Spark plugs burning uneven - Pics Included!

[ThreeHonks]

Thanks Tom. I have never heard of a FPR doing something like this before, but I will be replacing it and putting a nw set of plugs in it. I may just go with another stock regulator just because of cost. I might change to a parallel rail setup soon and dont want to spend money on a nice billet FPR when I wont even be able to use it when I change

[meissen]

Could it also be the fuel rails can't handle the fuel you're using? I vaguely remember reading something about how the fuel rails will dump more fuel into the cylinders closest to where the incoming fuel is and by the time it gets to the return side it leans those cylinders out.

[MP81]

Could it also be the fuel rails can't handle the fuel you're using? I vaguely remember reading something about how the fuel rails will dump more fuel into the cylinders closest to where the incoming fuel is and by the time it gets to the return side it leans those cylinders out.

You know, I recall hearing that as well.

[DETROITMUSCLE]

he was considering that option, I assume guys have taken the stock rails to more hp than this though. (not to discredit ryan's setup in any way)

[wasjo6431]

Could it also be the fuel rails can't handle the fuel you're using? I vaguely remember reading something about how the fuel rails will dump more fuel into the cylinders closest to where the incoming fuel is and by the time it gets to the return side it leans those cylinders out.

Brian you are correct. on the lt1 the fuel rail is fed from the rear. regardless how you look at it If the fuel rail isnt good enough of the pressure is too low to occomidate the fuel usage. the rear cylinders will recieve more fuel leading to leaner and leaner as you work your way to 1 and 2. think of it as a hose if you poke holes all the way down it or drill them in it eventually the last hole is getting less water through it.

[meissen]

The first pic of the 7, 5, 3, 1 is a perfect picture of it leaning out as it goes from 7 to 1, too.

[Boost Addict]

Why the cold plugs?

[wasjo6431]

"Before I started this project I spent a good deal of time talking to Brett Clow over at Aeromotive about possible fuel system upgrades. According to Brett, the LT1 has excellent fuel rails, but fuel pressure and flow consistency starts to suffer above 350 horsepower as Chevrolet plumbed the rails in series. While Brett admitted there are cars making more than 350 horsepower in stock configuration, those same engines could make even more power if they were converted to a parallel system such that each rail is supplied with fuel independently. Because I may add more power later, I chose to run my fuel rails in series, but upgrade to AN fittings and an external regulator so I would be ready to run a parallel system later. While bumping up fuel pressure will only give temporary horsepower gains on an LT1, an Aeromotive regulator will allow you to run the optimum pressure for a given injector, connect an Auto Meter fuel pressure gauge, provide consistent pressure and look good doing it. In addition to setting up an external regulator, I'm going to cover Aeromotive's on-rail regulator (part No. 13107)." This was in Chevy HP magazine heres the link http://www.gmhightechperformance.com...use/index.html

[DETROITMUSCLE]

great info John. I see exactly where your coming from here. Personally I'd like to see another set of plugs in a similar car to Ryan's. I know the LS1 rails aren't parallel and they are fine up to high hp levels (800+) so will there be some plugs running a hair richer than others, sure. I just don't see that much variation because of the rails themselves I think there is another issue here and the regulator seems the most viable culprit at this point.

[wasjo6431]

Jeff i totally agree on that the rails themselves are capable of high HP numbers on both the LT1 and LS1. The rail isnt the issue. based off the front plugs being extremely lean the regulator is either preventing enough fuel to enter the rails the pump isnt pumping enough fuel to the regulator it would be great if he could monitor fuel pressure on a WOT stint. for one run. I remember watching mine at the track go from 15 to 4 at WOT by the time i got 3/4 down the track causing fuel starvation. His issue seems like its fuel pressure related. hes got big injectors bigger injectors let more fuel pass but also depends on pulse length. and fuel curve. But the plugs are telling me its fuel starved up front. because the first two cylinders are recieving the most fuel and then from there it progresses. Idk if hes running a stock pump or a high volume fuel pump. IDK what his HP numbers are. But this tells me he really needs to at least be running and adjustable regulator or at least replace the existing one. So its two things it could be and thats Fuel pump or Regulator but hte issue is definately fuel Pressure not being any where near equal on his rails all the way through. which no matter how you look at it with a fuel rail the fronts will recieve slightly less than the rears. Hopefully he doesnt end up with any cylinder wall wash damage due to this

[Fox Slaughter]

The lt1 fuel rails feed from the back off the riverside bank first to the front crosses over and feels the passenger rail from the front doesn't it?

[DETROITMUSCLE]

I believe he has an upgraded walbro 255 pump and the regulator is being replaced this afternoon.

[JoeliusZ28]

"Before I started this project I spent a good deal of time talking to Brett Clow over at Aeromotive about possible fuel system upgrades. According to Brett, the LT1 has excellent fuel rails, but fuel pressure and flow consistency starts to suffer above 350 horsepower as Chevrolet plumbed the rails in series. While Brett admitted there are cars making more than 350 horsepower in stock configuration, those same engines could make even more power if they were converted to a parallel system such that each rail is supplied with fuel independently. Because I may add more power later, I chose to run my fuel rails in series, but upgrade to AN fittings and an external regulator so I would be ready to run a parallel system later. While bumping up fuel pressure will only give temporary horsepower gains on an LT1, an Aeromotive regulator will allow you to run the optimum pressure for a given injector, connect an Auto Meter fuel pressure gauge, provide consistent pressure and look good doing it. In addition to setting up an external regulator, I'm going to cover Aeromotive's on-rail regulator (part No. 13107)." This was in Chevy HP magazine heres the link http://www.gmhightechperformance.com...use/index.html

hmm, im curious what my plugs look like now...

[MP81]

Pull 'em and find out!

[DETROITMUSCLE]

Pull 'em and find out!

X2 get on it, you've got nothing better to do today