Buick Grand National Gas tank swap for BETTER performance.

On this episode we swap BACK to a stock turbo Buick gas tank and explains why you should NOT use reproduction tanks if at all possible..

[@TomuchLogic-ko8bz]

I started with the twin hellcat pumps from racetronix which supposedly holds 1000hp to the wheels but started running out of fuel at 870 Horsepower. I couldn't put 40 lbs of boost. So now have the magnafuel 750 inline pump. Went back to dyno and made 1139 Horsepower in my Buick GN v6 82/80 HPT turbo with TA performance aluminum block and se-b heads. Hoping for 8.50s

[@AJsSpeedShop]

Did you have the twin 450s or 525s? I thought about doing the new Racetronix kit with the 525s but…if you say they are only good for 870 rwhp on e85 then it will be borderline for my future build. I have a new TA block sitting here that I’m saving up to build. Your car makes crazy power, I’d love to hear the details on your build!

[@TomuchLogic-ko8bz]

@AJsSpeedShop yes that's what I had the twin Hellcat 525 pumps or they call it 1050. And it ran out of fuel at 870hp. So to be safe and make sure I had enough fuel I had to go with an inline pump. Especially on E85

[@AJsSpeedShop]

Well that’s good to know…and disappointing at the same time. I love using inline pumps but, you’d think twin 525s would do more the 870 rw. I know triple 525s will go 1200 rw on e85 on LS stuff…. Sucks to have to cut up the tank to add another bung for an external pump/line but… I guess it is what it is. I only plan to make 900 rw or so but…I don’t like being on the borderline with fueling.

[@TomuchLogic-ko8bz]

@AJsSpeedShop no you don't want to be on the borderline. Best to be safe and have more pump than you need.

[@anyvisionfilms]

lol.. you just saved me. Thanks!

[@ceegee6261]

I use an aftermarket, no issues running a stealth 340 however I agree the dish on the bottom is not a great design I was considering putting fuel tank foam to create a better baffle of sorts.

[@Bige4u]

Well thats disapointing about the spectra 307c fuel tank, and just about all other aftermarket ones as well. I planned to use the same for an edelbrock proflo-4 efi swap on a ZZ4 crate engine icurrently residing in my '79 malibu 2dr coupe, just a weekend only cruiser, no racing. So thanks for the heads up and nice find on the original OEM tank.

[@AJsSpeedShop]

For sure. I hope it helped you out. Look at the new Aeromotive G Body tank with their foam encapsulated pump, it would probably work for you.

[@Kurt.24]

Good info there 👍

[@crismartinez3779]

Great info. Thanks.

[@AJsSpeedShop]

For sure. I hope it helped you out!

[@petertowers9579]

I have another question, what ohms is the stock fuel sending unit on the GN? I'm going to install the fuel level gauge but I can't find anything on it.

[@gautamkumar-nk7ck]

Should show how to swap

[@TSargeant]

Thanks for the info! I have a tank that looks new but the filler neck is not connected? Why someone would be so cheap as to get a tank without the filler neck installed. I’m gonna replace the tank soon! What is your recommendation for a tank? The stock tank is nowhere to be found because I bought the car about seven years ago. Recommendations???

[@AJsSpeedShop]

If you can’t find an original/oem turbo Buick tank, your only real option is the new Spectra GM407c tank or a custom tank from Rick’s Tanks…. It’s expensive but a nice option…. Right now I’m on the Spectra tank but it’s a pain in the ass to fill up every time. I’ll be going back to the oem tank as soon as I can fix it. Probably this winter.

[@intisity5649]

Love your Buick gn what rear end are you running in that beast.

[@AJsSpeedShop]

It is the original 10 bolt that has been rebuilt with a Truetrac posi unit and Moser axles. New US Gears and Timken bearings.

[@petertowers9579]

Hello Aj im going to be adding a fuel level gauge to my 86 gn and i was wondering if you know what wire is the one that goes connected to the gauge from the sending unit?

[@AJsSpeedShop]

It’s a pink wire from the sending unit to the gauge. And then the sending unit has a ground wire.

[@petertowers9579]

@@AJsSpeedShop perfect 👍 ok so my green wire from the glowshift gauge to the pink wire? Also would I need to unplug or disconnect the original gauge of would it be ok to leave it connected? Thanks.