43 replies to this topic

[RWinstanley]

One of the main problems with the NA engine is that as mensioned above it's not designed to be a high specific out put engine and the inlet valves are designed to give good low down torque by providing alot of 'tumble' at low engine speeds, at the expense of flow capability at high engine speeds.

Edited by RWinstanley, 22 September 2005 - 10:50 AM.

[Dodge]

Hi Rick, had the same desire to upgrade my N/A earlier this year and decided to go for Courteney's CS4 upgrade: Full Miltek zorst, pre-cat removal, air box mods and panel filter, new cam shaft (no idea of the spec!) and finally a remap. total cost about ₤2K. It's transformed the car, 168bhp, extended the power band and rev. limit to 6700, and thanks to the Miltek a much more purposeful zorst note, which I think is easier to live with than the VSE which I remember being a lot higher pitched. If you're coming to the Nat. meet I'll take you round the track to compare. R22 AVX (in silver). Hope this helps you to decide the best way forward. Good luck. Dodge

[clipping_point]

One of the main problems with the NA engine is that as mensioned above it's not designed to be a high specific out put engine and the inlet valves are designed to give good low down torque by providing alot of 'tumble' at low engine speeds, at the expense of flow capability at high engine speeds.

From what I´ve heard the inlet valves are allright.

They are even considered slightly too large for the inlet channels. So by increasing the inlet channel some 15-20 %, and fitting a larger inlet, the inlet valve flow capacity is used at its full.

It may even be counterproductive to fit bigger valves, as it may disturb the flow.

[RWinstanley]

Sorry didn't explain very well due to trying to get the post in, within the hour i get for lunch (IT Big Brother Watching). What I meant by the valve design was the all of the geometry between the manifold gasket and the cylinder as a whole not the actual area of the valves. As the design is such that the air flow comes in to the cylinder through a tight bend so that at low engine speeds the air flow tumbles turbulently. This produces good air fuel mixing and subsequently good torque. However the compromise is that at high engine speeds the tight angle restricts the flow. It was rumoured that there was another valve design that was tested at the beginning of the L850 project that produced more power than the design chosen. Rob

Edited by RWinstanley, 22 September 2005 - 07:36 PM.

[Thorney]

It may even be counterproductive to fit bigger valves, as it may disturb the flow.

We've found that. The stock valves are actually pretty good.

[minime]

dbilas found the stock valve size is good...but on the head that i have in mine they have put a 3 angle valve setup which they say optimises it further...the head and cams that have been supplied to me was specified to provide more torque i think this is why the cam profiles are as follows inlet 256 dur 12mm lift exhaust 248 12mm lift

[cicastol]

i'm returned from a track day in France,this gave me the opportunity to test my new mods,really impressive!! now with the dbilas intake,exhaust,and 266° cams,i've been able to reach and even surpass the exige S2 on track!! The only down note is the A\F ratio of 13.5 on WOT (mesured with wide band lambda) probably is better to go a little richer near 12.8 -13 ,i will ask dbilas if is possible to increase the fueling more with a new ECU program....

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[clipping_point]

I HAVE to get a wide band lambda of my own, u lucky bastard!!

[Tony_M]

Stage 3 TMS NA - 175bhp Sweet... (...and she's got a boot)

[Speeding]

Why not buying a complete Ecotec 2.0L Supercharged Production Engine for $3,665.00.
http://www.auto123.c...spy?artid=22752

[paulf-cam]

Why not buying a complete Ecotec 2.0L Supercharged Production Engine for $3,665.00.
http://www.auto123.c...spy?artid=22752

Thats not the production engine, its the crate engine which is missing the ac pump, pully, belt, starter, alternator and engine cover. Oh and ECU!

I guess you might be able to swap some of those off the 2.2, but the pully and belt would need ordering separately.

Cheers, Paul

[clipping_point]

Why not buying a complete Ecotec 2.0L Supercharged Production Engine for $3,665.00.
http://www.auto123.c...spy?artid=22752

It will need a stand-alone ECU and a special flywheel so the cost will be considerably larger than at the first glance...

[vocky]

Actually the standard valves are a mass produced 'safe bet' and are a poor design They are shaped for cheapness and every performance valve I've seen has undercut stems and are swirl-polished. The size of the valve depends on the engine spec and a manufacturer will never fit an ideal valve for performance, just economy. So just replacing the standard valves, without changing the size, will give an increased flow and thus more potential power Here's a pic of 'si valves' average spec performance valves, spot the difference if you've seen a standard valve.

Edited by vocky, 25 September 2005 - 09:09 AM.

[Thorney]

I didn't say the valves couldn't be improved upon, simply that they were pretty good, budget doens't necessarily mean crap Replacong valves on their own is a little pointless as the while the engine is apart you might as well gas flow it and blueprint it properly (thats waht we do any way)

[vocky]

that's my point, a standard head with standard valves is good, but a gas flowed head and decent valves is so much better

[cicastol]

I HAVE to get a wide band lambda of my own, u lucky bastard!!

It's really a great tool,i have the dynojet wide band commander,it that works pretty well,you can ceck fueling with great precision is very impressive to watch the ECU working in closed loop maintaining an ideal 14.7 /1 A/F ratio during part trhottle!!

[Thorney]

that's my point, a standard head with standard valves is good, but a gas flowed head and decent valves is so much better

Wehn we gas flow the head the whole topengine is sent over and the valve tolerances checked and re-ground if necessary.

[iceman]

A mildly highly tuned 2.2L engine should be pushing out 200bhp +

never a truer word said..

..it's a personal choice/driving style thing but give me! a zooped n/a any! day of the week (and weekend)

[clipping_point]

I HAVE to get a wide band lambda of my own, u lucky bastard!!

It's really a great tool,i have the dynojet wide band commander,it that works pretty well,you can ceck fueling with great precision is very impressive to watch the ECU working in closed loop maintaining an ideal 14.7 /1 A/F ratio during part trhottle!!

This one?

Dynojet

Seems to be a bargain!

[Black Knight]

Did anyone try good ol' lowering the head thus increasing compression bit on this engine?