[QUOTE=JesseR92;52665443]2strokes need back pressure if I recall.[/QUOTE]
Yup, but that's because they don't have valves, so they're dependent on the backpressure pushing the air/fuel/oil mixture back into the cylinder.
As for wether or not a fourstroke needs backpressure, according to the dealer I bought the aftermarket exhaust for my KTM (right after the exhaust had been on a extensive dyno test comparing exhausts) it runs better with the baffle in, even with a proper tune.
[QUOTE=Gulen;52666375]Yup, but that's because they don't have valves, so they're dependent on the backpressure pushing the air/fuel/oil mixture back into the cylinder.
As for wether or not a fourstroke needs backpressure, according to the dealer I bought the aftermarket exhaust for my KTM (right after the exhaust had been on a extensive dyno test comparing exhausts) it runs better with the baffle in, even with a proper tune.[/QUOTE]
[QUOTE=Van-man;52665553]Yep
[t]https://upload.wikimedia.org/wikipedia/commons/5/52/Arbeitsweise_Zweitakt.gif[/t]
And technically so do 4-stroke engines with "internal EGR" (exhaust valves overlapping the intake stroke, so it is only on engines with adjustable exhaust cam timing)[/QUOTE]
[QUOTE=JesseR92;52665443]2strokes need back pressure if I recall.[/QUOTE]
NO
a 2 stroke expansion chamber does not work on backpressure, in fact it is a negative pressure zone designed to scavenge out exhaust gasses.
the confusion comes from the fact that it uses acoustic pressure (ie not gas pressure, but sound) to force unburnt fuel back into the combustion chamber
dont try to school me on 2 strokes im fpaa's resident 2 stroke expert for a reason
[editline]10th September 2017[/editline]
if it worked on just backpressure alone you wouldn't need a fucking cone just a straight up wall would do a better job and cost a hundredth the price
the chevrons in that diagram represent acoustic waves. notice how the grey smoke in the diagram doesn't follow the waves at all
if you tried to make power on the theory that backpressure improves power then you'd see that it just doesn't fucking work
[editline]10th September 2017[/editline]
in fact that diagram is shit and useless for all but the layest of laymen because it shows chevrons coming straight otu of the combustion chamber when in reality they're more like forward slashes until they hit the expansion cone
[t]https://i.imgur.com/qxfRGC6.png[/t]
So 9 months in, and exactly 49,000 miles on the dot, I had to get towed.
I'm 90% certain it's the fuel pump, cause the engine cranks, and the fuel pump sounds like it wants to explode.
Shit sucks too cause it's at the beginning of my work week, while I'm dropping a shitton of money on dental work and additional shit for the car. But hey, at least it crapped out in an area where I could easily get it towed. Woulda been nicer if it was on my way to work so I could bang out for the day.
[B]Update the next day
[/B]
So just replaced the fuel pump, 130$ and 150$ for the tow. I made out pretty good, car's back on the road.
why do you think 2 strokes are always so loud? if they wanted to make it quiet it'd be an easy fucking job to put a baffled muffler before the expansion chamber and it wouldn't impact performance if backpressure was the only issue
[editline]10th September 2017[/editline]
read a fuckin book and stop breaking my automerge
[editline]10th September 2017[/editline]
(by a fuckin book i mean gordon jennings two-stroke tuners handbook and a. graham bell's two-stroke performance tuning
[QUOTE=butre;52666443]why do you think 2 strokes are always so loud? if they wanted to make it quiet it'd be an easy fucking job to put a baffled muffler before the expansion chamber and it wouldn't impact performance if backpressure was the only issue
[editline]10th September 2017[/editline]
read a fuckin book and stop breaking my automerge
[editline]10th September 2017[/editline]
(by a fuckin book i mean gordon jennings two-stroke tuners handbook and a. graham bell's two-stroke performance tuning[/QUOTE]
Christ are you ok?
I have a sneaking suspicion my package from Rockauto dissapeared off my doorstep.
I really wanted to get the front brakes done this weekend.
It kinda sucks because I splurged on the discs and got the mid grade ones for my scamp.shoes and flex hose is cheap to replace but those discs wernt cheap.
[editline]10th September 2017[/editline]
Oh just checked my Tracking number,Parts still on their way just sat in customs for a week....really.....
[QUOTE=metallics;52666528]Christ are you ok?[/QUOTE]
people saying wrong things about 2 strokes triggers me
also if I don't make a big deal about how they're wrong people will think they're right
Never posted here but wondering if any of you might have any advice:
Been driving my shitty 10 year old 1.2 Clio for a while now and looking to upgrade to something more powerful for my next car.
