FAO AtomX

Blue_2_2

You wrote this is my project build:

This was a fairly simple modification
Two more phases lined up for this engine

Phase 1a 220
Phase 2 250
These phases will be using second hand GM parts and still NA

No exotics parts, just good thermo-dynamics

Explain your comments!

what is Phase 1a and 2?

50bhp MORE is a bold claim!

ATOM_X

I have two projects lined up for cheap reliable power using standard GM parts

both revolve around increasing compression ratio (C/R) only

the beauty of these mods is that all the work can be done in a weekend visit

Option 1a

fit Z22yh pistons & rods, ex stock modified Z22se crank, balance shaft delete & ex-stock re-worked cylinder head (standard valves, porting exhaust only & skim option) C/R 11:1 and 12:1
I predict 200bhp on standard TB & 220bhp on 68mm TB

Option 2

fit Z20net pistons & rods, ex stock modified Z22se crank, balance shaft delete & ex-stock re-worked cylinder head (standard valves, porting exhaust only) C/R 12.4:1 and 13.09:1
I predict 220bhp on standard TB & 250bhp on 68mm TB

I will be demomstrating Option 2 with un-modifed crank & standard TB at the RR day

BLUE PETER DISCLAIMER
THESE MODIFICATION'S MAY LOOK STRAIGHT FORWARD
but
PLEASE DO NOT TRY THEM AT HOME WITHOUT EXPERT SUPERVISION
if you do especially on option 2 you WILL lock up your engine and die

alanoo

Dear Dr Lee,

Have you got somewhere the weight of the Z20net pistons ?

(Have a Z20Nel / B207L here, but had no time to open it yet)

exmantaa

Very curious to these NA results, bearing in mind some comments I read about the Z22SE's port design not very good for high gas speeds... (Read: high NA power...)
;-)

vocky

the standard ports do need some tweaking to make them flow better.

GM got 325 bhp NA running high octane fuel 😃

ATOM_X

exmantaa said:
Very curious to these NA results, bearing in mind some comments I read about the Z22SE's port design not very good for high gas speeds... (Read: high NA power...)
;-)

They are not results but predictions
everybody has the right to make comments!
Some contributors make lots of comments, but this volume of opinion does not qualify them as experts
I would rather prove my predictions with good solid results

alanoo

exmantaa said:
Very curious to these NA results, bearing in mind some comments I read about the Z22SE's port design not very good for high gas speeds... (Read: high NA power...)
;-)

The port design is indeed not ideal for high RPM power but... ₇₀₀₀ is not "high" rpm, the ports are not that small too. Even not ideal does not mean that it will not work at all 🙂

On the .org too I read someone saying the Honda K20 were ports hugely bigger, this is not true, they are only very slightly bigger.

the BTCC ports are actually not a lot bigger than stock too,

The exhaust ports are a much much bigger issue than the inlets

ATOM_X

The holy grail for reliable torque on a 4 valve petrol N/A engine is 94 ft/lbs per litre
BMW M3 considered to be the best efficient petrol N/A engine is 81 ft/lbs

Engine designers would love to produce engines with level torque curves if they can
Then the next goal is to allow the engine to spin up as quick as is possible
this is what produces high BHP figures

High compression ratios with low rotating mass equal high power engines

winstar

ATOM X said:

exmantaa said:
Very curious to these NA results, bearing in mind some comments I read about the Z22SE's port design not very good for high gas speeds... (Read: high NA power...)
;-)

They are not results but predictions
everybody has the right to make comments!
Some contributors make lots of comments, but this volume of opinion does not qualify them as experts
I would rather prove my predictions with good solid results

That would be me and the comments come directly from the people who designed the head from the days when I worked at Lotus in Powertrain CAE. What I actually said was that the deisgn prduces good torque at lower engine speeds at the expense of being able to deliver the same torque at high engine speeds therefore the specific output will always seem low compared to somthing like a Honda K20.

While I'm here I'm intreaged how you intend to use the Z20net pistons and rods with a z22se crank to get such a high compression ration

ATOM_X

winstar said:

ATOM X said:

exmantaa said:
Very curious to these NA results, bearing in mind some comments I read about the Z22SE's port design not very good for high gas speeds... (Read: high NA power...)
;-)

They are not results but predictions
everybody has the right to make comments!
Some contributors make lots of comments, but this volume of opinion does not qualify them as experts
I would rather prove my predictions with good solid results

That would be me and the comments come directly from the people who designed the head from the days when I worked at Lotus in Powertrain CAE. What I actually said was that the deisgn prduces good torque at lower engine speeds at the expense of being able to deliver the same torque at high engine speeds therefore the specific output will always seem low compared to somthing like a Honda K20.

