drag racing suspension

[whereda40at]

i had tein hr coilovers with 15X8 welds with 275/60/15R nittos drag radials at 12 psi, anit lag and 400whp. the car is a s13 hatch.

now its all the same but i have stock shocks and springs. my best 60' is 1.89 on the coilovers and 1.73 on the stock shit. im getting new m/t et streets very soon. what else can i do to lower my 60'?
coilovers again? adjust something? any help is good.

[Nismoknightska-t]

lower the new et streets down to 11psi.. you should break a axle or the tranny if they are still stock...

install subframe spacers.. and maybe go auto, if you have the money..

[whereda40at]

i have dds axles and a 300zx/mazworx trans. my drivetrain is good for over 600hp all around.

i was thinking of getting subframe spacers. they are to get rid of the wheel hopping right?

[SuperiorS14]

hks drag dampers or try adjustable shocks with stock springs.
remove sway bars

try adjusting your launch rpm

[whereda40at]

hks drag dampers or try adjustable shocks with stock springs.
remove sway bars

try adjusting your launch rpm

i no longer have the coilovers. i have no sway bars. my susp. is completely stock. i have the anti lag set perfect for the way it sits now. i know that i need new tires. i was looking at sub frame bushings and spacers and staying with the stock shocks and springs

[SuperiorS14]

if you shocks havent been change i suggest replacing them with at least oe replacements if not some adjustables.

[HYPNOTIK]

You should've kept your coilovers and bought new springs and then had them revalved for drag. Tein will revalve them for around $100 per shock. I'd def get some subframe spacers. What is your alignment like?

Or you could get some HKS drag suspension.

[Nismoknightska-t]

i have dds axles and a 300zx/mazworx trans. my drivetrain is good for over 600hp all around.

i was thinking of getting subframe spacers. they are to get rid of the wheel hopping right?


they will help for sure..

o yeaa put your alignment to 0.. and put the et streets to 11psi..

the tires you are running right now suck!! get a 26-10.5-15 et street..

[Shadowhunter]

You gotta tell us what you have so we can tell you what to improve. LSD? Motor mounts? 1 piece axle? All that stuff would help tremendously. A list of what has been done in this situation would be ideal.

[sr20boostn20]

If you want a lower 60, i suggest you get some slicks.

nothing crazy just an 26x8.5x15 or a 26x10.

my best 60 with stock suspension and a 26x8.5 is 1.59. thats with the stock tranny and a vlsd.

I just picked up Kw variant 3s for my drag set up, their in the car but it hasnt hit the track yet.

[whereda40at]

You gotta tell us what you have so we can tell you what to improve. LSD? Motor mounts? 1 piece axle? All that stuff would help tremendously. A list of what has been done in this situation would be ideal.

i have a 300zx trans, 1 piece 900hp steel drive shaft, 1.5 ats/carbonetics lsd, dds 600hp axels, avid titanium motor mounts, import inteligence perfect launch anti-lag, 400whp/385tq.

i know i need new tires. the nittos blow and are shot. but even when they were good my 60' was 1.7. i am getting the m/t et streets. i also am going to get subframe bushings and spacers. ill look into the hks drag suspension.

anything else recomended? i do need a front end alinement. do they do the back too?

[lazysk8er2]

if you wanna adjust the back your gonna have to get adjustable ruca's and basically replace traction rods n stuff in the rear so they can become adjustable.

i say screw the spacers get solid mounts for your subframe. more likely your stock bushings are welldone. also do solid/polyerethane bushings for your suspension. possibly a short shifter would help (i cant tell if you have auto or manual 300zx trans)

test and adjust the gearing (rear end) also thats more proportionate to your setup.

[whereda40at]

if you wanna adjust the back your gonna have to get adjustable ruca's and basically replace traction rods n stuff in the rear so they can become adjustable.

i say screw the spacers get solid mounts for your subframe. more likely your stock bushings are welldone. also do solid/polyerethane bushings for your suspension. possibly a short shifter would help (i cant tell if you have auto or manual 300zx trans)

test and adjust the gearing (rear end) also thats more proportionate to your setup.

its a manual trans. i have a short shifter. im just looking to lower my 60' i have mph. i trap 120mph. i could trap higher but my tire presure has to be really low to get out the hole. so thats basicly my whole goal is to get the best traction with the max amount of tire pressure so i dont have to sacrifice so much top end.

btw best run was 1.73 60' 11.74 @ 118 mph. i have trapped 120 but my tire pressure was at 15. those runs it was at 9psi

[jr_ss]

Soft springs/struts out-back and run the opposite up-front. Adjusting the rear camber to zero would increase the amount of rubber on the track as well. I would also suggest getting anti-squat bushings, I know I've seen them somewhere for the S-chassis.

