Dip between 3-3500rpm RR printout inside

[Chris205]

Had my car down at RS tuning in leeds during the week where it was ran for a diagnostic check and a couple of power runs

Do other people have the same dip at 3-3500 rpm on a standard mapped car?

I'm convinced the timing is slightly out on it however paul thinks its not something to worry about? I never felt that dip in any of my other clio's so just wondering if this is something out of the ordinary?

 

[Chip-mk1]

Not a big deal really, wouldnt waste money having cam timing redone just for that unless you are due a belt anyway.

Hell of a variation between the two runs though, what was done in between?

 

[Chris205]

Not a big deal really, wouldnt waste money having cam timing redone just for that unless you are due a belt anyway.

Hell of a variation between the two runs though, what was done in between?

Hi chip, thanks for the reply mate, I'm more than likely to be getting the dephaser done soon with the water pump, so a belt change is immenant, which I hope at the same time to put a set of 438's in it.


Changes are ITG Maxogen, de-cat and yozza cat back

 

[townlea]

I haven't got a dip on my graph and that's on standard map. I wouldn't worry about it like Paul has said.

 

[Jon.G]

I would personally say its down to a modification, probably the ITG Maxogen.

When I went last year I did a comparison between the Ph2 Airbox and a Ph1 airbox. If you look at the below graph, the Ph1 airbox run is in green and the ph2 airbox is in red. The ph1 airbox drops torque and power between 3k and 3.5k, however not as much as yours.

Bare in mind that my car has been mapped as well.

 

[mitch1503]

mate its exactly where mine sort of levelled out and then started climbing again and as you know mine's standard other than the milltek cat back so i wouldn't worry

[/IMG]

 

[MartinR]

I can't find my before and after graphs!! but i had the same problem but was due to a dodgy plug, once changed i never had that dip

 

[Dan519]

Got an AFR graph?

 

[Russ_16v]

Have you a copy of the afr's mate?

Edit: Danny beat me to it lol

 

[Chris205]

I dont mate sorry, I may have them from when it was standard though I'll have to have a look through the file

 

[Chip-mk1]

Hi chip, thanks for the reply mate, I'm more than likely to be getting the dephaser done soon with the water pump, so a belt change is immenant, which I hope at the same time to put a set of 438's in it.


Changes are ITG Maxogen, de-cat and yozza cat back

Two possibilities really:
The combination of modifications has resulted in a big drop in ve at that point.
Its not quite been mapped right to suit a smaller change in ve at that point, thus throwing the afr's out.

Paul should be able to email you a graph with afr on it of you ask him for one, the rollers save all that info.

 

[micheal leck]

Christ its lecky that 20 pound dose that get me the wiper running gear and wire arms ? Frayed sending ya a email but it's saying ya r all full ha ha just pm me bk ?

Lecky

 

[Chris205]

Christ its lecky that 20 pound dose that get me the wiper running gear and wire arms ? Frayed sending ya a email but it's saying ya r all full ha ha just pm me bk ?

Lecky

Yeah mate

 

[micheal leck]

Thanks dude

Lecky

 

[jpbacs12]

Might seem like a stupid question what fuel have you been running in the car? and have you changed it very soon before your power run? reason I ask is that the closed loop fuel trim might not have caught up with "new" fuel and with your mods might not burn as efficient with that fuel yet! which also leads to what one of the lads has said about the spark! as this engine is knock controlled and if you dont have a good clean burn (spark/Fuel) you will get det and the knock control will r****d your engine in order to protect it and hence you will loose torque! also the fact you have a de-cat now you exhaust gases will flow more freely (less back pressure) which can also make you see a drop in torque but im not so sure that much of a drop! lol

 

[mitch1503]

iirc he only ever uses Vpower

 

[Jon.G]

Might seem like a stupid question what fuel have you been running in the car? and have you changed it very soon before your power run? reason I ask is that the closed loop fuel trim might not have caught up with "new" fuel and with your mods might not burn as efficient with that fuel yet! which also leads to what one of the lads has said about the spark! as this engine is knock controlled and if you dont have a good clean burn (spark/Fuel) you will get det and the knock control will r****d your engine in order to protect it and hence you will loose torque! also the fact you have a de-cat now you exhaust gases will flow more freely (less back pressure) which can also make you see a drop in torque but im not so sure that much of a drop! lol

