Supercharger install

[clownmidget]

Rising rate FPR worked? The problem is the zero point in add-on forced induction. The FPR wasn't designed to recognize boost. Most production boosted cars use the same 'vacuum' profile, and a 1:1 or variable rate fuel pressure regulator under boost. What this does, is allow ~67psi of rail pressure for the injectors at 1.5pressure ratio.

I'd also venture that another Mr. T application FPR from a turbo car or truck, would bolt into the rail without spending the major bucks on the BEGI or others. You lose some of the adjustability in terms of fine tuning a variable rate regulator, but very few production cars use something other than 1:1 anyhow.

My fascination is in that fuel pump resistor circuit, that is triggered by the ecu. I suspect that testing it would show that it's either kicked by rpm or more likely by the WOT switch to go 12v. Using the Supra pump, don't you need to decrease fuel pressure during vacuum (since you are in essence a stock truck unless in boost), or live with the overfueling inherent to this supra fuel pump mod?

ST

Well, right now nothing - the BEGi 2025, boost control, fuel pressure gauge, etc - is on the truck. I went through the CA smog testing and wanted to be as "compliant" as possible. But I also don't have Christo's A/F ratio wide-band gauge setup to allow me to know when I'm running rich/lean. You may be correct that at no boost (vacuum) up to ambient I'm in a rich condition. Hell, I may be running rich at boost. I do know that with stuff set up I do not get the high end lean, knocking, etc. But now that I've got another two year ticket to play I'm looking at following Christo's experience with the SMT6/7 piggyback ecu, running a wide-band 02 sensor for A/F ratios and likely plumbing in the two injectors I have on the cross-over tube.

 

[SUMOTOY]

Still didn't hear me Scott. let me define. A bottleneck is the item that is currently athe limiting factor.

....

Like said above, what good will adding a FPR if you haven't added a larger pump to provide the fuel.

Because you put the chicken before the egg? System pressure and system flow isn't the problem at the zero point yet. Rail (/regulated/control pressure) is the problem. You did it backwards Romer. When you put in a mod that requires more fuel pressure, that's a fuel pressure regulator problem FIRST. If you now have the extra fuel pressure in the rail, and it causes a system pressure problem (pump cavitation or rail cavitation), replace the pump.

The way you have your truck setup you are relying on the stock FPR to supply more fuel in the rail at 43.5psi. You should have much closer to 67psi in the rail. How does a Supra pump do that with a stock regulator? I say it can't unless the regulator return line is backfeeding pressure into the rail.

What you are trying to do is run the duty cycle of the injectors to max and use the stock regulator? Ok, but then you have reached semistatic or static duty cycle injector problem at 43.5psi, still not a system pressure issue. Up the rail pressure, injector duty cycle goes back down. System pressure and flow hasn't changed.

Man you guys are tough...


ST

 

[SUMOTOY]

Well, right now nothing - the BEGi 2025, boost control, fuel pressure gauge, etc - is on the truck. I went through the CA smog testing and wanted to be as "compliant" as possible. But I also don't have Christo's A/F ratio wide-band gauge setup to allow me to know when I'm running rich/lean. You may be correct that at no boost (vacuum) up to ambient I'm in a rich condition. Hell, I may be running rich at boost. I do know that with stuff set up I do not get the high end lean, knocking, etc. But now that I've got another two year ticket to play I'm looking at following Christo's experience with the SMT6/7 piggyback ecu, running a wide-band 02 sensor for A/F ratios and likely plumbing in the two injectors I have on the cross-over tube.

I think there is a lot of learning to be had in fuel systems. I'm glad the Supra pump works, I suspect that's more to the proper catalyst than proper fuel.

I have spent a lot of time looking into the fuel system on the 80. I believe I have a pretty clear understanding of it's operation (heck it's simple compared to my CIS days). I'm just not convinced that the Supra pump is a welcome addition to the mix, it's just another variable to properly tuning the fuel demands of a boosted 80.

The nice thing is that Mr. T gave us some really big injectors, so that part really doesn't need to change. I think the best mod would be to use a stock turbo FPR from the Mr. T bin that is a bolt in to the rail. I interchange them all the time at my shop, and it can really help dial in the fuel needs of the engine.

Jumping on the supra fuel pump seems pretty counterintuitive to me, nee, premature, given the pressure ratios we are playing in.

