13 replies to this topic

[kek700]

 med_gallery_2_34_15297.gif   23.42KB   6 downloads can anyone tell me why the torque curve from a mildly modified 2.2 N/A has a drop in the middle of it ?

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•  med_gallery_2_34_15297.gif   23.42KB   3 downloads

[SteveA]

There could be all sorts wrong with it. I would start by looking at spark plugs and coil pack.

[siztenboots]

Difficult to say without knowing what the AFR was like, plus general condition of ignition system . Was it properly warmed up, ie. not on choke ?

[kek700]

No I have seen this on a number of torque curves on a 2.2 N/A engine, and took this one for an example. I have not noticed this dip in any other engines torque curve before, except engines with some race type camshafts. maybe i am wrong and unluckily have only seen this dip on the few i looked at? Plus the fact that this engine seems to produce as such not very impressive torque figures and even less impressive power relative to its modern construction. Also worst of all it seems very difficult to get any good (reasonable) power from it without spending silly amounts of money.

[kek700]

I have just read my last comment, i should have said power not torque.

[speedster]

That's my plot.

APR is HERE

The consensus on the figures was; head work needed! That the standard flow and valve train setup does not work very well.

Edited by speedster, 04 April 2008 - 10:20 AM.

[EdButler]

They all have that dip to an extent at round 2-3k rpm, however yours seems to not recover untill 5k! It could be a problem with the fuel pressure if you have changed your inlet pathways. Either way there are some experts and comparison RR results on www.z22se.co.uk Does the "Mildly Modified" include a remap at all? I think these engines (like most!) really, REALLY need a remap to account for every single mod you've made, otherwise they get rather tetchy.

[speedster]

List of mods for this run HERE

Currently I am using a SAFC-2 to help out the AFR.... No remappers in my part of the world so it's all DIY!

Lowest point on the graph represents an overall dip of between 8-9 lbft of torque, that a minimum of 157.8 lbft of torque.
Not sure it can be classed as a hole (please check the scaling on the left) but please correct me if I am wrong.


BTW the graphs are both torque. Power curve for that dyno run is this one CLICKY

Edited by speedster, 04 April 2008 - 11:27 AM.

[kek700]

Interesting responses. You have done quite a lot to eliminate any of the inlet and exhaust problem areas. it would be interesting to see what could be done to the cylinder head with respect to porting shape and perhaps valve enlargement. Also finding a cam to extend the torque making it flatter into the 3k to 6k region to improve to power under the power curve at these rev points. I would readily give up the torque at the 1.6k to 2.5 k region. I would have thought that about 220bhp is possible at 6.5k to 7k, with the mods you have done to your engine, meaning that you should be able to get away without investing a lot of preventative dosh in crank, rods and pistons.

[speedster]

Interesting responses.
You have done quite a lot to eliminate any of the inlet and exhaust problem areas. it would be interesting to see what could be done to the cylinder head with respect to porting shape and perhaps valve enlargement.

Also finding a cam to extend the torque making it flatter into the 3k to 6k region to improve to power under the power curve at these rev points.

I would readily give up the torque at the 1.6k to 2.5 k region.

I would have thought that about 220bhp is possible at 6.5k to 7k, with the mods you have done to your engine, meaning that you should be able to get away without investing a lot of preventative dosh in crank, rods and pistons.

Ohhhh! 220BHP would be bliss!

vocky used wasted stem valves with some head porting and he brought himself into the 200's. I have a head on the bench at the moment so hoping to follow into that realm. Not sure I will remove the balance shafts like vocky though. ...

Any recommendation on cams?

Cheers,
Steve

[kek700]

If only? Engines are a bit of a mystery to me? but it does seem that if a enough people put the effort in; Engines can be made to produce good power. Trouble is there is no reason at the moment to encourage the development of the z22se motor, it does require a lot of development work on the dyno, with no race series, ect. There just is insufficient time allotted to the engine. I also think that TMS just cannot spend the time either, they are running a business. You would never think that a 145hp+ could ever be extracted form a 1300cc mini miglia engine. especially with the restriction imposed by the formula. So I am sure that a magic approx 220 bhp at 6.5k-7k is possible, and reasonably cheaply, it is just a case of (how). And probably there would be a few arguments on what is meant by cheap. certainly you are not getting away with a special after market air filter to get the 220bhp.

[vocky]

So I am sure that a magic approx 220 bhp at 6.5k-7k is possible, and reasonably cheaply, it is just a case of (how). And probably there would be a few arguments on what is meant by cheap. certainly you are not getting away with a special after market air filter to get the 220bhp.

mine was 215 bhp (179 wheel hp) last year, I have since fitted a 2.5" exhaust and an underdrive crank pulley so should be 220 bhp now

[kek700]

I am impressed. That's is the sort of power I would only dream of getting for a reasonable outlay. From the bits I have read on the forum no one has got anywhere near that. Apart from a throttled boddied engine from Itay or perhaps Spain ??? that cost a lot though. Could you if possible list the modifications, and have you any idea what performance gains were made with what mod? Did you do a rolling road run before you started modifying so as to quantify your performance gains. My aim is to go for TB when I have enough money. the problem is that they just don’t produce sufficient power on there own. although they do give a reasonable top end gain. So I was hoping a cam change and TB would produce enough power with just these two changes, other wise it starts to get too expensive. And also i dont want to spend loads of money witout being reasonably sure of getting an end result. Do you have a torque curve from your latest rolling road run. sorry to ask all this, but if you could oblige it would be quite useful.

[vocky]

the original thread and the links to www.z22se.co.uk within the thread have the engine specs

vx220.org