Going to test drive a 300hp SEAT Leon Cupra soon, just wondering if there's anything stuff to know before driving a much more powerful car for the first time? You guys probably know more than I do :v
[QUOTE=tom1029;52666872]Never posted here but wondering if any of you might have any advice:
Been driving my shitty 10 year old 1.2 Clio for a while now and looking to upgrade to something more powerful for my next car.
Going to test drive a 300hp SEAT Leon Cupra soon, just wondering if there's anything stuff to know before driving a much more powerful car for the first time? You guys probably know more than I do :v[/QUOTE]
When in doubt, flat out.
Seriously though, assuming its the fwd hatch, it wont be that much different, it will just move itself much better. Just don't drive it like a knob to start with?
My car's engine has, for the last two days, not started properly after sitting over the night (that is, using it the next morning). It starts, but it chugs for about 10-15 seconds before returning to normal. Also, as it chugs, black smoke comes out of the exhaust pipe.
Not sure what is causing this, since it only happens the first time I use it in the day. Is it just that the engine is cold?
[QUOTE=FlandersNed;52667060]My car's engine has, for the last two days, not started properly after sitting over the night (that is, using it the next morning). It starts, but it chugs for about 10-15 seconds before returning to normal. Also, as it chugs, black smoke comes out of the exhaust pipe.
Not sure what is causing this, since it only happens the first time I use it in the day. Is it just that the engine is cold?[/QUOTE]
Never experienced myself, but all sources say black smoke = oil or unburnt fuel in exhaust. So your gaskets that keep your oil place must be leaking.
[QUOTE=metallics;52666981]When in doubt, flat out.
Seriously though, assuming its the fwd hatch, it wont be that much different, it will just move itself much better. Just don't drive it like a knob to start with?[/QUOTE]
Yeah it was fine. One I tried was actually an auto so pretty easy. Was fun, want one now.
Anyone here lease? I'm looking at leasing one of these now, found a deal for 2 years, £240/mo which seems like an amazing deal compared with what I've seen on similar cars (Audi S3, Golf R / GTI etc).
It's probably unburnt fuel. Probably really rich in open loop
Or your injectors are leaking so gas is pooling when it sits over night.
[QUOTE=tom1029;52667388]Yeah it was fine. One I tried was actually an auto so pretty easy. Was fun, want one now.
Anyone here lease? I'm looking at leasing one of these now, found a deal for 2 years, £240/mo which seems like an amazing deal compared with what I've seen on similar cars (Audi S3, Golf R / GTI etc).[/QUOTE]
Depends whether you actually want the car and the mileage limits suit.
If you do up to average UK mileage (12k miles /year) and dont care about sacking in the car at the end of it and getting another (because the final payment is probably huge too), go for it.
I do more like 20-30k/year and where they will actually offer a lease it's extortionate because the car they get back wont have much resale value.
[QUOTE=metallics;52667551]Depends whether you actually want the car and the mileage limits suit.
If you do up to average UK mileage (12k miles /year) and dont care about sacking in the car at the end of it and getting another (because the final payment is probably huge too), go for it.
I do more like 20-30k/year and where they will actually offer a lease it's extortionate because the car they get back wont have much resale value.[/QUOTE]
Yeah 12k miles is about what I'd need. It all seems pretty good, my only concern is if I had to change job for some reason (not planning to but you never know) and I'd need to do more. However it's only like 10p per excess mile so wouldn't be too bad if I had to do a bit more.
Leasing seems like by far the best value, I got quoted by the dealer today for PCP: £5000 deposit, 48 month contract: £369/mo whereas lease is only £2k down and £240/mo (for 2 years only which I prefer).
Just changed my oil, only about 3k miles on it but it still looks like new oil. Went with Castrol edge HM, first time going synthetic so we'll see how it goes.
Hoonigan on youtube is getting really entertaining lately.
[media]https://www.youtube.com/watch?v=t58BmZ5h1H8[/media]
still alive buts super windy. as expected. still have power too. steam link and controler letting me sit bac and relaz, and typing is low and akward.
So my radiator isn't doing much work, and is presumably all plugged up with crud. Do i have to replace it or would just flushing it until the water coming out is clear as glass be enough to get it back in order?
[T]https://puu.sh/xwJKy/837c736285.JPG[/T] [T]https://puu.sh/xwJKC/fe0bcaf46b.JPG[/T][T]https://puu.sh/xwJKx/540f9a623a.JPG[/T] [T]https://puu.sh/xwJKB/9a36639dda.JPG[/T]
Also came across these the other day. The 4C is gorgeous in person
[QUOTE=Strontboer;52668029]Hoonigan on youtube is getting really entertaining lately.
[media]https://www.youtube.com/watch?v=t58BmZ5h1H8[/media][/QUOTE]
Definately. I get more entertainment value from their DT vids than i get from all the motor trend shows lately. Its a great mix of a showcase on cool ass cars and also a bunch of buddies foolin around in the shop.
