update on head flow numbers

[topcat 11]

Ok,

for all you keen people who have been waiting,everso patiently i must add.

the pics show the one exhaust port sporting the new 3.5mm larger valve and a standard

the head has been bored out and a new seat fitted.

looks good though,not sure this is going to work in an NA setup,but in a turbo setup,

the theory is more flow to push more gas through=more HP with less boost,

which is going to work well cause we're going to run 9.3/1 compression

had the unit tested on the flow bench,the standard valve pushes 70 cfm at 10 inches of pressure at 4thou valve lift

the new valve passes a little over 87cfm at the same pressure.up 20% give or take

shame the head guy couldnt follow a simple instruction and do the all important 28 inch test,for the turbo

application.helps to plot hp estimates.nevermind. we'll have to wait for the dyno when its all together.

thought I'd change my user name just in case the numbers are 'exciting'

yes thats correct,the old valve head fits inside the new seat.

hope the results will be worth the time and $$

[kiwi535 538]

Ok,

for all you keen people who have been waiting,everso patiently i must add.

the pics show the one exhaust port sporting the new 3.5mm larger valve and a standard

the head has been bored out and a new seat fitted.

are the valves from the E34 version of the M30?

[Mike 1]

Very interested in this, I want to go a similar route with my build, larger cam, reasonable compression, bigger valves should all mean higher HP with less boost as you say. Where did you source the oversize valves? Care to share a bit more on the specs? eg cam profile? i take it you just going to run with stock pistons? otherwise what made you go with 9.3:1 cr?

[topcat 11]

Pistons have been ordered,will be 95mm forged alloy,flat tops as the compression has been calculated to be 9.3/1

useing the e34/e32 head.not ideal turbo numbers,but am planning not to run more then 10-12 psi of boost and not below 98 octane.Also with the higher compression,will have less lag etc,and with alittle head work should give good number when finished

the above from part 1 of the 537i build.

boring the pots out to 95mm,so more cc for the same bowl in the head= higher compression.

could have taken 0.5-0.7mm or so off the head surface,but we needed to get new pistons anyway.

valves are stainless steel blanks,machined down to fit.could have gone with chevy units but the keeper groves

were not in the right place.

cam i'm going to be using is the early e12/635csi type. refered to as the 270,or the 272.

newer engines have the 260 units.so not going wild as such.could have a cam made for round the 500 to my

specs,which would make more go.but if the wife cant drive it round town,then i'm not interested

[mr E34 11]

Have you enlarged the inlet valve or just exhaust?

[topcat 11]

Have you enlarged the inlet valve or just exhaust?

just the exhaust,intake is big enough.

[Gus 5]

i have been reading a thread on e30tech (dan martins turbo thread or something like that) and he has produced some very interesting results

v nice intake manifold, exhaust manifold, nice turbo, good management and tuning...stock engine except for head bolts and he is making around 450hp on the stock m20.....might be other areas to spent $$ on before going internal? (although lowering compression is a must in some engines)

[320guy 0]

i have been reading a thread on e30tech (dan martins turbo thread or something like that) and he has produced some very interesting results

v nice intake manifold, exhaust manifold, nice turbo, good management and tuning...stock engine except for head bolts and he is making around 450hp on the stock m20.....might be other areas to spent $$ on before going internal? (although lowering compression is a must in some engines)

He made 475WHP, so its a bit over 500 at the crank. He has a flash short runner intake manifold, thats about the only mod to the engine really. He also has ARP head studs with a standard head gasket, the engine hasnt been rebuilt.

[topcat 11]

He made 475WHP, so its a bit over 500 at the crank. He has a flash short runner intake manifold, thats about the only mod to the engine really. He also has ARP head studs with a standard head gasket, the engine hasnt been rebuilt.

at 15 pound boost,with everything at max efficiency we can plot double the stock HP.

at a guess he's running 20+psi.seen bent conrods at 25,so,i think long term this project is

going to be seeing the shop-often. not for daily use

[320guy 0]

He drives it daily He is running 22psi AFAIK.