Hey,

I've been trying to search as much as possible about the sterling carb. Most of what i found was just feed back on how awesome it is. I have a couple of questions concerning it though.

1)What what kind of fuel pump is recommended? And also fuel line diameter?

2)Do you still keep the same air cleaner or does it need to be modified? (IE. extend the front of it to get air from outside)

If anyone knows any decent priced fuel pressure regulator and guage please send me a link. Thanks

 

fuel pressure would stay around the same as stock... you would have to tune with your needs. on my nikki's i often run 6 - 8 psi base pressure. it really all depends... one thing is for sure, you need a better fuel pump than stock.

i used to run a holley blue with a holley regulator. i also hear the carter pumps are bad ***.

 

yeah, carter pumps are pretty cheap

thats what rx7carl runs on his 7's, i believe

 

Carl recommends 2.25-2.5psi, but more flow than the stock pump can provide at the high end.

Personally, *I* recommend the Mallory Comp 70 fuel pump. It's silent compared to the Holleys and Carters, no audible clicking sound, and provides 70GPH@6psi. Of course 6psi is way too much, so you have to get a fuel pressure regulator. I've got a Holley 1-4psi regulator. (all aftermarket fuel pumps have this too-much-psi problem, so they all need regulators)

Basically, when you first get your Sterling you can use the stock pump but you won't get the performance that you'd get with an aftermarket fuel pump and pressure regulator. Fuel line diameter can stay the same.

Jon

 

With any performance carb you should upgrade the fuel system with a higher volume pump and a regulator to supply the additional needed fuel at hi power. The stock line and filter are ok.

Even with the stock setup a better airbox/filter will improve the performance. The flowbench and butt dyno prove this. The ISC piece is great as is the RB powerpulse.

 

This might be a stupid question, but I'll make a fool of myself anyway. lol. I have a spare stock pump, and was wondering if you could use two stock fuel pumps like this: Line from tank splits to two lines, each goes through a filter and a pump, then the line is rejoined again before going to the carb. This would give you two filters and two pumps. Would this be worth trying?

 

thats how the old RB dellorto fuel pump was set up. Dual 6 psi facet pumps which are no longer in production IIRC. Im just not sure if the dual stockers would have enough pressure/volume to support a non-stock engine/carb.

 

If you use the stock pickup and supply line, the 2 pumps would basicly cancel each other out at thier maximum psi rating. Yielding no more than the maximum of what one pump could put out. If you run seperate pickups and merge the 2 pumps into a larger supply line, you will increase flow rate and hold the psi. If the larger line is too large, psi can drop, yet still have the flow rate.

I suggest the seperate pickups, even though the stock pick up quite large, because it is on the suction side of the pumps. That is a lower psi side and needs a larger cross section to achieve the same flow rate that the post pump side has.

 

Why is FBII recommending 6-8 psi and and Viper says Carl recommends 2.25-2.5...???

That's a mighty big difference.

 

I always ran 2-3 psi on my Yaw with a Carter pump.Yea,its a little loud,but not excessively.
The trick to making it work consistantly is the low pressure regulator...the 1-4psi Holley that Viper mentioned....and a good pressure gauge.

 

The pump puts out 6-8 psi but gets regultaed down to 2-3 psi with the regulator. Or maybe Zac is on crack.

 

yes, i am on mucho crack i actually run 6psi base pressure... which is a massive drop from the 50 or so psi the fuel pump is putting out. then at 0hg the regulator shoots up to 15psi, then under boost it's a 1:1 increase WOOOOOT!

this way i have a bit of pressure when boosting only a couple psi around half throttle to keep my afr's in check.

 

Thanks for the input Trochoid, but I'm not sure if I agree with this. If an aftermarket pump is capable of feeding a Sterling properly while still using the stock pickup and fuel lines, then it seems the dual pump setup would be able to also. Sterlings need volume, rather than pressure, from what I understand.

I realize that the really slick thing to do would be get a nice aftermarket pump and regulator, but that takes more money. I already have the parts necessary to do a dual pump, so was wondering if it would be worth trying. Hell, I need something to keep me busy over the winter....

 

Well kentetsu, find something better to do over the winter

From Paul Yaw's website:

"The stock fuel pump is barely adequate for its intended purpose. Do not even consider running an aftermarket induction system with the stock pump, two of them wired in parallel, or any other combination. This goes for the Facet as well. A large rotary vane style pump is the only thing worth running, and as I said before, the Carter has proven to be the best. (It is also the least expensive!)"

Yaw's nikki carbs also used 2-2.5 psi.

 

summitracing.com for a Carter pump and holley pressure reg.

 

Well, I guess that settles it then. Straight from the mouth of Yaw. Thanks man.

 

I think what Yaw's saying is that if one stock pump is barely adequate, two in parallel still wouldn't cut it on higher flow set-ups. There are ways to figure out how much fuel flow is required for a given engine power, roughly. There is sound principle behind doing parallel pumps, though.

Putting pumps in parallel increases the total flow rate of the system, but not the pressure output. If we neglect flow losses, the flow rate should double for any given pressure drop. In the real world, it's probably more like 1.6 times the flow rate since the rest of the line isn't changing. Max pressure does not increase with this type of arraingement.

The added benefit would be to have redundancy in the fuel system. If the pump design won't allow backflow, or if you added a check valve to each of the two branches from the pumps, you would have a pump to limp home on if one went out.

So even if the fuel flow of two stock pumps isn't adequate to your set-up, there would be a pump where this set-up will work well.

 

Well, thats kind of along the lines that I was thinking. Should give you roughly double the flow capacity, right? Maybe I'll try it out if I get bored and can't afford a hot pump/regulator by spring...