Pinking S/C IS help!!!

[appletree]

Right, i've just bin out for a run in the IS and it suddenly started pinkin at WOT in 4th and 5th, in 4th its only very slight but in 5th it quite bad!

Now i've not changed anything on the car the fuels lower than i've ever driven it before but not on the red make yet and the light hasnt come on, cant see why this would make a difference but its another variable.

aslo just connected up the Laptop and the inlet temps between 42-45C depending on throttle position whoich is what it was when it was mapped the only other thing i've done is put a 325 (3.64LSD) on the car does anyone think this could be the problem???? its now having to pull a higher gear at the top???

ive just tryd putting my spare set of plugs in that are one grade cooler running and it has made a slight difference but there still pinking there.

Could ui try just upping the fuel pressure alittle???

[billgatese30]

try filling the tank first, seen as this is the first thing (and easiest thing to try) that you have noticed to change since the pinking started...if its still there then start again..........if it goes away then it may be fuel pressure, keep an eye on it through out the next tanks usage

[Turbo-Brown]

Don't piss about with the fuel pressure when you've got the Emerald in there!

You can do a block increase of sites by some percentage of your choice (highlight some cells in the fuel map and press Enter)

Save the map first so you can go back easily

[Ant]

the load vs rpm has changed with the higher final drive so I'd sugest leaving the fuelling alone and playing with reduced timing where the det has ocurred.

intake temps aren't that high dude

was this mapped Alpha N or speed density blended( with map sensor )

[appletree]

Right ive just filled up will petrol and its still doing the same, its still only doing it in 4th and 5th between 3.5krpm (comming on the cam) to about 4,5krpm past that is ok!

how much should i be increseing the sites by?? and is it a fueling issue or a timing issue or both?? and yes i have saved the map to start with and have 3 different maps to play about with so i'll play with one of the spares.

[M5pilot]

Putting a higher final drive will have no effect on the mapping in any way what so ever!

Evo-S

[appletree]

Yes Ant it was mapped using a MAP sensor and then the normal temp, rpm and throttle position inputs.


I thought a higer final drive was like riding your bike in 1-2-3-4-5 gear and then swoping to using only 3-4-5-6-7 gear your putting the same power in but the work your doing is more? is that the right way of looking at it?

[Ant]

Sal, it will affect the mapping( iMHO)

example:

peak N/A torque causes issues with boost, so DW moves load sites to concentrate the mapping in that area to reduce the tendancy to det, now with the higher final drive those sites are now in the "wrong" place, so given the overall hike from an assumed 4.1:1 diff to a 3.64:1 diff thats a big change

Hence the question, Alpha N, Speed den or blend of both ???

you'd have to concede, if everything else remained the same, yet it now dets where it didn't then it would affect the mapping

remember this is real world driving, not steady state on a dyno.

[appletree]

Thats what i thought Ant i think before the peak torque was between 3-3.5krpm and now the cars seams to pull stronger up the revs more.

In your opinion would i be better to take it back to DW and get a full remap or is it only a case of changing a few sites?? i'll will ing to have a go although i havent done anything with it before.

Just a few more bits i can drive up to th opening of the second butterfly on the throttle in 5th before anything starts to pink and by this time the revs are 3.5k also my AEM air/fuel ratio guage is reading 13.1:1 at WOT when the pinking starts, i dont know how accurate this is as i've never been able to check it against a calibrated test bed

[Ant]

Matt, change the AFR target to 12.1 @ that site and see if the det is improved.

TBH I'd forgotten the twin TB setup, the second chiming in would certainly have a huuuuge effect on the overall throttle area with the manifold pressure changing rapidly at the same time.

I dont have much experience with emerald so a call to DW would be a wise investment of time dude

re the WB, calibrate in free air every three months to keep it tip-top.

[Turbo-Brown]

The engine has no way of knowing what it's driving so the final drive ratio won't have made any difference to the mapping.

Look at it this way (some people will recognise this from another site)

If your N/A or S/C (possibly turbocharged engines would be the exception) engine made 200bhp at 6000rpm and you floored the throttle with the car in neutral, the instant the crank gets to 6000rpm the engine is making 200bhp. That's not affected by mechanical load on the engine and as such the fueling and timing requirements are exactly the same as those required to hold the engine back at 6000rpm on full throttle on a rolling road, up a hill or whatever.

[appletree]

i understand that the engine is still only working between th same 0 -6000rpm range with the same fuel, inlet temps...... as before and there for in any gear as the engine doesnt know what gear/fianl drive your in but surely the the engine is working harder going up a hill or pulling a larger gear on the flat

Why would you have to dropdown a gear in small engine car? if the engine will go up the hill in 3rd why wont it pull the car up in 4th? the engine doesnt know what gear its in and still has the potential to make the same power??

This is whats happed to my car its lost 1st and gaind a 6th gear its the Load thats changed and thats what i thinks the problem.

Would anyone else have any idea what else could have suddenly changed to make this problem??

