Ideal Fuel Pump

geminilover3236 · Post by **geminilover3236** » Fri Dec 21, 2012 7:21 pm

So I'm getting fuel cut when drifting. Basically I can get through 1 full corner or a few munji's in at full throttle (3rd gear), using second seems to bring it on quicker (high revs). And then fuel cut hits and I have to back off coz there is literally no fuel to burn. It seems pretty evident to me atleast that the carby is starving for fuel and needs the bowl to refill before we can deliver reliable power again.

Specs;
G200Z, high compression, sidedraft dellorto 40, stock tank fuel pump

What I am looking to do is fit a surge tank, using the stock pump to lift to it and then another pump to take the fuel to the carby. However I do have plans to go carbi turbo when this engine packs it in so I am looking for a pump that I can use now and when I go turbo.

Any ideas.

elky · Post by **elky** » Sat Dec 22, 2012 8:01 am

i use a facet style pump on the drag gem never had fuel issues, tho i am not goin around corners

i got the pumps if you want one

LOK15 · Post by **LOK15** » Sat Dec 22, 2012 8:10 am

Holley blue with pressure reg.

Burntrubber · Post by **Burntrubber** » Sat Dec 22, 2012 2:33 pm

X2 holly blue and surge tank

tobytj · Post by **tobytj** » Mon Dec 24, 2012 5:30 pm

Single or twins?

If you are running a single dellorto it could be the size of the needle and seat. A standard 40 mm dellorto is only designed to let fuel in the bowl for half and engine cos they normally run in pairs.

You can buy a larger needle and seat specifically for single carb set up.

If the needle and seat can't keep up the bowl fuel level will be too low and your mixture will lean out.

You need a pump that can run 2.5 psi any higher and you risk flooding

geminilover3236 · Post by **geminilover3236** » Mon Dec 24, 2012 5:57 pm

tobytj wrote:Single or twins?

If you are running a single dellorto it could be the size of the needle and seat. A standard 40 mm dellorto is only designed to let fuel in the bowl for half and engine cos they normally run in pairs.

You can buy a larger needle and seat specifically for single carb set up.

If the needle and seat can't keep up the bowl fuel level will be too low and your mixture will lean out.

You need a pump that can run 2.5 psi any higher and you risk flooding

Single.
Sweet, that's really good info there Toby, thanks. I have no idea of the history of the carby so it's entirely possible it is a small needle and seat.

I was wondering about the pressure too. cheers.

geminilover3236 · Post by **geminilover3236** » Mon Dec 24, 2012 7:02 pm

http://www.dellortoshop.com/contents/en ... _shop.html

They have 3 different sizes:
170
200
350

What do you recommend Toby?

archangel62 · Post by **archangel62** » Tue Dec 25, 2012 8:14 pm

Just further to this, is it normal for big single (or twin) carbs to run out of fuel with a stock pump? For some reason I thought a standard pump would supply plenty of fuel? I know people use stock pumps as lift pumps on powerful cars, but maybe the pressure drops...?

Post by **Gene FJ20DEBT** » Wed Dec 26, 2012 9:05 am

i get surge of somesort in my gemini drifitng(twin downs) and iv almost given up trying to sort it out.. iv tried pumps, surge tank, extensions on the on my emoltion tubes, differnt needle and seats.

goldgem · Post by **goldgem** » Fri Dec 28, 2012 9:30 am

Gene have you tried baffles in your float bowls? I know a lot of speedway cars use those because of sideways surge on the speedway.

geminilover3236 · Post by **geminilover3236** » Fri Dec 28, 2012 8:51 pm

goldgem wrote:Gene have you tried baffles in your float bowls? I know a lot of speedway cars use those because of sideways surge on the speedway.

Baffles was something I considered with the nikki but fixed any issues by cutting the float allowing more fuel in the bowl.

tobytj · Post by **tobytj** » Tue Jan 01, 2013 6:49 pm

geminilover3236 wrote:http://www.dellortoshop.com/contents/en ... _shop.html

They have 3 different sizes:
170
200
350

What do you recommend Toby?

There is also a 225 available which is probably the one you want.

http://www.dellorto.co.uk/merchandise/p ... ectionID=1

My Bible on this is Des Hammill's book on tuning

one choke per 2 cylinders

- 400 cc per cylinder 2.25mm
- over 400cc per cylinder 2.50mm (except you can't get one)

as these recommendations are for fairly well modified engines a 225 should do the job. That is what I run on the 4ZC1.

for one choke per one cylinder (i.e. twin

- up to 400cc per cylinder 1.75mm
- up to 500cc per cylinder 2.00

I believe the 350 size is for a gravity fed application - like a Harley

geminilover3236 · Post by **geminilover3236** » Wed Jan 02, 2013 3:07 pm

Thank you very much toby, great help!
Do you think I would have to go to a 350 after putting a turbo after the carby to keep up with things or the 225 should suffice.

tobytj · Post by **tobytj** » Wed Jan 02, 2013 5:23 pm

I would not use a 350. It is not designed for use with a pump and the float pressure would struggle to seal such a large needle valve.

A 225 will be fine.

Post by **Gene FJ20DEBT** » Thu Jan 03, 2013 10:05 am

goldgem wrote:Gene have you tried baffles in your float bowls? I know a lot of speedway cars use those because of sideways surge on the speedway.

nah i havnt. are these a part i can buy? or custom jobby?

its odd cos my car will run on the track for 2-3 hours then all of a sudden it will start surging.. even if i fill the tank up again full.