QuestionHi Josh, i'm a motorsport engineering student at swansea institute in wales, uk.
We have a major project to do as part of our course.
I've decided to Polish and Port my e30 325 sport cylinder head to gain extra performance. I'll be rolling roading the vehicle before and after, as well as flow benching the head before and after to get results on the difference gained.
Would this also help the cracking head problem on these cars through allowing more cool air to pass through and minimise overheating?
Can you tell me anything you know that might help me with this. ie: porting techniques on this head or anything you feel might be helpfull.
I'd be deeply greatfull for any help!
Cheers Ryan
PS: Think i read you our Chairman of American BMW magazine?.....in the early summer i worked for BMS - Bullet Motorsports Speedlab in Santa Ana CA for work experience....do you know Chris Welch the owner?
AnswerRyan,
I think you have me mistaken with someone else. I am a member of the BMW Car Club of America (BMWCCA), but I'm not the Chairman.
That's great that you get to travel to another country to learn motorsports! (are you from the UK or US?)
I'm probaly not much older (24) than you are, and I too was enrolled in Motorsports school. College was calling my name so I went that route instead (engineering).
To be honest, you wont see much gains from Porting/Polishing the head on an M20. These motors are pretty much tapped out, and dont show improvements from modifications very well. Literally you could spend $5,000 on bolt-on mods and still be making 200hp (30hp gain). The only real way to make these engines make high HP is to put a turbo on them. The down side of this is that the engine probably wont last long.
But there is a purpose to you doing this so I say go for it. Since you are doing it for your school and for fun it's not going to hurt anything to try. Just dont be expecting 25hp from this (more like 5hp... if that).
If you are running headers, just match the ports to the headers. Grind out some metal and then get a fine polishing bit and polish it smooth. If you plan to keep the manifolds then you can port those as well.
I doubt you will see lower temperatures from porting. Infact in most engines you will actually raise them. Sure you are pulling more air through and it does cool, but you are also adding more heat. Since the engine is getting more air (and hopefully more fuel) it should make a larger explosion in the cylinder and cause more heat (unless you are running really rich). I've never had a head crack, the only real problem I know of with these engines is the rocker arms breaking when used with an aftermarket performance camshaft.
Check out this website, its full of useful information.
www.e30tech.com
If you have any other questions, please feel free to ask.
Josh