They passed me a Kenworth T800 for this week, comfy and smooth as hell, also a 18 speed, wish i would use these truck more often.
[img]https://i.imgur.com/XdPNdNK.jpg[/img]
So many pretty gauges
[QUOTE=butre;52666443]why do you think 2 strokes are always so loud? if they wanted to make it quiet it'd be an easy fucking job to put a baffled muffler before the expansion chamber and it wouldn't impact performance if backpressure was the only issue[/QUOTE]
You are basically making the silly semantic argument that a carefully timed reflected pressure wave in the exhaust is not backpressure
Just because you understand the theory of how something works doesn't mean you have to be rude about it when someone makes a slightly lacking description / uses a word in a slightly different way
This is a Christian server, be civil
So we've got trouble. A friend of mine traded a rusted out Ranger for an Impreza Outback Sport that ran on 3 cyl. Compression test showed cyl 4 0psi. Right. Online says #4 exhaust is super common to burn valves on this engine (EJ22)
Out we come.
[img]https://i.imgur.com/HKwSVr0l.jpg[/img]
So now the CSI happens, trying to figure out the fate of the engine.
2 different head gaskets... the blue one was on the side with the issue. Most likely aftermarket.
[img]https://i.imgur.com/JxHe1SXl.jpg[/img]
[img]https://i.imgur.com/crYClcyl.jpg[/img]
And here's the culprit.. burned exhaust on #4. Along with some interesting deposits (You can see the other one looks real nice).
[img]https://i.imgur.com/RUxmpFZh.jpg[/img]
Here's what gets me... #4 has a super, super shiny piston head. A lean condition I can see burning all the deposits off of everything to leave it shiny.. but this has those carbon deposits on the valves. An oil burning condition would leave carbon deposits on the valves, but this has a super clean piston.
[img]https://i.imgur.com/ZzDtZCxh.jpg[/img]
What the hell happened to this motor? The cylinder wall is covered in oil on #4.. but my buddies poured some oil into it to see if it would help compression when they were testing it, so I can't tell if it's from the rings leaking or not. The oil is fresh and gold so I think it's from the compression test.
Previous owner said it had "headgaskets done" but obviously it was only one..
The plug for cyl #4 appears to be brand new, so I can't tell anything from it.
The rockers are manual adjust on these engines, and online it seems that 0 clearance/improper adjustment can/has been known to cause to cause this.
If the piston is brand new did it burn a hole in the old one?? That sounds like it would be from a lean condition. I think it gets a new injector on #4 to be on the safe side. I've never seen a piston that clean in an engine with 180k miles on it before. Trying to put the puzzle together so it doesn't happen again when I rebuild it..
I obtained an MG TF 160 the other week, any other MG F/TF fans around? Will post pics later
They have a nice little community built up around them
From what it looks like, whoever did the headgaskets didn't do them right.
That's likely a felpro headgasket, they don't have a good history in the Subaru community.
It doesn't look to me like the head was machined or anything.
Felpro gasket + no machining could mean some oil seaping in and leaving those deposits.
The EJ22 series is one of the bulletproof engines. Needing a headgasket is usually a redflag that it has had poor maintenance for an extended period.
As far as clenliness of the piston, burning coolant will clean the piston. Burning it for extended periods will make it look nearly new.
[QUOTE=FordLord;52670474]From what it looks like, whoever did the headgaskets didn't do them right.
That's likely a felpro headgasket, they don't have a good history in the Subaru community.
It doesn't look to me like the head was machined or anything.
Felpro gasket + no machining could mean some oil seaping in and leaving those deposits.
The EJ22 series is one of the bulletproof engines. Needing a headgasket is usually a redflag that it has had poor maintenance for an extended period.
[B]As far as clenliness of the piston, burning coolant will clean the piston. Burning it for extended periods will make it look nearly new.[/B][/QUOTE]
Cool so can I just pour coolant into my intake for a while and receive brand new pistons as a result? :v:
[QUOTE=Trekintosh;52670534]Cool so can I just pour coolant into my intake for a while and receive brand new pistons as a result? :v:[/QUOTE]
Pour in sand to port your head afterwards
now the struggle begins of having a brand new car, it's forecasted to drizzle a bit this week, but it has 5 hours worth of dead bugs on it
oh well gotta wash it anyways
[QUOTE=Trekintosh;52670534]Cool so can I just pour coolant into my intake for a while and receive brand new pistons as a result? :v:[/QUOTE]
It's the water content that cleans it, iirc.
Check on Youtube, there are a lot of videos on using water vs seafoam/etc. Usually water works just as good, just takes longer.
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