Technical Thread

>>>/QTDDTOT/

no fuck off

oh sorry i guess you guys just want more benchracing and misinformation as if this board doesn't have enough of that

What car and what disciprine. Or, more usefully, what car and what is it failing to do that you require of it?

Why would you want a different cam? The only thing it does is increase horsepower at RPMs that you rarely touch on the street, kill lower end torque and give you crappy driveability with a shitty sounding idle.

I love cutaway illustrations!

3/10

Is he wrong though?

>Mechanical thread.
I mean, it's not like he created his own thread. So.

Alright, Veeky Forums, how bad of an idea is it to swap in higher compression cylinder heads into my engine?

What for?

2/10 and falling

What is the deficiency you're trying to counter? Have you tried skimming the head?

it's not a bad idea unless you're planning on turboing it too or some other retardation.
if you do it right it will be fine

Well, yeah, but he asked about internals.
Because some cars, especially smog era V8s, came with garbage cams.

No I want to stay n/a, so I was thinking it'd be a good way to get some more horsepower since I'm only making about 170 right now since I resurfaced my heads

garbage how?

Not that great at anything besides cutting emissions. They have crap heads, crap exhaust, and crap intake manifolds as well.

Yeah but that's pretty much every eco production car.
You can do a lot to an eco car just by changing that type of stuff too. I'm pretty sure if you make the exhaust pipes a little bigger that helps too but I'm not sure.

FF in drift

There was a lot of valve overlap to control emissions.

If you're buying a car with a V8, it's not like you care about gas mileage or emissions.

I meant in general even with non v8 production cars. This V8 eats gas meme needs to go away, I drove a 95 GT that got 25-31 mpg as long as I didn't put my foot down at every light. When you talk older classic V8's then yeah, you're pretty much just stuck with shit mileage.

It just happens as you modify the car. More power means more fuel consumption.

Cables conduct less electricity when they're warm/hot. How long do you leave the hood open before it will start?

You probably have a bad engine ground run a wire from the negative battery to the engine and see if it's better

Requesting cut away of a Lancia Stratos please.

About the time it takes me to open the hood, get back in the car and start the engine. So, maybe 15 seconds?

Yeah, thought you meant in just a general V8.
I also like the people who add chips and etc to make a car run quicker/faster and then complain when their I4 Camry explodes with 215k miles.

It's weird, for me I cant imagine adding mods without touching the internals to handle my added mods and people do it everyday, but then again a lot of those same people are running cheap engines.

A good cam shouldn't lose that much bottom end in a b18 with decent cams and a tune you will lose 15 ft-lbs at low rpm but gain 50HP and get a fatter power band

If you are not running forced induction cams and tune make all the power

Try changing you air filter. Your air flow may be too restricted with your hood closed.

It depends on the engine. You won't kill a car with heads/cam/intake/exhaust unless it has really, really shit internals. That's just improving flow, not like you're cramming boost into it.

How is air flow to the engine related to the starter not turning?

The filter is clean by the way.

right sorry. woke up 20 minutes ago. have someone slowly lift up the hood while you keep the key in the start position. another thing to do is the tedious work of searching for continuity with a voltmeter.

Continuity between where?

Everything on google is low-res or tiny but here

[sand people noises]

For the Group C fans ITT

if the final compression ratio is 9:1, there isn't a problem. Increassing the compression beyond that can restrict the torque, and thus the power, because if it starts detonating you'll have to advance the spark more than ideal to compensate. If it's forced induction, then there's no point whatsoever.

High compression N/A engines need exhaust manifolds that flow really well to be able to eliminate as much exhaust as possible from the combustion chamber, and tend to work better at higher revs because the fuel has less time to ignite.

The best to start with modyfing your car is to change the intake tract. And I don't mean to change the air filter (which makes practically no difference), i mean checking the entire piping.

autospeed.com/cms/article.html?&A=111369

The article above puts it better than I could. You can modify it further by doing the same to the exhaust (keeping the manifolds stock), although the results might not be as noticeable (and no, putting huge exhaust silencers/fart cans in the back actually makes it worse from a power perspective).

To go beyond that means spending a lot more money because then you start into modifying the intake and exhaust manifolds themselves, but by that point you'd be better off porting the heads as well to be able to take full advantage of them, so then you also need to change the camsaft and the valve springs... But being N/A the results probably won't be drastic as you'd hope, and the cost would be getting pretty close to what you'd pay for a brand new engine.

The hood thing is bizarre, but probably a red herring. I'd check relays and fuses, a very rough guess is your relay is getting stuck open somehow, and opening and closing the hood may jostle it enough to free it up again.

battery to starter solenoid. check the resistance with hood open, and below the hood level where the starter won't turn. what car is this?

No crank? That means you probably have a bad ground. Usually there's a ground directly from the starter, sand it down a bit and hopefully you'll be better.

e-mail these guys:

youtube.com/watch?v=S3g-mvFihdA

...strange, a lot of starter issues are due to cold, not heat.

When it doesn't start, is the starter doing its job and is it making any noises?

