Is the LPE accurate enough it doesn't need a straightener? Doesn't show 1 on their site. Still seems tough to justify 300 for it. I like the ls7/Spectre cause I can choose to keep the stock IAT or switch to the LS7 embedded in the MAF.

 

The quality hitachi etc are $45+ from say rockauto and they would normally only use a delco likely which are higher obviously.
I put a few in from 2012 to 2015 most like the ls7 but the way the straw design works it directs the sample to it. Much better design and less area used. Quite a good design and doesn't look like it would need a straightener since it brings the air to it.

Delco 2131585

Compact and great design.

It would likey use a ford style maf sensor housing/adapter which spectre has as well. So still relatively inexpensive.

 

interesting may have to take a look at those on the next one.

 

Sorry, I don't watch the forums that closely, so I missed this previously. If you go to our new streaming site, you'll see that we took the previous DVDs and split them into smaller segments for each topic. If all you want is the scaling exercise, you can get just that segment. Be warned that it won't include some of the things we recommend you do for setup that allow this to work seamlessly the first time. If you skip things like proper injector data setup, I can't help you with scaling.

 

I've been fighting a fuel pressure drop issue. It was originally with a single 255, no surprise. Swapped to a Walbro 450 and continued to have issues. Did a hotwire hit and added another 255 in parallel. Now base pressure is much higher but it still drops during WOT, but at least I'm able to keep a reasonable AFR. Running out of ideas on what could be dropping the fuel pressure. I even replaced the stock in-tank regulator. I'm logging fuel pressure at the shraeder valve on the stock rails. Only other thing I can think of is clogged fuel filter so swapping that too.

With all that said, its hazing the 315 tires in 3rd gear.....and spool is GREAT now. Loving this setup! Just need to resolve this fuel drop issue.

 

are you logging fuel pressure and injector duty cycle? any correlate-able data there? what does dropping the base pressure do?

you might just be at the point where a real boost ref'd reg is needed,. sure helped my old set up...even just deadheaded to the rails it was like night and day

 

come to think of it, I bet that’s what helped hurt my motor.

 

I know guys like @JoeNova have deadheaded some high HP stuff, surely more than my little ol rear mount is making. I can tell from fuel pressure drop and IDC that I'm having to enter MUCH higher MAF airflow than what it would be if rail pressure is constant. My MAF table is skewed 50% and max Hz airflow is like >400g/sec . Essentially the higher g/sec in the MAF transfer function is fudging to account for the drop in fuel pressure which in tern skews fuel injector flow rate. It's "working" I would just prefer it to not drop so I can enter correct airflow values.

 

Probably the regulator itself isnt capable of metering the flow over the wider range of flows now required.

Although a sensor placed local to the pumps may reveal more, in case somehow there is a huge drop from rear to front

 

Wouldnt that mean that the regulator would let MORE fuel to the rail, not less? Interesting idea of getting a sensor at the pumps.

 

Hard to know what it might do if it cannot cope. But the inflated pressure at the low end, to reduced pressure at the top end...something is amiss.

I assume it is not adjustable ?

Clearly on any line there will be a pressure drop. The longer the line the more drop, the thinner the more drop, and also the more that is consumed at the end the more drop.
Dead end systems can work for good power, but the line size would probably need to be larger than for say a full flow system where the reg is close to the injectors. And the reg near the pumps would probably need to be more capable too, as it's working in a less than ideal location.

 

I'm pretty sure people have done 800whp on a stock fuel line and rails, I'm guessing I'm around 600whp so more than enough room, but obviously something is amiss. I replaced the intank regulator thinking maybe it was leaking and bleeding pressure it didn't do the trick. It is not adjustable or boost referenced. Just very odd.

 

I'm sure you could do more on stock lines and rails.

But was their pressure stable ? Not boost referenced ? other ?

Seems common cause after pump changes etc was leakages on the pipe from pump to hanger ?

Whilst you dont want to see pressure drop....as long as it isnt silly low ( factoring in FP from MAP ), and it is always repeatable....is it really a problem ? Not ideal of course, but not necessarily a problem.

It's only when it changes behaviour to unexpected it becomes a problem.

 

I replaced the feed line since I added a second pump and a Y. Idle pressure is about 70 and drops to about 50. Not crazy low but still seems odd with a 450 and 255 both pushing. Yes technically I'm working around it because I can account for it in the maf table, just trying to figure out why it would drop 20 psi of pressure. At least I can command a rich enough AFR now where I couldn't before.

 

if the reg cannot cope with the flow of the larger pumps at low loads, not surprising pressure is high there.
IMO that higher pressure is more indicative of that problem.

If base pressure for that reg should be 58psi....then you're only losing 8psi at higher loads.....less of an error than the 12psi above at low load.

So it's not so much it's dropping 20psi....first it's inflated by 12psi, then returns to normal at some point, then falls by 8psi ? It should never be at 70psi in the first place.

50psi at the rails less what ? 10psi boost ( not sure you've mentioned how much boost ) ? other....only leaving 40psi to inject. Still not bad, but I wouldnt want much or any lower

 

That is a good way to look at it. I hadn't considered it's not really a 20 psi drop it's more like 8. I've seen other setups with Vette regulators hold higher pressure during a pull on an otherwise stock system but good thought. Yeah boost is about 10 psi.

 

sir, we dont talk about corvette regulators in here

 

What's do bad about Vette regs?

 

well they tend to give you the kind of problems youre experiencing. sometimes. but not all the time. just when i use them? or only on days that end in Y?

it's a system with a lot of design constraints. change one variable and boom you got 70psi at idle, or in my case 90psi at idle

 

Interesting didn't know they were so sensitive.....only thing I knew was they are noisy lol.