While I'm here I'm intreaged how you intend to use the Z20net pistons and rods with a z22se crank to get such a high compression ration

Yes this head has wonderful torque characteristics and I will not aim to lose those. my plan is to increase torque early and mantain as flat a curve for as long as possible, I am not trying to emulate the k20 so there is no reason to draw comparisons

I should hope YOU are intrigued!
As it is a little bit different!
I am sure YOU can work it out!
how but please dont ask!
for the moment that is

TheHood

So Dr Lee, should I be putting off my order for Eagle rods and Wiseco pistons?

I'm mainly interested in running a higher rev limit safely to make the most of my cams / ported head.

ATOM_X

TheHood said:
So Dr Lee, should I be putting off my order for Eagle rods and Wiseco pistons?

I'm mainly interested in running a higher rev limit safely to make the most of my cams / ported head.

I have been running my Zafira with standard se bottom end but with mods for 3.5 years

I have been running at over 200 for 36,000 miles with the limiter @7500

I am taking out the engine in the next two weeks (there is nothing wrong I just want to check)

I will replace with phase 2 engine

My advise for now is wait until I see how the standard se has coped

Brains are free
Exotic parts are expensive

TheHood

ATOM X said:

Brains are free
Exotic parts are expensive

Amen to that :thumbup:

alanoo

winstar said:

While I'm here I'm intreaged how you intend to use the Z20net pistons and rods with a z22se crank to get such a high compression ration

I actually don't see any reason why it shouldn't work, rod big ends are the same, + at stock there's a lot of clearance at TDC so it could be a very easy and smart solution; not sure how it would cope with aftermarket cams.
Only issue I can see is that these pistons are not designed for such a low rod ratio / angle and the pin/rings position may not be ideal for a long stroke engine; may lead to heavy slap, friction and skirt wear if this is the case

vocky

I'm sure they would require valve pockets for high lift cams, but a small price to pay for high CR dunno..

alanoo

machining valve pockets on a cast piston is a bad idea unfortunately

ATOM_X

alanoo said:
machining valve pockets on a cast piston is a bad idea unfortunately

Correct

ATOM_X

vocky said:
I'm sure they would require valve pockets for high lift cams, but a small price to pay for high CR dunno..

I never mentioned high lift cams in fact this engine is standard cams

ATOM_X

alanoo said:

winstar said:

While I'm here I'm intreaged how you intend to use the Z20net pistons and rods with a z22se crank to get such a high compression ration

I actually don't see any reason why it shouldn't work, rod big ends are the same, + at stock there's a lot of clearance at TDC so it could be a very easy and smart solution; not sure how it would cope with aftermarket cams.
Only issue I can see is that these pistons are not designed for such a low rod ratio / angle and the pin/rings position may not be ideal for a long stroke engine; may lead to heavy slap, friction and skirt wear if this is the case

the rods are longer than SE's

alanoo

ATOM X said:

alanoo said:

winstar said:

While I'm here I'm intreaged how you intend to use the Z20net pistons and rods with a z22se crank to get such a high compression ration

I actually don't see any reason why it shouldn't work, rod big ends are the same, + at stock there's a lot of clearance at TDC so it could be a very easy and smart solution; not sure how it would cope with aftermarket cams.
Only issue I can see is that these pistons are not designed for such a low rod ratio / angle and the pin/rings position may not be ideal for a long stroke engine; may lead to heavy slap, friction and skirt wear if this is the case

the rods are longer than SE's

Yep I was very interested in these rods with a custom lighweight piston and 2.2 crank, and I tried to have a confirmation of that while I once saw on a US forum that :

L61 94.6mm 141mm 1.5:1
LSJ 86mm 144.84mm 1.68:1
LNF 86mm 144.84mm 1.68:1
LE5 99mm 143.7mm 1.45:1

Except the real CtoC length for the L61 is 146.50mm, so it was simply wrong

Good to know the Z20ne* are in fact really longer