Jump to content
SAU Community

Recommended Posts

hi there i was just wondering if any 1 could help me and tell me if it even does any thing...if this method has a name what is it called ?

ok in 2nd gear get my rev's to 4500 then i put the clutch in halfway keep the throtal around halfway to biuld up the rev's then push the clutching in fast and put it into 3rd gear then let go of the clutch.

Thanks...

Link to comment
https://www.sau.com.au/forums/topic/59217-gear-change/
Share on other sites

was told it gives that extra power in changing gears but i may of got it mixed around or some thing......

im just trying to learn about cars/n stuff. i had a friend that was teaching me about them but he's just passed away resently. :'(

if any 1 could give me a few tips would be handy :)

-Thanks

Link to comment
https://www.sau.com.au/forums/topic/59217-gear-change/#findComment-1130748
Share on other sites

double clutching is when you r in gear, lets say 1st, put the clutch in, put it into neutral, let the clutch out, put the clutch back in, put into 2nd, let clutch out.

I have no idea why that line of "not double clutching when you're supposed to" line was in fast and the furious. cause u wouldnt do it in a drag race...it was done on really old cars like moris minors where the box wouldnt handle it..

maybe there is a more modern thing that they call double clutching, but that is what i have always known it as. It also helps on dodgy boxs like my dad's subaru :)

Maybe you are talking about flat shifting...where u just leave the throttle pinned instead of backing off...but that's not really the impression i got from your post.

Either way, it sounds like a good way to wreck ya box and clutch for the sake of a few milliseconds?

Correct me if I'm wrong

Link to comment
https://www.sau.com.au/forums/topic/59217-gear-change/#findComment-1130761
Share on other sites

*have to lift my chin off the floor*

Okay, when you shift up a gear, the next gear has LOWER revs than the last!

Why people think reving the car before a shift is going to do anything is beyong me. Notice how when you engage the next gear the revs DROP!

Double clutching is nothing like that, can't be stuffed explaining it, but the only time you double clutch up is in a old school car which can't shift fast enough, so when you try to shift, the revs drop to idle before you engage the next gear, then is when you rev to make it engage, as some old cars wouldn't engage. Or in a modern car when you stuff up, and the revs drop to idle, you can give it a little blip to make it smooth, but it's not necessary in modern cars.

Now, if you have to do that, you must be shifting incredibly slowing.

Link to comment
https://www.sau.com.au/forums/topic/59217-gear-change/#findComment-1130809
Share on other sites

The first post in this thread is a terrific way to spend $800 on a new clutch every 3 months.

Double clutching is generally done if your syncros are stuffed, or if your like me and you ocassionally do it when putting around town just to be gentle and kind to your cars gear box. Its a nice clean way to change gears and learn about rev matching.

Link to comment
https://www.sau.com.au/forums/topic/59217-gear-change/#findComment-1131234
Share on other sites

Double clutching is generally used on downchanges, but it can be used on upchanges on very old cars where the gearbox synchros are pretty knackered. The basic principle is to match the speed of the gearbox input shaft to the speed of the output shaft, and reduce the load on the synchros.

Most common on downshifts, there are 2 variants - heel/toe and double clutch.

In a heel/toe, most common on modern cars to prevent the rear wheels trying to drive the engine when you engage a lower gear, the idea is to blip the throttle in the middle of the gear change, while the clutch is depressed and the gear lever is in the neutral position between gears. This brings the engine speed up to the match road speed of the lower gear. It is usually done by applying brake with the toe of your right foot, and pivoting the heel of your foot around to blip the throttle, hence its name - heel / toe.

With double clutch, instead of having the clutch depressed, you release the clutch while blipping the throttle, then depress it again to engage the gear. This is to match the engine speed to the road speed when the synchros are crook and don't actually do the job they are supposed to.

Hope that all makes sense.

Link to comment
https://www.sau.com.au/forums/topic/59217-gear-change/#findComment-1131386
Share on other sites

Double clutching is nothing like that, can't be stuffed explaining it, but the only time you double clutch up is in a old school car which can't shift fast enough, so when you try to shift, the revs drop to idle before you engage the next gear, then is when you rev to make it engage, as some old cars wouldn't engage. Or in a modern car when you stuff up, and the revs drop to idle, you can give it a little blip to make it smooth, but it's not necessary in modern cars.

Now, if you have to do that, you must be shifting incredibly slowing.

Can't say I've heard that before. How old are you talking here? Even my friend's 1940s Vauxhall shifts fast enough. Anyway, the usual time you double declutch is on a downshift, not an upshift.

