clio 182
Heres my turbo
Megane 225 pistons and rods
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Decided to turbo my 182
- Thread starter stevenajames2012
- Start date
Heres my turbo
Megane 225 pistons and rods
clio 182
My manifold will be here soon
Very nice, sorry to hijack your thread btw. Also strange how your log manifold has circular exhaust ports?
I'm redoing my cam timing tommorow, ill lock crank at TDC, loosen inlet pulley and manually rotate the cam until the piston hits the valve and upload a picture to show what angle this is and show you the sort of cam timing angle that is required.
I'm redoing my cam timing tommorow, ill lock crank at TDC, loosen inlet pulley and manually rotate the cam until the piston hits the valve and upload a picture to show what angle this is and show you the sort of cam timing angle that is required.
clio 182
That's ok mate information I wanted to know too. Oh ye I didn't notice that lol that's odd :/ don't know if that will work :/ what you think?
Had a play with the cam timing today, it was all a bit of a guesstimate really.
See picture...
The exhaust cam stays at 0 degrees, i bent my timing too to approx 7 degrees of r****d on the inlet. THe dephaser always biases towards advance (think its something to do with the spring), so its probably worked out more like 5 degrees. But the engine runs happily with the VVT plugged in now, no noises and drives fine.
See picture...
The exhaust cam stays at 0 degrees, i bent my timing too to approx 7 degrees of r****d on the inlet. THe dephaser always biases towards advance (think its something to do with the spring), so its probably worked out more like 5 degrees. But the engine runs happily with the VVT plugged in now, no noises and drives fine.
clio 182
will this manifold work guys? The ports are round instead of a oval shape? Cheers
Just so it doesnt hit the piston, but the decreased overlap should help aswell i believe on boost?
R5 gtt, R27 F1 team
well i'm probably just as clued up on cam timing as you are but after reading several forums etc this is what i understand:
retarding the inlet cam reduces overlap which makes for a slightly more sluggish bottom end, that's because to get the max VE an n/a engine relies on ram filling/scavenging.
however when the turbine wheel starts to create high back pressure especially at higher revs with smaller turbine wheels and a/r ratio the backpressure could exceed the inlet pressure resulting in filling the cylinders with hot air. that hot air is going to heat up the burning mixture without the effect of more burning because of the low oxygen already burnt gasses. this in return will result in less fuel burning and less timing due to the knock limit getting closer because of the hotter gasses.
so contradictionary to an n/a which will need more overlap at high revs to efficient fill the cylinders, a turbo engine will need less overlap to reduce the hot, burnt gasses from returning back into the cylinders. obviously when using a larger turbo which equals less backpressure more overlap could be used.
because of this thread i'm looking into retarding my inlet cam on my F7R turbo too. obviously toying with it will give best results but i'm curious how Chip thinks 4-5 (8-10 crank)camshaft degrees r****d would affect.
btw, by looking at the graph you posted roughly measuring told me the Megane has 37,5 degrees of overlap with approx. 0,3mm lift opposed to the f4r's 45 degrees overlap with approx. 0,7mm lift. (this is all measured from my computer screen so not accurate at all, assuming the graph itself is right, but atleast it gives some indication of what we want to achieve).
i hope where not steeling this thread too much but i guess Steven will learn from this too.
retarding the inlet cam reduces overlap which makes for a slightly more sluggish bottom end, that's because to get the max VE an n/a engine relies on ram filling/scavenging.
however when the turbine wheel starts to create high back pressure especially at higher revs with smaller turbine wheels and a/r ratio the backpressure could exceed the inlet pressure resulting in filling the cylinders with hot air. that hot air is going to heat up the burning mixture without the effect of more burning because of the low oxygen already burnt gasses. this in return will result in less fuel burning and less timing due to the knock limit getting closer because of the hotter gasses.
so contradictionary to an n/a which will need more overlap at high revs to efficient fill the cylinders, a turbo engine will need less overlap to reduce the hot, burnt gasses from returning back into the cylinders. obviously when using a larger turbo which equals less backpressure more overlap could be used.
