port and polish

[bluee36e36]

I'm thinking of getting a full port and polish, along with a 3 angle valve job and new lifters and valves. About what would the power increase be and would it increase a good amount with an after market chip upgrade or is it just a waste of money? the increase for a chip is like 10-15 horses, would this increase a lot with a port and polish on the cylinder head?

[Dinan 95]

I have no clue on a BMW
We ported my friends Camaro Heads, and holy crap the difference was amazing.
It totally woke up the engine.
You get better top end power, but the best part was low and mid reange power was alot better along with thottle responce.
I don't know how much it would cos though, that really is the question for you, adn that I don't know.
If its not too bad, I'd do it!

[wulley1]

I've been told it can be worth as much as 40hp. Were are you getting the work done? How much are they charging?

[CBD328is]

It all depends on how much optimization BMW has done on the heads already. As mentioned above, porting a set of 5.7 liter heads on a camaro will make a huge difference. That was the first set of heads I ever ported. The seat of the pants feel told me I gained power, but the chassis dyno told the story (+30hp, +20 lb-ft). Of course, there was a lot of meat to be cut out of the heads I had on the motor. Take a Honda CBR 600CC head and try to port it. Not only will you not gain much power, if any, you'll also probably hit a water jacket! I'm no expert on the BMW heads, so you may want to start talking to the BMW engine performance shops and get a good idea of what performance gain is possible.

[wulley1]

the shop I talked to said they switched to titanium valves that had thinner diameter stems to increase air flow. Most of their port work was done on the intake/exhaust ports.

The shop I talked to specialized in building m3 race engines.

[Deloriant]

Although you will get big gains, you will notice a big drop in engine response. One of the reasons well known Japanese tuners like Mine's (Michizo Niikura) don't mess with changing the bores is because of that loss. Big power is great...but engine response is crucial.

[bluee36e36]

thanks everyone! i'm going to get the work done at EIP Tuning in westminster, maryland (European Import Performance). They are going to charge me 1100 for everything, 3 dyno runs. i'm still not sure if i want to through that money down.