lz9 3900 V6 buildup

[ericjon262]

if I need more fuel, I think I'll do a surge tank with, high pressure pump inside, at a lower pressure, the 340 LPH I have should be more than enough for anything I can throw at it.

[Shaun41178(2)]

I hear ya. I thought of a surge tank too but they are expensive and then I'd have to figure out a place to mount it.

Going with a magnafuel 4303 would prob be about the same cost or cheaper than a surge tank for me.

Your 340 will prob be enough but if you switch to e85 it's a whole nother ballgame. 450s run out of oomph quickly

[Shaun41178(2)]

New fuel parts in. New wiring, and I am upgrading to 1/2 inch fuel line over stock 3/8th, and doing the highest flowing walbro in tank. I had a 450 and now installing a 535.

Hopefully the new wiring, larger lines, and slightly larger fp will give me the room to hit 600 whp.

IMG_20220908_204337519_HDR~2.jpg (1.86 MiB) Viewed 3934 times

[eHoward]

Thanks for sharing…. Looks like you cut a ton of lag out

here are a couple more screenshots of the boost controller vs boost controller off.

boost controller.jpg

no boost controller.jpg

big difference for spool up. its prob worth another 60 tq at least from 3500 to 4k rpm.

[Shaun41178(2)]

Ready for installation.

IMG_20220915_220323695~2.jpg (1.68 MiB) Viewed 3879 times

[ericjon262]

did you ground your sending unit through the harness?

[Shaun41178(2)]

Yes. Just like factory harness, the only change I made was the power wire to the pump. That's straight off the relay now, but I used the ground wire and sending unit for the fuel gauge off the factory harness.

So the new zietronix is wired to the factory harness in the engine bay for the ground and sending unit.

[Shaun41178(2)]

Initial pull in third gear with new setup showed afr in the 10.0-10.5 range. I was around 12.0 before, Which means I am about 1.5 to 2 points afr richer without any tuning with the new pump, wiring and line upgrade on initial tuning I've pulled about 8% or so.

I'll have to retune for sure, which I expected, but it appears I def have more fuel now.

[Shaun41178(2)]

So I have done more tuning and have pulled around 10% or so fuel now from what was required with the 3/8th lines and 450 pump, compared with the 1/2 inch line and 535 no check valve pump

I am still a bit rich which I can clean up later as I am still in the low to mid 11s air fuel, which is better than the low 10s I was at initially after the pump change. I figure I'll end up pulling a total of about 12-13% overall.

Here are some screenshots of some logs. This is a third gear pull. I wanted to show the boost duty cycle I am commanding vs rpm and howuch boost that duty cycle is commanding.around 5k rpm it's about 15 lbs, and up top from about 6100 rpm to 6500 it's around 19-20 psi.

This increase should help with the torque falling off up top as much, which of course increase overall HP. Timestamps show 1.7 seconds from 5k rpm to 6500 rpm

boost vs rpm 1.jpg (50.96 KiB) Viewed 3739 times

boost vs rpm 2.jpg (49.62 KiB) Viewed 3739 times

[Shaun41178(2)]

Thought I'd post this crappy pic for y'all as I had it out and about over the weekend.

IMG_20221105_173530883_HDR~2.jpg (1.87 MiB) Viewed 3689 times

[Series8217]

Looks great!

[Shaun41178(2)]

So I am still trying to max out this single pump setup. After some testing I discovered that even with the new wiring, I still wasn't getting proper voltage to the pump. Logs showed voltage was dropping into the upper 11s, at 6k rpm, where fuel demand is very high. Pump voltage is down, it means fuel flow is down.

The boost a pump wires in pre pump, and essentially amplifies the voltage to the pump up to 17.5 volts when under boost only. Simply put it works. After one session of street driving, I have pulled about 13% so the device is working correctly.

I hope this will allow me to turn the boost up to 20 lbs or, maybe, even more. I'd like to try 25 lbs on e85 and see if the engine will stay together.

IMG_20230101_193840708~2.jpg (1.68 MiB) Viewed 3508 times

[pmbrunelle]

If you were dropping a few volts before, possibly some connectors and wiring were being overloaded.

Keep an eye on the voltage drop; if it increases beyond what it is today, it's probably the connectors/wiring degrading due to overload.

[ericjon262]

I was recently shown this:

https://www.racetronix.biz/p/connector- ... 50/rcs-027

It would require a bung made to install it on a tank, but has 2x 280 series pins, which supports way more current than the 150 series pins, and it also has 2x 150 series pins for the sender. Hopefully I don't ever have to take mine apart again, but if I do, I'll make a bung and run that, with the 280 pins as the power feeds, and ground through the sender.

On another note, I wish racetronix's website was organized in a manner that stuff like this was easier to find.

[Shaun41178(2)]

If you were dropping a few volts before, possibly some connectors and wiring were being overloaded.

Keep an eye on the voltage drop; if it increases beyond what it is today, it's probably the connectors/wiring degrading due to overload.

I think it's the alternator that isn't keeping up. The microsquirt logs batt voltage and it's dropping at the computer. Idle or crushing will be around 13.1 according to the log. Upper rpm it shows in the upper 11s. So I'm assuming for now that batt voltage is dropping on all systems.

I ran all new wiring for my pump and although there could be problems with connections, I'm not leaning that way as of now.

[The Dark Side of Will]

Which alternator are you running?
Are you running the Fiero accessory drive?

[Shaun41178(2)]

Stock alternator but prob an AutoZone type replacement at this point. Also running fiero accessory system

[The Dark Side of Will]

Also running fiero accessory system

You're probably slipping the belt at high RPM then

[Series8217]

13.1 is barely enough to keep the battery charged. The alternator may be fine but there could be a big voltage drop due to corroded or insufficient wiring to your fuse panel or ECU.

I got a huge improvement in performance from my charging system by running the alternator sense wire ("S" terminal) all the way to where the fuse panel bus wiring hooks up. I can't remember exactly where this is on a stock Fiero but it's two ~10 awg cables, red and red/white if I remember correctly, with fusible links. The stock wiring might omit the S wire altogether or jump it to the alternator output terminal. This is bad.. You want to at least run it to the end of the alternator cable so the voltage regulator in the alternator can make up for the voltage drop on that cable.

[The Dark Side of Will]

That's another good point. All that current goes through the ignition switch and there are multiple connections along the way.
The Fiero does have the sense wire connected to the output stud.

However, you do need to be careful with running the sense wire somewhere else. Running it to the fuse panel bus bar will ensure that you get system voltage at each fuse, but if that path has a greater voltage drop than the path to the battery, the voltage at the battery will end up too high, which will damage the battery.