Jump to content
SAU Community

Recommended Posts

Hey guys run my car down the 1/4 last week for the first time wasnt very happy with the result came out with a best time of 14.8 which to me seem pathetic to my mods, correst me if im wrong!

my car is making around 180rkw mods are

adjustable boost set 12psi

walbro pump/adjus reg

foward facing intake

fmic

adjustable suspension similar to teins quite stiff

goodyear f1 tyres with good tread

manual with standard clutch- clutch not in the best cond but dont think it slipped

To bare in mind also the whole boot is taken up by sounds which could weigh a bit but not enough to make my 1/4 this crap surely?

There were alot of other skylines and cefiros with less mods than my car and way craper tyres pulling alot better times than me but the one thing i noticed is their cars seem to squat down and launch but mine just sorta wanted to sit on the spot then slowly move foward if you get me.

ANY help or ideas would be much appreciated, id like to atleast crack the 13's!

Link to comment
https://www.sau.com.au/forums/topic/157338-improving-my-14-mile-time/
Share on other sites

mate it is a lil slow, my stock s2 33 with only turbo back makes 169rwkw and my best pass on slicks is 13.426 and on 19x10 street tyres i got a 13.700. should be at least running the same as me with those mods and power...

im going to the wsid, u live in sydney? come down and we can chat

Klenn, If you could give us the rest of the details that follow with the 14.8 ET you ran like:

60ft (indication of how good your launch is)

Trap/Terminal Speed in MPH (indication of how much power your making)

Along with your ET these figures prove valuable in giving you better advice on where you can improve.

What size rims/tyres where you running? 16/17/18" 225/255 wide etc.

For you information:

I was previously running consistent 14.2 and a best of 14flat with around 190-210rwkw and getting 60ft's of 2.3-2.5 trap speed of 103-105mph this is with my heavy 17" sparcos running decent dunlop tyres 255 width at the rear.

I then switched to my r33 stockies 16" with good toyo t1r's in 205 width only tyres, and straight away i got:

consistent 13.6 ET with best of 13.5 ET same trap speed of 103-105mph but my 60ft improved to a 2.0-2.1 as opposed to 2.3-2.5 I was SHOCKED! and was trying sooooo hard to break into the 13's..

my 2c

Hey guys run my car down the 1/4 last week for the first time

So you went for the first time, worked out how the whole night runs and made it home with the car in 1 piece... well done!

Now go back again (or for the next 6mths if you have to) and practice practice practice.

Klenn, If you could give us the rest of the details that follow with the 14.8 ET you ran like:

60ft (indication of how good your launch is)

Trap/Terminal Speed in MPH (indication of how much power your making)

Along with your ET these figures prove valuable in giving you better advice on where you can improve.

What size rims/tyres where you running? 16/17/18" 225/255 wide etc.

ok guys cheers for your help so far,

hope these are what your after

60ft-2.462

And speed- 93.97mph

my tyres are 235/45/17 with good tread.

any more info you need please let me know cheers.

As mentioned above, what was the 60ft time?

Do you get wheelspin off the line, or bog down?

A good set of tyres will help rub off lots of ET.

as for wheelspin it sorta felt like 1st gear didnt get me anywhere i could be wrong but it felt like it topped out really quickly like it was wheelspining, i think thats part of the problem the back wheels are already 2 or 3 fingerwidths inside the guards so when i go to pull away i dont think it can bog down because of the stiffness on the bum????? also i didnt let any of my tyre pressures down which could of helped me i suppose.

So you went for the first time, worked out how the whole night runs and made it home with the car in 1 piece... well done!

Now go back again (or for the next 6mths if you have to) and practice practice practice.

Quoted for truth!

+1.

Experience shaves a lot off your time too :) Its a little tricky getting used to how a car hooks up and takes off at a drag strip. Trying to find the optimum way to launch and accelerate and a good tyre combo isnt something most people get right on their first ever try. Keep at it, guaranteed with experience you will lose tenths off that time at the very least.

this might be a silly question but, will your ET's improve with just stock rims/good tyres on the rear?

Also given full stick with 215/45/17's on the upchange to 2nd i am getting wheelspin all the way to 3rd will lower pressures stop this or will I also need to be lighter on the change?