How would you explain mine then?
http://www.cliosport.net/forum/show...ntout-inside&p=8818757&viewfull=1#post8818757

 

[jpbacs12]

How would you explain mine then?
http://www.cliosport.net/forum/show...ntout-inside&p=8818757&viewfull=1#post8818757

You cant really tell whats going on unless you have in cylinder traces, or at least see what the output is for the knock sensor at this point is. At a quick look the ph1 box obviously doesnt flow aswell as the ph2 (only a guess as i would need a flowbench to prove) not only is there a dip in torque but also power exactly at the same point. it is a little bit different to chris 205 as yours is happening a bit earlier, but as it seems from what everyone is saying this may very well be a point at which the engine is reaching a high load point (high pressure/high heat) which is a prime area for "det" which in turn will cause the knock control to kick in an r****d your timing hence the torque dip, as i said though it takes alot more investigating than 5 mins lol if you get me. Just a qucik est! hope helps a little

 

[jpbacs12]

iirc he only ever uses Vpower

wel thats good for a start lol, but if his spark/burn isnt that good at that point, and which from what everyone is saying is a prone point for torque dip, any poor combustion is only likely to be made more prominent, which would mean more retarding!! this is only a quick guide not "law" lol my mate is a knock control expert at ford he would elaborate to the heavens end at which point you would be very bored!!

 

[mitch1503]

wel thats good for a start lol, but if his spark/burn isnt that good at that point, and which from what everyone is saying is a prone point for torque dip, any poor combustion is only likely to be made more prominent, which would mean more retarding!! this is only a quick guide not "law" lol my mate is a knock control expert at ford he would elaborate to the heavens end at which point you would be very bored!!

lol tbh mines pretty much ran on 95ron and the day of the graphy i maybe chucked a daft 10er worth of Vpower in.. the only difference i find with my car on Vpower is the cold start lumpiness isn't as bad... it does get the odd bit Vpower/momentum from time 2 time but its not religiously ran on it

 

[jpbacs12]

lol tbh mines pretty much ran on 95ron and the day of the graphy i maybe chucked a daft 10er worth of Vpower in.. the only difference i find with my car on Vpower is the cold start lumpiness isn't as bad... it does get the odd bit Vpower/momentum from time 2 time but its not religiously ran on it

Its grand if you dont because the fuel trim should look after itself (just means you wont get the full potenial from your car), and if you want to run 99 etc it can let you exploit a little bit more from the engine and trim it the other way!

 

[mitch1503]

Its grand if you dont because the fuel trim should look after itself (just means you wont get the full potenial from your car), and if you want to run 99 etc it can let you exploit a little bit more from the engine and trim it the other way!

tbf tho mate look at the graph i posted.. thats only got a cat back exhaust and there was about 3/4 tank of 95 in when i chucked the Vpower in so doesn't seem 2 do 2 bad on 95 lol

 

[Chip-mk1]

Its grand if you dont because the fuel trim should look after itself (just means you wont get the full potenial from your car), and if you want to run 99 etc it can let you exploit a little bit more from the engine and trim it the other way!

Fuel trim shouldnt be effected by different octane, the octane is just a measure of det resistance not of a different lambda value at the end of the day, plus anyway on our cars we only have a narrow band sensor so accurate fuel trim on full throttle isnt possible anyway.
Relying on the knock sensor to keep pulling timing out on 95RON fuel is a bad idea because it means inducing small amounts of det again and again to keep triggering it, and it also means you get worse economy due to the lazy timing when the knock sensor does activate.
Total false economy and if you are unlucky enough to have a bad piston in the engine (the casting quality of these pistons is very poor and its not uncommon for one to have major imperfections that weaken it) then its quite likely to break up if you keep exposing it to det which sends shockwaves through it or retarded timing which ups EGT's

