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Porks bike carbs and boost project

Idle jets are fairly easy to reach, il have a fiddle.......then play with jets HA!

Managed to find right sized c-clip for vac advance arm , so proper first drive tomorow :D tried earlier in the rain.........not a chance, jus look at the pedal and the tyres spin up lol

I ****ing love this thing!!!!
 
At idle it should be between 14-15 under load 13-14 then under boost between 11-13

At 17 its running very lean and is likely to melt rings or valves
 
l_jonez said:
At idle it should be between 14-15 under load 13-14 then under boost between 11-13

At 17 its running very lean and is likely to melt rings or valves
Click to expand...

AFR is one thing, timing is another though ;)

Sticking to AFRs, stoich for cruise conditions on light throttle, tending towards 13:1 by zero vacuum and tending towards high 11's under boost is a basic guide which most seem to apply. Probably a lot harder to achieve on carbs than EFI though....not just a laptop job.

Running a little richer might cost you a few % in lost power potential but it's better to be safe than have a meltdown and you're not going to be into borewash territory with those numbers.
 
Exactly , there the kind of things you rather go wrong at low speeds than high speeds , i was gonna say youd be less likely to hear them at high speeds but you have as good as no exhaust so :p ...... All the same :p
 
Not yet mate, jus bolted on straight out the box lol
Could do with a proper set up, they were ok till the colder weather set in, guess that affects it
 
Skinner_87 said:
Have you thout about upping them a bit?

I know we're are on very different set up but when I ran 1.35 I had good WOT AFR's but when I came off throttle and back on I had AFR's of 17+ and the same on idle. I went up to 1.5 in the end
Click to expand...
praps needed more damping paul ? :) (vacuum restrict, or stronger spring maybe ?)
 
You can richen the idle mixture on SU's by taking a very fine file and just filing the tiniest amount off the widest section of the needle, refitting and checking and repeating until desired fueling is achieved. Can be done along the whoke lebgth of the needle too for a proper bodge needle tuning ;)
 
Should only affect the mixture up to 1.8k ish after that the needle and jets take over. If the idle screw is affecting the whole rev range then the needle and jet is to lean.
 
If I undo my idle mixture screw any more, I run the risk of it falling out lol

Are there larger idle jets availanle
 
Skinner_87 said:
Hi frank, I'd been reading up on this there's vacumm holes in the front of the carbs that can be blanked off with plastic factory plugs, exactly as u say vacumm restriction :)
Click to expand...
it would worsen the throttle response even more tho eh paul, variable venturi (dashpot type) carbs were an improvement on slide carbs for emissions and mpg, but the slide/dashpot will only lift in relation to airflow (ie, the throttleplate may be wot, but the slide may be only 1/3rd lifted, and you have to wait for the revs to rise before the slide lifts fully) you dont see vv carbs fitted to crossers and the like eh :)
and slide carbs have to run very rich due to having no acceleration enrichment, i personally would use the carb throttleplates as throttlebody,s and then use the factory injector system, and a MAP sensor
 
frank said:
it would worsen the throttle response even more tho eh paul, variable venturi (dashpot type) carbs were an improvement on slide carbs for emissions and mpg, but the slide/dashpot will only lift in relation to airflow (ie, the throttleplate may be wot, but the slide may be only 1/3rd lifted, and you have to wait for the revs to rise before the slide lifts fully) you dont see vv carbs fitted to crossers and the like eh :)
and slide carbs have to run very rich due to having no acceleration enrichment, i personally would use the carb throttleplates as throttlebody,s and then use the factory injector system, and a MAP sensor
Click to expand...
2014 I'm hoping for ITB's to make the most of the CGA :) a friend has started mapping and had offered to help with the install and I'm sure I'd pick it up too.

I see what you mean frank, it's like having turbo lag some times (waiting for the slides to open) its ok at high revs if you keep her lit :) I'd been told to look into if the carbs were ram air type as well as in the bike the air is sometimes used to help raise the sliders

I'd looked into flat side carbs but they were crazy expensive!
 
Been thinking about what to do with exhaust, I don't wanna go all way to the rear, so was wondering about a side exit, but the cars really low (coz it's badass) and worried about it hitting everything
So was considering making something like this......

e5atunaz.jpg


Then carrying on the flat square pipe out to the side, should be ok, right? Obviously I dint want it to be restrictive in any way.
 
run it along the gap between the tank and heelboard like mine neil (where the stock one goes) mine is a few inches short of the sill :)
 
pork said:
Been thinking about what to do with exhaust, I don't wanna go all way to the rear, so was wondering about a side exit, but the cars really low (coz it's badass) and worried about it hitting everything
So was considering making something like this......

e5atunaz.jpg


Then carrying on the flat square pipe out to the side, should be ok, right? Obviously I dint want it to be restrictive in any way.
Click to expand...
The cross sectional area is reduced when flattened Neil
 
Not yet, was gunna do a long one at weekend, but the offside wheel bearing is fooked!! The whole car shakes when turnig
 
Just wont you dont burn youreself getting in our out , evebs if you put heat gaurd mesh on it you run the risk of someone burning themselves or you burning yourself if you park up somewhere with loads if people
 
frank said:
run it along the gap between the tank and heelboard like mine neil (where the stock one goes) mine is a few inches short of the sill :)
Click to expand...

i did this style side exit on my last micra. followed the std exhaust along past the bend after the mid silencer, then carried straight on out the side of the car from there. i failed MOT because i was plowing exhaust gas onto my back wheel......... i failed on lots of other things as well though!
 

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