Based on:

'60ft-2.462

ET 14.8

And speed- 93.97mph'

The general rule of thumb for 60ft's is for each 0.1 you reduce your 60ft by you shave off approx 0.2 off your ET.

So in your case just with practice you should be able to get your 60ft down to 2.0-2.1 after some more runs and by dropping(adjusting your tyre pressure). HENCE in the current form you should be able to net a 14flat given you run an approx 2.0 60ft.

I suggest:

-Empty OUT your boot!, esp the sound gear + spare tyre/tools/jack

-Run 30psi tyre pressure in the rear tyres and drop it through out the night and monitor your 60ft to see if you improved or not <don't go lower then 20psi at the bare minimum> THERE isn't a tyre pressure pump at WSID so you'll have to pump it back up on the way home.

Do that and PRACTICE, PRACTICE PRACTICE + PRACTICE and you'll see results your asking for :)

My mate in his twin turbo supra the first time out a few weeks ago with 214rwkw ran a 14.4 and best 14.2 with average 60ft of 2.3+, THEN we headed back on wednesday 21st DIDN'T change anything at all, first run FLUKED a 2.0X60ft and got a 13.7 the rest of the night he never saw 13's ago lol BUT he was still alot happier.

my 2cents

Stock rims and a good set of tyres will improve your times a great deal (they are usually lighter aswell). The old rule is that if you can go 0.1 faster to the 60ft mark, you can double the savings at the 1/4mile. So if you go from a 2.4 60ft to a 2.1, you'll be well on your way to knocking over half a second off your 1/4 mile time.

CEF11E - Take some pressure out of your tyres, 25psi would be a good place to start, then lower it by 2 or 3psi if your still not happy (make sure you bring a portable air pump to pump them back up for the drive home). I wouldn't go much lower than 18-20psi on normal street tyres. I run 13psi on slicks.

The more traction you have the better (as long as the clutch holds up). You can leave with more boost too :):laugh: A good few free revs prior to launch will see you leaving with positive boost pressure.

Fixxxer :mad:

A good few free revs prior to launch will see you leaving with positive boost pressure.

Fixxxer :(

Sorry, not true. Not possible in a manual at *this* level. Free revving the car before leaving the line is a very silly way of working out what type of launch revs suit your car. Experiment with holding the throttle at different rpm and work out where you're quickest to 60ft.

Sorry, not true. Not possible in a manual at *this* level. Free revving the car before leaving the line is a very silly way of working out what type of launch revs suit your car. Experiment with holding the throttle at different rpm and work out where you're quickest to 60ft.

I was just about to ask the same question so what your saying by having positive boost is to sit at the line idling then just put your foot down and let out the clutch at a certain revs so the cars on boost OR to sit at then line holding i suppose the 3-4 grand mark and then releasing the clutch as well as putting the foot down??

Thanks for your help so far guys,

So you guys are stating tyre presure is crucial but what about suspension does this not have a big impact on my current setup-does my car not make enough power to be worrying about the suspension for traction ect??

I was just about to ask the same question so what your saying by having positive boost is to sit at the line idling then just put your foot down and let out the clutch at a certain revs so the cars on boost OR to sit at then line holding i suppose the 3-4 grand mark and then releasing the clutch as well as putting the foot down??

You won't have positive manifold pressure until your car is under load and you're off. The best you'll see on the start line is very little manifold vacuum - not boost. Just do it the way you described in your last sentence above and you'll be fine. Don't worry about tyre pressures or suspension for a while.

Sorry, not true. Not possible in a manual at *this* level. Free revving the car before leaving the line is a very silly way of working out what type of launch revs suit your car. Experiment with holding the throttle at different rpm and work out where you're quickest to 60ft.

Point noted, I probably should have been more direct and stated that this is not suited to all applications. The vehicle I am talking about is well over-tyred, is light, and isn't set-up to bounce off a rpm limiter on launch. Bringing revs up to a certain level does not bring on boost as well as a number of free (over)revs and then a launch with this vehicle. All best 60ft times have been recorded this way. A 1.47sec 60ft time is not too shabby for a street car :)

Most normal skylines would be better suited to find a rpm level that best suits there car, then launch.

