More isight to our fuel problems when we up the boost

[BaylorCamaro]

It's a slow day at work and I've been doing some digging and one thing lead to another, which lead to yet another and it's getting to the point where I can't even trace how I got to where I am with some of the information, LOL.

First let me start off by making this side note, some (or a lot) of you may not find this nearly as interesting as I did, and others (Gretchen, Cant_C_Me, etc) probably already know most of this, especially Gretchen since he's gotton around the fuel issue and frankly his build is BEAST.

So as some of you may know, this issue first came up really big when I was testing out the super charger OD pulley. Yes technically the turbo guys ran into it first when they had high boost but they could simply dial back their boost. However when running the OD pulley and going WOT our fuel system cannot keep up. We (the community, Tracy, Vince) figured this was the case after my first set of data logs. However it was confirmed by Vince after reviewing my logs when I was at the drag strip. The fuel system is already showing signs of not being able to keep up in first gear, second gear is pretty bad and third gear is terrible, according to Vince. My wideband was reading rich, which had me confused as to why it would read rich when there is a problem with the fuel system keeping up, so this is what Vince had to say about it:

"The reason you’re getting missing at 5000 RPM is because it’s trying to inject too much fuel. It’s a DI motor which means it has to inject the fuel between the time the intake valve closes and the time it’s ready to ignite the mixture. At 5000 RPM the fuel demand is such that it’s still trying to inject fuel when it’s trying to ignite the spark plug. It’s like peeing on a fire, it doesn’t work so well. It’s [AFR] probably in the mid 10s because of the injection window misfire. It’s a symptom of the fuel system starvation, not a cause."

I got really interested in trying to learn more about everything (in general) so I did some poking on the internetz and found some interesting things. The Solstice/Sky and Cobalt SS run into a VERY similar issue when they're trying to make a lot more power by either increasing boost OR running e85 (on their already boost motors). The Solstice/Sky guys are getting around the issue by adding an additional injector set up. Here's an excerpt from a guys post:

"So my point here is this, a lot of guys are beating their heads against the wall trying to get more fuel pressure and volume out of the high pressure pump. It's not the right way to "fix" this problem. It plain doesn't work. It helps a little bit to keep the pressures high enough that you can try to get the fuel into the cylinders, but at best it's a band-aid. There's only one way, in my humble opinion (lol), that you can "fix" the LNF fueling issue, and that's with additional fuel. You can do that with either a full port fuel injection rail setup, like Antonio (Sky888) is doing, or a 5th injector setup. Jeb is going to put together the same 5th injector setup that I've been running on my car. We'll see if it does to his what mine did to my car. I'm sure it will, which means Jeb may be the first Kappa LNF over 500whp after we're done. Last time I dyno'd my car it put down 460whp/460wtq, on my conservative street tune."

This is post #27 found here:
http://www.skyroadster.com/forums/f5...64/index2.html

Vince posted a couple months ago on the Cobalt SS forums about working on the HPFP I assume the same one that we're trying to put into the Camaro. They actually briefly touch on the V6 Camaro and our fuel pump and Vince states how we're having problems as well. However this thread is only useful to about page 2 or 3 and then people take it WAY OFF topic and flame some guy. And I thought OUR forums were bad at times, but these Cobalt guys make us look like a bunch of tree hugging, peace pipe smoking care bears.

http://www.cobaltss.net/forums/2-0l-...3/hmmm-278599/

[scrming]

So... to summarize... the stock injectors/HPFP/fuel system cannot stuff enough gas in the cylinder QUICK ENOUGH... so you have to have a secondary way of getting enough fuel in cylinder in the allotted amount of time... and the reason it looks like you are running rich is because you are spraying gas way too late... Ok... i can follow that...

[V6owner]

How much would it cost to add a 5th injector?

[BaylorCamaro]

Originally Posted by V6owner

How much would it cost to add a 5th injector?

Not sure, but I think the meth can fix that. In the Solstice forums someone briefly mentions it.

EDIT

The meth would fix it, or really help it. Exhibit A - Gretchen

[KMPrenger]

Originally Posted by scrming

So... to summarize... the stock injectors/HPFP/fuel system cannot stuff enough gas in the cylinder QUICK ENOUGH... so you have to have a secondary way of getting enough fuel in cylinder in the allotted amount of time... and the reason it looks like you are running rich is because you are spraying gas way too late... Ok... i can follow that...

I remember when Baylor posted Vince's response to this in another thread....kind of left me scratching my head lol. But now I get it!

