162 replies to this topic

[siztenboots]

it will be the ratio of crank pulley and sc pulley , if they were the same diameter, then it would mean 2 cylinders each get half the full rated SC charge per cycle

[techieboy]

No idea how to calculate it but obviously depends on the pulley size. I'd guess an SC revolution with a small pulley is probably something like 0.50 of an engine revolution. Maybe.

 

Would like to know how to calculate all of these variables and volumetric efficiencies etc to understand the compression/efficiency graphs but maths and engineering principals were never my forte and it's why I always pay the money.

 

2.2 litre NA 4-pot consumes 1.1 litre of air per engine revolution and that's about where my knowledge peters out.

 

 

[Andrew aka Stuwy]

No idea how to calculate it but obviously depends on the pulley size. I'd guess an SC revolution with a small pulley is probably something like 0.50 of an engine revolution. Maybe.

 

Would like to know how to calculate all of these variables and volumetric efficiencies etc to understand the compression/efficiency graphs but maths and engineering principals were never my forte and it's why I always pay the money.

 

2.2 litre NA 4-pot consumes 1.1 litre of air per engine revolution and that's about where my knowledge peters out.

 

 

 

so it has 2.2L of space, but only uses 1.1L...

 

no I don't understand either

[siztenboots]

because its a 4 stroke , 2 bangs per crankshaft revolution

[slindborg]

An alternative solution would be to run a larger pulley to lower boost and make the engine more efficient. Ported to the max stage 3 cams high flow inlet and exhaust. Is it possible the Harrop is trying to cram in more air than the engine can use?

 

boost (MAP) is merely an indication of how resctrive the engine is at breathing....

 

If you make 300bhp with 1bar of 'boost' (MAP = 2Bar) and someone else makes 300bhp with 3.5Bar of boost then yours is better

[Exmantaa]

Crank pulley is 6.25", a Stage 2 M62 SC pulley is 3.35"; do the math...

[techieboy]

So, 6.25" crank vs 2.9" SC pulley means my guesstimate wasn't far off.

[techieboy]

Which also means that at 7500rpm with a 2.9" pulley I'm in the no-go zone for the M62.

[siztenboots]

[techieboy]

[smiley]

What i've collected so far on harrop's on 2.0:

 

 

Of course it will be more accurate once we get more conversions, dyno sheets and logs.

 

Edited by smiley, 03 January 2014 - 04:09 PM.

[oakmere]

An alternative solution would be to run a larger pulley to lower boost and make the engine more efficient. Ported to the max stage 3 cams high flow inlet and exhaust. Is it possible the Harrop is trying to cram in more air than the engine can use?

  boost (MAP) is merely an indication of how resctrive the engine is at breathing....   If you make 300bhp with 1bar of 'boost' (MAP = 2Bar) and someone else makes 300bhp with 3.5Bar of boost then yours is better

That is what I am getting at. At this level of tune the head will need some serious work to keep restrictions down. There is no point in head work at stage 2 as the std head can flow the required amount but trying to put 50% more air through is going to cause issues.

[techieboy]

Glad I bought a couple of larger SC pulleys for whatever finally happens next, engine wise......

 

 

 

[slindborg]

Glad I bought a couple of larger SC pulleys for whatever finally happens next, engine wise......

 

 

 

you mean nothing....

 

 

 

This 'chucking more boost' in is what the idiots did in the 80's FFS, matching the rest of the engine to the airflow and picking a suitable air pump are the key requirements here.... not simply spinning something up so fast its well outside its efficiency zone and requireing mental cooling.

[techieboy]

Nothing wrong with the 80's. It was a fine decade.

 

Now I just need a CNC Heads style flow analysis graph on the head to see what it flows as standard, then a breathed on head, then with higher lift/longer duration cams in and finally with oversized valves.

 

And I wondered why I'd decided to move back to a Stage 2+ sort of set up from the Stage 3.

.

[slindborg]

Matt, you just need to drop a fresh z22se in there as it is and then you will be happy again (for 5 mins) The 80's were quite a good push in technology but also in many cases a crime against engineering

[techieboy]

But...but....but...I've got two B207's sat in the garage. Don't say that.

[Exmantaa]

Stock B207, C20LET flywheel, triggerwheel for OBD (or use LSJ ecu) plus some LSJ cams or bigger => 280+ SC-HP's all day long.

 

Now to this new manifold; how much $$ would we talk for a small faundry run for some rough castings manifold size??

Edited by Exmantaa, 03 January 2014 - 10:49 PM.

[CocoPops]

But...but....but...I've got two B207's sat in the garage. Don't say that.

Hurry up and fit one of them, I still want your lightened flywheel (goes off to find thread where you offered it!)

[CocoPops]

But...but....but...I've got two B207's sat in the garage. Don't say that.

Hurry up and fit one of them, I still want your lightened flywheel (goes off to find thread where you offered it!)

Found it.... Only April last year

How much of a hurry are you in Lee? I've got one fitted to the car at the moment but it will be surplus, with the new engine which I've got a different one for.

I'm not, so that sounds ideal http://www.vx220.org...supgraemlin.gif

Stick my name on it.

http://www.vx220.org...supgraemlin.gif

That's my kind of timescale. http://www.vx220.org...IR#/biggrin.png