Its just a generally stupid idea to run a car around on a fuel that is worse than it is mapped for, especially on the older less sophisticated ECU's

 

[jpbacs12]

Fuel trim shouldnt be effected by different octane, the octane is just a measure of det resistance not of a different lambda value at the end of the day, plus anyway on our cars we only have a narrow band sensor so accurate fuel trim on full throttle isnt possible anyway.
Relying on the knock sensor to keep pulling timing out on 95RON fuel is a bad idea because it means inducing small amounts of det again and again to keep triggering it, and it also means you get worse economy due to the lazy timing when the knock sensor does activate.
Total false economy and if you are unlucky enough to have a bad piston in the engine (the casting quality of these pistons is very poor and its not uncommon for one to have major imperfections that weaken it) then its quite likely to break up if you keep exposing it to det which sends shockwaves through it or retarded timing which ups EGT's

Its just a generally stupid idea to run a car around on a fuel that is worse than it is mapped for, especially on the older less sophisticated ECU's

It will definitely be affected by octane, as the octane level is directly connected to the burn rate of a given fuel by means of the mass burn faction chemistry equation and specific heat of the given fuel (which will take into account the air burned with the fuel) ie changing your lambda/AFR ps ecu startegy should store the "new" learnt values as it goes along so it wont have to always be detting inorder to find the issue(also apart of injector drift due to aging)! and as I work in an oem car company I know first hand that it is not great to run a car that is mapped for 98ron on 95ron, but as we factor into account "rest of world fuels" not being as good as European fuels the manufacturers will take into account different fuels when calibrating the engine, because if they were so sure that all the fuels would be the same in the areas the car is being sold they would (for this reason) not have bothered to put knock control on the enigne! point taken about the wide band didn't know as haven't looked into it yet with this engine but it will have a fuel trim to compensate injector ageing etc.

 

[Chip-mk1]

It will definitely be affected by octane, as the octane level is directly connected to the burn rate

Indeed it is, absolutely I agree with that.
But the burn rate and the fuel mixture arent correlated in the way that you are implying.
You said fuel trim, which to me means making the car fuel richer or leaner, and the speed of burn isnt what governs that, its the stoich value of the fuel which does so.
A faster burn rate (ie lower octane) will need ignition r****d to cope with not fuel trim.

ecu startegy should store the "new" learnt values as it goes along so it wont have to always be detting inorder to find the issue(also apart of injector drift due to aging)!

Again injector drift is a different thing to different octane ratings, injector drift has no real implications for ignition timing requirements but has a lot of implication for injector timing requirements.

You seem to be getting confused between injector timing and ignition timing perhaps?

and as I work in an oem car company I know first hand that it is not great to run a car that is mapped for 98ron on 95ron,

On that I think we all agree, and its that which wasnt coming across in some of the previous posts which were implying there was no downside to 95 RON fuel, there is, and potentially in the F4R in particular, there is an issue with the pistons breaking up in extreme cases.

but as we factor into account "rest of world fuels" not being as good as European fuels the manufacturers will take into account different fuels when calibrating the engine

While I am sure that you do so right now to a very high standard, did renault do so well enough more than a dozen years ago when these cars were developed? Im guessing not or they wouldnt have been sticking an octane sticker in the petrol cap of everyone so that they could point to it in order to avoid warranty claims if someone ran the wrong fuel and killed their engine?

because if they were so sure that all the fuels would be the same in the areas the car is being sold they would (for this reason) not have bothered to put knock control on the enigne! point taken about the wide band didn't know as haven't looked into it yet with this engine but it will have a fuel trim to compensate injector ageing etc.

Compensating for injector ageing (or lower voltage for that matter which also requires a longer opening and closing time) is a very different algorythm to the one required for a lower octane value which requires a different ignition timing.

I cant help but feel you are posting based on snippets of info you have probably heard from some very knowledgeable people (as its clear from the way your posts are worded that someone who knows a lot about mapping has been involved in where you got the info from) but that perhaps you have slightly misinterpreted some of that info due to a lack of firsthand experience with regards to mapping?

