General Supercharger Thread

Can’t tell you anything for a fact, but that is what fixed mine. Here’s a dump of some of the pertinent posts in response to resolving another guy’s issues with a stage 2 Harrop who had the same startup problem as myself and Zphilip. These people are way smarter than me, just sharing. His was ultimately fixed (via VFtuner) by injector adjustments. There could be several factors at play for the startup issue as far as airflow and injector tuning.

 

Yea, I just think your issue was different than Philips is all. We implemented what your tune had and it didn't make any difference. Though those quotes are interesting because the TRD tune had drastically higher startup airflow values at cold temperatures than any other tune Ive seen and is what my truck uses. But it's only valid up to like 32F.

 

It may also be that his require similar adjustments but not the exact same values. I was sent about 4 different iterations of the tune that solely had changes made to the airflow adder until it was dialed in. It was pure trial and error, and it may take the same thing to get his right as well. What works for one truck likely won’t be the exact values that work for another.

 

Pump shipped, FedEx says Friday delivery!

 

Thanks for this. Lots of info here. My cold starts are fine which is why I don’t think I’m losing fuel pressure. It’s the warm starts (30 mins to a couple hours after shutdown) that are real bad. I’m not talking an extra second of cranking, but 5+ seconds.

 

I'm all over trying to figure out the long/repeated crank glitch. I have somewhat erratic and time limited opportunities to trial and try to collect symptomatic data, but I'm willing to try some various tune settings.

 

Got the first of 2 submersible hoses & direct wire kit for the pump.

Am I deleting the oem power & ground or splicing these to them?

Very little documentation with this.

 

I ran the thicker wire to the terminals I linked before, bypassing the stock plug, I didn't splice.

 

So no OEM pump power connected, just the fuel level sender is connected, the relay is getting power from an ignition switched fuse I assume?

Thanks

 

Correct, I used the same IGN source as the Harrop supercharger coolant pump, that way the fuel pump comes on at key-on and I wait a couple seconds until I hear fuel going through the FPR before I crank.

This is from their instructions:

 

Cool except I have 2 taps there. The first is my 18+ Sequoia headlights. threes company!

Lol

 

Well, the good news is the voltage trigger for the relay doesn't draw much power, so you might be good....I haven't run into any issues yet...

 

Mine from Amazon is still MIA, but hopefully Summit will deliver tomorrow. Radium Engineering bulkhead kit should arrive tomorrow as well if everything goes as expected. I really hope this fixes your issues.

 

I'm sure the relays for both pumps & the headlights don't draw that much. I have spare fuses in case.

I hope you get it soon my bulkhead parts are scheduled to deliver Friday. I'm hoping to have the truck back from the dealer tomorrow, the Tacoma feels so small. lol

 

Does anyone know what the Injector Constant is for a non-FFV naturally aspirated 5.7L engine? Or several from different Model Years if they vary? 0.122747? I'm tinkering with an idea....

 

https://forum.hptuners.com/showthread.php?81934-Toyota-Repository/page2
might have what you're looking for, or a good starting point

 

As of tonight, I’m making airflow changes and trying warm starts. Then waiting an hour or so and trying new values. Maybe after a few nights of this back and forth nonsense, I’ll have something to report.

 

Stock is 0.131663 and that corresponds to about 400cc (even though I think the stock injectors are claimed to be 440cc I had read, but calculating from the constant it comes exactly to 400cc). TRD greens are 535cc and use 0.098381. My 715s use 0.073613.

If you need the injector inverse constant, stock (400cc) is 1.77887, TRD green 535cc is 2.37921, and 750cc is 3.33539.

And for anyone's reference, injector constant is (Old cc)/(New cc) * (Old constant). Injector inverse constant is (New cc)/(Old cc) * (Old inv constant). Injector constant linearly gets smaller as the injector gets larger, and inverse constant linearly gets larger as injector gets larger.

 

Is it safe to assume harness side + means ignition switched fuse?


Also, I found another fuse to tap, seat heater is switched on ignition & high amp.

 

According to that diagram, blue would be the IGN tap, yellow is power to pump, red to battery, black to ground. You will also need to supply a ground for the pump.

 

Have a look at what Deatschwerks suggests with their 650s.

 

Wow, that is odd.

I have wondered how important the injector constant is, it would seem like if it's off then the MAF would just compensate for it? I think there is some trickery that can be done with it, but I haven't tried it yet.

 

Yup, blue is "harness side" It came with a separate ground wire for the pump!

Hopefully I get it back today & can get going on this, appointment at Xact the 14th.

Thanks

 

Radium bulkhead connectors & duckbill out for delivery! woot!

 

This is kind of what got me to wondering if it's influencing the long crank times that I'm seeing. I'm wondering if a smaller value would result in less fuel during cranking, as it seems I'm seeing too much and getting blue smoke from the tailpipe when my truck does eventually fire. There's also a recommendation from one of the folks over at HPT forum to not calculate the injector constant, but rather to adjust it until you're seeing 2-5% rich (on the LTFTs I assume) and then adjust the MAF from there. I may give this a try this weekend to see if it gives me better starts. These long rich cranks have me kind of paranoid that I might be washing the cylinders walls with fuel. Could be unfounded though...

 

That's what I was thinking. Adjust the constant, that would effectively change your cranking fueling which most of us can't adjust otherwise, then MAF to get LTFTs back in place.

In regards to the forum post, that does make sense but I've never done that since I didn't adjust anything besides the injector constant when I upgraded and it was correct out of the gate using the scaling method. So I've never thought about it outside of that, but it would make sense.

What I've wondered is when the MAF flow values get maxed out, can you decrease the MAF values and decrease the effective injector size (ie increase constant) at the same rate? Ignoring the potential cranking fueling limitations, would that allow the MAF to come back into range? Maybe scale the desired air load tables so air load, injector, and MAF values all stay proportionate to each other but can they move up and down without affecting other systems?

 

You did change the "dead head" (Offset) times though, right? I've wondered if those could have an effect on cranking.

LOL, I'm not even sure I can get my head around that yet! Baby steps first. We need to get SlowNStock over here...

 

Of course I changed the dead head My understanding is the dead head is just the delay for the injector to open at a certain voltage, so it's effectively the "injector advance" you need to get fueling when you actually want.

I was talking to SlowNStock the other day. I made a spreadsheet to calculate timing based off his tuning guide since I was getting confused by what a datalog was doing. Turned out it was just shifting and that's why timing went to 0deg

 

Yep, I noticed the definitions that appear at the bottom of the tables when hovering over the settings in HPT.

I have his tuning guide bookmarked and reference it every once in a while checking to see if I've missed some facet when I wander on some random hypothesis, trying to grok this thing called "tuning".

 

Dealer sent a pic of the open head, looks new! If I move the FPR back behind the head, can I run a hose from one port to the driver fuel rail and the other side where the oem FPR was & the return to the return hardline?