Faster 60foot time?

Please use This Area For Telling Us About Your 1/4 Mile Times ONLY, Any Non Related Postings Will Be DELETED By Me Or Moderators!!!

Moderator: phpBB2 - Administrators

User avatar
JSF55
Gold Member
Gold Member
Posts: 971
Joined: Mon Dec 04, 2006 4:15 pm
Location: Swansea
Contact:

Faster 60foot time?

Post by JSF55 » Mon Jul 05, 2010 1:51 pm

Right the 60foot time on the pop is crap at 2.524 :( so what technique do i need to get 1300kg of steel off the line quicker, it runs a 4 speed hp22 box gearing works ot at about 20mph/1000rpm in 3rd which tops out at about 88 over the quarter. Is the convertor stalling out too low? i think i can just about hold it on the brakes at about 1600rpm. after that the front tyres give up :lol:


So thats where it went !

User avatar
kiwicar
Moderator Gold
Moderator Gold
Posts: 5461
Joined: Sat Nov 18, 2006 5:00 pm
Location: Milton Keynes

Post by kiwicar » Mon Jul 05, 2010 2:56 pm

As far as I see it there are three factors here you can change to effect your 60
1 Grip
2 Torque band
3 reaction time in getting the brakes fully off

If you are spinning wheels off the line then you need more grip, this can be helped with anti squat suspension geomitry (if it is a 4 or 5 link set up). Anti tramp bars and slapper bars and moving shock mountings about if you have cart springs locating everything.
If you have enough grip and you aren't spinning wheels then you need more torque or be better placed in the torque band. Where is peak torque on your engine? how many revs do you have between the engine peak torque and peak power? A looser torque converter will give you more torque off the line, but if you are bearly able to hold it on the brakes on the line you may want to upgrade a bit before you fit a looser torque converter, also if you do you will probably want to gear it up a bit so you don't run out of revs at the top of the track and to make use of that part of the power curve off the line.
For the last one, light weiight footware and more caffine.
poppet valves rule!

mgbv8
Gold Member
Gold Member
Posts: 5326
Joined: Sat Nov 18, 2006 7:57 pm

Post by mgbv8 » Mon Jul 05, 2010 3:25 pm

What is the stall speed of the convertor? If its a road use one I suspect it might be around 1700rpm. I use a 3000rpm stall convertor.

If you have a low stall convertor and your engine responds well when going to full throttle instantly from idle, you could try launching from idle rpm. This will give the engine a bit of a run up before it hits the stall speed and may get you away a bit quicker. The downside may be less fuel economy on the road.

Is it the front tyres losing grip or are the brakes slipping a bit?

I use slicks on the rear and launch with nitrous so I can hit 60 foots around the 1.5-1.6 area.

As Mike says, you need to know where the engine is making its best torque so you can utilise this for better gear shifts.

User avatar
Coops
Site Admin
Site Admin
Posts: 6142
Joined: Fri Nov 17, 2006 7:43 pm
Location: Newbury, Berks
Contact:

Post by Coops » Mon Jul 05, 2010 3:40 pm

i was running 2.3ish 60fts
changed to a pair of BFG drag radials and went straight to 1.8 60fts
Regards Tony C (COOPS)
Image
MS2 V3.57 Ecu mapable efi and wasted spark ignition.
Rotrex C38-91 supercharger and Cossie RS500 Intercooler @ 14psi of Boost. 404 RWHP, (4.6)
New Forged 4.8 V8 kitted out with the dogs Cajones of parts and a procharger D1SC. 2017 :D
Sponsored by: www.v8performanceparts.co.uk, www.interpart.biz, www.caprisport.com & www.baileyperformance.co.uk

User avatar
kev_the_mole
Gold Member
Gold Member
Posts: 1022
Joined: Sat Nov 18, 2006 9:41 pm
Location: Las Islas Purbequias

Post by kev_the_mole » Mon Jul 05, 2010 4:00 pm

I was thinking of improving my times by launching from an Acme Bungee Catapult. I've seen Wile E. Coyote do it and I know there's no cliffs near Podington :D
Image


It's an engine Jim.....but not as we know it ;)

DaveEFI
Forum Contributor
Forum Contributor
Posts: 3860
Joined: Fri Feb 26, 2010 4:27 pm
Location: SW London, UK

Re: Faster 60foot time?

Post by DaveEFI » Mon Jul 05, 2010 4:03 pm

JSF55 wrote:Right the 60foot time on the pop is crap at 2.524 :( so what technique do i need to get 1300kg of steel off the line quicker, it runs a 4 speed hp22 box gearing works ot at about 20mph/1000rpm in 3rd which tops out at about 88 over the quarter. Is the convertor stalling out too low? i think i can just about hold it on the brakes at about 1600rpm. after that the front tyres give up :lol:
Torque converter stall speeds are usually over 2000 rpm.
Dave
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y

User avatar
JSF55
Gold Member
Gold Member
Posts: 971
Joined: Mon Dec 04, 2006 4:15 pm
Location: Swansea
Contact:

Post by JSF55 » Mon Jul 05, 2010 4:15 pm

I didn't expect so many replies so soon ! there's no tyre slip, my mate confirmed this, the car squats down and goes ! it's a full jag irs in there ... heavy :( tyres currently at 20psi bf goodrich something or others :?
The fronts are quite skinny 145x15 firestone 560's, they loose grip before the brakes will ! torque should be low down the rev band, hurricane cam rhodes bleed down lifters, standard SD1 exhaust, well to the Y piece anyway :lol: upgrade planned over the winter is too slot in a 3.9, so i might just have to curb my enthausism ....... mmmm ....nitrous :twisted:
So thats where it went !

