Bike carbs... WHA?!?

[zuum510]

okayfine is the GOD of 510realm... no need for this info.

[okayfine]

As far as power... these carbs and similar ones of them are being used by top tuners in japan for racing... so I'm not really paving new frontiers here.

How much more interesting would this thread be with some objective measurement?

This is the same argument I found all over when researching ITB conversions. Everyone thought it was the dog's danglies, everyone bagged on the stock KA intake system as being restrictive, people claimed 30HP just from swapping to ITBs. Only no one had ever dynoed the resulting conversions to check the facts? Why not?

"Look at the Drift King's AE86, he's got ITBs, I want them. They rock!"

Angling them up allows you to use a longer runner without interfering with the brake master though...

How much longer is the manifold due to being angled? It would appear from your pictures to be nearly insignificant.

I have yet to come across any negative feedback on the swap, or anyone trying to sell off a setup with a manifold... tells me good things.

Neither did any of the people espousing the benefits of ITBs. It's not there if you don't look for it. Heck, I was even marginalized on NICO when I came back with my dyno sheet con ITBs.

I DID increase the main jet size, as yet no other jets have been necessary... like I said runs great, no bogging. I drove the car last night and it RIPS, does need a little more fiddling but not much, I may richen fuel mixture but thats about it.

How are you determining appropriate mixture? Wideband O2 sensor?

The nice thing with the mikuni's I am using, they are good for both low end power AND high end power... the slides act like a variable venturi, they are vacuum operated and as the engine rpm INCREASES the slides open more increasing both fuel and air...

Just like SUs.

[okayfine]

... so I'm not really paving new frontiers here.

But you could be. This is why I made my "dyno test" comment.

This could be an interesting avenue for other 510ers to pursue, an alternative to Weber DCOEs, Mikunis, SUs, et. al. With some effort on your end, you could open up an uncharted path for others. Do your research, do your testing, pour all your results into the510realm (or DQ ) and have others follow, make improvements, etc.

Otherwise it just amounts to "I can has motorcycle carbs on my 510? KTHXBYE." Lots of people come up with wild ideas. Some see them through. Few go to the lengths necessary to really prove out their modifications. This is an interesting idea to me, I'd like to see more about 510-specific applications.

[iceD]

okay, that dyno sheet is from a KA? Was that 12 valve or a 16 valve? Either way that is 8 to 10 percent drop in HP if it stock, it seems to me? That sucks.

ice D

[heirfaus]

I DID increase the main jet size, as yet no other jets have been necessary... like I said runs great, no bogging. I drove the car last night and it RIPS, does need a little more fiddling but not much, I may richen fuel mixture but thats about it.

How are you determining appropriate mixture? Wideband O2 sensor?

My thoughts exactly. It's just show until you actually know whats going on. Slapping on some ITB carbs is cool, but not worth any merit to others unless you can prove it's doing what it's supposed to.

[CorAce]

As for me, I would like to see this thread to its fruition. Being on such a strict budget with so many upgrades I want, this might be an affordable alternative to my Weber (it can’t be any worse). I under stand wanting to get every last hp out of your car, but the one thing I love about 510’s and the dime community as a hole is that no two cars are alike. I have never seen such diversity in a common package.

Zuum510
In your unbiased opinion, did you notice any difference in power over your pervious setup?

[zuum510]

or this...

[rnorrish]

zuum,
this is a great project. just by posting this you will inspire others to think about.
thank you.

[510ER]

Hey Zumm! i dont care if you dyno it i Just want to see some more video of you driving man! i think this is bad ass! you have built something that you wanted to and right on brotha! enjoy your ride

[okayfine]

okay, that dyno sheet is from a KA? Was that 12 valve or a 16 valve? Either way that is 8 to 10 percent drop in HP if it stock, it seems to me? That sucks.

WTF are you talking about?

It shows 145HP at the wheels. The KA24DE is only rated by Nissan at 155HP AT THE CRANK.

[okayfine]

Btw, slodat, and thought sharing the seatbelt thing was bad... Jeez, I really was here to share something I thought was fun... Not fun now!

One of those things is not like the other. Steve posted his results from ordering new seat belts for his car, providing his order sheet and pictures of the resulting installed products. Various Ratsun peeps kept on with comments like "Man, $20 junkyard belts are good enough for me, you paid way to much!" ad nauseum.

You posted some cool-looking motorcycle carbs you slapped on your L16 after reading a UK magazine article, spending ~$400+ to avoid Webers or SUs. As such, it WOULD be interesting if there were some facts to prove why they're better than the established alternatives, or IF they are better. There's no proof in your pudding, and as such it is an incomplete project. If there's no conclusion one way or the other, what have you done, really?

I don't mean to be critical, honestly. I'm excited about the prospects. I just wonder at the point of your wrenching. You COULD further 510 knowledge by doing objective measurements, instead you're unhappy that people don't just accept your half-baked project.

You don't even have to dyno it, though it would obviously be ideal. Take it to the track and run it on the dragstrip, then run it again with your stock setup. Heck, even with the dragstrip as a tool (and, hopefully, a wideband O2) you could make useful improvements on your own, and then report the results - your improvements in subsequent runs given the adjustments you made.

Or, hell, go measure 1/4 mile stretch of flat road and run some times in the middle of the night. Or wideband results that at least show you're not running dangerously-lean in the upper rpms. Something.

[okayfine]

For the price it would cost me to go dyno and tune this, YOU could go buy your own and explore it's true capabilities... Go for it if that's what your into

It cost me $40 to get three pulls on a dyno. I piggybacked on to a SoCal SE-R dyno day the first time, and a VW club meet the second time. If I can buy a set of carbs like you have and a manifold for $40, I'd do it.

Obviously I can't. And if you have $400+ to drop on carbs and a one-off manifold, you've got $40 to find a dyno day to crash. It's not like it costs $400 for a couple pulls and a print out.

[okayfine]

Being on such a strict budget with so many upgrades I want, this might be an affordable alternative to my Weber (it can’t be any worse).

This is what I'm talking about. Is it better than stock? Is it better than a set of SUs (at twice the cost)? Is it better than a set of Webers (at half the cost)?

[510-Trevor]

Is it better than stock? Is it better than a set of SUs (at twice the cost)? Is it better than a set of Webers (at half the cost)?

I would hope they would be better than stock or the weber 32/36 upgrade.
If they are, what I see as the best part is the availability along with price point. I could easily source these and someone to tune them locally, but a pair of webers or SU's (not to mention parts or someone who can tune them) is not any where near as easy. For a street car, if these can out perform or even just equal the 32/36 weber, they would be a great alternative.

[okayfine]

but a pair of webers or SU's (not to mention parts or someone who can tune them) is not any where near as easy.

I don't agree with that, specifically about SUs.

Good used set of SUs is ~$200. Won't need parts, throttle shafts don't leak, etc. Bolt-on-ability and all the information in the world is available about SUs on a 510. You can figure out how to get them up and running in a day between reading the available information and twiddling with the set on your car. A decent set of SUs will stay in tune, only needing occasional replenishment of the dashpot oil level.

R1 carbs for $100+ and you need to make a manifold. Then you have to figure out how they work, jets, choke, vac port - none of it is rocket science, but it is unknown. Makes it more difficult.

Moreover, there are a couple very good DQ articles (even available online for free) that talk about properly adjusting and tuning the stock and DGV carbs, along with performance modifications that can be done. I'd wager that most stock carbs are functional but not optimal. Comparing a well-tuned, modified DGV on an average L16 to any other carb setup (even my beloved SUs) would open lots of eyes, I'd bet.