Fueling & Injection Fuel Pumps | Injectors | Rails | Regulators | Tanks

H/C/I Walbro 450, what else?

Old 11-25-2018, 04:21 PM
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Default H/C/I Walbro 450, what else?

Planning/buying parts for a winter build.

Just doing BTR4/TFS 220/FAST 102/36 lb injectors.

I picked up a Walbro 450 because I may want to do E85 in the future.

Car has 45k miles on it, and is bone stock right now.

My question is what else should I do while I have the tank down?

What kind of RWHP can the 450 support? What is the point of the hotwire kit and when should I look at doing that?

Thanks for the advice/suggestions.
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Old 11-26-2018, 02:17 PM
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Anyone have any advice on this?

From what I have found searching, I should look at a hotwire kit as well as a new FPR as the stocker might not be able to control pressure from the 450.

Is this something that I could just call racetronix on? Would they be the correct contacts?
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Old 11-26-2018, 05:57 PM
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I could write a book on what you should do now that you have the tank dropped since you intend to switch to E85 in the future especially since you have a 98.

The bulkhead connector:

Unfortunately Racetronix does not supply an upgraded bulkhead connector to replace the stock deficient bulkhead connector. There is an upgraded bulkhead connector for the 1999-2002 model years however. But it can not be swapped into the steel 98 tank bulkhead.

A single 340 or 450 draws too many amps and the tiny single terminal on the stock connector can't handle the current, so you have to run your own wire thru the tank to power the pump. Ask me how I know the connector can't handle 17 amps?

The fuel pressure regulator and return styel fuel system:

I tried the C5 filter and it would not hold pressure to 58 lbs. The lowest was about 71-73 lbs which according to Racetronix is hard on the pump and reduces pump life.

You will have to switch to a true return style anyway with E85 as the tiny 5/16 inch line from the filter to the pump is too small for E85. So the future will require a true return style fuel system with an FPR and gauge.

Fuel Lines

Racetronix has a kit with larger lines - feed and return. The bottle neck, however, is right at the tank fuel module return line inlet. It is pinched down from 3/8 to 5/16 inch. So it doesn't make much sense to run 6 AN/3/8 " return line from the rails all to the way to the tank and then bottleneck and reduce down to 5/16" ? It's need modification.

Modifications for easy removal or maintenance.

Which is why now that you have the tank dropped, planning ahead and installing the lines now with modifications will mean you won't have to drop it later. It will be a xxxxx to try to install PTFE lines to the tank without dropping it again later if/when you switch to E85. You will be able to swap the pump with a trapdoor, but IMO you won't be able to run the lines in the same location as the stock hard lines even with a trapdoor unless you drop the tank. Or you can route them like I did.

Some will say it's easy to route the lines. On a 99-2002 yes much easier. On the 98 not so if using stiff and hard to bend 8 AN PTFE fuel line.

Hot wire kit and dual pump.

The dual 510 pump kit for the 98 is not advertised on the Racetronix site, but the owner will source all of the items for the pumps and hot wire kit and give you a price. It's not too much more than a 340 hot wire kit and C5 filter kit.

Dual 510 LPH - e85

So how can you run two pumps off of the stock bulkhead connector, but you can't run a single 340 or 450? The hot wire kit runs each pump off of two terminals on the plug of four terminals rather than one single. The remaining two terminals power the fuel level sender. One single ground is run thru the bulkhead to handle the grounds for each pump freeing up the second terminal of the connector for a second pump..

The hot wire kit is essentially two hot wire kits with one harness and relay for each pump.

A single relayed circuit for each pump

A hobbs switch fires the secondary pump when needed if boosted. An added plus is that each harness has its own circuit completed with a weatherpak plug. Switch plugs and you can swap the primary pump to the secondary and the secondary to the primary to even out the hours on each pump. It takes less than 30 seconds to switch the plugs and the lead to the hobbs switch.

Hobbs switch and vacuum block


Last edited by dlandsvZ28; 11-27-2018 at 10:36 AM.
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Old 11-26-2018, 11:49 PM
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Hot wire kit is to keep the pump alive by providing power the little wire can't handle. I was getting 68 psi at idle with the stock in tank regulator, but I've never tried the Corvette filter regulator, but I know it would be lower than the 68. I have one at the shop and another 450 pump, but not sure if I will have time to test it this year, busy time. I'm running the 450 in take to a Canton fuel filter and the stock line to the engine bay. I ran it a very short time with a home made hot wire kit and shortly after got an upgraded bulk head connector from Racetronics. I now have a Russell screw on adapter to -6an, a Y to each fuel rail. From there to a Weldon fuel pressure regulator and I'm returning through the old 5/16" charcoal canister emissions line to the tank. The 98 is nice in that you can pull the in tank regulator and put a 3/8" return line very easy. I thought the 5/16" line would be an issue so I set it up to 43psi and returned the from the regulator to a gas can. Then hooked it up the the 5/16" return expecting the pressure to jump some, but it didn't. I can hear it at the two tight bends and the gas is moving to fast to be at the fuel rail, but since it's after that part of the system I'm having no issues.

You can see the stock stuff here. I bought the car with this jacked up hole already cut in it.

Walbro 450lph pump with stock in tank regulator.

Here you can see how the 98 regulator can easily be removed and a 3/8" hose added to return to the bottom in the tank bucket. Also, the larger yellow Ractronic bulk head.

This is my Weldon regulator. Used this spot because it goes right from the bottom to the 5/16" return line.
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