What Can I Do To My Diff

[altezzaclub]

I'm getting 1.5" stainless steel tubing from my dads work I'm learning to weld like a master from my dad best mate and I'm skiming the head once i have the money to do so and down draft webbers and i have my cert 1 in auto motive

 

Great! Get a set of extractors, the 4-1 are the most common, and then go 2" to the resonator under the passenger's seat and 1&3/4" to the back. Guys use 2" all the way through as well, so whatever you reckon.

 

Any idea of how much you're going to take off the head? I had 15thou skimmed off mine, but I haven't got it back together to try it out yet. If I was building a weekend warrior instead of my daughter's road car I'd take off at least 20thou. That will need to be ported and matched to the inlet and exhausts too.

 

Then get the cam ground to suit your plans for the car. Either good mid-range torque or aim for higher revs if that's where you'll be driving. There are 7 or 8 companies cut cams for them in Aussie.

 

Side draught carbs will cost more but produce more grunt. If the weekend racing is more important than driving it to work you'll eventually need a pair of side draught Webers. A great option would be the quad carbs off a motorbike if you have a good engineering workshop behind you!

 

Somewhere in there have your dad skim the flywheel at his work and take 2 or 3Kg off it, that always helps.

 

That will give you the best power for buck. You can get more, but every extra bhp will cost twice as much as the last. Somewhere on here are the dyno figures for various people's 4Ks, but basically if you get 70RWKW you'll have one of the best in the club!

 

While you're earning the cash for this keep your eyes out for Corona lower control arms & lowered springs to suit the height you want. Fit them in somewhere along the way and you'll have handling to match the increased power.

 

Then you can go get an LSD diff out of a van at a wrecker and fit it!

[azzy_10]

Great! Get a set of extractors, the 4-1 are the most common, and then go 2" to the resonator under the passenger's seat and 1&3/4" to the back. Guys use 2" all the way through as well, so whatever you reckon.

 

Any idea of how much you're going to take off the head? I had 15thou skimmed off mine, but I haven't got it back together to try it out yet. If I was building a weekend warrior instead of my daughter's road car I'd take off at least 20thou. That will need to be ported and matched to the inlet and exhausts too.

 

Then get the cam ground to suit your plans for the car. Either good mid-range torque or aim for higher revs if that's where you'll be driving. There are 7 or 8 companies cut cams for them in Aussie.

 

Side draught carbs will cost more but produce more grunt. If the weekend racing is more important than driving it to work you'll eventually need a pair of side draught Webers. A great option would be the quad carbs off a motorbike if you have a good engineering workshop behind you!

 

Somewhere in there have your dad skim the flywheel at his work and take 2 or 3Kg off it, that always helps.

 

That will give you the best power for buck. You can get more, but every extra bhp will cost twice as much as the last. Somewhere on here are the dyno figures for various people's 4Ks, but basically if you get 70RWKW you'll have one of the best in the club!

 

While you're earning the cash for this keep your eyes out for Corona lower control arms & lowered springs to suit the height you want. Fit them in somewhere along the way and you'll have handling to match the increased power.

 

Then you can go get an LSD diff out of a van at a wrecker and fit it!

 

if i go to 2" would there be enuff back pressure from the 3k-c

[ke70dave]

dude please do not post again like that, it takes an extra 0.5secs to write a PROPER post with good punctuation and spelling. you can't expect people to put much effort into replys if your not putting the effort in yourself.

 

have a read of this

 

http://www.rollaclub.com/faq/index.php?tit...a_tough_K_motor

 

and once you have read it all, get back to us with further specific questions.

 

good luck!

 

also you don't want back pressure, the reason that making an exhaust pipe to big is bad is becuase the smaller the exhaust pipe is the greater venturi effect is present.

 

ie, when gases flow through a pipe, the gas at the exiting end tends to "suck" the gases through the pipe, and gives a bit more power due to the exhaust being "sucked" away from the engine. if you make the pipe to big for the amount of gases you are flowing (ie 5" exhaust on a 3k) there is not enough gas to create the ventur effect, no sucking of exhaust, less power!

Edited March 20, 2010 by ke70dave

[nickkkk]

if i go to 2" would there be enuff back pressure from the 3k-c

 

 

 

 

i put a 2 inch exhaust on my ke26 wagon with a free flow muffler

it went heaps better and to loud so i added a hot dog at the front

and yep its worth it, people can't beleve its only a 3k engine it flies

[Doogs]

also you don't want back pressure,

 

This is not entirely true. In a mild street build you do still want some back pressure for torque in the low and midrange. Obviously if you fit extractors you want them to be less restrictive than a standard manifold and have them "scavenge" effectively, but you do still want some back pressure. It is the same reason as to why you don't want huge inlet ports, if the airspeed drops too much it will be useless in the mid to low rev range (yet flow a shitload up high).

[Taz_Rx]

:dance: ^^^yeah dave said "you don't want back pressure" and then proceeded to explain the scavenging effect of why you do want back pressure.

[styler]

although similar due to vacumn and effect i might be able to define the terms better somewhat...

 

the venturi effect is a vacumn caused by a constant flow going through a small diameter pipe that progresses to a large diameter pipe,

eg fuel out the jet in carby

 

the scavenging effect is a vacumn caused by the previous high velocity charge in a single pipe,

eg extractors in an exhaust system

 

but you guys are right about the whole idea of it all :dance:

Edited April 21, 2010 by styler