head porting

4th June 2004, 06:23

hi, thinkin of getting port and polish.
but after it is done , with the standar ecu map, would it make a sufficent differenc, or would i really need to get a chip.

4th June 2004, 06:24

also i timed the cams, hopefully done them right but didn't really seem to make a differce, is it also because of the ecu, i mean i have timed the cams but the ecu still sends the same amount of fuel so is a chip needed to feel the differce.

4th June 2004, 15:28

not much difference in power for port and polish, all it does it stops some of the turbulence that occurs in the engine. New ecu will help, but until u get other engine mods sorted, the difference in power wont b unbelievablly quick, etc...
Kind of a waste of money on port n polish.
Save up and get some other mods that enhance performance much more, like throttle-bodies, im not sure if u can do it to a Sax, but would b better than port and polish. More expensive aswell. Gotta ask Cituning or GMC, they are the specialists, im just some1 giving soem quick advice.

4th June 2004, 23:18

port and polish is a good idea if done properly, and if you can justify the cost.

What they do is to open up the inlet and outlet ports, thus allowing a grater quantity of air to flow through.

However, if you are raising the quantity of air flowing in then you must up the amount of fuel to match or the engine will run lean, wich is not big or clever! so you'll want to do a re-map/chip set up properly on a rolling road.

When you have the head done you MUST make sure that only the exhaust ports are polished, as the turbulance in the inlet is very important as this aids the mixing of the fuel and air, lowering this turbulance will increase fuel consumption and lower power.

I'm guessing you've got a vts, if so look into the throttle housing and if there is a lump cast into it have this bored out, the one on the vtr reduces the size by almost half, makes a big difference.

Pete

4th June 2004, 23:19

its not really going to cost me much, because i will remove the the ports myself, and i'm going to get it done for cheap, i'm in turkey, ist going to cost me around 10 pounds.

4th June 2004, 23:23

what is 'throttle housing'?
why only should i port the exhaust ports? if the inlet ports were polished to, wouldnt the air flow in better?

4th June 2004, 23:44

the throttle housing is the bit that the accelorator cable attatches to and if you take off the pipe from the air filter housing and look into it there is a brass plate inside that opens and closes the hole when you move the accelorator.

What i ment was that, yes, you should port the inlets but should leave them in a matt finish, by using a cross buff bit, not polish them.

What you are doing is removing the inlet and exhaust manifolds and making the holes leading to the back of the valves larger buy removing aluminium from the head with a rotary file mounted in a drill or die grinder, but you will need to be very carefull not to make them too big. Obviously the head will need to be off the car and totaly stripped of all it's components, cams, valves, etc....

It's all about rounding off all the sharp edges inside the ports.

Pete

4th June 2004, 23:49

alright thanks, so the inlets should not be polished but ported just a bit, and the outlet ports should ported and polished, did i understand correct?

i got the throttle housinng, but what mod is there to do for the thr. housing.?

5th June 2004, 00:30

the thr.housing is made of cast ally, and if you look inside so you can see the brass plate, on the air filter side there may be a lump on the top half of the inside of it, so the outside is round and the inside is not....with me so far?

well, the mod is much like the porting mod, but you need to make the INSIDE of the thr.housing round and again using the cross buff give it a matt finish, be carefull not to make the wall too thin and be sure to get ALL of the filings out before you run it on the car.

Pete

5th June 2004, 00:32

oh sorry, you DID understand, port ONLY on the inlet, and port AND polish on the outlet.

Pete

5th June 2004, 01:12

thanks pete i kind of understood, i'll probably have a better understanding once i look in the throttle either tonight or tomorrow.

you wouldnt have a picture of it done would you?

and by the way what mods do you have on your car

6th June 2004, 00:03

i have circled the part of the throotle, is that the part you are saying that should be ported.?

6th June 2004, 15:07

that's the bit, only on mine it was some what larger.

My engine mods to date:

Haltech e6k ecu
Pipercross filter with cold air feed
Msd dis-2 ignition cdi module
bmw mini cooper s coil pack
bmw 330ci fuel pump
3.0 bar fuel presure regulator
oil breather catch tank
lm-1 wide band afr controler
2.5 inch exhaust leading to 3 inch rear can with 4.5 inchtail.

twin 40mm jenvy throttle bodies(sat in a box waiting to be fitted)

Still lots left to do but it's ok for now.

Pete

6th June 2004, 16:31

why bmw 330ci fuel pump, i was told that vts pump are even stronger than bmw 520's?

what is oil breather catch tank and Msd dis-2 ignition cdi module

7th June 2004, 23:29

330ci fuel pump because it runs at a higher presure than the vtr pump and gives a higher flow rate.

msd dis-2 is a unit that takes the ignition signal from the ecu and jumps up the voltage to around 480v then dumps that into the coil multiple times per ignition firing.

What this does is to give a much stronger spark(115mj@40,000v) and where as the standard one gives a single spark across the plug the msd unit makes the spark last for aprox the same time as it takes the cam to turn 20 degrees. this means that at idle the msd will give the equivelent to 12 sparks per event as apposed to the standard 1.

The oil catch tank is an ally bottle that you feed the crank case breather into so that the oil vapor sticks to the tank returning back to liquid instead of the being fed back into the induction.

Pete

7th June 2004, 23:38

msd dis-2 , how can i do this mod? what would ineed, do you have pictures of it? actually i didnt really get the system fully , sorry

8th June 2004, 00:06

If you go to www.msdignition.com all will be explained.

Although, considering i'm not using a citroen ecu it may be that you cannot use one on yours, but check out the web site, and have a look.

Pete

8th June 2004, 06:57

supersav sorry i keep on askinda the same thing, but i'm going to get the thro. housing in a couple of days, i took pictures of the parts and i wanted to make sure that i would port the right places.

also i realized that the part is not really big, would it be worth porting?

8th June 2004, 23:37

yeah that's kind of the bit, although it's not the same as the one i had.

On yours that lump isn't that big so you'd probably not gain that much from the mod.

On mine the lump came down infront of the thr.plate almost as far as the spindle, so i gained something like 40 percent more air flow capability.

Like i say though, it's probably not going to give you much benifit, so would be a load of work for little return. If you do decide to do it, all you're doing is to file down that lump you've circled so that the there is nothing to restrict the amount of air going into the engine.

best of luck

Pete