Hey Everyone,

I have an N/A 416 stroker in my 01 Z and I’m planning on converting it to flex fuel. It currently has a racetronix 255 pump and hotwire kit which has kept up fine on gas, but will be undersized when using heavy ethanol blends. I’m currently a bit over 500whp on premium but have too low of compression, so there’s a bit more room to grow there. After the heads are milled and it’s able to run E85, I expect that number will be a bit above 550whp. So I’m looking to put together a fuel system capable of at minimum 600whp on E85.

I don’t want to worry about fuel starvation if I drop below ¼ tank, so I don’t want to lose the factory jet pump functionality by going to a big in tank pump or a separate external pump. I see racetronix has a 340lph drop in pump with the jet pump incorporated, but at 58psi it only moves 325lph including what goes through the jet pump, so it seems like it would be pushing the limit.

So I’m left with a couple of options:

1. Optimize the fuel system to get every ounce of performance from a racetronix 340 pump
2. Add a surge tank with a walbro 450 and feed it with the 255 pump that’s already in the car

For the 340 in tank option I’d switch to return style fueling to gain that little bit of extra capacity, and if necessary I could add a boost a pump. I’d really rather not rely on a boost a pump if I don’t have to, but I’m guessing there probably wouldn’t be much choice.



If I go the surge tank route, my plan would be to have the in tank pump send fuel through a 97-98 filter, feed the surge tank, then return back to the main tank. From what I understand I’d also need to add a regulator to the return line in order to keep feedline pressure high enough to make the passenger tank venturi pump operate.

I’d probably mount the surge tank in the center cubby in the trunk and build a firewall flush with the trunk floor. Doing it that way keeps it well protected and should let me keep pretty much the full trunk cargo space. To keep things simple I’d probably go with a returnless surge tank (likely a Radium FST-R) which would save me having to run a return line and redo my fuel rail setup.

If I can make the in tank pump work without a boost a pump, that would be my number 1 choice. But by my calculations that’d be iffy, so I’m leaning toward the surge tank option. What do you guys think? Anyone have experience with the racetronix 340 pump? Any surge tank recommendations, or alternative options I’m not thinking about? Input is definitely appreciated. I realize this isn't forced induction or nitrous related, but it seems like you guys have the best handle on fuel systems.

 

depending on hp goals a single intank 550 with the proper fuel lines should handle it fine

no need for all this cost and complexity to go corn with a NA application.

If you need more, pair it with another pump triggered by boost.

The surge tank stuff isn't the way to go from a cost and packaging standpoint

 

Thanks for the reply Rkreigh, I appreciate the insight.

As I mentioned, I don't want to worry about fuel starvation during cornering when the fuel level gets low, which is why I would like to either keep the jet pump functionality or use a surge tank. If there are larger pumps that incorporate the jet pump, that would be ideal, I just haven't found them. That said, it's certainly possible I'm overthinking the fuel starvation issue. How low can the tanks be safely run without the jet pump on an auto-x course?

I understand that there aren't as many benefits with ethanol going NA compared to boosted, but I'd still like to do it because it gives me flexibility down the road if I decide to add boost. But frankly the main reason I'm looking at it is because I think it would be cool to have a working flex fuel setup. I get that it's not the way to go for good performance per dollar return, but neither is a solid roller NA stroker compared to stock cube and boost.

 

Yep a Walbro 525 should get the job done.

You can also look into the lonnies set up: http://www.lonniesperformance.com/vettefuelsystems.htm

Or you can call Bret https://www.corvetteforum.com/forums...wnbluez06.html
and he will get you set up.

KT

 

@BLOWNBLUEZ06 makes an intank walboro 525 setup that retains the oem jet pump. There are a few different ways to retain the jet pump no matter which direction you go. I used russell adapter fittings on both of the fuel tank hats and braided line between the tanks and then put a Y block in my feed line sending one of the lines to the engine and one of the lines to the passenger tank. I tapped the inside of the ORB fitting feeding the passenger tank for a 1/8 NPT plug and drilled a 5/64" hole(same size as the factory orifice) through the NPT plug and my jet pump works fine.

 

Thanks for the replies. I'll hit up blownbluez06 and see what his system is all about. I saw some posts on how people have kept the passenger tank venturi pump working with custom y fittings with a drilled orifice (looks like that set up is for when you're exceeding the capabilities of the stock lines), but I haven't seen anything about how to retain the in tank jet pump that keeps the fuel bucket full since it's built into the pump end itself. I'm guessing I'm just overthinking that part of it and should just plan to not dip too low on fuel level.

 

Bret's setup places the in tank pump vertically with the pump sock filter resting on the bottom of the tank at the very back where the fuel will slosh under heavy acceleration. There is no bucket to fill and you won't ever have to worry about it, his setup should allow the pump to pick up fuel down to the very last drop in the tank.