Need help with 60's

JG33RD · 30-11-2011, 10:23 PM

Having really crap 60's I thought I might be able to get somewhere with carb tuning, however it seems my carb is not the problem, deatails are XB sedan approx 3200lb full manual c4 5000 stall (not built for this car) 3.7 rear 26" M/T drag can only manage about 2000rpm off the line without creeping out of stage, flashes to around 4500 (shed test only lol) shockes are competition engineering front and rear set 90/10 front and 50/50 rear, no noticeable wheelspin and can only manage a best of 1.9 flat with approx 500fwhp and 426ftlb. Any help appreciated.

FreddyDUZ747 · 30-11-2011, 10:37 PM

What rear brake setup do you run,is their a line lick used to clamp rear brakes?

What diameter and car did the convertor come from.

Are the 3.7's in their for possible NOS or just a street/strip compramise?

JG33RD · 30-11-2011, 10:50 PM

Drum rear's, I use a line lock to stop pressure to fron brakes. Diameter I'm not sure, maybe 10" came from an XP ute 530+hp, 3.7's are there because that's what I started with before the converter and extra torque/power. I have a mini spooled 4.11 to go in but thought I should get beter with what I have.

Work Horse · 30-11-2011, 10:59 PM

Quote:

Originally Posted by JG33RD

Drum rear's, I use a line lock to stop pressure to fron brakes. Diameter I'm not sure, maybe 10" came from an XP ute 530+hp, 3.7's are there because that's what I started with before the converter and extra torque/power. I have a mini spooled 4.11 to go in but thought I should get beter with what I have.

Do you mean the back brakes?

JG33RD · 30-11-2011, 11:02 PM

Yeah sorry, using it to stop rear brake lol

FreddyDUZ747 · 30-11-2011, 11:05 PM

Id get the 4.11's in if you still have 800-1000rpm useable power left when crossing the line in top gear.

So while staging and stalling her up you have eff all front brake pressure,is this correct?Try hooking it up to lock the rear brakes and leave front brake pressure normal.Have the switch setup to a purge button on the steering wheel and use it like a trans brake so to speak.Sounds like not enough rear brake pressure to stop the creep.Solution above fixed it for me

If its a 5000rpm stall then its no more than a 9"

Is it a nitros convertor by chance?

JG33RD · 30-11-2011, 11:14 PM

Freddy I have at least 1000 left up my sleeve just thought I should get better with what I already have (probably wishfull thinking) not wanting to F%^k around with brakes at the moment but thanks for the idea, definately not a gas converter. Thanks for your help, very much appreciated

FreddyDUZ747 · 30-11-2011, 11:16 PM

What drums are you running?

Disregard some of my last post as you changed the line lock thingy lol.I still think its a brake issue.Is the convertor a loose or tight 4500?

Work Horse · 30-11-2011, 11:18 PM

Line locks are designed to hold the front brakes on during a burnout so you don't fry your rear brakes. And stop the car creeping forward when staging.

I've not heard of anyone using a line lock on the rear brakes, but whatever works!

dieseltrain79 · 30-11-2011, 11:20 PM

YOu still want to use the front brakes to help it creeping .

However if its a 5k convertor and your creeping @ 2000rpm , you really need the extra front brakes to help hold it .

Flash and Stall are 2 different speeds . Maybe its designed to flash alot more ? Or your engine cant make the torque to make this convertor as loose as it was on the old engine .

I would try Freddy's suggestion with the brakes , but i would be throwing in the 4.1's in a heartbeat

Have you tried Sitting @ 1500rpm and then jumping on it ? Sometimes allowing the FLash to pul it out of the hole works . Just look at some bigger cube engines .

Otherwise Transbrake will sort it our once and for all ;)

JG33RD · 30-11-2011, 11:29 PM

Thanks DT, no haven't tried that yet, will do next time out. I've no doubt mine doesn't make as much tq as the engine/car it was built for (was just a lend me to try). $.11's will be in after xissy so do you think a 1.9 is acceptable whith my current combo?

JG33RD · 30-11-2011, 11:30 PM

Freddy i tink I calculated 10% slip

xdclevo · 01-12-2011, 12:06 AM

Quote:

Originally Posted by dieseltrain79

Have you tried Sitting @ 1500rpm and then jumping on it ? Sometimes allowing the FLash to pul it out of the hole works . Just look at some bigger cube engines .

Thats what i do, and found best ET. Probably around 1800-2000rpm, then hit it.

Quote:

Originally Posted by JG33RD

can only manage about 2000rpm off the line without creeping out of stage

Very weird that a convertor that flashes to 4500 will creep fwd at 2000rpm with brakes on?

JG33RD · 01-12-2011, 12:29 AM

Quote:

Originally Posted by xdclevo

Thats what i do, and found best ET. Probably around 1800-2000rpm, then hit it.

Very weird that a convertor that flashes to 4500 will creep fwd at 2000rpm with brakes on?

Shi7full brakes maybe.

Parfrey · 01-12-2011, 02:16 AM

Not sure what handbrake setup you have, but I use the handbrake as well in my EF, could only get about 1psi off the line without it and now i can get 5psi.. 1.81 60' on a stock stall.

jcxr · 01-12-2011, 11:43 AM

Quote:

Originally Posted by Parfrey

Not sure what handbrake setup you have, but I use the handbrake as well in my EF, could only get about 1psi off the line without it and now i can get 5psi.. 1.81 60' on a stock stall.

How do you use a handbrake and also have a safe tension on your seat belts?

dirty · 01-12-2011, 08:43 PM

Drag racing in group three is all about being consistant, not fast. Of course we all can't resist the urge to go faster, and to improve the combo to it's best, and thats great. Consistant cars win meetings though.

