4722 replies to this topic

[Nev]

Timing in the VXT will vary a lot on engine load IMO though I am not sure if this is a genuine issue in real terms. Having looked at the difference between slack/mid/tight on the cambelt there must be a lot of variation in timing depending on how hard you are loading the engine. I spent some time moving the camwheels back and forth just to get the timing mark on the tensioner correct, this would vary a lot depending whether the engine is loaded heavily or idling etc IMO.

 

Im not sure if this will have an influence on a map in real terms, as so long as the variation remains the same for the longevity of the belt the ECU will presumably be mapped to take this dynamic load/unload timing variation into account.... *not sure*

 

Edited by Nev, 22 August 2013 - 02:21 PM.

[FLD]

 

 

I'll be interested to see what you think of the ECU.  I remember a lot of aftermarket ECU's having weak timing.  You could set a figure but it would still float around a fair bit.  Only Motec and DTA had tight timing.  I'll be interested to see what the new ECU's are like as this was quite some time ago!

 

Just out of interest.

How did you determine how "tight" the effective timing actually was compared to the map values?

 

 

It was done by having a fixed timing setting in the software and a (decent) timing light.  With some cheaper ECU's you could watch the timing float within a degree or two around the software setting.  Fine for a mildly tuned engine but for anything a bit more highly strung its a bit iffy.   Only with the motec and DTA did it stay rock solid and accurate every time.

[GF ORCE8]

So even at the fixed timing you could find these problems? That´s well...quite wow.... how is it then under transient engine operation?

I expected you measured it under full operation, that´s why i asked about the "how".

 

Has that been done on the same application (same engine and REF/SYNC System) and various ECU?

 

because there definitely are quite some engines out there which are harder to handel (if the OE trigger system is used) than others.

 

However, only working with Motec, Magneti and Pectel I don´t really have these problems at  least if the trigger system is fine.

 

Although I don´t plan to use any of the "cheap" stuff also in future at all.. its interesting to see that it can be that bad!

 

BTW I have my engine already running with an M800 and full stock actuators/sensors as well as wiring incl. connectors (adaptor box).

Just that my project is totally on hold because of not any time for the VX...... So apart from "idling" there is not any maping job done yet...

 

side note to Nev:

 

Ign timing is not really controlled by the crank to cam position. in fact the cam sensor only gives the info to the ECU when CYL1 is in TDC of working stroke.

Ign and Inj. always gets calculated from the trigger wheel of the crank. so crank to cam pos fluctuation (at least if its not "swallowing" a tooth of the crank wheel) on a proper trigger system (e.g. 60-2) has no influence on accurate ign timing or no.

Edited by GF ORCE8, 22 August 2013 - 02:38 PM.

[FLD]

It was indeed the same engine.  Twin turbo 7L LSx hybrid.  The engine was on a dyno stand and the owner was trying to find a decent ecu.  Started at the cheap end as most of us do despite having spent out big time on the engine.  It was some 15 years ago but from my vague memory it was checked at fixed RPM across a range (checked to see if it was a tickover issue).  Some were proper ropey right over the rev range.  Motec was by far the best we looked at.

 

[alanoo]

I won't say that I already told you that... but I did. Not getting a "good" standalone ECU, is really a false money and time saving. If you don't want to move to Motec or Pi stuff, get a Syvecs S6, they are really cheap considering the Life Racing background and functionnaly they have. Add to that some really nice stuff like the new iOS / Android dashboard app which could save getting a real race dash, or the Toucan stuff, it's really bargain

[Nev]

Haha, several people have said "told you so" but it is a matter of money in the main part (and also effort + time) and it's very easy to sit behind a keyboard and say that if you are rich. I will happily listen to anyone who's done 1/2 of what I have on a tight budget

 

I kept putting the ECU matter off for ages I know, as the car was drivable at 22 PSI and 485 BHP, but since it now make 35 PSI due to improved breathing and a couple of other mods it has become a matter of urgency. I would have preferred Syvecs, but the cost was at least £1000 more unfortunately and I had to draw the line somewhere.

 

How is your project coming along then Alanoo ?

 

 

 

Edited by Nev, 22 August 2013 - 04:44 PM.

[alanoo]

I'm not sure it's really a matter of money in the end to be honest, how much money did you spend on the engine globally and on tuning the OE ECU ? A mid-end standalone would have taken what, 15% of the budget ? But I agree, I did the same mistake at the beginning (and that's exactly what I said at the time, my biggest regret was saving on the ECU), so have many other hobbyists with serious builds. To answer about "my projects", I'm focusing on a quite extreme (and pricey) project for my Atom; as it may take some time I will build on cheap my second Speedster chassis with the second hand Saab I got and a SC kit, just to be sure I could get some track time in the coming months when the Atom won't be able to. I will update my old topic in a few days I guess. Hopefully in a few months I will get a garage built at home and things will finally move way quicker...

Edited by alanoo, 22 August 2013 - 04:53 PM.

[Nev]

Installing the new ECU will actually be about 35% of the original engine + mapping, so you can see why I held back.