[scrming]

Originally Posted by BaylorCamaro

Not sure, but I think the meth can fix that. In the Solstice forums someone briefly mentions it.

EDIT

The meth would fix it, or really help it. Exhibit A - Gretchen

mmmmmmm.... methanol.....

[Cymaro]

Wouldn't we need a 7th injector?

[BaylorCamaro]

Originally Posted by KMPrenger

I remember when Baylor posted Vince's response to this in another thread....kind of left me scratching my head lol. But now I get it!

haha yes I know what you mean and I'm sure many people were wondering wtf I was talking about. I wasn't too sure I understood what Vince was saying the first (two) times he explained it to me. I finally decided to do some digging to really try and understand this better, as I am far from a tuning guru!

Originally Posted by scrming

mmmmmmm.... methanol.....

Originally Posted by Cymaro

Wouldn't we need a 7th injector?

The "5th" injector I was referring to was for the Solstice and what they did. So it would be an additional injector, so I guess 7.

[GretchenGotGrowl]

Just to be clear, my 447 RWHP was on pump gas alone. We got near 500 RWHP on gas alone, also, but it was really missing up top. When we tried it with meth we ran into the MAF issue. So, basically the new HPFP will get us to about 500 once the solve the MAF issue (or use the PE cheat). However, then we run into the issue with our compression ratio. We've got to lower that to go much higher, even on meth.

So, yes, you can pump more fuel (gas or meth) in and solve the problem. But you will run into another. What we are planning to do after we get the new pistons (which lower the CR) is to inject fuel into the manifold. We haven't decided if we are going to add two fuel rails and 6 injectors (to get even fuel distribution), or simply use a nitrous plate and inject fuel at the TB. These are some things you guys should think about. I'm one of those guys that thinks meth should be there for saftey, not required. Others will have different options. It is disappointing that we have to do this, but until we can find a way to run either more fuel through the injectors we have in the time needed, get bigger injectors (very expensive) or add additional injectors to the heads (very very expensive), we've got to probably go old school on this problem.

[V6owner]

I just realized I meant 7th injector lol whoopsies

[TJ91]

now it all makes sense lol Ive been laying low trying to figure it out before but I like this thread!

[BaylorCamaro]

Originally Posted by GretchenGotGrowl

So, yes, you can pump more fuel (gas or meth) in and solve the problem. But you will run into another. What we are planning to do after we get the new pistons (which lower the CR) is to inject fuel into the manifold. We haven't decided if we are going to add two fuel rails and 6 injectors (to get even fuel distribution), or simply use a nitrous plate and inject fuel at the TB. These are some things you guys should think about. I'm one of those guys that thinks meth should be there for saftey, not required. Others will have different options. It is disappointing that we have to do this, but until we can find a way to run either more fuel through the injectors we have in the time needed, get bigger injectors (very expensive) or add additional injectors to the heads (very very expensive), we've got to probably go old school on this problem.

Yeah.... at this point I'm reverting to the stock pulley so I can actually experiance a proper FI set up at WOT. However having to deal with this crank pulley is going to be a pain in my rear!

Originally Posted by TJ91

now it all makes sense lol Ive been laying low trying to figure it out before but I like this thread!

yeah yeah yeah, you and everyone else. It was my fault for not explaining it, fully. I had everyone thinking I was a loon

[Can't_C_Me]

I agree with Derrick and I think Tracy has spoken before about adding injectors to the head. I know for a fact that boosting over 6psi's on any system on these engines will cause the MAF to max out. I have not had any issues with my MAF after dialing things down to 6psi's. Tracy had just informed me last week that he has even tried on my car to relocate the MAF but still had the MAF issue I had a buddy of mine when I was in the Army do the fuel injector into the TB for extra power and worked REALLY well. So this could also be another avenue we can explore like Derrick said.

The Meth theory like Derrick said can be argued if it's for safety or power. When I first got my car back from Tracy I was boosting 11-13psi's and the Meth is what kept me from blowing my engine to shreds and giving me the fuel to run that high with the large Meth injector. I'm also waiting for the pistons and cam's to surface to further my build and add a stage 2 clutch.

On a side note I was finally able to test the Jet MAF and it's crap lol. Sent it back a few min. ago for a refund.

[BaylorCamaro]

Originally Posted by Can't_C_Me

On a side note I was finally able to test the Jet MAF and it's crap lol. Sent it back a few min. ago for a refund.

Wow, that sucks.. Can't say I'm surprised though..