Fuel Time For More Fuel?

madspeed

Colonel Mustard
Founding Member
Nov 29, 1999
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Finally thinking about replacing my bad head gasket on my stock block turbo'd 333. Currently running a 255 high pressure in tank pump along with 60# injectors on stock rails. What's the hp limit my fuel setup is safe at? I'm guessing i should be around the 500 hp mark on 10 psi. Just wondering if a bigger fuel pump or a boost a pump would be of any help in keeping me safe??
 
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Above 500 rwhp a single 255 pump doesn't cut it. Years past I've used a 255 in tank and a Trex in line pump. Also I would start to look at upgrading your fuel rails. It's my experience that the stock fuel rails will support 42 lb injectors at 80% duty cycle. But I wouldn't push my luck past that. The ultimate upgrade would be sump the tank run some new lines aftermarket fuel rails and never look back.
 
I've seen the 340 support 630 rwhp on a recent dyno session we had with a customers convertible. To answer more directly yes it exceeds you stock block by far!
 
I really don't see how a fuel pump is going to help anything in this situation.
500rwhp is the blocks limit and even that number is an overestimate.

42's and a high pressure gss340 255 works with more than a stock block can handle.

Fuels system parts are ridiculously expensive. If there is no immediate future plan or back up plan in place for a race block, there really isn't any point in spending money on fuel parts.

Have the car dyno'ed and turn down the boost to save the block if it makes too much power.

Driving around a ticking time bomb gets old quick.
 
agreed, i'll say that i'm runing on a 9 year old Holley 255 pump and will likely be neding a new one before too long, might as well upgrade. I am also saving up for a Dart block to turn up the wick

If you want to change the pump as preventive maintenance, i get it. I was more or less responding to your original post suggesting you would like to make your setup safer. At 500rwhp, nothing is really safe.

I would slap a gss340 in the tank if you are worried about pump reliability, then when you get your new block build an entire fuel system. Budget 2 grand for it, my estimate on a fuel system was way the hell off.
 
The Holley pump i have is the high pressure version built for boost, basically the same as a gss340, so if im buying anything i should make it an upgrade

If you have an hp pump, i'd just leave it. Pumps don't go bad that often and it's a enough to supply your current setup. Walbro's are pretty damn reliable.

If you upgrade the pump there is no guarantee you are going to be able to use it later. Unless things have changed (and they may have) the stock fuel hat outltets will be undersized for your future use and they don't connect in any way to a real fuel system.

IMO, save your money and build the fuel system all at once.

And asphalt, it is NOT a good idea to oversize injectors, that is a sure fire way to land up needing a computer tune to get the car to run right. Run the parts you need now, not later if you want your car to run right.
If that were the case there would be no reason for anything smaller than 42lb injectors to exist.
Put 42lb injectors on a h/c/i car even with the right meter and see how it runs, it won't be good.
 
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