 

Anyway, I've bitten the bullet now, so hopefully all will turn out good. Having gear dependant/selectable boost control and TC will be a bloody godsend. My last set of rear tyres went bald in about 2500 miles just with moderately passive road driving, I don't like to think how long they'd last on a track

Edited by Nev, 22 August 2013 - 05:07 PM.

[GF ORCE8]

It was indeed the same engine.  Twin turbo 7L LSx hybrid.  The engine was on a dyno stand and the owner was trying to find a decent ecu.  Started at the cheap end as most of us do despite having spent out big time on the engine.  It was some 15 years ago but from my vague memory it was checked at fixed RPM across a range (checked to see if it was a tickover issue).  Some were proper ropey right over the rev range.  Motec was by far the best we looked at.

 

 

Definitely interesting! Although quite some things have happened since 15 years...

 

I'm not sure it's really a matter of money in the end to be honest, how much money did you spend on the engine globally and on tuning the OE ECU ? A mid-end standalone would have taken what, 15% of the budget ?  

 

Well definitely my point of view.

 

Sometimes it´s incredible how much budget gets spent on OE mappings, additional TC systems, additional loging solutions, software to communictae with the OE ECU, external shift lights, external.....whatsowever.

 

In many cases, the sum of all turn out to be higher than a proper standalone system, which delivers all in one, and on a level which is simply not comparable to an OE ECU being tuned.

 

Further so many people just aim for max power figures (and then mainly the peak power).

 

It is soo much more important how driveable everything is ( as long as you donßt aim for 1/4, but definitely then another car then the VX should be chosen anyway).

 

It´s just such a huge difference how driveable a (properly tuned) standalone system is compared to an OE system. The boost control possibilities, electronic throttle response etc. etc. are soo different.

Not speaking about functions like Overrun Boost (Anti Lag) automatic downshift-blip, launch-control, wideband Lambda monitoring and control....

 

Not get me wrong nev, its not re your project but just in general.

 

it simply is that most of the times a OE controlled 400+ BHP are much less usable and resultingly quick, than some finely controlled 300ish.

But you will expereince it very soon, even if your ECU choice really is not the highest range one, it definitely will outgun the OE by far.

 

And everybody who tells me about the good driveability of a OE Turbo..... Well you should drive a properly mapped standalone and then tell judge again...

Since the stage 2 and now stage 3 with LEH, big air CC nothing is even near to having nice driveability sorry guys.

 

So resultingly said.

Definitely from my point of view a standalone should NOT be the last finishing step.

 

With a standalone unit you simply get out the best of ANY system. And what sense does it make to install parts, whichs potential will not be fully explored?

i think wast eof money Would prefer to maximise output and result of existing system.

But finally, its everybody´s choice.

 

Haha, guess that was now some standalone commercial stuff no?

 

OK, end off topic from my side.

 

BTW fantastic project Nev, especially having in mind that you come from a totally different corner!! (business-wise)

[Darcini]

And of course hindsight is a wonderful thing We are all amateur tuners on here, with a few notable exceptions, so we learn by experience.

[alanoo]

And that was my point in fact, we are a forum, we share our experiences

[GF ORCE8]

[Exmantaa]

Does crank trigger resolution have an effect on timing accuracy?

f.i. Comparing the Z22SE 6-1 triggerwheel to the later 58-2 Bosch pattern. I assume the latter could be more accurate during engine transitions?

[Nev]

Comparing the Z22SE 6-1 triggerwheel to...

 

I think you're on the wrong thread mate; if you want to talk about lawn mower engines try this website LOL. JK, we all love the NAs really

Edited by Nev, 22 August 2013 - 10:41 PM.

[GF ORCE8]

Does crank trigger resolution have an effect on timing accuracy?

f.i. Comparing the Z22SE 6-1 triggerwheel to the later 58-2 Bosch pattern. I assume the latter could be more accurate during engine transitions?

 

In this case yes.  6teeth is not really a perfect setup for accuracy/performance.

But I´m pretty sure the new type is a 60-2 no, as is on the LET engines no? (normally you count the missing teeth also for the first number)

[Nev]

Managed to burn my forearm this afternoon changing the oil - not nice

[Ormes]

[Nev]

The evenings are really drawing in now and I can't get out after work in daylight any more. So I tried to go for a drive today at mid-day before the rain comes - complete waste of time with the congestion

 

This has me wondering what to do with myself this winter; the choices so far:

 

1) Build up a new bottom end to mate with my existing head for the eventuality of the current bottom end wearing out.

2) Buy a Jack Russell puppy and train him up fully (added benefit of fitting him in a special seat in the VX with goggles on and ears flapping in the wind)!

3) Be nicer to my girlfriend and bonk her more!

4) Get back to serious fitness (climbing, weights, some running, more karate comps), get my resting heart beat back down to 40, feel/sleep better etc etc.

 

Any suggestions ?!

Edited by Nev, 07 September 2013 - 12:28 PM.

[siztenboots]

stay away from ski slopes with rocks

[jameso]

3) Be nicer to my girlfriend and bonk her more!   Any suggestions ?!

She may argue, depending on the experience, that that's the opposite of being nice