My .o2

ST

 

[SUMOTOY]

Not exactly the FSM test, but the Supra pump w/BEGi 2025 will definitely let you put fuel pressure above 50 psi all the way through 8 psi in the intake manifold.

And that's good, that's what it's designed to do! The question is, will the stock fuel pump do the same thing?

I betcha it will without system pressure, pump cavitation or rail cavitation issues.

ST

 

[Romer]

I'm not tough, I am just trying to get you to agree that the fuel line itself is not the limiting factor here. I have said that 3 times and you have gone after the pump and FPR. At some point, the fuel line will be the limiting factor and need to be changed, but you would need a bigger pump than the supra and more . . .

You say chicken before the egg, I could say laying the ground work. Like you state your experiance, I have been designing and building spacecraft for over 20 years and have a masters Degree in Systems Engineering. You define bottle necks, barriors and kill them until you reach the performance you require.

Both the pump and FPR are in my opinion bottle necks for a supercharger. It then comes down to opinion on which is the better to replace first. I would not want the regulator capable (not spec, but in operation) of providing more fuel than the pump can, wouldn't this cause a lean condition.

 

[KliersLC]

Holy thread Hijack batman!!

I have nothing profound to offer, but......

From what I have read about putting superchargers on either of my rigs, neither performs at an optimun level as a "bolt on", and as such I will continue going slow. However, what you folks are discussing it sounds very similar to the problems people were having with TRD superchargers on the 3.4L in the T100. Leans out under WOT and then folks do a variety of successful and unsuccessful but mostly expensive mods to make it work.

Slow is better anyway........

 

[clownmidget]

And that's good, that's what it's designed to do! The question is, will the stock fuel pump do the same thing?

I betcha it will without system pressure, pump cavitation or rail cavitation issues.

ST

I bet it doesn't. I'm betting that the stock Land Cruiser pump with full 13.8 volts won't top 45 psi in the fuel rail

 

[landtank]

Not necessarily a given.

I was talking generically about pumps. If the pump doesn't meet flow demands it will not create pressure. feel free to tell me I'm wrong again.

Lower voltage at the pump doesn't mean longer life

My experience is if you run a DC motor on less voltage it will create less heat and run cooler. That usually means longer life. At least on my part of the planet it works that way.

 

[SUMOTOY]

I'm not tough, I am just trying to get you to agree that the fuel line itself is not the limiting factor here. I have said that 3 times and you have gone after the pump and FPR. At some point, the fuel line will be the limiting factor and need to be changed, but you would need a bigger pump than the supra and more . . .

The fuel line is a constant, so the only difference to flow is system pressure. It's a pipe Romer, it is a limiting factor to flow at a given pressure. What I'm trying to get you to go to is the 'other' side of the FPR, the fuel return line. That also is a limiting factor, that affects system pressure and rail pressure.

Both the pump and FPR are in my opinion bottle necks for a supercharger. It then comes down to opinion on which is the better to replace first. I would not want the regulator capable (not spec, but in operation) of providing more fuel than the pump can, wouldn't this cause a lean condition.

You don't know the pump can't supply that system pressure do you? So what you are saying above is that you want the injector duty cycle to go static or semistatic at 43.5psi when you should be using 67psi rail pressure, which is then causing a lean condition or an unregulated static fuel dump rich condition.

Romer, this is backwards, period. You can't run a 29lb injector at 43.5psi up that far in duty cycle. Run the calculations on RCeng site. The problem you have is control pressure, not system pressure

This isn't opinion, this is just straight up math. You aboslutely HAVE to exceed 80%DC to feed the engine at stock TRD boost, or you abslutely HAVE to increase the fuel pressure in the rail. The fuel injectors at 43.5psi can't supply enough fuel at 100%DC for 6.5psi boost pressure. You did this backwards, and if you are running 43.5psi in the rail with a Supra fuel pump, try disconnecting that fuel return line, it's running reallly high pressure (dangerously so IMO).

Romer, please know that my fuel system understanding is very high and well documented. I am not arguing with anyone, I am trying to get understanding of how fuel systems work.

ST

 

[landtank]

I had assumed that the Supra pump was only a higher flow pump. Does anyone know that it is also a higher pressure pump as well?

