you guys are all missing the point apart from steady and eed. If i put a 3.45 in it as is the ratio for 1st would totally f**k up my times on the 1/4. it would be up to 5000rpm in 1 second! the T5s for EAs have a really short ratio for 1st gear.

Whats involved in water injection?

AND IT ISNT AN AUTO!!! lol

s**t for brains. hmm lets look at s**t for brains...


one have you seen how tall the tyres are on a doorslammer? or what sort of rpm they run?? obviously not.
leaving the 2.92 gears in there mean one less gear change wich up to a point will be better then the having to change for the extra gear you need with 3.45 gears.

How much water do you think it will take to control knock at that sort of compression with a stock ECU, keeping in mind that water does not burn and the more you put it the less space there is for the air fuel mix.

the other reason no one ups the comp is because to get 11.5:1 with the stock pistons needs alot of metal taken from the head face. this brings valves and spark plugs closer to the piston, that will limmit the sort of cam you can run and/or being able to dial the cam properly
it also reasults in the timing chain being to long, causing it to rattle and flog the guides out.

and no im not changing the interior for the last f**k time. Its Poo brown and its staying Poo browne we are talking Performance here not interior

his car is not a doorslammer tool, it has to have some form of drivability / economy and run well on normal unleaded.

Do you think thats why not many people here run 11.5:1 + comp ratios and 5.33 + diff ratios?

im guessing you were the mechanic?

you do have a point, but 11.5:1 compression isnt all as high as you think! If a head's blueprinting is brought up to pro-stock standards (98% i think it is), 11:1 is not an issue!, you may even bump it up to 12:1 if done properly WITHOUT water injection, using right cam, etc...

The VALVES will NOT be touching the cylinder at that compression ratio, nor will the pistons haveto have domes. Dorrslamers run around 10:1 compression and have a valve lift of OVER 1 inch! using flat top pistons! a hot cam on a falcon 6 will rarely see a 600 though lift.


a small example here: my uncle has completely moded a 265 Valiant HEMI inline 6...he brought the compression ratio up to 12:1 using no water injection.....after it was run in abit, he was able able to take it up to 6500 untill it was pinning!...being afraid of the consequences he lowered it to 11.5:1 comp and takes the motor up to 7000rpm.....150000km's later (today) this engine still purrrsssss ... this result was achieved because of the blueprinting of the head which took over 1 month for him to complete

now the reason why i said water injection is just to keep it on the SAFE side (and since you will nobviously not blueprint the head, coz no one can be fkd)

im not pulling this idea out of my a**...people have done this and it works FANTASTIC!

I think you need to clarify here mate.

Obviously you are looking at getting a better quarter mile time and nothing else? So obviously, shorter diff gears (i.e 3.7's) aren't necessarily going to equal better quarter mile times.

For the money, cam selection would be what I would look at next. I don't know what the specs are on your cam you already have, but if it's good for low down grunt, ditch it for a cam that will give you power between 3,000 ish - 5,500 rpm as this is the rev range you are opperating in when dragging.

LSD is also something you should look at (don't know if you have a single spinner or lsd??)

Another area that gets overlooked is tyres. I'm not a tyre expert, so I don't know what to reccomend...

Failing that, I reckon the low blow turbo set-up is still the way to go...

save up more and slap a charger on it.

no i wasn't the mechanic

it's just that from what you keep posting you know very little about these engines, and what with the reference to doorslammers? the engine used have nothing in common with this engine and the valve lift they use cannot be compared.

Have you ever had any personal expiriance with these engines? ever taken to one with proper messureing equipment? to check these things?
ever built one? ever modded one your self?? untill you have, becareful of the 'advice' you give out

by the way full lift has fu#k all to do with it. it's the lift around TDC that causes problems.

the stock pistons are dished not flat. using flat tops would be enough to reduce the problems to a reasonable point but the only flat tops are made for the AU long rod. best you can get for the short rod is 5cc and thats only 3cc less then a stock EF piston. beats the EA by 10cc but the EA started with 8.8:1 one and uses a chamber volume very close to later head anyway.

Last edited by tickford_6 on Sat May 13, 2006 7:52 pm, edited 1 time in total.

he has a stage 3 crow cam which is pretty big as it is..
14.8@96mph.. hmm
what was your 60'? i bet it was about 2.3? maybe 2.4? which is pretty bad. Im running a combo in my car with less power and doing 2.10 60 foot times. Due to a 3.45lsd. I had a 3.08 ss before and couldnt get under 2.3.. dropped the 3.45lsd in and wam striaght away a 2.1 and shaved .4 off my 1/4 mile.
I think you will find if you can get ur 60 down to 2.1 or lwoer you will gain at least .2 of a second down the 1/4.

i have a 3.45lsd and find that i am running at about 4200 rpm across the line. Compared to a 2.92 where you would be on powerband peaking 3rd gear. Which is why the 2.92 diff is a good ratio... especially with the price of fuel

I would definatley reccommend a set of 3.9's which will find you peaking 4th gear across the line ultimatley cutting a few tenths of ur time aswell.

Your car has heaps of potential southy and $1000 on a 3.9lsd would definately net you a 14.6 at LEAST!! You could spend 1.5k-2k on an aftermarket computer run a good tune and go quicker.

That would be definately what i would do!

Stupid question time :

Is that 4200rpm in third? If so, what is your KPH at the 400 metre mark?

no 4th.
the extra gear change is a pain. even tho its a quick flat change.

my kph is 146.. or 91.2 mph.. compared to southys 96mph.. even tho i ran a slightly quicker time then him.

He needs to get his launch sorted out obvciously.

These are my Specs For My 14.8 Time:

Reaction time: 0.8376
60ft: 2.3690
330ft: 6.3652
660ft: 9.6919
660mph: 74.31
1000ft: 12.5204

ET" 14.8

1/4 mile MPH 96.82

So iv obviously got heaps of Top End power from looking at my MPH but maybe i need to improve on low down acceleration somehow?

Heathcoat? Have you ever seen a black supercharged VX Calais run?

yeah i thought so. u need to sort out ur launch... so definately a 3.9lsd mate unless ur concerned about fuel prices?
i THINK rollin says he does 2300rpm 5th gear @ 100kmh wich isnt really that bad. but ur 60 foot is poor because of the single spin diff basically.
how are you launchin?
I slip the clutch from 4000rpm to get my 2.1

what have u got in mind so far? id love to see ya go faster.