 

[jpbacs12]

Thats person you are talking about is me! and I run and engine dyno day in day out as my job as a calibration engineer, so I may just have a little bit of experience, and as getting mixed up, maybe I didnt spend enough time explaining but im fairly busy and only grabbing my lunch while reading this and talking to people and replying, so sorry I didnt give 100% attention! hands up,

what I said about the injector trim, was just to say that even tho it only has a 4 wire that there is still a little room for compensations and still an area for storing learnt values, as your ecu is learning all the time and will correct fuel and timing according to the fuel being used (closed loop control) also what after market ecu sellers call "automatic Mapping) which I would never use due to wrong values being learnt and big nasty spikes in the fuel and ignition maps!

 

[domjolly]

Not sure what it looks like on a graph but when I had a decat on my 172 there was a nasty flat spot at 3-3.5k rpm. Quite a few people have had the same thing as well from searches on here. Decat might be the issue if your on a standard map

 

[Chip-mk1]

Thats person you are talking about is me! and I run and engine dyno day in day out as my job as a calibration engineer, so I may just have a little bit of experience, and as getting mixed up, maybe I didnt spend enough time explaining but im fairly busy and only grabbing my lunch while reading this and talking to people and replying, so sorry I didnt give 100% attention! hands up,

Fair enough mate, if it was was just lack of time that made your reply not really make sense rather than lack of experience, it was just obvious there were glimpses of good knowledge in there even though it wasnt really right.

Perhaps you can reply again when you have more time to waste

what I said about the injector trim, was just to say that even tho it only has a 4 wire that there is still a little room for compensations and still an area for storing learnt values, as your ecu is learning all the time and will correct fuel and timing according to the fuel being used (closed loop control) also what after market ecu sellers call "automatic Mapping) which I would never use due to wrong values being learnt and big nasty spikes in the fuel and ignition maps!

Im not a fan of any automatic mapping TBH, there are certain circumstances it works ok, but personally I always just do the whole map myself so I know whats going on with it, especially with stuff like hot cams as often they wont actually want the "textbook" lambda values anyway due to all the overlap etc.

 

[Chip-mk1]

Not sure what it looks like on a graph but when I had a decat on my 172 there was a nasty flat spot at 3-3.5k rpm. Quite a few people have had the same thing as well from searches on here. Decat might be the issue if your on a standard map

If he asks Paul to give him the AFR printout, that should be very obvious on that plot if it is the case

 

[jpbacs12]

Im not a fan of any automatic mapping TBH, there are certain circumstances it works ok, but personally I always just do the whole map myself so I know whats going on with it, especially with stuff like hot cams as often they wont actually want the "textbook" lambda values anyway due to all the overlap etc.[/QUOTE]

ya the same as that, I usually try to get the four corners of the map first and then populate it from there, I wasnt having a go chip just a clash of minds lol , I totally understand what you were getting at, but until I find the calorific weight of 95ron and 98/99 ron I wont know lol, I understand you were saying that the high octane fuel will only help with det, which is what it is for! due to its colder burn and slower flame front, but as I said above it has other benifits also! just not gonna say anymore till I have proven it lol,

PS IMO because everyone is seeing this on the full load curve, I believe this is just a prone point for det in this engine and it is the knock control taking action retarding the timing to protect your engine and thus loosing torque!

 

[mitch1503]

On that I think we all agree, and its that which wasnt coming across in some of the previous posts which were implying there was no downside to 95 RON fuel, there is, and potentially in the F4R in particular, there is an issue with the pistons breaking up in extreme cases.


Well im not really worried about is as i covered 45k hard driving miles within 17 months give or take 1 or 2 months.. If it goes bang it goes bang

 

[jpbacs12]

On that I think we all agree, and its that which wasnt coming across in some of the previous posts which were implying there was no downside to 95 RON fuel, there is, and potentially in the F4R in particular, there is an issue with the pistons breaking up in extreme cases.


