At what point would I need an upgraded fuel pump?
 

My plan, for now, is to just put 720cc secondaries on my '87 TII and put my RTEK 1.7 in. Would I need a Walbro fuel pump, too? I already suspect that my stock fuel pump may not be delivering enough fuel... Fuel seems to cut at 6500 RPM, 5500 RPM when cold, and after last night when I replaced my fuel pump bracket because I had previously rendered the old one somewhat unreliable/safe it now wants to idle just a little bit lower. I can see that the fuel pump no longer feeds perfectly straight into the exit line from the bracket, it may have to do with the tube not going on as far as it needed to, but there wasn't much I could do about it. That would explain the lower start idle, however once warm it worked at the normal idle and it was particularly cold this morning compared to the rest of my time with this car (just since this summer). The car seems to starve for fuel just before 6500RPM now, but these results are within my range of error so I could just be imagining things. I have NOT put bigger injectors in yet nor have I switched out my ECU. I have pulled emissions if that could possibly make any difference.

Other details that might or might not help:
Straight downpipe, but I will finish the exhaust soon without cats. After porting the wastegate I also put one layer of washers on the wastegate actuator mount so it would open sooner and farther, just to be safe. I will probably put that back to normal once I finish the exhaust.

Upgrading the fuel pump should be one of the FIRST things you do when going for more boost.

Rat

I'm not looking to increase my boost right now, it will only happen unintentionally by boost creep, if it's ever able to.

I should also note that this apparent fuel cut happens REGARDLESS of whether I'm accelerating under boost or not. That said, it probably wouldn't be my fuel pump causing it...

it's still a very important step in a performance car. I'd recomend upgrading the fuel pump even if you aren't looking for performance mods. It can easliy be considered a reliability mod.

What I want to know is: is it necessary? Will my stock fuel pump be able to keep up with 720cc secondaries at 8psi boost, assuming I boost creep?

no it will not keep up. you are increasing the amount of fule, but not changing the fuel pressure or amount of Lph. Get the Walbro 225 High Pressure pump for $90 and be safe...

I'm also wondering about rewiring my fuel pump. I know how to do it...

I guess if I get the Walbro I should go ahead and rewire, but it couldn't hurt to do it with the stock pump even.

Well, you have responses from two people that know what they are talking about. Getting an upgraded fuel pump is paramount!

The stock fuel pump can only support the stock fuel injectors - 4x550.
This is *IF* you're getting fuel voltage at the fuel pump.
Forgot about it if you're still using the stock CRAP electrical wiring and bullshit fuel pump resistor circuit - the wires are corroded and bad!

Since you're already running larger fuel injectors, an upgraded fuel pump is a MUST.

A Walbro is like $100.
There's no excuse.

Side note, I just picked up a brand new Supra fuel pump off eBay for a little under $200 shipped.
Better quality, and I don't have to deal with all those fakes floating around...


-Ted

No, I'm not, I just have the parts on hand.

Don't worry, guys, I'm not going to try running the 720s without a better fuel pump. This is why I asked this question: so I didn't run in, blow my motor, then come crying to you later. I do appreciate the help.

All that said, I need to find what kind of power increases the RTEK 1.7 offers over stock... I should have planned a little better, but I'm getting there without breaking anything for the moment.

Rewired, upgraded fuel pump is $100. a new motor is way more than that.

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