1/8 to 1/4 to bench racing and street racing. All straight fun

Moderators: B17 Moderator, B16 Moderator

By yogib777
#228162
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
By yogib777
#237247
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
By yogib777
#237525
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
By yogib777
#237653
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
By yogib777
#237681
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
User avatar
By ProTo20
#237942
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.
By yogib777
#237978
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]
By yogib777
#238258
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
By cooper1122
#241018
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