because of this thread i'm looking into retarding my inlet cam on my F7R turbo too. obviously toying with it will give best results but i'm curious how Chip thinks 4-5 (8-10 crank)camshaft degrees r****d would affect.
btw, by looking at the graph you posted roughly measuring told me the Megane has 37,5 degrees of overlap with approx. 0,3mm lift opposed to the f4r's 45 degrees overlap with approx. 0,7mm lift. (this is all measured from my computer screen so not accurate at all, assuming the graph itself is right, but atleast it gives some indication of what we want to achieve).
i hope where not steeling this thread too much but i guess Steven will learn from this too.
You are correct mate, hence now I am on the 197 cams I am no longer using the vvt as I don't want egt going too high on boost. I will at some point wire it in for when at big throttle angles but low boost values though as at that point the extra overlap can increase power and also the higher egt will aid spool.
With regards to retarding it, I'm not convinced it is going to be beneficial performance wise to do so but every type of engine is different and I haven't personally tried r****d on the inlet cam on a turbo f4r with 172 cams like laines and the same turbo and manifold and It really is that specific. That said retarding the inlet in general is a safe way to go, as is advancing the exhaust to reduce overlap too so I would be surprised to hear of a problem caused by it. Its more overlap that is the dangerous game to play on boost.
With regards to retarding it, I'm not convinced it is going to be beneficial performance wise to do so but every type of engine is different and I haven't personally tried r****d on the inlet cam on a turbo f4r with 172 cams like laines and the same turbo and manifold and It really is that specific. That said retarding the inlet in general is a safe way to go, as is advancing the exhaust to reduce overlap too so I would be surprised to hear of a problem caused by it. Its more overlap that is the dangerous game to play on boost.
clio 182
I don't mind you stealing my thread but I wouldn't mind an answer about the manifold? Don't think it will work as the ports are round instead of an oval shape what you think pics above?
AndyRG said he used his fixed timing on his meggane turbo 8 degrees permanent advance to get his 326bhp which contradcits exactly what is discussed above about reduced overlap helping, which is quite strange.
But from what i can make out the timing change i have done will reduce my low end a bit (hitting a max of about 5-7 degrees advance compared to the stock 16), but will beneficial on boost and higher up. But like we all know, the proof will be in the pudding.
But from what i can make out the timing change i have done will reduce my low end a bit (hitting a max of about 5-7 degrees advance compared to the stock 16), but will beneficial on boost and higher up. But like we all know, the proof will be in the pudding.
How does it contradict what is above?
His EGT's would be higher doing that than if he hadnt, but that doesnt mean it wont still work, and there are other ways to help control EGT anyway, like design of manifold and how rich you run the engine.
The reality, putting all the theory to one side, is that within reason no matter where you swing the cam to on the F4R once its on boost it will just love it and go like hell IME!
R5 gtt, R27 F1 team
if it doesn't differ that much you maybe could work the manifold to suit your ports better?
Chip, wouldn't advancing the exhaust cam eat up more of the burning process since the valves open earlier in the cycle? so maybe better spool but less topend although because of less overlap it would still benefit over the whole upper rev range.
could be a good mix 'n match to get most spool ánd most power in revs. you f4r guys are lucky you won't need verniers, saves another 250 quid! although which isn't alot of money for the gains that may be had!
Chip, wouldn't advancing the exhaust cam eat up more of the burning process since the valves open earlier in the cycle? so maybe better spool but less topend although because of less overlap it would still benefit over the whole upper rev range.
could be a good mix 'n match to get most spool ánd most power in revs. you f4r guys are lucky you won't need verniers, saves another 250 quid! although which isn't alot of money for the gains that may be had!
I'd be trying to match the ports of that manifodl to the head. Im guessing the missmatch will create turbulence, decrease flow, increase EGT's / valve temperatures and cost performance. My manifold looks identical to your but the ports are oval and match the 172 ph1 cylinder head perfectly.
