Hi,

I will add a fuel catchtank to my EVO to make it work on the track.

I will be using 2 Bosch 984 fuel pumps which is one size smaller than the big 044 bosch pump. They are supposed to flow enough fuel for 900-1000 hp together.

The question is: will the stock fuel lines be enough or will the fuel pressure go up on low load because of too small return line?

 

I would think it would be too small. I haven't heard of anyone using that type of setup. Hopefully AMS or Buschur will reply becuase they have both built 1000hp fuel cell setups with dual pumps. I am pretty sure they had to replace pretty much everything though.

 

^^

 

The return line is too small and will the limiting factor. AMS's system uses the stock feed line as the return and replaces pretty much all of the feed lines with -8 AN line. The stock feed is equivalent to a -6 AN line. Hope this helps.

 

Go get some good fuel lines like aeroquip.

 

Is this a fact? What size is the stock return line?

 

Is what a fact? The stock return is probably equivalent to a -4 and will be the bottle neck. You will be fine on the stock lines and a single walbro fuel pump up to 550 or so whp, after that I would recommend a complete overhaul of the fuel system.

 

That the return line is too small? I mean has it been tested and found to be a problem?

I will not make more than max 600 hp but now when I install catchtank etc. I think it would be as good to go for really good capacity pumps if I would like to try running on E85 (ethanol) which needs 30% more flow.

 

Not sure what the corrosive properties are of ethanol compared to methanol, but when running methanol in a car all the rubber lines are replaced along with o-rings on injectors etc. as the methanol will eat the rubber. They are replaced with teflon lines instead.

I don't know if the stock lines have been tested, but here is some info. I took out of the AEM EFI Basics PDF document that came with my EMS that is a good item to refer back to when looking at fuel requirements.

 

Ethanol is not as aggressive as methanol, no need to change the materials.

Thanks for the doc.

 

Stock line is 1/4".
What is the flow rating of the pumps?

 

In stock fuel tank I will use a SARD 280 l/hr pump.

The bosch pumps that will pump from the fuel catch tank are rated to 380 l/hr together at 3 bar fuel pressure and about 300 l/hr at 5 bar pressure.