1/4 mile question??

**Stav** · 16-06-2005, 07:51 PM

What is the most important time for a racer in a 1/4 mile race?

Is the 0-100 speed indicative of a great 1/4 mile time or is it the power between 100 +which really makes a difference pulling the car to a great time?

Racecraft · 16-06-2005, 07:53 PM

the 60ft and mph is the key

**Stav** · 16-06-2005, 08:00 PM

So the quicker 60ft (18.28 metres) plays a big part? So would it be the best starting point to concentrate on 60 ft times on a six? If 60 ft times are great does this normally mean a great 0-100 and better 1/4 mile?

Racecraft · 16-06-2005, 08:04 PM

normally, if you can get the car off to a good launch the ET will be good. Saying that though a slow 60ft time but a healthy mph shows the car has good power and in an ideal world could run a better ET.

MO · 16-06-2005, 08:06 PM

And don't wheelspin when launching,maintain traction at all times.

**Stav** · 16-06-2005, 08:11 PM

So a car like mine which now puts out a respectable 137rwkws can benefit from all of the torque possible in the low to mid ranges??Right?

EFFalcon · 16-06-2005, 08:15 PM

it depends.
a 6 with a stock cam and stock stall will have a better 60ft time then a car with wilder cam and stock stall, simply due to the design of the cam and its peak power ranges.

mcflux · 16-06-2005, 08:21 PM

and having an awesome 0-60ft time would mean nothing if the car is geared so shortly that it's bouncing off the limiter 3/4 down the track (although in your case this won't happen!)

There are so many factors to consider...

**Stav** · 16-06-2005, 08:23 PM

Quote:

Originally Posted by EFFalcon

it depends.
a 6 with a stock cam and stock stall will have a better 60ft time then a car with wilder cam and stock stall, simply due to the design of the cam and its peak power ranges.

I have finally dialled the cam in and it has noticeably taken away some low end.I have recorded the wrong setting.At this setting my car felt like a line munching machine despite the less than expected peak power.The gtech will tell me how good it is at the moment. Ilike hearing your experiences because it gives me good ideas. It is true that the more low down torque and engine produces that the stall speed goes higher than a lumpy butt cammed engine.

**Stav** · 16-06-2005, 08:26 PM

Quote:

Originally Posted by Ghia5L

and having an awesome 0-60ft time would mean nothing if the car is geared so shortly that it's bouncing off the limiter 3/4 down the track (although in your case this won't happen!)

There are so many factors to consider...

Yes I agree with that .What I am intersted in is the engine power characteristics which make the car respectable.Does it sound to you that the line munching feeling I had is a better state of tune than the gluggier low down state of tune?

**Falcon Coupe** · 16-06-2005, 08:31 PM

Remember MPH is your HP, ET is only how you lay down the HP. MPH is everything.

EFFalcon · 16-06-2005, 08:34 PM

i'd still prefer a 12 second ET
then a 13 second ET while wheel spinning the first 1/8th track :P
as good as MPH is... its only gunna get u killed ;)

**Stav** · 16-06-2005, 08:39 PM

Quote:

Originally Posted by Falcon Coupe

Remember MPH is your HP, ET is only how you lay down the HP. MPH is everything.

I am limited in power.
True.My little bro has a bmw that put out 135 rwkws on the same dyno.Those things do 14 second quarter miles..its a 330ci coupe. Becuase I am limited in power I wonder if should stop worrying about getting more power or simply spend a day at a private track fiddling with cam settings,intakes and checking times. Adjust ,then time and see the differences.Adjust see time and then move to a better medium.?? What do you think?

mcflux · 16-06-2005, 08:43 PM

Quote:

Originally Posted by useless

Yes I agree with that .What I am intersted in is the engine power characteristics which make the car respectable.Does it sound to you that the line munching feeling I had is a better state of tune than the gluggier low down state of tune?

I tried to sound as sage as possible but you called my bluff! BAH! :monkes:

Well with a cammed six its power band will tend to be shifted higher up in the rev range. Ideally I suppose you should decide on your gearing, then see what gears/revs will be most common down the 1/4, and then cam it/tune it to match. But that's being short-sighted and focusing on the 1/4 only.

I don't want a 1/4 mile king, otherwise I would've bought a blown-350-equipped torana with some crazy gearing like a powerglide & 4.11 or shorter diff gears :P (or a rotary! or a turbo bike!) So in reality, my heavy Ford will score some 3.7 gears for a balance between street and acceleration ;) At the moment I can pull 108kph in 1st gear

: so she's hardly quick from takeoff!

-Dave-

mcflux · 16-06-2005, 08:45 PM

Quote:

Originally Posted by useless

.its a 330ci coupe.

(off topic) mmmm who else thought of a BA BOSS powered XA-C coupe when you read this?

:

**Stav** · 16-06-2005, 08:47 PM

Quote:

Originally Posted by Ghia5L

I tried to sound as sage as possible but you called my bluff! BAH! :monkes:

Well with a cammed six its power band will tend to be shifted higher up in the rev range. Ideally I suppose you should decide on your gearing, then see what gears/revs will be most common down the 1/4, and then cam it/tune it to match. But that's being short-sighted and focusing on the 1/4 only.

I don't want a 1/4 mile king, otherwise I would've bought a blown-350-equipped torana with some crazy gearing like a powerglide & 4.11 or shorter diff gears :P (or a rotary! or a turbo bike!) So in reality, my heavy Ford will score some 3.7 gears for a balance between street and acceleration ;) At the moment I can pull 108kph in 1st gear

: so she's hardly quick from takeoff!

