external fuel pump

[theamsoilguy]

I'm racing a 1g in chump car. Engine is stock but some boost creep happening (15 psi max stock tune).

I have installed a fuel cell and now I need a inline pump and fittings. I have a spare 255 pump but I dont know if I should buy a 190 instead. Fuel pressure regulator will get me a penalty with rules. So which pump will work best for me? I dont know if a 255 is going to cause a problem.

The stock fuel line has a fitting. I will need to adapt my an-6 line to it. I found a few links to a adapter but they were all obsolete. Anyone know what fitting I need and who sells one?

I didn't take out the stock tank. There are 3 lines. Fitting is fuel, then there are two lines with rubber. I think the thicker one is fuel return and the other might be a breather line. Anyone have a diagram so I can confirm which is which.

Thanks.

 

[SaulHudson]

The -6an will work with the stock feed line. The flares are not correct but it doesn't leak.

The feed comes directly from the pump housing.

The return is the bigger of 2 remaining lines and goes to a hard line in the tank in front of the pump housing.

The last line is the breather. There is a blue/green check valve in this line immediately right of the pump housing.

There is also a filler neck breather that runs opposite direction.

 

[theamsoilguy]

Thanks, will try my an-6 fitting. Isnt it a metric fitting and then the threads dont match?

Which pump a 190 or 255? I think I heard the 255 is too much for the stock regulator.

 

[LandSpeed-DSM]

190 should work fine, or a 3KGT VR4 pump. I've used both.

Port the wastegate hole on the turbine housing and consider running a cheap dumped O2 housing to take care of your boost creep. As a bonus this pair of easy mods will simultaneously drop drive pressure giving a margin of safety in the tune for extended racing through increased knock threshold as well as improve spool and pick up some power at the same boost level.

 

[theamsoilguy]

Already ported the hole, dropped the boost creep PSI from 18 to 15 ish. Cant run other parts or will get penalty laps . A slighty less good exhaust is going into the car and hopefully that helps. The current 3 inch exhaust goes into a rally car that has cams, bigger turbo. Then a cheap poorly bent 3 inch exhaust is going to get cut up and sent out the passenger door as I dont have much room now because of the fuel cell. That will also drop weight as I can remove several feet of xhaust. I will have to see what happens to the boost creep after this change.

I know a 190 pump will work, but I have a spare 255. Im not sure if a 255 is a bad idea on the car.

 

[LandSpeed-DSM]

Even on a 1G, it is most likely that a 255 will overrun the regulator. Especially if you will be doing the equivalent of a rewire to accommodate the in-line location.

Running a shorter exhaust may offset some of the restriction the poorly bent exhaust would provide to encourage more exhaust to leave through the wastegate.

Have you tested with shop air to see how far the flapper actually opens? There was a whitepaper put out by BorgWarner that showed they could get full total flow from the internal gates at ~50* open.

 

[theamsoilguy]

No testing with shop air. but when I fiddled with it I ground it down a bit to make sure it opened 90 degrees when I also ported the wasteage opening, I thought that was the desired result. This is just not stuff I have ever done before. Building race cars is a bit above my pay grade but I have a few cool toys now. I also already did the fuel pump relay thing.

Thanks, will play it safe and get the 190 pump.