stock TT fuel pump max rwkw?

Hi all,

Had dyno tune and hit 306rwkw, tuner noted that it was limited as the fuel pressure was dropping and leaning out up top. They suggest fuel pump or relay could be the issue. I have a new stock TT pump in there as research seemed to suggest they can go plenty higher but I could be wrong. Fuel system is stock except fuel rails and injectors.

Any suggestions?

Cheers

Liam

 

Stock pump can handle plenty.

Get rid of stock damper, get aftermarket fuel pressure regulator and 300 degree rails.

 

Thanks, that's what i thought, got the 300 deg rails already. Will look into the others.

 

Why remove the dampener? The stock pump is not an impeller type pump and thus creates a pulse right?

Are you suggesting an aftermarket fpr will also dampen the pulse?

 

What injectors are you running?

 

750cc. So shouldn't be an issue there.

 

I run 300rwkw on E85 with mine, Mark ran similar plus a 60 shot over that.

 

I used the stock rails for excess of 400rwkw.

Save the money on the 300 degree and modify the factory rails to parallel feed.
Maybe swap it out to a tomei reg or something (reasonably cheap) just to check it isn't the regulator

 

Make sure your fuel filter is new as well

 

Thanks for all the ideas, I've attached dyno sheet now. Tuner thought it was a failing fuel pump, but once told its new suggested to run a direct 12v feed to the pump and run a new relay, use old pump activation wire to turn relay on and off to get around any issues.

Thoughts on this option?

 

What turbos? That's hitting peak boost rather late?

And yes, most of us when pushing the car bypass and go direct 12v

 

Yeah, standard wiring is pretty weak so with mods getting a good connection capable of carrying plenty of amps without [notable] resistance is a good idea. You lose that nice quiet operation at idle but at least you get lots of boost. In another thread recently someone (I think kickerzx?) linked to an upgraded FPCU from ashspec that might be worth a look if you want to keep the Z luxurious.

 

My few cents...
You can do relay bypass at certain voltage of tbps, which will give you smooth run on idle and direct 12V at the pump when condition is met.

Something simple as this circuit can do the trick...
http://www.ebay.com.au/itm/5V-DC-1-...494330?hash=item2ee087d6ba:g:iokAAOSwPhdVNw1l

 

HKS2530. So decent size. Also ams manifolds. Z1 3 inch dumps with 3 inch exhaust. So plenty of air to move. Only breather mod is single pod filter.

Thanks all. Seems like the bypass is the way to go. Will look into that trick for idle as well. Thanks.

 

Incidentally, do you know what your AFM voltage is at that power level?

 

~4.8v

 

Update, relay installed and new tune hit 320rwkw with the intercoolers now limiting. So problem solved

 

How do you know the Intercoolers are limiting...

 

Tuner stated the intercoolers were heat soaking at any higher boost and hitting 70 deg. So kept it at 20 psi where they were dissipating the heat properly.