VX220 2.4L VVT ITB conversion

rabidh

Ok, quick update as it's been ages since I said anything. I basically got snowed under with work and didn't get around to doing much for a while.

I replaced the silicone hoses on my ITBs, but I still have a minor air leak where the old manifold joins the aluminium adaptor plate that goes onto the manifold. A bit gutted with this really because I'd cleaned everything up and put new gasket material in too. I should have just rammed hylomar everywhere.

Everything's running pretty well and properly mappable now though, but the cams are still not right and I don't get any real mid/high range torque. However I just got a reply on the hptuners forum (should have asked there earlier really 🙂 and got the following cam timings - which I'll try out tonight. It should make a much better base (as the other values I had were almost 20 degrees off in places.

I still have to do some hardware tweaks to the ECU before I'm happy (I had to get towed home once after I was driving back topless in the rain and the ECU got wet 🙂 ), and I might swap to using a more powerful processor instead of the two PICs I have currently - but that all depends on me getting a bunch more free time than I currently have.

I'll report back after i've tried these new maps 🙂

rik1083

cylinder air mass, does that mean you're running MAF?

rabidh

Unfortunately no, I'm running based on MAP.
It means I'm going to have to guess - but this is still a lot better than what I had previously 🙂

I'm still not sure about the huge change in timings at 0.48g - I wonder if it's some safety zone for after-market forced induction, or whether the top half of the graph is effectively economy, and the bottom half is for power.

edit: So rough calculation seems to go like this:

g/sec = g/cyl * RPM * cylinders / (60*2)

And I saw somewhere that very roughly, g/sec = 0.8 * bhp

Going by that, assuming 173bhp@5800rpm which is what the engine manages stock, we have 0.72 g/cyl

So I reckon that puts us safely in the big area in the bottom half of the graph (>0.5g/cyl) that's all the same. It must be what you get at WOT, and the rest is all for part throttle and is I guess mainly for economy. So IMO that makes tuning with MAP relatively easy - I'll just map everything to the WOT values 🙂

alanoo

Are these the OE cam angle maps or tuned ?
As you said, most likely it is for economy, but it could very well be for driveability issues too, even at WOT but low RPM

rabidh

OE maps. They're on some guy's turbo engine, but only because he hasn't touched the cam angles since fitting it.

Just been rewriting these maps for my ECU, and often the old map was around 10 degrees out at WOT (and the areas where it is out correspond to areas I've been feeling the power drop off) - so fingers crossed 🙂

rabidh

And it works much better!
Still not as mind-blowing as I'd hoped, but a great deal better than before, especially as I can now advance the spark timing without it sounding unhappy... I guess I just need to go on a rolling road and try some runs with the cam timing set a bit either side - I don't suppose anyone knows of a decent rolling road near cambridge that would take on a non-standard ECU (maps are still tweakable easily)?

Out of interest, do rolling roads use any special kit for sorting spark timing, like a plug-on knock sensor or ion-sensing plugs - or to they just do a series of runs with different values and generally use previous experience?

alanoo

Any update on this ?

rabidh

Yeah, just driven back from Cambridge in it 🙂

I've only done a few tweaks recently, but it has improved massively...

I sorted the mapping software, so I can tweak the spark, inlet and exhaust cam maps while the engine is running - it makes it much easier to drive around and tweak things with a laptop in the passenger seat.
I changed the cam maps so that it uses the wide open throttle map all the time. Now it only varies the cam position with RPM. It's made the throttle response a million times better and the engine a lot less jumpy on part-throttle (at the expense of some economy I guess)
I found the main reason for the lack of power. Because I'd rigged up my own pedal arrangement, in my haste to get the engine running I'd slapped everything together and then worked on the ECU. End result: Foot to the floor = only 2/3 throttle.

I'm still finding that power tails off a little at high RPM and I know that the run into the inlet could be more smooth, also I'd rather have the nice shiny pedal arrangement from Webcon. A few days ago I gave in and bought the Webcon ITBs and pedal kit, but without the ECU - so in about 3 weeks I should be able to fit it.

An interesting side-effect of the mapping change for the Cams is that it would be really easy to make a secondary ECU that just handled the Cam timings with RPM. It could potentially also change the crank pattern from the 58 tooth to the 7 tooth (or whatever it is) for the Z22SE/Webcon.

vocky

webcon use the Ford 36-1 trigger wheel pattern :thumbup:

rabidh

36-1 as in 36 teeth, with one missing?

