Cam timing making large changes to AFR?

[turboglenn]

Well, I had a perfect tune on E85 until i changed a few things a few days ago, and now i'm having to richen everything up under boost.

I've had to increase pulsewidth a TON way more than i'd expect for what seems like a minor change. And i'm running out of injector on 1000cc units at around 23 psi when before i could run 30psi at a aricher AFR before i cam to the same IDC

The one thing i did that i can see changing the AFR's is that i advanced the exhaust cam for more top end power (4* and it made a hell of a difference)

The other things is did were

1.) Run a new piece of rubber hose from the AFPR to the return line on the body (same size and ID just a different color *black* to make it blend in)

2.)although my 2nd pump doesn't run i replaced it with a matching 255hp for when i do decide to run duals again. Instead of just being unplugged like the previous pump (regular 255) The power wire is fed to it but the ground is dissconnected, and i tested to make sure it couldn't ground it's self externally and run and it cannot. there for it shouldn't be drawing any juice from the running pump ( am i right on that? I'm no electronic engineer)

I"m hoping to figure this out without undoing everything i've done over the last few days, the return line shouldn't matter, the power wire i'm iffy about and the cam timing i have no clue on it's effect on actual air intake changes.. any help would be apreciated..well, besides questioning the obvious BLT, wire connections etc.. since i've double checked everything and solder every wire joint, all should be well.

The only othe rthing i can think of is that maybe my fuellab filter is getting dirty, but i do have the SS mesh one, so i wonder if i can clean it fairly easily?? Anyone ever do that?

 

[delta448]

Advancing the exhaust cam is making the largest difference. By doing this you are effectively reducing the intake air dilution and increasing the oxygen content of the cylinder charge. The exhaust is expelled more completely before the intake air arrives.

 

[turboglenn]

I'm really starting to think there's more to this than just the cam timing unless it can make a full point of difference in AFR. I mean the extra power is there compared to when i was unsing less fuel, but it's getting to where one pump is not keeping up or feeling like the injectors or filter are dirty *shrugs*. I mean this thing is litterally smoking both front tires right to redline in third on dry pavement, that makes me happy as hell, but running out of fuel doesn't

I'm hoping that by hooking up the extra pump and increasing pressure i can decrease pulsewidth. I"m still scratching my hea about the power wire being split to both pumps too.. I think i may disconnect it completely today and see what happens (if i can brave the 15* temps outside) Other than that im skeptical about my distribution block and want to try another pre-manufactured part.

ONe thing i've gotten mixed answers on is this: Did walbro quit putting the check valves in their pumps? I remember when i could turn the key off and there would be fuel pressure still in the rail for quite some time, now it falls off as soon as the power is stopped.

 

[mikelv]

I would most definitely look into cleaning my injectors and filter on this one.
I been told I'm crazy, but the short time I ran E85, I had a horrible experience with it.


I got a great tune @ 28psi with it. The IDC on 1050cc Injectors were around 80%.
After a couple weeks on the same tune, I noticed my IDC's increasing to where it was nearly 95-97%.

I didn't bother running the junk anymore, and switched straight to 110 due to its availability here in South Carolina. I can't really tell you how to solve your personal problem but I will say this; The E85 I was using was possibly stored in a diesel tank making the mixture very dirty in my engine.

I had pulled the head, and had extreme carbon build-up, noticed the exhaust smelt extremely funny, and also clogged my fuel filter. I will never use that stuff again. 110 octane is 4 bucks a gallon here, and I don't drive the car daily. Just something to think about when you have to increase the fuel tables nearly 30%, it's not really even worth it IMO. If shit is getting dirty and clogged before the cumbustion chamber, then it's pretty obvious that the pump is going to have to work harder to inject the same amount of fuel to reach your target A/F ratio. At least that makes sense to me.

But like I said, I've been slammed for saying E85 burns nasty, that's just my personal experience. I've done it, and seen it with my own eyes.

 

[slowgsr]

Removing the ground for the pump you do not with to use is perfectly fine. It will make no difference if you remove both the positive and negative, or just the negative, or just the positive. The pump will not draw any current the way you have it set up.

Injector circuits always have a positive voltage at them, and are triggered by ground. Im sure you knew this however, just trying to give another example.

There is no patch for current to flow.

 

[turboglenn]

mike... I ran E85 all last year, and after it cleaned the tank and lines of all the crap that had built up over 10 years the car ran great! 30psi all day long with up to 25-27* of timing advance.

It's still running great, just the fuel demands got greater, but i already have a 2nd pump in the tank and am able to arm it in just a few minutes with the simple task of soldering the ground back up.

I was just hoping to find the reason the fuel demands changed so much before just throwing more parts on the car without diagnosing the current state of things.

slowgsr....thanks for backing up my thoughts on the current flow, I"m going to just fire up the 2nd pump here in a bit anyway and see if that brings things back to the rich side and allows fr me to get back under 100% IDC at higher boost. I actually logged 86% IDC at 23psi and 11:1 AFR at 6500 RPM with an injection time of 7.447ms... The engine is fine and detonation free all the way out to 12.5:1, but i'd rather tune to that than deal with having it as a "as rich as i can get" type of deal where things could get leaner and start burning things up too easily. PLus i swear that i get more HP in the top at midd to low 11's AFR as compared to 12.5 area, with most of the gain being seen up in the very top where it makes the difference if the car is going to need shifting at 7k or 8500!!!!! I like the 8500 better

 

[mikelv]

mike... I ran E85 all last year, and after it cleaned the tank and lines of all the crap that had built up over 10 years the car ran great! 30psi all day long with up to 25-27* of timing advance.

