I'm getting my stuff together to convert my returnless system to return style to support my new 370/WCCH heads/TVS1900 combination. What fuel pressure should I set the regulator at? It's going to have a boost referenced reg, too.

 

It seems like most of the builds I read set the base pressure at 58-60lbs and then let the boost referenced fpr bump it up 1:1.

What pump(s) are you going to run?

 

I'm planning on using a single 044 Bosch. If I need a dual pump setup, I might go with a GSS342 Walbro next to it. I was THINKING of starting in the mid 40's as base, since the Bosch (and most other pumps, also) flow better at a lower pressure. That's just my thoughts for now, (just thoughts)............. anxious to hear what others are running.

 

One of the fuel experts will have to chime in but I would imagine if you start out at such a low psi, you'll run out of injector. Stock psi is 58 so I wouldn't imagine you would want to start any lower. I also think running such a low base pressure would effect fuel atomization.

The single walbro will start to drop off pretty quickly at really high psi but a single Bosch 044 will be fine. The walbro drops from about 240lph to 205lph when going from 60 to 75. The 044 starts at about 280 and only drops to about 260. THat's a 14.6% drop vs a 7.1% drop.



I'm currently running only a single walbro intank (with a OEM returnless manifold) but I am going to switch to a surge tank and twins 044's.

Rick

 

Stock psi on the returnless system is 58, but what's the psi on the 03, and down return systems? Thanks for the info, that's why I started this discussion, I'm not sure my ideas are on the right track.

 

03 and down are about 48 idle and 58 wide open increasing 1 to 1 for each pound of boost after that

 

Your thinking is wrong, unless the injectors you use flow enough for your engine at 40 psi. If the injectors you choose are rated at the flow you need at 58 psi, then you will need a pump that will flow more than enough fuel at 58 psi. Running those injectors at 40 psi will drastically reduce the amount of fuel that they supply the engine.
It all depends on the intended use of the pump, you should be blind to the parts of the flow graph that you are not using.
Try to find a graph that rates a pump down to 0 psi, that would be usful to know how fast it would fill a swimming pool.

 

That's what I was looking for.



That's why I posed the question. Now..... I'm thinking of using a base pressure of 48-50 psi, then 1to1 for boost. Thanks for the input.





There's some good info on Kinsler's site. I think the 044 is the 10211 pump

http://www.kinsler.com/Cat_32_Pgs/Ca...l_Pump_Pgs.pdf

 

WorkTruc's description of pressures indicate that the stock base pressure is 58 psi. Base pressure is the pressure at 0 psi in manifold, which is the same at WOT or engine not running. The regulator lowers that in vacuum, and raises it in boost. Why would you want to lower that by 10 psi? If you are not tuning your engine, you need to ask the tuner what base pressure he wants. You cannot tune your engine accurately by adjusting fuel pressure.

 

I forgot, you set the base pressure with no vac line connected. I'll be doing the tuning myself.