Thank you very much.

I'm not sure exactly what compression I'm at right now, but it seems like there's plenty of reason to keep my cylinder heads as they are. I'll have to look for some other means before I tear open that whole pandora's box of compression

This is an improvement from the same frame.

There's a tool to check how much compression your cilinders are actually making though, it's also pretty useful to check if you have some sort of headgasket or piston segment failure.

01 Jetta VR6

When it does crank it starts just fine, when it doesn't, all I hear is a click, no turning of starter or engine.

the black wire on the left is the one that goes to the starter motor, both ends were cleaned.

step aside plebs

close but no cigar

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variable compression ratio rod

inboard brakes

where is your god now?

OHV vs OHC

in case you were confused

some historical context

Probably a typo, but you retard spark to stop detonation.

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Needs more Rover P6 with De Dion tube rear suspension and inboard discs
>tfw Rover SD1 was a downgrade from the previous model but with a better gearbox

new cars and suvs have horrible blind spots

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It was definitely a typo you generally advance ignition timing for a longer burn and more power

>bullet
>clearly still in its casing

Well I already know my head gaskets are fine now (it's an EJ-family engine so I kinda had to change them), but yeah I'm sure a buddy of mine has a tool like that, I'll ask him sometime

nubs should all do this, cross-threading spark plugs is very expensive

Was gonna shitpost and accuse you of ignorance but I make the same mistakes myself, type undersquare instead of oversquare etc.

Because 90s jaguars weren't already shitty enough

all tapped out

A click....just to make sure, did you check the cogs on the starter?

I have not.

bad solenoid or bad contacts somewhere

>Sometimes my car will not crank.

Crank? First, is there a clicking noise when you turn the ignition key? It can be a clicking noise from the relay, but there is typically a lounder one from the starter solenoid that engages with the engine in order to have the physical connection to turn (i.e. crank) the shaft.

>When it does crank it starts just fine, when it doesn't, all I hear is a click, no turning of starter or engine.

That sounds like a bad solenoid. I had a similar problem with an old car. It would start sometimes, but sometimes all I get is a loud click. The non-starting got worse and finally nothing but clicks one day. That car was an old one so it wasn't called "solenoid" which is the modern term but a "Bendix". In those days, people would say "oh, your bendix is bad" if you got a loud click but no cranking when you turned the ignition key.

Try googling this:
what does the solenoid in a starter do?

>new cars and suvs have horrible blind spots

It doesn't matter how tall/short I am, I can even go to my back seat and try to look back and cannot see. The interior rear dash is so high for styling purposes and the rear trunk lid is so high that I cannot see a lot of things to the rear now. And the rear pillars block so much that the traditional blind spot is really large.

These body styling changes are not good for safety purposes. Or they are there under the assumption that customers are FORCED to purchase rear view backup cameras and computer-aided parallel parking features.

And before you say I cannot parallel park, I can do so the very first drive in. But what I cannot do is NOT hit the car behind me as I back up because I genuinely cannot see anything but the rearmost part of its roof as my rear bumper approaches within 10 feet of that car. I tested and got out to check. My loss of visibility begins approx 10 feet away! So without a rear view camera, it is genuinely impossible to tell how far I can go back. I estimate from looking at landmarks on the curb but estimates are only guesses.

is this stupid questions thread? if yes:

what difference would 195mm make vs 205mm tires on 7" rims?

next to none, might be slightly more confortable. The aspect ratio of the tire is much more important.

They got rid of inboard brakes in the 90s.

Inboard brakes were pre 90s

The wankel rotor is at it's most efficient in the 4000-6000 rpm range

suspension tuning isn't a black art.

although with the tire pressure, I must point out that both increasing and decreasing the tire pressure beyond it's optimum will make it slide, and the chart assumes your tire pressure is above optimal.

>This thread is for discussing automotive technicalities and maintenance.

>implying the thread won't degenerate into some OHV vs OHC baiting or some other such turd-flinging shitfest like every other thread.

i learned this shit from /ovg/

>no mention of KPI, scrub radius, anti squat/dive geometry, suspension arm lengths, roll centre

there is a car cutaway specific thread on Veeky Forums

KPI and castor angle relate to camber gain or loss under steering effects, scrub radius and trail has to do with steering feel, which is why you have to reduce both on fwd cars to decrease or eliminate torque steer.

Suspension roll arm lenghts and roll center are both concepts that get thrown around a lot but actually just confuse something that is straighforward: that if the tire does not moving perfectly vertically, then the application of a lateral force will induce a vertical component through a ramp effect. In other words, jacking down or up the car.

if the inclination of the tire's path is towards the direction of travel, then we're talking about anti squat and anti dive. If the inclination of the tire's path is trasverse to direction of travel, then we're talking about a roll center height above or below ground.

Suspension arm lenght and geometry essentially describes how the inclination varies throughout the entire range of travel.

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I had a similar issue on my Subaru. I thought the starter was bad. Went to take it off and nut that held the ground wire on was finger loose. Worked fine after that.