Diff Gears or high stall for my car?

[dansedgli]

G'day guys,
I have a automatic turbo EB falcon as most of you know with about 200rwkw on a stock engine with 10psi.

At the last drag day it ran a 13.67 at 105mph. My 60' time was slow at 2.5.

What would be better to get my car off the line quicker?

Should I get a decent stall convertor or lower diff gears and why?
I will be going for more power soon as well, if that changes your answer.

Thanks guys
Dan

[EFFalcon]

my best 60 ft time is a 2.3 with the 3.45 LSD.. and my car was completely stock at the time..

[Casper]

diff, no brainer.
3.45 LSD, 2.20 60ft.

[xr8ute]

Was there much/any wheelspin with the 2.5 60 footer? What sort of rubber do you run?

My thinking may be off, but I would expect a higher stall converter would help more off the line assuming you have enough tyre for it.

Your current diff ratio is standard right? Is that 3.08:1?

[dansedgli]

Originally Posted by xr8ute

Was there much/any wheelspin with the 2.5 60 footer? What sort of rubber do you run?

I had no wheel spin at all I dont think using crappy old 14 inch 215 tires with 20psi in each. I was stalling it up to 1600ish rpm.

My thinking may be off, but I would expect a higher stall converter would help more off the line assuming you have enough tyre for it.

Your current diff ratio is standard right? Is that 3.08:1?

I have the standard eb2 3.27 non LSD.

It launches like a standard falcon auto.

[SpoolMan]

If you had no wheel spin with a 2.5, 60 foot time, you need something to get you out of the hole in a real hurry.
With 105mph it looks like you have decent amount of power, you need to get the revs up a lot more when leaving the line, get the power in more swiftly a Hi Stall would help there.
Not sure how big you can go before you have problems with the limp home mode.
You are going to need both diff and Hi Stall, and then more than likely you well need good tyres.
Question I have is what revs you stalling to when are leaving the line?
Do sit and spool the turbo right up before you leave the line?
When you get your 60 foot time right, your cars times are going to tumble.
105 mph suggests your car has much potential.

[toby123]

What RPM does your car start making boost? my car lost 2tenths off my 60' time just from going from 3.08's to 3.73's. I personally would do diff gears first as it may get up in the boost better just with that.

Toby

[AUIIIXR8]

STALL CONVERTER! If you don't have any wheel spin then the stall would be first. Best if you match it to your cam (or planned cam). Sylox put 3.9's in recently and went backwards. He had 3:45's as i do. His 60ft times were 2.33 average with 3.9 diff just as they were before change. I have a 2800 stall and my best 60 ft was 2.094. My worst on the night (3 runs) was 2.137. If your on a blower or turbo match your stall to your cam (peak torque) and take boost onset into account. Provided you have good tires your 60 ft will come down. 2.0 is possible. Hello 13.1 and possibly the magic 12's!!!!!!!! Do the diff second.
IMO high diff gears are for rev happy engines. the inline 6 is NOT rev happy. 3.45 after stall is an option though.

[dansedgli]

Thanks for the replies guys, I forgot about making this thread over the weekend.

XRFPV8 on my last few runs I was edging the rpm up by 100 each run. My last run was my fastest and I revved it to about 1650. Other than that on the street if I rev it over 1750-1800 the wheels will spin, my tires are a bit worse for wear though. I have replacements in the shed to go on. The turbo doesnt get much chance to spool under brakes.
With a 105mph trap speed what times do you think I would be able to run if I got my 60' down?

toby123- The car starts to make boost at about 23-2400rpm.

AU2XLSV8- Thats good to see your 60' times are so low and great to have a real figure from someone who has actually changed to a lower ratio.

It seems the stall convertor is a better choice than lower gears. Ill try and have the stally and an LSD in before the next drag day in april. Ill stick with the stock ratio for now.

Thanks for your help guys,
Dan

[eed-250]

105 is potential for a 12.

but 2.5 60 foot is really bad. Hope you can sort it out.

i heard the stall converters for the BTR 4spd are shit?
Id go with the higher ratio diff.
3.7s

[brenx]

High 12's are possible if you get the run perfect. I've ran 12.95@105.96mph. A highstall to get it up there spooling and some flash tyres and your set. Probably go faster ;)

Brenden

[AUIIIXR8]

Up to 2500rpm stall is fine on BTR. And boost is on at 2300rpm. She'll be making boost better. Do get a quality item though! I agree with brenx. 12's are possible with 105mph. This may even be higher with the stall.

[OED666]

I am not sure if Rollin is a member of this site yet, (he is a member of ff.com) and he has 3.9's like i do, and he has done a 1.9 second 60ft... and managed to run a 14.5. The best i have managed is a 2.15 60ft. Both of our cars are manual though.

What RPM does your car start to get on boost, as you wouldnt want it to be on or near boost when cruising on highway speeds, especially in the wet if you give it a little stick!!

[dansedgli]

If your just cruising it wont make boost. It drives like a standard car if you dont give it stick. It only makes boost when accelerating. I can do a burnout with no boost, it will boost and start spinning them then when I let the revs drop and sit at say 2000 it will stop boosting and keep spnning them as the load on the engine is too low.

When I race manual Gen 3's I wish my car was manual, they can launch so much harder than me and I always have to play catch up. I should be in front from the start, it would make races so much faster. The high stall should fix that.

Ill be stoked if it goes faster, thanks for the advice guys. Ill look into getting a standard 3.27 or even an XR6 LSD and get a stall for it after its dynoed next so I can get an appropriatly sized one.