User avatar
gelmonkey
Sergeant Monkey Face
Posts: 1304
Joined: Sat Jun 27, 2009 11:58 am
Location: plymouth

Post by gelmonkey » Mon Jul 05, 2010 7:08 pm

kev_the_mole wrote:I was thinking of improving my times by launching from an Acme Bungee Catapult. I've seen Wile E. Coyote do it and I know there's no cliffs near Podington :D
Mr Mole
You do make I larff.
Not really much help to JSF I'm sure but worth a thought though.


JSF nitrous it is then :D

cheers
Paul

User avatar
JSF55
Gold Member
Gold Member
Posts: 971
Joined: Mon Dec 04, 2006 4:15 pm
Location: Swansea
Contact:

Post by JSF55 » Mon Jul 05, 2010 7:56 pm

mgbv8 wrote:
If you have a low stall convertor and your engine responds well when going to full throttle instantly from idle, you could try launching from idle rpm. This will give the engine a bit of a run up before it hits the stall speed and may get you away a bit quicker. The downside may be less fuel economy on the road.
Thats interesting, as i've always held it on the brake and given it about 1500 rpm launches, i got an old video fromm shakey HRD 07
So thats where it went !

mgbv8
Gold Member
Gold Member
Posts: 5326
Joined: Sat Nov 18, 2006 7:57 pm

Post by mgbv8 » Mon Jul 05, 2010 9:02 pm

This was just over a year ago. Before I started running more nitrous. I used to bring the revs to about 1000 and then smack the pedal down as soon as I saw the 3 ambers. This picked the revs up quick and seemed to hit the stall speed of the converter to give me a good shove off the line. Now I have plenty of gas on tap to launch at high rpm without bogging.


User avatar
ian.stewart
Moderator
Moderator
Posts: 2419
Joined: Sat Nov 18, 2006 1:59 pm
Location: Far Far south, any further south and my feet are wet

Post by ian.stewart » Tue Jul 06, 2010 5:14 am

5k launches, Toyo 888Rs, and 1.5 60 fts ------------------ but it is a manual car
THE SMOKING GNU
12.604 with an old boiler of a RV8 and no gas
WHY are there so many IANS on this site???????

User avatar
kev_the_mole
Gold Member
Gold Member
Posts: 1022
Joined: Sat Nov 18, 2006 9:41 pm
Location: Las Islas Purbequias

Post by kev_the_mole » Tue Jul 06, 2010 9:00 am

Ian,

what's your technique from first to second. Speaking with an old-skool racer last night he reckoned that get it moving in first and then slam into second. No point in maxxing it in first otherwise you just get more wheelspin.

Cheers,

Ian

PS This year I've got 888R SG's
Image


It's an engine Jim.....but not as we know it ;)

User avatar
kiwicar
Moderator Gold
Moderator Gold
Posts: 5461
Joined: Sat Nov 18, 2006 5:00 pm
Location: Milton Keynes

Post by kiwicar » Tue Jul 06, 2010 10:39 am

Hi
If it is holding against the brakes at 1600 rpm, doesn't that make the stall speed of the converter about 1600 rpm or did I miss somthing?? If the rear tyres are not slipping then from a purly mechanical view point it would seem a good idea to put in a higher stall converter, say 2600 stall, then he should be within 1400 revs of peak torque and be off the line much quicker, once some way has been found to get the front tyres to hold it (big bag of cement behing the radiaror?). If the back end is squatting prior to launch it might be worth raising the front end mounting points of the lower trailing arms locating the rear suspension.
Best regards
Mike
poppet valves rule!

DaveEFI
Forum Contributor
Forum Contributor
Posts: 3860
Joined: Fri Feb 26, 2010 4:27 pm
Location: SW London, UK

Post by DaveEFI » Tue Jul 06, 2010 11:06 am

kiwicar wrote:Hi
If it is holding against the brakes at 1600 rpm, doesn't that make the stall speed of the converter about 1600 rpm or did I miss somthing?? If the rear tyres are not slipping then from a purly mechanical view point it would seem a good idea to put in a higher stall converter, say 2600 stall, then he should be within 1400 revs of peak torque and be off the line much quicker, once some way has been found to get the front tyres to hold it (big bag of cement behing the radiaror?). If the back end is squatting prior to launch it might be worth raising the front end mounting points of the lower trailing arms locating the rear suspension.
Best regards
Mike
I got the impression the brakes wouldn't hold it above 1600rpm. So keep well away from the end of the strip. ;-)
Dave
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y

User avatar
JSF55
Gold Member
Gold Member
Posts: 971
Joined: Mon Dec 04, 2006 4:15 pm
Location: Swansea
Contact:

Post by JSF55 » Tue Jul 06, 2010 11:13 am

kiwicar wrote:Hi
If it is holding against the brakes at 1600 rpm, doesn't that make the stall speed of the converter about 1600 rpm or did I miss somthing?? If the rear tyres are not slipping then from a purly mechanical view point it would seem a good idea to put in a higher stall converter, say 2600 stall, then he should be within 1400 revs of peak torque and be off the line much quicker, once some way has been found to get the front tyres to hold it (big bag of cement behing the radiaror?). If the back end is squatting prior to launch it might be worth raising the front end mounting points of the lower trailing arms locating the rear suspension.
Best regards
Mike
Ideally a higher stall speed would help, just not sure whats available for the zf4hp22, i heard they come in small medium and large :shock: the front tyres are the reason it slipped over the lights in the video, not the brakes :lol:
So thats where it went !

Post Reply

Return to “1/4 Mile Times”

cron