Yep that is another way to look at it! Boy oh boy this MAF is looking better and better every day

Like I said before you would have to have your brain recalibrated to hold one of these things at 1/2 throttle for any appreciable amount of time on the street.

 

Ski, keep this up and your not going to be able to get through the doorway!!

RBob.

 

That is correct but only since you probably forcing the ecm into a PW calculation that is over 100% DC and an injector can't be on more then 100% of the time.

 

Ahh but it can. string a bunch of saturated injector signals together and you get a PWM ouput without the peak rise for injector opening.

 

I wonder if tcc would let me join?I have an 87 formula though.I bet I could put a spakin on you vette boys.My formula weighs around 3300lbs.


I doubt it our cars are 3100lbs. and we have a guy that makes 600 foot lbs of torque in the series. Plus he can drive and has big ones (lol). Plus all the firebirds I have seen on the track park them self in the corners
Chuck
www.tccracing.com

 

This maybe true for the inital opening of the injector as it goes static, but once open, at 100% DC thats it, no more fuel. The ECM can scream for more all it wants; but if your out of injector.. your out of injector short of raising FP.

 

This thread just keeps getting better an better.

For WOT ski always talks about PE vs RPM. OK cool I understand what it does but what about PE vs Coolant Temp? I think I remeber Glen talking that it didnt have an effect at WOT, I think but could be wrong. Can someone clear this up please as it seems like a huge global change point for WOT fuel?

 

No, I said that you need to use "PE vs RPM" for WOT tuning. "PE vs Coolant" does not serve that purpose for WOT. I have never had a need to use "PE Air/Fuel %Chg vs Coolant" (it's full name) for any of my tuning. PE vs RPM works fine for me for WOT...been saying it for a long time - for both SD and MAF.

 

Glen

Thanks for clearing that up! I was a bit confused on that as there are threads floating around that state it is a proven method. But like a said I did remenber once reading you advised against it.

Do you by chance do know what that table does affect (PE Air/Fuel %Chg vs Coolant)? Is there any reason at all to change it?
Thanks!

 

I have never had a reason to change it. I've always thought it's the percentage change the ECM will make the A/F ratio at various coolant termpatures. I believe it is for Open Loop, but not positive.

I never go WOT until my engine is properly warmed up - so I never really thought I had a need to modify that table. If you were running your car in Open Loop all the time (and some do), you may find this a useful table. For Closed Loop, I find "PE %Chg A/F vs. RPM" works for me.

Maybe someone who uses it can explain why "this is the greatest table and everyone should be using it". Whether SD or MAF.

 

Don't get lost in another calculation.His duty cycle is not important.He has control of a/f ratio.Stop trying to find out whats wrong with ski's setup.This post is to verfy or debunk a theory.Can we finally agree maf : 1 :doesn't lose resolution(like has been preached)
)2:is limited to 350 hp,3ver 255gr/sec loses control of a/f ratio.Traxx has been the bigger man.In turn he has been the first to articulate why maf generally can't lose resolution.Let's wrap this one up here.I'm tired of freaking scrolling down

 

Traxx no disrespect,but I seen a link to this from the sd vs maf.I have not included SD in this thread.Nor publically have I ever said one system is better than the other.But why do I feel you are thinking of a swap to maf....

 

Guys,

Here is some more food for thought.

Last night I was looking at some dyno graphs that Corky sent me of his exact setup he is running now, before I decided to follow in his footsteps with my 406.

You would be SHOCKED to see that his AFR is way down in the 10s for much of his run, then barely touches out at 12.1.

Fellas I don't know about you, but that surely to me seems like he got a bunch of injector left.

When he dnyoed his car he was running the same FP he is now, down around 35-40 PSI. Last time at the track he was running 36psi, and still complaining he is fat. On hot days the fat condition naturally increases.

So I guess the chances of us pegging our injectors and having 1. Control over the AFR (I am doing a new chip for Corky this week). 2. The AFR would be down in the 10s for WOT, is about slim to none.

I think too many people put too much stock in other setups that can't do what we are. With that let me clarify. Do to the fact of efficiency, lack of expected ETs, etc people start pointing the finger at injectors etc just to find that they are throwing money away and even compounding the problems they have with big hard to control injectors.

No let me shoot down someone, i'm sure comment that the injectors are probably static right away and flooding the system, hence the 10 AFR on corks dyno graphs. If that were the case, then I wouldn't be able to change the pe vs RPM slight amounts on mine and see changes in the AFR on my dyno, now would I? Therefore that means that they in fact are NOT static and within some controlable limits.

I seriously just laugh when I hear guys saying they need 30+ lb injectors on their 383 or even funnier their 350 engines. Sure you can do it, but they are a bear to get tuned in and hogs at idle. Then I can see where you would need to adjust the MAF tables.

99% of all my part throttle adjustment is done at the injector constant for BLMs.

I suggest that everyone that has tuned their MAF system, take a step back to the original bin, set the injector constant to something close to actual size, take the car for a ride...log the BLMS. If they are above 128 then you need to lower the constant. If they are below 128 you need to raise the constant.

