b28 with 885 head ?

[Frany]

Hi i was windering. im curently running a m20b20 moter but it is race specked by robgreen engeneering in SA it reves to 9800rpm easy normally aspirated. hi comp pistons the works. Here is my question.. its got the 200 head on with small ports. can i fit the 885 head to it with bigger ports? and by how much wil it drop compreshion ? is it worth the upgrade ?

[bmwbmwbmw]

i am running a 2.8 built motor with the 885 head and 290/290 cam, runs perfect, power delivery is good, but it is in need of a remap and maf conversion, nothing that ant at a-tech cant do

[Frany]

so it is posible to put the 885 head on the 2.0 moter ? even with hi comp pistons it wont knock the valves ?

[E30SPORTMAD]

Hi am sure it will work ok as far as i think the 885 head is shaped correctly for the hi comp 325 pistens? anyone no if am right or wrong?

[Jhonno]

9800k on what bottom/top end spec?! On a 731 head?! I am 99.9% sure that head would not flow enough to make power beyond 7k..

[Frany]

9800k on the standard botem end sizes but cranck is running on a tipe of split ballbearings conrods aswell as cam, have low friction pistons all acordingly ballanced uses a difrent intake manifold with fenturies to spin the air and create a tornado effect through the intake ports. has the 200 head with lightweight valves stronger valve springs diffrent counter weight crank cut to match piston and conrod weight. makes 213hp@ 9100rpm with 241nm torque at 6000+- makes good power but think it will make more with bigger head ports ?

[m_jermyn]

Did someone step in poo because I smell something stinky here..

Or a wind up maybe.

[Andy325i]

Did someone step in poo because I smell something stinky here..

Or a wind up maybe.

*likes this!*

[Frany]

Lol it was not cheap engen was biult by a verry well known bmw race specialist Cost was R56000 aprox 5600 pounds has been building bmw race moters since the 1960's for south african race teams. dont know weather or not its ported thats why im asking if a 885 head will work cuz of bigger valves and better shaped head cavity. Any help ?

[m_jermyn]

No engine builder will put a 200 head on a "race motor" because the 200 head is shiit.

A 731 head will work better with the pistons you are using and retain the same comp ratio.

The valves in the 731 are the same as those in the 200 however the port size is almost double.



For the record I still think your telling porkies.

[m_jermyn]

9800k on the standard botem end sizes but cranck is running on a tipe of split ballbearings conrods aswell as cam, have low friction pistons all

WTF are split ball bearing conrods and what are low friction pistons?

Never heard of this black magic voodoo

[Barx325i]

bigger valves will always help, but if it's revving clean all the way to 9,800, leave well alone, it sounds like your 731 ain't exactly standard

changing the head will be a colossal faff, (to reach the same level of tune given remaps and getting everything either side of the spark just so) and assuming you want to go about things in the same way as this build has been achieved.

difficult call

Like Jhonno points out the 731 head you have, has been without question been played with to achieve any sort of worthwhile power past 7k

[m_jermyn]

He don't have a 731 head he has a 200 head!!!!!

[Barx325i]

just playing the game

[Ajsingh]

Lol a 200 head? The head that was designed for optimum economy in the eta?

Lol porkie pies!

[Frany]

Not split ballbearing conrod. The conrod in conected to the crank via a split ballbearing instead of a bush tipe bearing. and the cranck is running on the same split ballbearings used on the conrods. the cams also use the same tipe. lots of moterbikes run on those tipe bearings. pull one apart and have a look see at voodoo in motion. Now low friction pistons also known as slipper pistons, if viewed from the side it looks like a "T" all the ecess piston not used causes friction so it is done away with eg the ecess below gujen pin. have a visit to wiseco's and you too can buy voodoo. lol so back to my question. On the head its a 200 but im not shure if it has been ported or not cuz im unshure of port size on standard head. now the 731 if it has the same valves as the 200 i cant see it being that much of an inprovement cuz it bottel necks. the 885 head flows better cuz of better shape and bigger valves so will it fit and is it adviseble ?

[m_jermyn]

Do what you want mate... I still dont believe you.

As I said the 200 has the same combustion chamber as the 731 however the 731 has much much bigger ports and also 7 cam journals instead of the 200 that has 5.

The 885 and the 731 have the same port sizes however the 885 has bigger valves which lets it flow better at higher RPMS..

885 and 731 have different combustion chambers as they use a different shape piston.


Thats all you need to know.

[m_jermyn]

Oh and a DYNO sheet from you will prove me wrong.

[Barx325i]

could be a dyno sheet from anything tho

[Frany]

my 200 also has 7 main bearings. where can i uplooad pics and how ?

[Morat]

Whatever is really going on in that engine, my advice would be to take it to the original builder and ask the question. If you're getting that much power from a 2.0 there's no way it can be improved just by slapping parts on it.

[lance1a]

RGM does some pretty damn amazing stuff.........1000 BHP E30
http://www.rgmotorsport.com/html/customer_cars.html

[HairyScreech]

im listening....

[lance1a]

Click the link

[HairyScreech]

^^ i meant to the thread in general, seen some of the rgm work before.

i am confused about some of the specification choices for a road car.