the colder weather [45-50*f]


1st gear was smooth and straight, after that forget it
all over, hopping and bopping ,slipping and sliding

looked good just off the line though
ImageCP4_6451web-(ZF-0665-95524-1-002) by Barry, on Flickr

Re: Perhaps, a new drag launch

PostPosted:Mon Oct 26, 2015 8:59 am
by yogib777
after analyzing the data, and studying the pics, i believe this is the sequence of events

launch at higher rpm, 5000
no boost thru most of the 60 ft run

shortly after 2nd gear [shift point was 7000, on the track]
full boost develops

thus its performance in the 330 range
loses traction, dramatically, and begins to hop

while the 60 ft times hover in the 2.1s
the 330ft times are all over the place

learning:
lift, don't press, going into 2nd gear
back peddle 2nd gear


collected data from two other cars running out of 2js shop
verifies the same low traction 1st and 2nd gear on high tq turbo sentras

these two, with much greater hp than mine, were nearly impossible to hook up
even on 9" wheels and 235/40/17, good summer tires

the 275s definitely deliver superior traction

and for now at least a 26" tire is necessary
a 28" diameter tire would be the best
[lowering tq multiplication in the lower gears]

btw
launching under boost may not be a good idea with our limited traction

imo

Re: Perhaps, a new drag launch

PostPosted:Tue Nov 17, 2015 8:15 am
by yogib777
a comparison of launch attitudes
both on r888s
both 2.1s to 60 ft

1st
old drag set up
7kg springs front, 8kg springs rear
looks cool but look at the weight transfer to the rear
Image

new setup
12kg springs all around
a little better
ImageCP4_6463web-(ZF-0665-95524-1-001) by Barry, on Flickr

Re: Perhaps, a new drag launch

PostPosted:Tue Nov 17, 2015 9:56 am
by ProTo20
I think you need to look into the NT555R or a bias ply drag tire for best results.

I know a few Honda guys pulling off 1.7 60 foots with the right tire.

You should be in that range easy.

Re: Perhaps, a new drag launch

PostPosted:Sat Nov 21, 2015 8:15 am
by yogib777
i was so thrilled by being free enough to go in totally off the street
36psi in the tires

that i am seriously thinking of DRs for next season

i have had good luck with toyo tires
both the R1Rs and the R888s
now they make a DR in 275/40/17

also checked the nittos 555s and 05s
cheap and big enough
http://www.jegs.com/i/Nitto/726/40156/10002/-1
the advantage is the 15" wheel, allowing a much bigger sidewall

these have better tread but less sidewall
http://www.jegs.com/i/Nitto/726/40585/10002/-1

btw
i did get one 1.8 run
lol

i was happy with that time
i was able to beat the vq times on slicks [at this track]
on r888s
7.9 vs 8.5 in the 1/8

those 1.7s hondas should be turning 7.6s in the 1/8
yes?
[very low 12sec 1/4s]

Re: Perhaps, a new drag launch

PostPosted:Tue Dec 22, 2015 12:28 pm
by yogib777
running 29 psi in the tires
resulted in enough stick

to snap the axles on the 1st burn out
somthing is working

1st broken axles in 12 years


far as i got
ImageCP4_1380web-(ZF-5022-41486-1-001) by Barry, on Flickr
Imaged7svC5jbkqBF by Barry, on Flickr

Re: Perhaps, a new drag launch

PostPosted:Tue Dec 22, 2015 12:29 pm
by yogib777
long tow home from tenn.
ImageDSCN1189 by Barry, on Flickr

Re: Perhaps, a new drag launch

PostPosted:Tue Dec 29, 2015 10:12 am
by yogib777
indeed

now we have developed further mods
i stuck with oem axles for replacement for now

more clutch slipping and the use of the water box to ease load on the axles during burnout
and more clutch slipping on launch
will be tried

this will let us see what the stock axles can actually deliver

Re: Perhaps, a new drag launch

PostPosted:Tue Dec 29, 2015 10:13 am
by yogib777
we also increased fender tire clearance and may be the 1st sentra to run 28x10.5 slicks

Re: Perhaps, a new drag launch

PostPosted:Mon Aug 22, 2016 6:20 am
by cooper1122
I'm havingtrouble with pop-ups and new tabs for 'Mackeeper' among others, launching themselves in Safari on my ... You installed the "DownLite" trojan, perhaps under a different name. ... Drag the selected item to the Trash.