R5 gtt, R27 F1 team
don't forget as you've seen in the chart the timing of the megane is different from the start, so maybe advancing his inlet cam on the Megane standard timing would still be retarded compared to the F4r standard timing. i don't know what turbo he used but if he used a larger unit that the original one for instance it would benefit from having more overlap as the turbine would suffer less from backpressure. i hope this makes sense to you
With how cheap the right one is, seems to make more sense to just bin it and get the correct one TBH
Its always a compromise.
You can easily choose to move the timing on an F7R as well, just take off the keyways and time them where you want on the standard pulleys.
don't forget as you've seen in the chart the timing of the megane is different from the start, so maybe advancing his inlet cam on the Megane standard timing would still be retarded compared to the F4r standard timing. i don't know what turbo he used but if he used a larger unit that the original one for instance it would benefit from having more overlap as the turbine would suffer less from backpressure. i hope this makes sense to you
He's on different profile cams too, hence what I said above about dont try and draw conclusions from different specs. What works well on one wont on another automatically, the devil is in the detail.
Bottom line is the standard timing works well on a turbo F4R, so I see little value in changing it unless you are doing some monster build chasing every last BHP to be honest.
won't that result in slip of the pulley? if not then yes, that would be a good solution
If its tightened up correctly it shouldnt be a problem, but I have no intention of warranty'ing it for you, lol.
Ive done it though without issue, I filed the keyway to allow it to move rather than complete removed it.
Because its so specific to the exact combination of parts, its something you'll struggle to draw general conclusions on which directly relate to your own engine, so it makes it a harder one to discuss in a way thats useful.
bottom line with cam timing is always trial and error is the only real way.
R5 gtt, R27 F1 team
going to file the keyway to allow it to r****d the cam by a few degrees. running the car and logging afr's so i can see what is does to the VE
i've heard of a friend who's EGT became very high so they couldn't/wouldn't make it produce more power (on t34 turbine opposed to my gt28rs). thats why i'm toying with the idea of changing it.
i've heard of a friend who's EGT became very high so they couldn't/wouldn't make it produce more power (on t34 turbine opposed to my gt28rs). thats why i'm toying with the idea of changing it.
What ignition did it have on the top line?
Must confess I wouldnt be bothering trying to run that sort of thing on 95 personally, seems pointless to spend thousands building an engine and then compromise it to save 3p a litre on fuel!
R5 gtt, R27 F1 team
i'm not sure mate, think it has adaptronic and wasted spark coil. but there could be an other issue i don't know about....
does 95 opposed to 97 make that much difference? i wanted my 9 mapped on 95 aswell as there are getting less and less pumps out here selling 97.
difference here is more like 15 cents a liter. not that i care about that but if i'm not able to fill it up with good premium fuel it would s
*ck bigtime when i want to floor it!
does 95 opposed to 97 make that much difference? i wanted my 9 mapped on 95 aswell as there are getting less and less pumps out here selling 97.
difference here is more like 15 cents a liter. not that i care about that but if i'm not able to fill it up with good premium fuel it would s
*ck bigtime when i want to floor it!
It makes a lot of difference if your engine is marginal on ignition timing already due to high comp etc.
clio 182
I think ill just bin it and get the right one save the hassle.
clio 182
What's the mega squirt S1 v3 like chip?
clio 182
With mega squirt its all about who built it. James Murray is who I would recommend to get it from over here. I know him quite well so if you say I sent you he will have plenty of time for helping you out I'm sure.
So which is best for running my car the omex or mega squirt? Cheers
Both will do it. Omex is better supported by mappers, mega squirt has far more sophisticated fuelling algorythm and far better boost control. Quite a tough call tbh, I would ask whoever will be mapping it for you which they prefer. Scoff for example loves adaptronic and that's also very capable.
clio 182
Ok mate is scoff on here? Cheers chip
clio 182
I know I read his thread very nice priced too for installing and mapping it dans thread is interesting I read all of that lol can learn a lot off his thread fp ill try and get hold of scoff tomorrow somehow you got a number for him?