All you are doing in the above paragraph with adjusting the constant is this.

If you have a BLM that is above 128 that mean that without the o2 sensor the mixture would be lean, therefore the ECM is adding fuel to make the mixture 14.7. Here in this case I say to lower the constant, because this tell the ECM in its calculation that it does to determine the PW that the injectors are actually smaller than they are. Or should I say smaller than they were at the logging of the first set point.

If you have a BLM that is lower than 128 that mean you are fat/rich, and the ECM is pulling fuel from the tune to achieve the 14.7. Here in this case you want to tell the ECM that it has bigger injector by increasing the constant, therefore in its next calulation the fuel will by trimmed and BLMs will increase closer to 128.

I have found that using this method you can bet all your BLMS within +/-5, and most will be nearly dead nuts on.

This is why your throttle response will increase dramatically if your BLMS are on or near 128 opposed to say a 108 reading across the boards. What you are doing by achieving the 128 reading is eliminating the ECM from doing any sort of corrections to fuel. These corrections if they are there, or you are not at 128 or thereabouts is happening every time you move the gas peddle, or increase/decrease the load on the car, entering into a hill, picking up a fat chick for a ride .

In the nutshell if you have 128 across that boards that means that the ECM is make NO adjustment to the fuel under cruise conditions. The further you are from 128 on either side the more correction and more sluggish the car will feel.

Now run out and try it!

 

No, my point of raising the "injector size" is so you can review your choice of injector size so they don't prematurely burn out and accidentally toast your motor due to a lean condition.

If you don't care about your Duty Cycles and feel you have plenty of injector left - go for it. It's not my motor, it's your motor and you have every right to do to it what you wish. If it ends up toasting your motor, you are the one that will need to pay to fix it, not me.

I do plenty of things people don't recommend doing. I was adjusting MAF scalar tables over two years ago. I was running an A/F ratio of over 17:1 in Highway Mode with 47* spark advance with excellent results (US 29+ mpgs out of an L98 through mountainous terrain and passing cars like no tomorrow is pretty good in my books. This is inspite of all the warnings that I would burn out my cat, especially because I dont' "cycle" my Highway Mode to richen the cat. Well, two years later my cat is still working just fine.

Does this mean that I am right and the others are wrong? Not necessarily. It just means I haven't had a problem (yet). But I am curious how long the cat can take it until it dies. So I am pushing it on purpose to find out what the limits are.

After I am done with this, there is a good possibiilty that someone will rely on my experience with Highway Mode and use it as gospel. They should not because they may find out that their cat doesn't last more than a couple of months.

Same with your injectors. The only place where this becomes a concern is WOT. You may STILL have "plenty of injector left", you may have less than you think. You may be only one WOT pass away from injector failure, you may be thousands.

The whole "injector sizing" formual is to help people size your injector that will work in all situations. The first time I ever saw that formula was 10 years ago from TPIS (long before this board ever existed). What you have proven is that sometimes you can get away with a smaller injector than the formula suggests if you have an efficient motor. The question of "how long" has yet to be determined.

My raising of the injector issue is not to criticize but to advise you to review it so not to toast your motor. If you are confident those injectors are "just fine", then go for it. I just didn't want to hear a couple of months later that you had major problems with your motor and it was because of too small of an injector and they failed.

And I won't say "I told you so" if sometime down the road you should suffer injector failure. As I said, it's your motor. You have every right to do to it that you want and try seeing how far you can push the envelope.

Just be aware there are a LOT of newbies that rely on others experience and may rely on yours, only to suffer the consequences. That is why I am very careful what I tell people - even if I had an experience that contradicts what the "experts" say. I am more interested in why I didn't experience the problem the "experts" said I would - not to say "I told you so".

 

I'm done with this thread.The point was proven,end of story.

 

Glenn,

Please if your gonna post in regards to the injectors, put something on the table that is relavent. I would recommend #24 injectors in a second for any engine n/a 406 or smaller with condidence they will last.

I am not the only one running these injectors, true I only have a few passes on this engine, but corky has raced nearly every weekend with his cranking in the low 11s for over a year.

I raced my 350 that was in the 12s all last summer with the same upper end that is on this. Now please tell me why they wouldn't work on a 350, 383. 406.

And the reason of well, its not written (calculation) by the experts wise is not gonna cut it either. I think we have seen this here in the last few days in regards to what used to be gospel is now being reconsidered by many.

I know what an engine lacking in fuel feels like, they basically fall flat on their faces. Take a look at my video of Run#1 when I did not have enough gas in the tank, you will see the front of the car drop ~1ft then lift again when fuel is supplied again. Trust me my friend, this car in the Run#2 is lacking nothing but traction.

Corky and I would be happy to share anything with anyone in regards to our setups. Tonight I plan on getting some logs with Ease, but with open exhaust on the Highway, leaving my neighborhood, then going WOT for any appreciable amount of time is gonna be tough. I will try though. But as I said before. I have the injector constant set to a value other than it really is, so I think any reported pulse width is gonna be reported incorrect. Am I correct in thinking this?