Fixxxer

  • 1 month later...

hey mate,

if you having trouble with 60ft times, soften up the suspension if you can, lower your pressure to about 28psi, and launch (riding your handbrake if your not scared to) this will decrese the chance of crappy tyres wheel spinning!

im my 32gtst year ago, my best was 14.1 with front mount, pod, and cat back exhaust with 14psi.

then i started to launch harder and ride the clutch a little, got 13.9. then my old man has been around it for years, now builds drag cars, which i raced when i was yonuger, but he advised that maybe my tyres are shitty, and to use the handbrake... i tried it and it worked, went 3 separate time in my gtst, each time got quicker! 14.1, then 13.9, then after hard launches and handbrake riding, i got it down to 13.4 @ 98mph, 60ft - 2.003

my gtr now has run best of 11.7, but after this build it should be closer to high tens at 130mph or there abouts!

goodluck, and if you want any help or me to come and watch you launch etc, let me know! cheers, Garth

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • It would be well worth deciding where you want to go and what you care about. Reliability of everything in a 34 drops MASSIVELY above the 300kw mark. Keeping everything going great at beyond that value will cost ten times the $. Clutches become shit, gearboxes (and engines/bottom ends) become consumable, traction becomes crap. The good news is looking legalish/actually being legal is slighly under the 300kw mark. I would make the assumption you want to ditch the stock plenum too and want to go a front facing unit of some description due to the cross flow. Do the bends on a return flow hurt? Not really. A couple of bends do make a difference but not nearly as much in a forced induction situation. Add 1psi of boost to overcome it. Nobody has ever gone and done a track session monitoring IAT then done a different session on a different intercooler and monitored IAT to see the difference here. All of the benefits here are likely in the "My engine is a forged consumable that I drive once a year because it needs a rebuild every year which takes 9 months of the year to complete" territory. It would be well worth deciding where you want to go and what you care about with this car.
    • By "reverse flow", do you mean "return flow"? Being the IC having a return pipe back behind the bumper reo, or similar? If so... I am currently making ~250 rwkW on a Neo at ~17-18 psi. With a return flow. There's nothing to indicate that it is costing me a lot of power at this level, and I would be surprised if I could not push it harder. True, I have not measured pressure drop across it or IAT changes, but the car does not seem upset about it in any way. I won't be bothering to look into it unless it starts giving trouble or doesn't respond to boost increases when I next put it on the dyno. FWIW, it was tuned with the boost controller off, so achieving ~15-16 psi on the wastegate spring alone, and it is noticeably quicker with the boost controller on and yielding a couple of extra pounds. Hence why I think it is doing OK. So, no, I would not arbitrarily say that return flows are restrictive. Yes, they are certainly restrictive if you're aiming for higher power levels. But I also think that the happy place for a street car is <300 rwkW anyway, so I'm not going to be aiming for power levels that would require me to change the inlet pipework. My car looks very stock, even though everything is different. The turbo and inlet pipes all look stock and run in the stock locations, The airbox looks stock (apart from the inlet being opened up). The turbo looks stock, because it's in the stock location, is the stock housings and can't really be seen anyway. It makes enough power to be good to drive, but won't raise eyebrows if I ever f**k up enough for the cops to lift the bonnet.
    • There is a guy who said he can weld me piping without having to cut chassis, maybe I do that ? Or do I just go reverse flow but isn’t reverse flow very limited once again? 
    • I haven’t yet cut the chassis, maybe I switch to a reverse flow. I’ve got the Intercooler mounted as I already had it but not cut yet. Might have to speak to an engineer 
    • Yes that’s another issue, I always have a front mount, plus will be turbo plus intake will big hasstle. I’ve been told if it looks stock they’re fine with it by a couple others who have done it ahahaha.    I know @Kinkstaah said the stock gtt airbox is limiting but I might just have to do that to avoid a defect so it atleast looks legit. Or an enclosed pod so it’s hidden away and feed air from the snorkel and below Intercooler holes like kinstaah mentioned. Hmm what to do 
×
×
  • Create New...