[whereda40at]

but dont you want squat with a drag car??

[SuperiorS14]

btw best run was 1.73 60' 11.74 @ 118 mph. i have trapped 120 but my tire pressure was at 15. those runs it was at 9psi


damn... jeff(nismoknight) can correct me if im wrong but i believe a local (cerio) ran a 10.7x with around 400hp(pistons,2871, z32 trans, etc) im not sure what tire he runs i think he runs et streets. maybe jeff could chime in and help out. you should be running better times.

[HYPNOTIK]

Subframe spacers
SPL PARTS (http://splparts.com/main4/index.htm)

[sr20boostn20]

Why run a street tire at the track if your looking for better traction?

[z2roll4life7]

Why run a street tire at the track if your looking for better traction?

So you can Drive there

[sr20boostn20]

^^^^ your kidding right?

i used to drive there too, on street tire,

then I take 10 mins out of my day and change my wheels,

and cut 1.5 1.6 60s all day.

[jr_ss]

but dont you want squat with a drag car??

Yes and no. Too much of it can hurt camber angles and take away traction. Not enough squat will induce wheel spin, you have to find the perfect median. Like I said I think someone sells ones you can adjust, I.e. add a spacer and take away one to dial in the perfect setup for your car.

[HYPNOTIK]

someone sells ones you can adjust, I.e. add a spacer and take away one to dial in the perfect setup for your car.

The link I posted, second one down.

[whereda40at]

The link I posted, second one down.
those were the ones i was looking at getting.

i drive my car on the street with my welds on it. so i have to go with a street tire. i would love to do a slick but ill get pulled over every 5 minutes instead of 10.

that 240 with 400 that went 10, what tires he running, psi, car weight? those all play a factor too. too low of a psi like i have to run now with my nittos kills my mph. from at 9psi my mph was 116 and at 12psi it was 119

[QuickSpoolSR]

what setup is giving you 400hp at 12psi? it is an sr right?

[whereda40at]

what setup is giving you 400hp at 12psi? it is an sr right?
no 12 psi was my tire presure. sorrry about the confussion. im running 18 psi on my turbo.

[Nismoknightska-t]

but dont you want squat with a drag car??

Not really.. all the drag v8s have really stiff rears…



damn... jeff(nismoknight) can correct me if im wrong but i believe a local (cerio) ran a 10.7x with around 400hp(pistons,2871, z32 trans, etc) im not sure what tire he runs i think he runs et streets. maybe jeff could chime in and help out. you should be running better times.

not 10.7 but yes he was in the 10s.. hes on a full slick.. and about running better times, it all depends on the track/weather/tires/shifting/boost/ect..


Why run a street tire at the track if your looking for better traction?

Because et streets are the same as slicks almost.. just street legal and they do not grow.. best street/track tire..


those were the ones i was looking at getting.

i drive my car on the street with my welds on it. so i have to go with a street tire. i would love to do a slick but ill get pulled over every 5 minutes instead of 10.

that 240 with 400 that went 10, what tires he running, psi, car weight? those all play a factor too. too low of a psi like i have to run now with my nittos kills my mph. from at 9psi my mph was 116 and at 12psi it was 119

Just get the et streets.. its simple..

That 240 has slicks.. and is max psi for a gt2871r..

dude mph doesn’t matter really.. My s13 went 10s with 116mph... Worry about the car hooking first and then worry about mph..

[whereda40at]

just to follow up.....

i was at the track on nov. 4th for imports vs. domestics and mickey thompson had some 275/60/15's on sale so i got them mounted at the track. turned my anti-lag to 5k, tire presure at 16psi and heated the tires up a little bit. launched the car and BOOM broke my dss 600whp axle. no wheel hop, just saw the front come up and down real fast. i moved a total of 7" off the line. haha i found traction. so now i have to get it repaired and try again next season with my 600whp set up im doing in the off season. also i have to roll the rear fenders for the tire to fit.

thanks for all the help. m/t ftmfw!!!!

[S13 curtis]

if you're at 400whp in an s13 shouldnt you be trapping in the mid 120's.

[ATLspeed]

....gotta love breaking an axle

[whereda40at]

if you're at 400whp in an s13 shouldnt you be trapping in the mid 120's.

i put down 350whp on a mustang dyno which is like 400 on a dyno jet. depends on who you ask for numbers. i think it might be the trans geared differently. i had a dog box and trapped a best of 11.90 @ 120 and with the 300zx trans i run now i trap [email protected] same mods. only changed out the trans. tire pressure was lower on the 11.60 at 10psi and was at 14 with the dog box.