-Dave-

Being a daily driver and alround car + auto I will be looking for that fat torque curve.I think this will show up in better times.

stockstandard · 16-06-2005, 09:37 PM

I dont think that any amount of fine tuning cam timing is going to get much better times unless the cam is way out (which yours shouldnt be now). I am no 1/4 mile expert, but when it comes to auto's I think the key is just to get of the line as hard as possible without smoking it up (a little wheelspin isnt that bad) and then keep the hammer down. Gear ratios and stall convertors will help you do this!

My 1/4 mile times are an example of what you dont really want - cossed the line at 95mph showing I have got good power for a NA I6, but with a relatively slow ET of 14.8 showing that I couldn't get that power down well (3.08 open wheeler diff). If I matched the gear ratios with the engines power band I would have a much better ET.

**Stav** · 16-06-2005, 09:40 PM

Lets face it...an i6 can only make so much power even with a full rebuild. 200 rwkws on a normally aspirated six doesnt happen...So I think this the way to go test then time it!!!The dynos are a great tool but dont necessarily give time improvements on mods.

**Stav** · 16-06-2005, 09:44 PM

Quote:

Originally Posted by stockstandard

I dont think that any amount of fine tuning cam timing is going to get much better times unless the cam is way out (which yours shouldnt be now). I am no 1/4 mile expert, but when it comes to auto's I think the key is just to get of the line as hard as possible without smoking it up (a little wheelspin isnt that bad) and then keep the hammer down. Gear ratios and stall convertors will help you do this!

My 1/4 mile times are an example of what you dont really want - cossed the line at 95mph showing I have got good power for a NA I6, but with a relatively slow ET of 14.8 showing that I couldn't get that power down well (3.08 open wheeler diff). If I matched the gear ratios with the engines power band I would have a much better ET.

I think you are right.Getting the max power to the ground without wheelspin is the ticket to a quicker car.Or a manual conversion for the AU.I was shocked to find that from manual to auto the difference can be 15rwkws !!So for the price of the conversion I would be getting better power to the ground and more control on takeoff.

EFFalcon · 16-06-2005, 09:46 PM

the power difference between a manual and a auto is not 15rwkw.

stockstandard · 16-06-2005, 09:49 PM

I agree. manual vs auto isnt 15rwkw (that would put a stock manual ef/el xr6 at around 125rwkw). Its more like 5rwkw peak power and I hear that somehow autos produce more torque down low for some reason (torque multiplication??). Manuals in general might have 15 more kw due to the fact that they are more likely to be modded (being a more sporty car).

**Stav** · 16-06-2005, 09:49 PM

how much do you think it is?Have you seen it?

**Stav** · 16-06-2005, 09:51 PM

Quote:

Originally Posted by stockstandard

I agree. manual vs auto isnt 15rwkw (that would put a stock manual ef/el xr6 at around 125rwkw). Its more like 5rwkw peak power and I hear that somehow autos produce more torque down low for some reason (torque multiplication??). Manuals in general might have 15 more kw due to the fact that they are more likely to be modded (being a more sporty car).

ok ..so just say I go the higher stall converter should I see an improvement or uncontrollable wheelspin?

EFFalcon · 16-06-2005, 09:54 PM

well that depends completely on ur car.
my car has no traction issues at the moment.
but it it did, and i added a stall, then i would have more problems..

**Stav** · 16-06-2005, 09:57 PM

My AU is a 1720 kg car. With the wrong cam timing it would smoke the tyres uncontrollably around corners like it was possessed.I think I liked it better that way ..it felt a crapload quicker despite its slightly lower power figure.

**Stav** · 16-06-2005, 09:59 PM

I have talked to some other au owners here in Sydney with much more power than me and from the sounds of it I will blow their doors off 0-100 kmph.Big power on dyno and a slug on the street.I suppose with a six cylinder we are somewhat limited to make the best of what we have..which isnt too bad when put to the ground properly.

Walkinshaw · 16-06-2005, 10:09 PM

DELETE ME

stockstandard · 16-06-2005, 10:09 PM

Quote:

Originally Posted by useless

I have talked to some other au owners here in Sydney with much more power than me and from the sounds of it I will blow their doors off 0-100 kmph.Big power on dyno and a slug on the street.I suppose with a six cylinder we are somewhat limited to make the best of what we have..which isnt too bad when put to the ground properly.

the only way to know is to take your car to the 1/4 and try them

I would say give your car a run as is. Your timeslip will let you know exactly where your actual strengths and weaknesses are. Then youll know what you should be putting your time and money towards improving.

If nothing else it is a hell of a lot of fun!

Walkinshaw · 16-06-2005, 10:10 PM

Get a decent suspension setup and tyres to eleviate your traction problems.

A very mild I6 needs all the low down power is can get to get a decent 1/4mile time. Trading 40nm down low for 10kw up top wont work for auto I6's.

**Stav** · 16-06-2005, 10:25 PM

Quote:

Originally Posted by Walkinshaw

Trading 40nm down low for 10kw up top wont work for auto I6's.

I agree.

Quote:

If nothing else it is a hell of a lot of fun!.

Yep I had gotten into a bit of a psychotic rut with power levels..now I see that Its better to smoke it a bit off the line with a smile then smile once a year on dyno day!!