JmfnB
JmfnB MegaDork
3/13/20 7:16 a.m.

The Lexus has a PWM controlled fuel pump. The engine controls the pressure in a returnless system and the tank holds a basic regulator and a pulsator. 

 

I was considering adding a turbocharger to the car but the fuel system can not be easily modified. I can spend $500 on an unlocked tuned LS400vvti ECU from Russia and then source a fuel rail, return lines and a new pump and hanger. Not as cheap as I want. 

 

Would it be possible to use the factory pump to fill a reserve tank then feed the engine from the reserve via the correct pump and an adjustable boost referencing fuel pressure regulator and the appropriate fuel rail? 

 

Whick system would get the fuel pressure sensor? 

 

What would the hive do?

Stampie
Stampie UltimaDork
3/13/20 7:29 a.m.

The correct way to control your fuel is through engine management not fuel pressure. You're working hard for a Micky Mouse solution. What kinds of tunable engine management does Toyota have?

Stampie
Stampie UltimaDork
3/13/20 7:30 a.m.

Or if you really want a easy/cheap solution how about a Hobbs switch controlling an extra injector in the intake tract?

alfadriver
alfadriver MegaDork
3/13/20 7:32 a.m.

It's likely that the fuel pump is quite a bit oversized for the power output.  So you should be able to up the power *some* and it will still work.

But if you are talking about direct injection pump, there's not much you can do with that.

JmfnB
JmfnB MegaDork
3/13/20 10:11 a.m.

Someone has stated that the OE system can handle 7PSI from a .63 trim T3.

Stampie
Stampie UltimaDork
3/13/20 10:27 a.m.

In reply to JmfnB :

But if it's tunable then you're just bigger injectors away from all the boost. 

Robbie
Robbie MegaDork
3/13/20 11:51 a.m.

Plumb in a large sidedraft carb right on the compressor outlet.

Keith Tanner
Keith Tanner MegaDork
3/13/20 11:55 a.m.
alfadriver said:

It's likely that the fuel pump is quite a bit oversized for the power output.  So you should be able to up the power *some* and it will still work.

But if you are talking about direct injection pump, there's not much you can do with that.

We can run 575 hp V8 engines using the stock pump on a 155 hp Miata :)

The direct injection pump, if I understand correctly, is best viewed as a multiplier. Increase the pressure from the low pressure pump, you get more out of the high pressure pump. But that's crude, it's like going back to the early 90's with rising rate fuel pressure regulators.

I'm late to the party. What is this Lexus? 

JmfnB
JmfnB MegaDork
3/13/20 11:58 a.m.

In reply to Stampie :

I haven't found anyone that has the capability. On Lextreme there is a guy in Russia who will sell an entire control module with a box tune and the immobilizer bypassed for $500. 

JmfnB
JmfnB MegaDork
3/13/20 12:05 p.m.

In reply to Keith Tanner :

Oh it's a 2001 Lexus GS430. 

I know that no matter what I can not really exceed 10psi with a perfect tune. Between the connecting rods, 10.5:1 compression and limited ignition. 

I wanted to run RX8 auto injectors (about 540cc), E-85, a HX35 divided plenum and was looking at about 390hp (up about 100) from the combination. The car is losing weight like a Hong Norr Cadillac, actually maybe MORE than that. It's 3700lbs now. I want it to be a lot lighter and I have a plan.

JmfnB
JmfnB MegaDork
3/13/20 12:07 p.m.

Also I'm not thinking a direct injection pump. I would be using the OE pump to fill a fuel tank and using that fuel tank to supply the injectors.

bentwrench
bentwrench SuperDork
3/13/20 12:11 p.m.
Stampie said:

Or if you really want a easy/cheap solution how about a Hobbs switch controlling an extra injector in the intake tract?

NO NO NO NO NO this is wrong on so many levels!

bentwrench
bentwrench SuperDork
3/13/20 12:19 p.m.

You are asking for advice to do the same thing that the diesel bros just got fined 2mill for......

 

If this is a race car you need to ditch the factory ECU and maybe the electronic trans.

 

Streetwiseguy
Streetwiseguy MegaDork
3/13/20 12:28 p.m.

Why are you worried about the pump?  It's pretty rare that a pulse width pump ever sees the high side of 50%, so there is probably lots of fuel delivery to handle a bit of boost.  If you are trying to increase pressure to the injectors to compensate, like a rising rate fuel regulator, there are better ways.

I'd spend more time worrying about the mass air or map, and allow it to compensate using injector duty cycle.

JmfnB
JmfnB MegaDork
3/13/20 12:42 p.m.

In reply to bentwrench :

It's a car that will only be used for the Challenge. Then dismantled and the engine will go into a 1958 Panhard Dyna Z. If the Federales feel the need to punish me for bastardizing that French hunk of shart them they are welcome to. In the current condition it will never be used for more than a Challenge car.

JmfnB
JmfnB MegaDork
3/13/20 12:54 p.m.

In reply to Streetwiseguy :

It is very possible that I am focusing on the wrong bottleneck in the system. I felt that in using E85 and the much larger injectors I would be pushing the PWM pump too far past it's capability. I assumed that having more volume and the ability to raise pressure with boost would be an easy button 

I am not uncharted territory but the info available for this is spotty and I have never researched this before. 

I did look into a few answers to getting the MAP signal to where it would need to be. Priced a little on the high end this looked like a good answer Splitsec.com

Stampie
Stampie UltimaDork
3/13/20 3:47 p.m.
bentwrench said:
Stampie said:

Or if you really want a easy/cheap solution how about a Hobbs switch controlling an extra injector in the intake tract?

NO NO NO NO NO this is wrong on so many levels!

It's tagged as a Challenge car. 

Our Preferred Partners
v6kgSEITtwMetGScMSQl0lZtFgcdWYsfVpgcmOemF6LZoLgO6F2jxoP81fMtYwCu