[Nismoknightska-t]

just to follow up.....

i was at the track on nov. 4th for imports vs. domestics and mickey thompson had some 275/60/15's on sale so i got them mounted at the track. turned my anti-lag to 5k, tire presure at 16psi and heated the tires up a little bit. launched the car and BOOM broke my dss 600whp axle. no wheel hop, just saw the front come up and down real fast. i moved a total of 7" off the line. haha i found traction. so now i have to get it repaired and try again next season with my 600whp set up im doing in the off season. also i have to roll the rear fenders for the tire to fit.

thanks for all the help. m/t ftmfw!!!!

same thing happen to me @ boti last sunday.. i left on the trans brake @ 4800 and boom!! here is a video of my first run..

YouTube - NISMO KNIGHTS @ BOTI 2009 FONTANA (http://www.youtube.com/watch?v=Qvb8BTYdRGU)

next time try to preload the car before launching it, to get all the slack out of the drivetrain so you dont shock it..

[whereda40at]

new follow up...........
i made a nice pass this season. went 11.2 @ 121mph. had a 1.56 60' car now makes 380whp on a mustang dyno

mods are: port polised s13 head
kelford step 3 cams
everything else supertec
brian crower 2.3 stroker
gt2876r @ 18 psi (internal wastegate)
stock susp.
sub frame spacers
300zx manual trans
1 piece drive shaft
dss 600hp axels
1.5way carbonetics lsd
launch set at 4900
tires at 16 psi
air temp at the track was 97 F

new goal is to hit 10's without touching the motor. maybe new final drive or wait for a colder night?

suggestions are welcome.

[Slo_240sx]

Those are nice numbers. What size tire are you running now? I would try to get some adjustable coils to help you fine tune the launch. Your 60' is good but I think it can be lowered a bit. You'll lose MPH on the top end but your ET will show. My IRS friends (Im running a solid axle in my 240) gained by getting some adjustable RUCA's. We dialed it in to run the rear wheels flat during squat, it helped alot. Your power should be good enough for 10's with a good 60".

[whereda40at]

yea i think that it needed to be cooler out too to get get a lower time. i might go to the track this weekend and ill report back.

im in the black car. YouTube - sherrodsmith22's Channel (http://www.youtube.com/user/sherrodsmith22#p/u/19/I1eoqMUwpxo)

[Vetal]

To the OP, what did you do to improve from 11.6 to 10.8 seconds?
Are you on stock suspension?
Did 1.5way LSD help much? Is it much better than stock VLSD?

Our trap speeds are similar, it's only that you run 1.2 seconds faster :))

[[email protected]]

He's .520 quicker in the 60ft then you.
Rule of thumb is for every tenth you can cut off out the hole is good for 2 tenths up top

To the OP, what did you do to improve from 11.6 to 10.8 seconds?
Are you on stock suspension?
Did 1.5way LSD help much? Is it much better than stock VLSD?

Our trap speeds are similar, it's only that you run 1.2 seconds faster :))

[Vetal]

Thank you..... You just helped a lot lol!
"You're much faster, what did you do? - Hey, he's much faster."

[DallasTXjdm]

Two year old thread but excellent information! whereda40at did you end up upgrading your suspension? Which tires did you use to cut your [email protected] MPH 1.48 60' pass?

[steve shadows]

Sorry if someone has already mentioned this but the stock S chassis shocks and springs in good condition have always been my favorite for a solid launch with some MT et streets or some M&H tires for street slicks.

[[email protected]]

Sorry if someone has already mentioned this but the stock S chassis shocks and springs in good condition have always been my favorite for a solid launch with some MT et streets or some M&H tires for street slicks.

They work to a degree but there are better ways to go about it

[Vetal]

Sorry if someone has already mentioned this but the stock S chassis shocks and springs in good condition have always been my favorite for a solid launch with some MT et streets or some M&H tires for street slicks.good condition? I remember reading somewhere that people used BAD stock shocks to help launch

Santos, what's better then? Except HKS Drags, of cause :)

[[email protected]]

good condition? I remember reading somewhere that people used BAD stock shocks to help launch

Santos, what's better then? Except HKS Drags, of cause :)

His doesn't make one for s13 last time I checked.
Fortune auto makes some but I haven't heard anything about them.

I personally will be using sme QA1s. I will be machining a top mount to bolt up to the stock location then dial it all in

I will be using the biggest sway bar I can find for the rear or I'll fab up a anti roll bar set up with heim joints for adjustability

Basically be using my car to find every way possible to put all the power I can to the ground

[Vetal]

Are you going to use QA1 HALs? For which car?

[[email protected]]

Are you going to use QA1 HALs? For which car?

