Morning!

so i came across the full carb kit for the 12a by rotaryshack including the 45 weber
the intake and everything ready to go.

i did some searching but wasnt able to find an answer to my dilemma.

am i able to use the stock fuel pump with this assembly? I know with the 48ida and the holley setups it needs be to done but haven't heard anything about the 45 needing a fuel pump and regulator.

Im ready to swap my carb this week so any advice would be great,

dan

 

I don't have that kit per se but I run the same Weber with a lake cities intake. I run a Holly blue fuel pump and Carter fpr and I have ZERO problems waaaay more reliability then my old niki set up with the 10000 potential vacuum leaks.

 

im selling some weber 45's in the 1st gen for sale section you should check them out along iwth an intake and fuel setup holley

 

Might want to search "Rotarshack" on this forum before buying.

I ran a stock-like carter pump with no regulator on a single 48 DCO and 48 IDA, no starvation issues here. The DCO was used on a track day with no issues. Carbs want high flow and low pressure.

 

^Even the stock nikki likes 60+ gph, so the stock pump is junk

 

The stock pump is probably not sufficient to tune it correctly. Webers like to see 4-6 psi and will
need some serious flow (>40gph). The stock pump barely makes 3 psi and only flows about
30gph. Now with a Dellorto you can use the stock pump but it doesn't have the flow required to
sustain WOT for more than a few seconds.

Oh and stock nikkis do not need 60 gph. Modified nikkis sure, but not the stock ones.

 

Lol? Where did I say "needs" 60 gph? I said its what they like, and its true. Modified or not, the stock pump can barely handle the needs of even a stock 12a... Mix that with an aggressive driving style, perhaps modified exhaust, timing, etc... Ive used 3 different pn's of the factory pump (new) for testing my nikkis, and even a totally stock(not stripped) nikki will have flat spots after hard acceleration or prolonged WOT.

At least, in my experience. Im sure theres plenty of variables with elevation/climate/engine condition or w.e., but thats why I said it the way I did in the first place.

 

just bought my setup, thanks for all the quick replys, I was told this one is rejetted and is made to utilize the stock fuel pump thank god.

im hoping everything goes well and I wont have to dump more money into a fuel setup.

I just got my compression test done yesterday and was super happy with my results!

however now my starter is on its way out..

 

45 dcoe and 44pph are too small IMHO.

 

Too small as in the carb is too small for the 12a? Just curious b/c I just got my Mikuni 44PHH running (not completely tuned as I haven't had a chance to get it on the track and it's not road legal) and it's way better than the stipped Nikki I was running (granted, I modded the internals of the Nikki and never got a chance to test it so a heavily modded Nikki may do better).

 

there isnt much of a difference between a modded nikki and 45/44. why dont you borrow a 48 sidedraff or IDA so you can feel the difference.

 

Jetted to run with the stock pump?

 

Now somebody will jump in and say a 48 is too large for a 12a.

 

Because I live in Louisiana and wankels are few here much less a 12a. Too many trucks. I've seen a total of 2 rx-7's in my 25 years here, both FD's and one of them was at the race track.

 

No, a 48 is not too large. I run the dell but it requires a high flow low pressure pomp. I have the Carter
4070 at regulated down to about 2.5 psi and its runs great.

 

plus you can always change the venturies

 

was told the stock pump also runs at 3 psi which is what this kit calls for as well

 

The stock pump has a much lower flow rating though and a larger carb will need more flow than the pump can provide. Pumps aren't rated strictly in PSI but also for flow rate.

 

the stock pump puts out considerably less GPH at its limit, which is about 3 psi. Traditionally non-positive fuel pumps make less GPH at higher pressure. Theres a graph breakdown on FAST's website that makes it pretty easy to understand. You can get more GPH at lower pressures, which is the opposite of what you might think will happen.


As Id said before, your results may vary.. But know that even a small-ish carb is going to out demand that little stock pump, which was BARELY enough to support a 105 hp 12a NEW.

Most of the used pumps I pick up dont flow anything better than 12-15 GPH, which s a *trickle* compared to what it should be putting out.

 

I was being sarcastic, seeing as contradictory shenanigans rule the interwebs...

 

sweet kit, stock fuel pump and a clean fuel filter worked great for my car. let us know your results...

 

I have a read that the dcoe 45 only requires 2-4 psi. Seems to work for me but I'm still running the Mr. Gasket 5-9psi fuel pump

 

im running the 45 on stock fuel pump at 3 psi with a cheap regulator from kragen haha. and its great so far. I had a big problem with leaking fuel from my horns. but I adjusted my float bowl level and it seems perfect now. pretty happy with my setup.

 

after a couple days of driving with no further leaking im sensing hesitation and lake of power through the higher rpms witch is where I should be getting most of my power.

I don't have a afr gauge, but im thinking im running too rich anyone suggest a psi to run the 45 at?

currently at 3.

 

What jets and venturi are you running?

The fuel system just needs to keep the float bowl full. You're not running enough flow if there's no power at sustained high rpm like wide open throttle on a straightaway at the track. Too much and it leaks, as you know.