Realistically, if a cam timing ECU was made, unless it was very clever the engine would take one more rev before it started, but I doubt that's such a big deal. I think it'd do pretty well after that.

rabidh

Bad News... A few weeks back I'd made a few tweaks and had everything going great. Took it for a 40 mile drive to my folks, everything perfect. Nice sound, fuelling good, lots of power... Took my dad for a quick spin and just 200m outside the village (_4000rpm, WOT) the engine just started running on 3 cylinders and firing out one of the TBs 🙁

Towed it back and didn't have much chance to work on it until this weekend. It was a bit of a labour to get into it... I'd put the engine in then the clam on, and the extra 2cm length (for VVT) at the top means you can't even get the rocker cover off without cutting the clam, not to mention trying to undo the sprockets. Anyway after much anguish I got the head off:

plugs slightly bent
debris lurking in the inlet manifold of cylinder 3
the block:

3 of the 4 cylinders have the exact same piece missing, with the hole going right through to the piston ring. Frankly it's amazing it ran at all. The head is a bit pitted and one or two valves look bent but it's more or less ok.

Right now my feeling is that there was an electrical failure on the ECU which jammed the valve phases over to the far end of their travel. I have a log from the ECU of the moment the engine trashed itself, so I'll have to analyse that. Even so it seems really strange that exactly the same piece of all the pistons failed (why not the other inlet valve's edge?), and that there isn't noticeable damage to the edges of the valves... Also god knows why piston #1 is so pitted when I have ITBs and a 4:2:1 exhaust manifold - I don't have huge balancing pipes so I don't see how that much crap can make it back into the cylinder.

I still don't really believe that the LE5 is designed such that an electrical/software failure can do this to your engine, but I may just be in denial 🙂 I'll try and work out the valve profiles and see if it's possible that they can actually touch the pistons. If not I don't know what it could be...

So in summary, if you're thinking of getting a 2.4L engine... don't.

God knows what I'll do now... I've kept all the old wiring so I may just put a stock Z22SE back in it. To be honest I'm a bit fed up with engines now... I could go electric, or fit pedals or something.

vocky

personally I would fix the 2.4 bottom end and junk the vvt head, but if you decide to sell let me know

rabidh

It's a plan...
I ordered the WebCon kit (without ECU) a while back - I haven't heard from them yet, but I could get the ECU too and fit a trigger wheel and Saab head (how much do they cost now?). I'd have to get it machined out to the larger bore though (it seems in the states they sometimes don't bother, but that would worry me too much after all the trouble I've had 🙂

alanoo

Strange failure, but it can surely be VVT related.

The strange bit is having the exact same damage on 3 pistons, wonder if it is not knock related as this zone is normally a bad mixture zone notsure.gif

vocky

if you want the full itb kit Webcon will supply it direct and if you quote me they will price match TMS [£1850 inc vat]

TMS are selling the itb kit at well under the rrp :silent:

alanoo

Oh, if you're selling the 2.4 crank, I'm interested 😃

EDIT : ah vocky is already on it indeed :thumbup:

rabidh

You guys are vultures :p
But yes, I'll let you know if I do get rid of it 🙂
Is anyone trying to get rid of a saab head? Or is it cheaper to get to a scrappy now the cars are getting older?

vocky

we really want you to fix it, so by us being vultures you realise not to sell it :lol:

saab heads are getting cheaper, you can buy a complete engine for £450-500 these days

ATOM_X

rabidh said:
You guys are vultures :p
But yes, I'll let you know if I do get rid of it 🙂
Is anyone trying to get rid of a saab head? Or is it cheaper to get to a scrappy now the cars are getting older?

Hi Gordon
I have a complete low mileage saab engine awaiting breaking
If interested I can bring head down to you for approval on Sunday
as I am visiting bedford

alanoo

rabidh said:
You guys are vultures :p
But yes, I'll let you know if I do get rid of it 🙂
Is anyone trying to get rid of a saab head? Or is it cheaper to get to a scrappy now the cars are getting older?

But what do you plan to bolt your Saab head to ?
I feel sorry for this, but the 2.4 bottom end is most likely dead... The liners will be almost certainly scratch marked and as these are already bored to 88 mm, I doubt they could be rebored +0.25 or 0.50mm with some safety in mind :crazy:

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