[Turbo-Brown]

You need to drop down a gear because for any given engine speed with full throttle, you can only make one given amount of power. If the small engined car can't make enough power on full throttle to maintain speed up the hill, you must enable the engine to go faster and (hopefully) make more power.

Look at it another way:

Power is the rate at which your engine is doing work. That rate of work is directly proportional to the amount of fuel it burns/unit time so, if we took an example where each 1unit of fuel in the Emerald's map could make 1bhp, we'd see that the point corresponding to load site 15 and the 6000rpm speed site would contain the number 200.

Now we can see that, revving the engine on the drive in neutral with full throttle, at the instant the engine reaches 6000rpm, it's consuming 200bhp's worth of fuel. Despite the fact that your 200bhp isn't doing anything useful, it's still being made.

Anyway, back to the problem, check that the ECU is still reading the TPS properly. We had one melt on my engine and it was just giving a reading of 58% or something like that, almost regardless of the actual throttle position.

Perhaps re-align the throttle pot at least as it only takes a minute.

Mabey check for collapsed exhaust components after that.

[jkarran]

I'd have to agree, in theory the engine doesn't care if it's driving a high diff, low diff, propeller or generator set. However, it may always have been detonating at the load/rpm sites that are now a problem, it's just that with the other diff in you passed over them quickly so didn't notice or care, perhaps the new diff and your driving style are just putting you in a region where it pinks a bit.

Other thing to consider is the fuel. If it was a bit marginal already it may only have taken a small change in fuel blend to upset it, winter's coming on fast and the fuel blend will be changing. Maybe try some different fuel from another station, see if it helps.

I wouldn't play with the FPR to fix it, use the computer, at least that way changes are easily quantifiable and reversable.
jk

[Ant]

^^^ agreed, but anything other than a MAF/AFM besed SD metered ECU setup is very sensitive to changes. Even a change in airfilter required the low rpm high load sites on Sals Alpina with MBE to require tweaking.

the point at which Matt triggers the second butterfly may have changed and that could cause a momentary lean spot hence the pinking ? again cant say 100% as I'm unsure whether the Emerald uses TPS drive AE, map based or both.

but taking the text Alex has posted literally, surely you could map an engine in neutral just be revving it...... which of course you cant

[jkarran]

You could if your ego sensor had a fast enough response* and the flywheel was heavy enough

*no chance with real world engine acceleration rates and sensor response speeds.

Wouldn't take account of any heatsoaking effects of course but in theory there's no reason why you couldn't use a flywheel as a load other than the fact it'd be a monumental pain in the ass!
jk

[Turbo-Brown]

In theory, you could......but only if you could put data in the map fast enough.

The only reason it's not practical is that you can't make adjustments for full throttle at 3000rpm with no load on the engine to prevent it accelerating past 3000rpm for example. It's also why it's a bit of a pain to map on the open road, the load and speed sites are constantly changing and it's very difficult to get bang in the middle of a speed/load site.

In the same way, because we're only revving with full throttle in neutral, the engine will only make our 200bhp for the instant it's doing 6000rpm but, as there's no load on it, it wil very quickly rev beyone 6000rpm.

EDIT> beat me to it JK

[ste]

You could if..... .......the flywheel was heavy enough

...afterall, an engine dyno is essentially a very heavy flywheel.

Manufacturers map engines when they are out of the chassis sat on a dyno cell.

[M5pilot]

Ant,

why is then that when people change their diffs on FI and NA cars they don't need to get a remap??

What the probable cause of Matt's problem is that certain load points haven't been mapped.

Steady state dyno tuning is essential for getting the best out of a car and in practice cars mapped on the dyno are better than those mapped on the road.

Evo-S

Sal, it will affect the mapping( iMHO)

example:

peak N/A torque causes issues with boost, so DW moves load sites to concentrate the mapping in that area to reduce the tendancy to det, now with the higher final drive those sites are now in the "wrong" place, so given the overall hike from an assumed 4.1:1 diff to a 3.64:1 diff thats a big change

Hence the question, Alpha N, Speed den or blend of both ???

you'd have to concede, if everything else remained the same, yet it now dets where it didn't then it would affect the mapping

remember this is real world driving, not steady state on a dyno.

[appletree]

I can see what you mean about sitting the car on the drive and be able to map it but my car doesnt pink when its sat on the drive in nutral reving it to what ever..

Spoke to dave walker yesterday and he says that the diff change WILL have changed the conditions the engine is now running in, the main problem is that now the engine is staying in a persific place for a longer peroid of time, that may have been mapped fine when the car wasnt going to be running there for a long time however now the engine is staying in the same place the conditions that were OK before my be alittle off when the engine running in the same place for longer.

Dave suggested that in his experience the problem is now that the chamber is given longer to heat up under conditions that may have been exaptable when the revs passed them quickly but now the longer time has given the chamber chance to heat up and make a hot spot (probly the spark plug) which is causing the pinking the fix is pritty much what Ant suggested to retard the timing 2degrees in the problem area and try again.

report back later!

