Tech Spam thread - because 1/4" BSP gets 5 hand spans to the jiggawatt

[Steelies]

slide carbs (non CV) on cars?

go.

 

edit - 

 The slide carburettor has the same piston and main needle as an SU carburettor, however the piston/needle position is directly actuated by a physical connection to the throttle cable rather than indirectly by venturi airflow as with an SU carburettor. This piston actuation difference is the significant distinction between a slide and an SU carburettor. The piston in a slide carburettor is controlled by the operator's demands rather than the demands of the engine. This means that the metering of the fuel can be inaccurate unless the vehicle is travelling at a constant speed at a constant throttle setting - conditions rarely encountered except on motorways. This inaccuracy results in fuel waste, particularly as the carburettor must be set slightly rich to avoid a lean condition (which can cause engine damage). For this reason Japanese motorcycle manufacturers ceased to fit slide carbs and substituted constant-depression carbs, which are essentially miniature SUs. It is also possible - indeed, easy - to retrofit an SU carburettor to a bike that was originally manufactured with a slide carburettor, and obtain improved fuel economy and more tractable low-speed behaviour.

[tortron]

just fit SU's

[Steelies]

sigh

[Seedy Al]

this for carry?

or hilux?

Or Falcon?

Or the other thing sitting in Joes meat market?

[Yowzer]

sigh

Hide injectors under manifold and use carbs as slide ITBs

[Nominal]

Hide injectors under manifold and use carbs as slide ITBs

 

Now there is a practical and workable answer!

[Roman]

Sorry, Steeeeelies, this should explain it for you (Goat has)...

kicker, not sure as yet but thank-you. I'll see what is in there now and then try and figure out what I need using mathematics.

Don't expect an answer immediately/in the next year.

The Toyota speedo drives only go in one way, without rotating but have different sized gears.

I think the trick is... That it's spinning off something thats rotating 90 degrees to its direction, so it can accomodate a bigger or smaller gear by floating the gear slightly further forwards or backwards.

As the part it spins on in the gearbox looks like this.

 

[manlymanman]

May I ask why you have ball hairs on your speedo-drive

[Roman]

Because it goes in a wet hole.

[Seedy Al]

that's one stinky hole then..............

[Roman]

That awkward moment when your speedo drive is too short.

[Steelies]

not for anything in particular Re carbs, but if they'd work well enough then why not individual throttles for everything?

[Kiwibirdman]

not for anything in particular Re carbs, but if they'd work well enough then why not individual throttles for everything?

 

Cost and complexity.

[Steelies]

mmmyes. guess they'd end up being wang-jang china carbs too. throttle linkages would be hilarious

[Spencer]

What's the actual question? Flat slides are awesome at WOT so good for some bikes etc, can be less complex. CV just adds some vacuum feedback which you can tune for efficiency at part throttle. Then EFI with any throttle combo that moves enough air can be tuned good for everywhere. Choose your cost/complexity/dort option that suits.

[Steelies]

wondering if anyone's had experience driving a car with slide carbs. it seems general internet consensus is they give you exactly what you ask for, which isn't always what the engine needs.

i was wondering how this translates into actual experience like 'couldn't parallel park without doing burnouts' or 'constant nightmare at the lights' etc

[Spencer]

Same as my XR200 with a slide carb, you can tune around it but will use more/less gas at almost all part throttle openings and due to this it will make less power/less efficient  at part throttle. Depends on the car how drivable it will be, 86 foamers ran them a few times I have seen on the internets (those keihin 4 slide combo things) with no real problems. 

 

Its like putting a average tune at part throttle, on a 4K this wont matter fuck all it may use more gas. On something with big cams and shitty low speed behavior it will make it way worse possibly. Something like a Qjet aims to have the best of both worlds, big open chamber mains and variable vacuum driven needles on the small primaries, works great but ads complexity.

[tim13]

at Steelies , I had Mikuni flatslides on my spittie , they were fitted before I bought it so basic setup was already done , drove great but had a few minor issues with leaks and getting correct fuel pump and pressure . car is still in wellie and I can put you in touch with current owner if you want ? cheers Tim

[Steelies]

thanks Tim! i wont need to look at the car (way too much to do at the mo without thinking about actually starting another project hah) but would like to hear about any issues you encountered driving it.

i would make an assumption that setup would require faffing around and  gremlin hunting in any case.

[Seedy Al]

hah, just pulled the back cover off tezza diff housing, hmm, the lsd appears to be invisdable

 

Guess they are getting a phone call tomorrow to supply something less gay

 

thanks guys

 

Thighs

 

LSD diff head being dropped off on Monday. hot dog