X2 for stage it at 1500 or even 1700, just find a rev level that is easy for you to do. Very hard to cut a good light when you are fighting with the car to hold still, not to mention that you are probably giving yourself a different rollout every run and that changes your RT.

dieseltrain79 · 01-12-2011, 11:08 PM

If its leaving the line @ 2000rpm which is way under the torque curve , your probably finding it lazy out of the hole which is why its not cutting the 60's .

If you try less revs and allow the " flash " to pull it out of the hole , being up around 4k+ should pull it out and get into the 1.7's or even 1.6's .

If my little 150 cuber ( yes 2.5L ) 6 cylinder with some boost can run 1.60 60's on radials ( with more in it ) weighing 3680 pounds with driver , surely yours can get very close to matching that

Good luck next time out . Boosted cars are very different to N/A cars . Boosted cars dont just need rpm , they just need boost . N/A cars need the rpm and to be in the Torque curve well and truly , to pull the lump out of the hole .

Mates Cortina with a windsor has gone 10.9 on radials using just 1800rpm then flashing ( bout 3500-4000rpm ) . Its gone flat 1.6 60's .

JG33RD · 02-12-2011, 11:38 AM

Thanks dirty and DT, definately will try that idea and see how it goes. At the moment I don't race comp only the street meets as they call them here, although I wan't to be consistant I'm more interested for now in seeing what I can get the et's down to. It's about having fun for me but the poor 60's aren't making me smile lol the car really hooks in when I change into 3rd but there is no road left and the rev's are just starting to climb. I had talked to a local racer about it before and he told me a few things which got my et's from a 13.1@106 with a 2.02 60' to the current pb of 12.61@108 with a flat 1.9 60' never changed anything apart from the way I drove it so it shows that advise/ideas are invaluable, so thanks to all those who gave advise and ideas. Will hopefully getting a run next Saturday so will post up the results then.

drcoupe · 25-12-2011, 11:42 PM

G'Day JG33RD

Did you have any success with improving your 60' times?

DR

JG33RD · 27-12-2011, 09:33 AM

No DR, didn't get there. Got called out to work and the weather was looking sus anyway, I think it got cancelled so was better off at work making money. Local track hasn't posted a new calendar yet so have to wait and see, hopefully I can get a run in soemtime in Jan, if the weather holds out (which I doubt). How about you, ran that 11 yet?

JG33RD · 08-01-2012, 01:17 AM

Got some passes in tonight, new pb's 12.48@108.69 1.831 60', new best mph of 12.82@109.75 2.1 60'. Tried launching from 1500rpm but didn't seem to work, I think that's more my burnouts at fault threre, first pass tried that but no time slip given the next time I tried I got the 2.12 60' but ran 109? The best 60' was leaving the line the way I have sone before but my burnout was a bit more intense, it may be the burnout that it causing my bad 60' times. Anyway I'm happy with the times I have with the gears currently in the rear and thanks for the advise given by everyone. Will be changing to the 4.11's and giving the tyres a bit more curry in the future.

JG33RD · 08-01-2012, 01:19 AM

I forgot to mention, the convertor seemed to be flashing to around 4000-4200 not 4500.

drcoupe · 08-01-2012, 09:16 PM

G'day JG33RD

Great to see you are making progress, do you mean by the burnouts that you are having traction issues?

DR

JG33RD · 09-01-2012, 09:18 AM

Quote:

Originally Posted by drcoupe

G'day JG33RD

Great to see you are making progress, do you mean by the burnouts that you are having traction issues?

DR

I didn't think I was but it seemed when I did my burnout up to the line the car seemed to hook up better. I hope going to the 4.11's I can pick up 1-1.5 tenths at the 60' which should see at least that in the ET. I remember reading someones post in another thread saying what ever you can take off your 60' you can double that and take off your ET, I hope that's right. My best previous was 1.9 60' and 12.61@108.69 my best from Sat night was 1.831 60' and 12.48@108.69, worked the numbers out on the calc and what I gained on the 60' x2 and sub from the ET worked out to 12.47! So it seems there may be some truth in that statement.

F6 JET · 09-01-2012, 10:45 PM

when u say its creaping is that with front brakes locked?

how big is ur cam? do u have enough vac pressure in the bootser to hold the fronts on lock to get it up to stall

vac tank might be a good option and cheep it ur fronts arent holding ya

JG33RD · 10-01-2012, 05:27 PM

Yeah with front brakes locked although they are just cheap standard pads, I remember someone else posting about using different pads for foot brake starts. Don't know about booster vaccum, what's involved with a vac tank? Cam is Howards 296/306 .630/.644 adv 104 I/cl not sure if that's the specs you're after.

F6 JET · 11-01-2012, 06:01 PM

if its to lumpy it wont hold enough vac in the booster for the brakes to clamp hard enough a vac tank is like less than $150 and hold a decent amount of vacuume so the booster will hold pressure

its very common with big cam set up's and creeping through traffic by the 3rd brake press at the lights its usually creeping on ya on the street

so do u have enough force to lock the wheels at the staging lights or is it creeping ie still moving?

just a thought thats all

JG33RD · 11-01-2012, 07:48 PM

Not sure if I fully understood that F6 but I don't have any trouble holding it in stage below 2k rpm, it's only when I try to get the thing launching closer to the "stall" speed that it wants to creep through the stage beam. I understand there is a difference between stall and flash speed and I stated before I thought it flashed to 4500 which isn't right it's closer to 4200. Thanks for the info on the vac tank, might have to keep that in mind also.

F6 JET · 11-01-2012, 09:06 PM

ok when u stall it up will the front tyres slide (locked) or roll like ur letting the brake off?