[appletree]

Right i've been playing with the mapping and had a steep learning curve in using the emerald soft ware which i must say is very easy to use like a nokia if you know what i mean.

Anyway in the end ive retarted the ignition timing3 degrees in the problem area which has totaly removed all of the pinking.

I'am happy again now!

[Gortour]

Well done Matt.
Looking forward to seeing this car on Saturday.

[Turbo-Brown]

The diff hasn't changed the conditions the engine's operating under though really, it's just showed up a spot which wasn't mapped properly.

I've a feeling that the mapping for the upper reaches is done using power runs and mixture logs rather than holding one speed/load site which is why it wasn't picked up during mapping on the rolling road.

[appletree]

Possibly so Turbo brown, i think its fair to say that we were al right in what we were saying up to a point.

I cant quite remeber how Dave walker mapped the high end stuff, i think theres a feature on the emerald were you can set two points say 3000rpm and 3500rpm and then ask the computer to "fill" in the rest, so this might be a part thats been over looked due to it running good enough on the old conditions to not worrent fine tuning that area.

[jkarran]

Nothing too bad then Matt, that's good news! PPC article was good and well deserved, that's a seriously tidy car
jk

[M5pilot]

I would have expected Dave to map the engine properly. As T'Brown correctly points out, the fact pinking occured under a different condition (load, temp.....) clearly shows mapping had not been done to the extent it should have.

Matt, as I said to you on the phone the other day, your just too nice a guy. Anyone else would have taken the car back and asked for a more complete job.

Evo-S

[appletree]

I may have been tempted to but its 300mile odd to daves and in a car you cant use 4th an 5th in properly...., he did offer to sort it out but its along way and said i could probaly do it from my house if i wanted to save the jerney.

[Kos]

I would have expected Dave to map the engine properly.

Evo-S

dave walker been mapping for years sal, i think he knows what he's doing considering he's designed his own ecu's .

if i recall correctly , there was an issue with the intake temp when the mapping was done and a quick solution had to be found when it was on the rollers to continue the session, and mat hase since then changed the rad for the charge cooler for a more affective one to lower the intake charge temp. this is no fault of dave then .

re the diff, i am in agreement with ant on this one, the mapping done with the original 4.1:1 diff, if so moving to a taller diff will have some affect on the mapping as the engine is under load for longer in any gear and being FI it affected a fair bit more and sensitive to intake temps than NA imo. what you have to consider is that emeral has not got any knock sensors where as most car you map are on original ecu's which have factory knock sensors.

[Turbo-Brown]

Surely saying that fitting a taller alters the mapping is the same as saying that driving up a steep hill alters the mapping, or having a car full of fat people has the same effect.....or even worse, driving fat people up a steep hill?

Your maps should let you hold any load you want, all the live-long day so long as the uppy downy bits don't let go.

[Demlotcrew]

I have to agree turbo-brown, there is no way changing the final drive ratio could affect the mapping of the engine and i to conclude the mapping 'may' not have been done right at the time but also at the same time the whole setup might have developed an air leak which is a known problem for SC engines. I really doubt that Dave would have risked not doing the job well.

Will be interesting to see if the pinking comes back.

[Kos]

i belive the original map was not given enough margine and now with a taller diff under different rpm the loads different now and "high lighted" a problem which wasnt noticed before.

again i go back to the fact ( it was mentioned in the write up ) that there were propbs witht he charge cooler and intake temp which almost called it quits on the mapping, no fault of daves, these things happen to the best of them

[Demlotcrew]

TBH i cant see how the map would have been so far off (3deg) that a diff change highlighted the problem.

Me thinks something else has also broken/worn out.

[Kos]

TBH i cant see how the map would have been so far off (3deg) that a diff change highlighted the problem.

Me thinks something else has also broken/worn out.

i'm not a maping expert, just posting my thoughts .

[Turbo-Brown]

If the site in question was in the upper reaches of the throttle/rev range I believe that mapping is carried out using power runs and mixture logs and not holding load for prolonged periods of time which could explain why it wasn't picked up.

To my mind, it doesn't matter how much experience you have doing a particular job, errors will always creep through the net. I work with a team of technical designers. Unlike most companies, we employ a stringent double check system before issuing drawings which weedles out 99% of errors. However, they do find their way through every once in a while.

What matters then is how the problem is dealt with and, by the sounds of it, Emerald offered to fix the problem and also gave advice on how to overcome it which is what really matters.

I still have the utmost faith in Emerald and will be taking my car to them once the new engine's complete without the slightest hesitation!

[Gunni]

This is obviously a compensation tuning problem,
the higher diff allows for the engine to maintain the same rpm longer and build heat faster,
in this case to fast,
It sounds like the car wasn´t tuned on a steady state dyno as that would have put the maximum load possible
at each rpm and load cell.

Load is not just air pressure load or throttle angle, but also
Air Temp
Coolant Temp
and snap throttle movement,