 

[SUMOTOY]

I was talking generically about pumps. If the pump doesn't meet flow demands it will not create pressure. feel free to tell me I'm wrong again.

System pressure vs control or rail pressure. You are right, that's the definition of pump cavitation or rail cavitation. Demand exceeds supply. See posts.

My experience is if you run a DC motor on less voltage it will create less heat and run cooler. That usually means longer life. At least on my part of the planet it works that way.

I find that in fuel pumps to be not applicable. Fuel pumps are rated at a voltage 13.8 at 100% duty cycle. You can claim that lower voltage creates less heat, I don't have to agree or disagree. Me, I'd look at an in tank pump and point out that better heat management to pump life is a full tank of cooling fuel. Even my wife knows this during the summer months.

I also find that the fuel pump resistor has nothing to do with longevity, everything to do with return line pressure.

ST

 

[clownmidget]

I had assumed that the Supra pump was only a higher flow pump. Does anyone know that it is also a higher pressure pump as well?

Rick, here's some good info (http://www.stealth316.com/2-fuelpumpguide.htm)

 

[reffug]

I'm cracking up myself, I just have a lot of more obvious questions... Where exactly is the data that indicates that the supra fuel pump is REQUIRED for low boosted 80? ST

Data hmmmmmmmmmm

Maybe you should be come aquainted with the search function.

How about a truck with a completely new engine due to the fact that it ran lean without the supra pump and send #'s 5 and 6 skyhigh.

I would say thats pretty good data. IMHO

Course I'm not nearly the authority that some individuals seem to think themselves to be so what do I know.

 

[Romer]

You still don't understand what I am saying about the pipe. You keep answering a different question.

 

[Romer]

Rick, here's some good info (http://www.stealth316.com/2-fuelpumpguide.htm)

Excellent article Mike. thanks for that

 

[reffug]

You still don't understand what I am saying about the pipe. You keep answering a different question.

i.e. a very consistent modus operandi.......................

 

[SUMOTOY]

You still don't understand what I am saying about the pipe. You keep answering a different question.

I don't understand what a pipe has to do with the fuel. Your analogy was bad in the firt try, it's unclear to me your point in subsequent tries.

Maybe this....
The fuel pipe is the same diameter, so to increase flow you have to increase pressure or increase pipe diameter. So, since the diameter is the same, you need to increase pressure to increase flow? If that's your point, take it. Back to the rail, If you have made no changes to create a *need* for increased flow or pressure, it won't do any good. You are either returning more fuel to the tank, or you create a backpressure causing a rise in rail pressure.

Romer, stay at the fuel rail, it's easier. I'm happy to stick this out, there is no question in my mind you have done this backwards. Do them (Supra pump and rising rate FPR) together? Fine, now you might have increased the head room for the supra pump.

ST

 

[Romer]

Your welcome to your opinion.

 

[SUMOTOY]

Data hmmmmmmmmmm

Maybe you should be come aquainted with the search function.

How about a truck with a completely new engine due to the fact that it ran lean without the supra pump and send #'s 5 and 6 skyhigh.

I would say thats pretty good data. IMHO

Course I'm not nearly the authority that some individuals seem to think themselves to be so what do I know.

Not enough information? Let me see if I can guess what happened, then you send me to the thread. Stock injectors, stock fuel pump, stock fuel pressure regulator. Truck ran lean enough to blow the motor.

The supra pump isn't the solution to the problem. It's still lean if it's not using a rising rate fuel pressure regulator.

This is math, not just accepted theory. You guys need to get Probst book on fuel injection. System pressure doesn't solve an injector size problem. Rail pressure does.

ST

ST

 

[SUMOTOY]

Your welcome to your opinion.

There is no opinion here, it's just math! Ken, go to the RC engineering site. The fuel pressure is 43.5, pick HP, I used .55 and 80% duty cycle.

A 29lb injector at 43.5psi can't flow enough fuel at 80% DC with 1.5PR on the 1FZE motor. Put the Bosch 600HP race pump on it, at 43.5 rail pressure you can't flow enough fuel to your motor with a 29lb injector. Period. Notice they don't ask for system pressure in that formula anywhere, because they believe it's a given you can get to the rail. What's KEY is what's in the rail.

Get Probst book on fuel injection. I wish this was opinion. Fuel isn't magic or random installations, it's just math. Reread post #6 and post #13. Please.

ST