Link to comment
https://www.sau.com.au/forums/topic/59217-gear-change/#findComment-1131510
Share on other sites

Double DE-clutching.

Different to double clutching.

Double De-clutching is down, double clutching is up.

Some old cars need it, say morris', haha, and trucks things like that.

Cars whose gearbox is sloppy, synchros worn, things like that. Not necessarily all "old" cars, just a characteristic of a few of them.

Link to comment
https://www.sau.com.au/forums/topic/59217-gear-change/#findComment-1131533
Share on other sites

just dont do it.

if you want an interesting gearchange (and plenty of interesting things happening to your clutch/gearbox/engine) just try changing gears very fast without lifting off at all (flat shifting like some others have explained)

its best if you try it in someone elses car, such as a hire car :)

Link to comment
https://www.sau.com.au/forums/topic/59217-gear-change/#findComment-1133219
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • I will rebutt this and the preceding point from Dose....but without doing any calcs to demonstrate anything and without knowing that I am right or wrong. But... The flow capacity of a fluid transfer system is not limited by the smallest orifice or section of conduit in that system, unless it is drastically smaller than the rest of the system. OK, I use the word drastically perhaps with too much emphasis, but let's drill down on what I really mean. The flow capacity of the system is the result of the sum of the restrictions of the entire system. So, to make an extreme example, if you have a network with 3" pipe everywhere (and let's say a total length of only a few metres) and that 12mm ID restriction of the oil filter connection being the obvious restriction, then for any given amount of pressure available, the vast majority of all the pressure drop in the system is going to occur in the 12mm restriction. But.... increase the length of the 3" pipeline to, say 1000m, and suddenly the pipe pressure loss will likely add up to either be in the same order of magnitude, possibly even exceeding that of the 12mm restriction. Now the 12mm restriction starts to matter less. Translate this to the actual engine, actual oil cooler hose sizing, etc etc, and perhaps: The pressure loss caused by flowing through the narrow section (being the 12mm oil filter port, and perhaps any internal engine oil flow pathways associated with it) is a certain number. The pressure loss through, say, -12 hoses out to the cooler and back is negligible, but The pressure loss through -10 hoses out to the cooler, at the exact same length as the above, starts to become a decent fraction of the loss through the 12mm stuff at the filter port. Maybe even it starts to exceed it. I could actually do these calcs if I knew 1) how much oil was actually flowing in the line, 2) gave enough of a f**k to do things that I hate doing for work, voluntarily for a hypothetical discussion. Anyway - I reiterate. It's not the narrowest port that necessarily determines how much it can all flow. It is the sum. A long enough length of seemingly fat enough pipe can still cause more loss than a semmingly dominant small bore restriction.
    • To pick up what Dose is putting down. Not a lot of point running a huge hose if the motor is still restricted to the smaller size... It's only capable of flowing so much at that point...   *Waits for GTSBoy to come in and bring in the technicalities of length of pipe, and additional restriction from wall friction etc etc*
    • Hooley Dooley these things have some history! If i sell them they will need a certificate of providence to prove they have been in the hands of verified RB20 royalty! They have been stored in a plastic tub, away from sunlight and moisture. They are in mint condition. And they will stay that way, as i have sprung the money for a set of shockworks coilovers. I'm just working on getting them in at the moment, after rebushing the rear of the car, and while the subframe was out i welded in the GKtech reinforcement bracing as well.  They will get a workout at Ararat King of The Hill in November. I ran 48s on the short course there a few months ago, and i am hoping with new bushes and shocks in the rear i can launch a bit harder. There was a fair bit of axle tramp when i tried too hard off the line. a few of the corners had dips mid way which also made the car feel a bit unsettled, hopefully this will help there too.   
    • Food for thought, the stock oil filter thread is a 3/4-16 UNF, which has an ID of about 10 to 12mm (according to ChatGPT lol). Now compare than to an 10AN, which has an ID of about 14mm (Raceworks is 14.2mm, Speed flow is 14.27mm).  
    • Yep, totally get that. However hooking in for Generator back up is only a few hundred bucks for the wiring. You could put a couple of those in (for different circuits explicitly) and run a couple of baby generators. Bonus, you can balance them across different circuits, and now have backups in your backup. I'm looking at buying places that won't even have water etc, and I don't mind the idea of getting off the electric grid either, even with everything you've said. This country already has enough power outages that even the mains grid isn't that reliable anymore. I do agree though on spending a bit more to get better gear, and to add some extra redundancy in to the system too.
×
×
  • Create New...