ka24de intake manifold

[shift0246]

ok serious question dont know if its been asked i actually used the search button this time!!! ok me and my freind were discussing about my intake manifold,we were thinking about going to the local junkyard and getting a intake mani and porting and polishing it ourselves, i was thinkin wouldnt be a bad idea,you know like taking out anything not nessasary like the restrictive stuff, and i wanna know what you guys think? then i also wanna ask if the sohc would bolt up to the de,and is the sohc throttle body larger than the dohc?

[pr240sx]

Both manis are differentt and the are not compatible (sohc-dohc)I think that throttle size is the same

[9240sx]

Yeah the throttle bodys are the same..I dont think you will see alot of power gains by porting the manifold..unless you have a Turbo or some aftermarket cams,Headwork......If you have a s13 KAde you can always remove the butterflys in the manifold..Again you wont see much gains on a mosty stock engine..But if you got time and money,Why not..

[DjPantsSpecR]

buy it and hack it up. the stock runners adn plenum are useless (to an extent) but a spare upper manifold can be used to make whatever intake manifold you want

port and polish will give you bull**** as a result. you can make a design flow where you want it by moderate porting and polishing, you need to change runner lengths and (to a less extent) plenum size

[Bigvinnie]

How about something like this. These guy's have the right idea..... Pretty pricey though....http://www.xcessivemotorsports...tep=2

[xekushnr]

only port and polish if you know what you're doing. i cant tell you how many times me and my buddies have benchflowed stock parts then again with the P&P and have LOST power. if you're lucky enough to have access to one, flow it stock for a control number, and keep flowing it after each little bit of work you do. if the numbers start dropping, stop.

[Jiggyfry]

hes right, be very careful how you go aboot porting the intake. Take off too much ,aterial and you could peirce a coolant jacket ! You could also screw up the airflow and actually lose power. When i rebuilt my ka24de I did a port matching and port and polish job myself. I did notice more power in the high end but overall id say very minimal gains. If you want to try it as a learning experience, go for it but be prepared for mistakes!

[Bigvinnie]

I don't believe the runners to the KA need any type of serious honing. Just a lite grind to remove any type of burs and imperfections that were in the cast. Increasing the diameter width too much decreases swirl, which actually hurts the atomization process. The intake ports to the head on the other hand can use a slight port job(very miniscul), using a grinding method only(NO polishing). The metal should remain rough to help allow air and fuel to mix as it passes by the valves. Remove imperfections around the valves and port opening. Exhaust side can use a bit of porting only since the exhaust gasses are heavier and hotter , than O2 by itself you would want tem to pass through sooner, you can actually polish the exhaust ports and make them smooth. Although increasing the exhaust ports to large in diameter can cause lack in flow, can cause the engine not to pass smog, and if the ports aren't even then it can also cause scavaging to become unbalanced from cylinder to cylinder. Use caution when doing this type of work. Always get it flow benched when you are done.....

[pr240sx]

The metal should remain rough to help allow air and fuel to mix as it passes by the valves.

That is perfectly correct on WET manifoldsOur is dry and fuel/air mix at the back of the valve, on the head, NOT on the manifoldYOu can polish the hell out of the manifold. You CANT (at least not recommended) the intake port. Because your explanation.

[Bigvinnie]

That is perfectly correct on WET manifolds

I don't know too much terminology on the difference between wet and dry manifold systems. I am assuming when you mention wet manifold that you are talking about carburation, or DPI (dual point fuel injection). Is this correct?The head ports use rough porting since technically it is wet, injection is delivered through the head before passing the valve.
Modified by Bigvinnie at 10:11 AM 5/4/2006