Still researching that so I don't want to put I of out their till I know it works

[inopsey]

[QUOTE=Vetal;4587221]good condition? I remember reading somewhere that people used BAD stock shocks to help launch [QUOTE]

typical zilvia style. who in their right mind would drive over 100mph on blown shocks; never mind recommend it ? sounds like a smart thing to do

[Vetal]

good condition? I remember reading somewhere that people used BAD stock shocks to help launch
typical zilvia style. who in their right mind would drive over 100mph on blown shocks; never mind recommend it ? sounds like a smart thing to doHere: Tune Your Ride - Car Craft Magazine (http://www.carcraft.com/howto/ccrp_0512_tuning_your_car/viewall.html)
For the front suspension, the old racer trick was to use "dead" stock shocks."Zilvia style" enough for you?

[inopsey]

whatever. if you think a few tenths in the quarter mile is worth the risk of losing control of your car into the wall then who am i to tell you what common sense is.

[steve shadows]

Another good setup is stock GOOD shocks and Eibach sportlines, used this to get 1.5s in the 60 ft with 440 whp for a while.

I also had some old Tien HEs that we would soften all the way up on BF goodrich comp tas.

The biggest thing in my past experience is TIRES and making sure you are soft and weight transfer goes where you want it. Next is the clutch you are using and your launch point. This is really where it will all come together.

BF goodrich Comp TAs were the best for me, then came the M&H street slicks and then the MT ET Streets.

[Vetal]

Steve and other fast guys... Can you give me some advise on my car, what's the best I can do? I have basically stock suspension with lowering springs, old S13 VLSD, 26x8.5 ET Drags. What could I do to improve launch/weight transfer/60ft? I see whereda40at runs stock shocks/springs and other suspension but with subframe spacers, should I copy that setup?

[Vetal]

Good old thread here...
Since last post I have swapped lowered springs back to stock and I THINK it improved traction a bit. However there is big downside to that - car looks like stupid offroader now, with probably 3-3.5" between tire and arch in front. Not so bad in the rear.
Please help me to invent something that could retain stock springs BUT allow me to change ride height! I would gladly use some coilovers for the front if they they would cost reasonably AND not hurt traction, but I don't know of any...
Maybe we could come up with some idea?

[Vetal]

Anyone? :)

[ashtonroche]

the key on rwd cars is to keep the weight transfer to the rear. Reason why the op went faster on a stock setup is because his old coilovers were probably too stiff and not valved correctly.

Stock suspension is not the best but a properly valved shock even on stock springs would do a pretty good job. Basicly you want 0 damping on the initial compression of the shock and full damping on the rebound of the shock to keep the weight from transfering back to the front too quickly.

Key is to keep the weight planted at the rear.

Hell even stock springs and a proper drag shock that is two way valved would work great. They make drag specific coilovers for this reason, just gotta pay up for them. They will have soft rear springs and two way valving so you can play with settings. But most from what ive seen you use zero damping on compression and full dampen on rebound.

For FWD this is exactly the opposite. Stiff as hell rear springs, Full damping on compression and 0 damping on the rebound. This allows the weight transfer to the back to be quickly "bounced" back to the front. Hell if I can pull 1.5 60's in my fwd Sentra, no reason when dialed in that a 400whp 240 couldnt pull 1.4's or better even on drag radials.

[ashtonroche]

Another thing people often forget to think about in drag racing is alignment. And even for rwd this applies.

What the hell do you think happens when your rear end squats down 4" or so on a launch. Your wheel alignment and camber change drastically. For you rwd guys you would want to set up your alignment so that when its in the launch and acceleration position that the contact patch of the tire is at its best. So both the toe and the camber are as close to "0" as you can get during that launch and acceleration.

So dependant on the suspension setup and actual squat you get, make you adjustments as necessary. Best thing to do would be to record the back tires with a Gopro during launch and see whats happening and then make changes from there.

You want to keep the ride height up as well but not too high. Basically about stock ride height would be fine or little higher if your fitting big tires. But i can bet you during launches your getting a bit of toe out and negative camber. Not the best for traction.

[ashtonroche]

And lastly, diff

Of course the stock vlsd isnt going to be the best diff for drag racing. You want something locks quickly and stays locked. Hell a welded diff would pretty much be your best bet but if you have other things going on with the car that arnt setup right, a welded diff can be not soo good. But seriously, a completely locked diff is the way to go. Full traction at the same time and same speed from both wheels together. Best way to go.

[ShakotanGazelle]

Ford 8.8 axle + full spool.

[whereda40at]

wow, my old thread was still alive. I still swear by this info for drag racing. I even have my 1.5 way carbon plate diff for sale.