It's still running great, just the fuel demands got greater, but i already have a 2nd pump in the tank and am able to arm it in just a few minutes with the simple task of soldering the ground back up.

I was just hoping to find the reason the fuel demands changed so much before just throwing more parts on the car without diagnosing the current state of things.

slowgsr....thanks for backing up my thoughts on the current flow, I"m going to just fire up the 2nd pump here in a bit anyway and see if that brings things back to the rich side and allows fr me to get back under 100% IDC at higher boost. I actually logged 86% IDC at 23psi and 11:1 AFR at 6500 RPM with an injection time of 7.447ms... The engine is fine and detonation free all the way out to 12.5:1, but i'd rather tune to that than deal with having it as a "as rich as i can get" type of deal where things could get leaner and start burning things up too easily. PLus i swear that i get more HP in the top at midd to low 11's AFR as compared to 12.5 area, with most of the gain being seen up in the very top where it makes the difference if the car is going to need shifting at 7k or 8500!!!!! I like the 8500 better

Yeah man, I hear you, I figured I'd share my story, give you some insight. I just had real bad luck because everywhere else I've turned, they've always told me E85 is god's give to DSM'ers. Cheap speed.

 

[turboglenn]

Yeah man, I hear you, I figured I'd share my story, give you some insight. I just had real bad luck because everywhere else I've turned, they've always told me E85 is god's give to DSM'ers. Cheap speed.

Yea, it sucks you had such bad luck with it.. It clogged a lot of filters when first making the change over, but once evertyhing was good it was better than any race gas i'd ever bought and was cheap at the pump. I run pump 92 in the winter because on days like today when it was 11* when i went tot start my car it took almost 10-15 minutes of priming, starting, stalling , starting, priming etc..etc.. I'm having to come up with a new cold start tune all the time and it's one of the hardest to get down IMO, on pump I got some good baseline rules, on E85 it's just guess-n-test for now until i learn more about it's behaviour in the cold.

 

[mikelv]

Yea, it sucks you had such bad luck with it.. It clogged a lot of filters when first making the change over, but once evertyhing was good it was better than any race gas i'd ever bought and was cheap at the pump. I run pump 92 in the winter because on days like today when it was 11* when i went tot start my car it took almost 10-15 minutes of priming, starting, stalling , starting, priming etc..etc.. I'm having to come up with a new cold start tune all the time and it's one of the hardest to get down IMO, on pump I got some good baseline rules, on E85 it's just guess-n-test for now until i learn more about it's behaviour in the cold.

I hear you on the cold, I spent the last six years in Alaska with my DSM, and I'm from Maine so I understand.

You ever thought about a block heater? That would more than help the situation, and actually prolong engine life.

 

[turboglenn]

I hear you on the cold, I spent the last six years in Alaska with my DSM, and I'm from Maine so I understand.

You ever thought about a block heater? That would more than help the situation, and actually prolong engine life.

Yea, i want one bad, just with all the other crap i've replaced lately (mainly the steering rack) i'm a little on the broke side AGAIN... just can't get ahead to get my new turbo ...arggggg

And now the car is magically wanting more and more fuel that it needed before and everything so far checks ou fin.. I'm lost if upping the base pressure doesn't bring things back in check *bangs head on desk*

I can use air pressure to bring the fuel pressure over 100psi and have it return just fine, i can't figure it out for the life of me. the pumps are both wired with 12 gauge direct from the battery (only been using one until tonight), feeding from enlarged passages in the hanger to -6 line for a foot to the distribution block and then more-6 all the way to the rail with the factory feed being the new return. It functions like normal, doesn't leak as far as i can find and has always been consistant until this recent change in a few minor things.

But like i said, tonight i enabled the 2nd 255HP and am dialing the fuel pressure in tomorrow, i figure if i get 60% increase in flow it should show if i'm lacking in injector or the problem is elsewhere..... For a car running 30 psi daily what 's a good base fuel pressure that people get away with? I"m just way behind in HP for running out of fuel at this point and have got some serious concerns about finding what the hell is wrong. I was making great power (and still am ) but I HAD plenty of injector to go and now i'm out at the same level of boost but he power is still there.. who knows... maybe changes in the e85 at the station making ghost ssues

 

[turboglenn]

Okay, so today i went from having the exhaust cam 5* advanced to 4* retarded and once again another HUGE difference in AFR. I had to add 10% and more to some of the cells in the 2 - 3k RPM range while cruising. The same pulsewidth that was taking me to 10.8:1 with the advance turned into an 11.5:1 in the midrange (showing more air/fuel use) but in the very top revs it got rich and kinda fell off. I believe i like the advanced cam more... Nothing like watching the tach pass 8k RPM right before you shift

I would have never thought that just taking the same cams nad changin overlap and timing would cause such major changes in the engine's needs.

NOW.... I want to know what I should be doing with the timing on this puppy with the different cam settings. With the retarded cam i'm sure i can add a ton of timing because there wasn't the slightest hint of knock anywhere at 25 psi and 20* locked timing under all boost levels above 10psi