Well im not really worried about is as i covered 45k hard driving miles within 17 months give or take 1 or 2 months.. If it goes bang it goes bang

There is a downside but, the knock control will look after this (but there is the question does this ecu have both r****d and also advance control to make the most of the high octane fuel or recover the loses from a period of running $hitty fuel because if it doesnt it will store the corrected for knock settings to protect the engine which will be retarded and when it come to running 98 again it wont advance forward again to bring the torque back so will remain in a derated form!), I have not looked into renaults control strategy or the engine properly yet, so not exactly sure yet how renault control strategy works!

 

[Chris205]

Thanks for all the input chaps, I'll get in touch with paul this week sometime and see what's happening.

I think it's from the de-cat, I may well put the standard 182 sport cat back in as tbh the exhaust is rediculously loud with a de-cat on.

jpbacs12 - cheers for the help mate, nice to know there is another technically minded person on here like chip, FYI its always been ran on vpower and always will be in my ownership

 

[jpbacs12]

Thanks for all the input chaps, I'll get in touch with paul this week sometime and see what's happening.

I think it's from the de-cat, I may well put the standard 182 sport cat back in as tbh the exhaust is rediculously loud with a de-cat on.

jpbacs12 - cheers for the help mate, nice to know there is another technically minded person on here like chip, FYI its always been ran on vpower and always will be in my ownership

No worries at least we can bounce ideas off each other in the future , as for getting rid of your de-cat, at top end you will see an advantage of the freer flow through the exhaust its just at the lower down slower speeds that you wont get maximum benefit but the standard manifold is a 4-2-1 which is the most common and main design to give the best low down torque. are you going to get a re-map or have you had one already?

 

[Chip-mk1]

ya the same as that, I usually try to get the four corners of the map first and then populate it from there, I wasnt having a go chip just a clash of minds

Likewise mate, no offense intended or taken from my side.

I totally understand what you were getting at, but until I find the calorific weight of 95ron and 98/99 ron I wont know lol

Its something I have seen research on but not got the results to hand for, and in many cases the higher ron fuels are a LOWER calorific value, for the simple reason that ethanol is a cheap way to increase det resistance but is slightly lower in calorific value.

For an extreme example, E85 for example is about 110 RON but has a calorific value about a 1/3 lower than normal petrol, so you actually need to add a hell of a lot more injector duration when mapping on it, which is exactly the opposite of what your posts would have implied to people.

Its quite counter intuitive, the RON value really isnt telling people as much as they think it is in most cases!

I understand you were saying that the high octane fuel will only help with det, which is what it is for! due to its colder burn and slower flame front, but as I said above it has other benifits also! just not gonna say anymore till I have proven it lol

I like people who want their posts to be accurate, I am of the same mindset.

PS IMO because everyone is seeing this on the full load curve, I believe this is just a prone point for det in this engine and it is the knock control taking action retarding the timing to protect your engine and thus loosing torque!

Its a high comp engine and in the midrange the VE is quite high, combined with a long stroke that all leads itself quite well to inducing det, so its not a surprise if the knock sensor has triggered.
That said though, from other engines Ive seen knock on the rollers I would expect a more vertical dip down not such a smooth curve if it was a knock r****d strategy causing it. It may well just be a VE dip as a result of the mods done to it.

 

[Chip-mk1]

jpbacs12 - cheers for the help mate, nice to know there is another technically minded person on here like chip, FYI its always been ran on vpower and always will be in my ownership

Agreed, I like having technical peers to discuss stuff with, but with me being the old man of the forum it doesnt happen as often as I would like, lol

 

[Chris205]

No worries at least we can bounce ideas off each other in the future , as for getting rid of your de-cat, at top end you will see an advantage of the freer flow through the exhaust its just at the lower down slower speeds that you wont get maximum benefit but the standard manifold is a 4-2-1 which is the most common and main design to give the best low down torque. are you going to get a re-map or have you had one already?

Cheers mate, yeah I was aware the car would lose the low end torque with a slight gain on the top end, its just become more apparent now and with a car I find already struggles with low end torque its the last thing I need.

It's still on the standard map mate, however this will change soon as I plan on fitting cams then getting it custom mapped