I would love to come up with a more accurate way to measure the injectors needed for these cars. I put my setup into one of the online calculators and it said I needed 45 lb injectors. To me that is a bit off.

Trust me I would love to come to find out my engine is not running to potential. That mean I would be running 10s all day long with correct injectors. But since the AFR at WOT is well within my control, as any movement of the values, and is reflected accordingly on the WB, then I suspect the injectors are not maxxed. Corky's AFR of high 10 reading on the dyno further back this. What else could it be?

I have the stock pump also.

 

I think you are running the SVOs so technically that would be 26lb/hr once converted to GM standards.

This is a very tricky subject. There are tons of things to keep in mind when considering injectors and a blanket statement like ...

... will eventually get you (or most likely somebody else) in some trouble.

RPM plays a huge role.
Fuel Pressure plays a huge role (thus the fuel pump too!)
BSFC plays a HUGE role.
The type of injector plays a huge role.

I said before that I totally see how you could be getting the results that you are with the 24# SVOs. I'm not a doubting Thomas. But, I just wanted to point out that not everyone will get the same results that you are. If they are seeing high rpms and/or their motor has a high BSFC and/or they are using injectors like GM 24's then that could spell some disaster.

In any case - this is why I believe that the 24# SVOs work ...

http://www.celligent.com/tim/misc/injector.jpg

Key things to keep in mind about your setup is that you are probably producing some crazy torque numbers. Max Injector pulse width will usually occur at lower RPMs for you. Thus, you can get around the RPM killer (RPMs raises Duty Cycles FAST!). Your motor is built and probably has a lower BSFC. Running the SuperRam produces a VERY strong torque curve that artificially rams air creating a VE that is probably above 100% at torque peak.

This is fun!

Tim

 

I have. Including "real life practical experience" with tuning my buddy's 383 running 30# SVOs. But you must have either glanced over it or didn't read it. It was in those one of three or four posts you and kvu made in the last few days.

I would go "dig up" the post, but I honestly don't think you care about what I have to say. So I'd best be going to some place that would prefer to hear my thoughts. No hard feelings.

 

I think that there is just some miscommunication here along with understanding / interpretation of formulas. I think I explained it very well in the post I made directly before this one. In some cases 24# SVOs will work, in other cases they won't. It REALLY does depend on your motor combination and how you use it.

Tim

 

Glenn,

The reason for my comment is you are all too quick to jump on others and point out the *problems* without any real justification.

Sure, I said it before, you can tune an engine that is only suppose to have #24 lb injectors with 30#s, its just gonna be harder, and you are most likely gonna have your hand full.

I will admit I should have clarified my statement that any 350, 383, or 406 should be capable of running 24# injectors. I should have said at an RPM less than ~5600. Perhaps you can go higher than that, but I only know what my engine is doing.

I will out of respect go find the post you refer to glenn.

No one here has all the answers, that is obvious.

Trax, that is an interesting link/program you have there. But how do you explain Corkys, PSI at only 36 and running pig rich? Put a desired AFR of say 11.5, that would probably be nominal for what I saw on his graphs. Based on my 46psi you entered into the program it returned a 26 lb injector size that was at 95% duty ~4400 RPM, that means his would be <25# and probably maxed at ~3000 RPM.

I would be interested in finding out what his pressure and Duty cycle is maxxing at.

 

Glenn,We all want to hear what you have to say.We might not agree or see eye to eye.But you have alot of knowledge,I value it.Ski's problem is not with you personally.But the maf folks are doing something right.We deserve respect for it.Instead of getting upset just find out his pw @ redline.Then you can prove your case and/OR find out what's really going on.Get the data from ski,he'll give it to you.

You agreed w/ me that there is good reason to adjust maf tables(in some cases,most from what I see).This is one thing grumpy has fought me over.If you agree with me then just say it.I sometime you feel like you are stuck in the middle of old alliances and pioneering new methods.

 

I can't explain it ... not totally.

http://www.celligent.com/tim/misc/injector2.jpg

Using what you told me about his injectors being at 36psi and plugging the resulting flow values into the 'Nominal Pulse Width' calculator we get a pulse width of 15.71ms using 11.5 AFR. Plugging that into the DC calculator gives less than 100% DC at 3800rpms.

First off - I don't think you guys need to worry about 4400rpms. Max PW is gonna be really close to max torque. Both of you guys are running SuperRams and making max torque around 4000rpms.

I am just trying to rationalize things using formulas readily available. So far - I think I am coming pretty close to lend evidence or proof for what you guys are doing. Keep in mind that I am putting this stuff out there to try to support your statements ... not to discredit them.

The one formula that is not making sense right now is the popular injector maximum horsepower formula. Of course - I am ASSuming 485 hp. Maybe you guys are pushing LOWER horsepower numbers but are making such HUGE amounts of torque that is feels like bigger horsepower? I don't know. In lots of ways my Long Tube Runner car would feel a lot faster than my current setup. It made more torque but had substantially less horsepower.

Tim

 

I'm just lurking on this thread, but i found this comment interesting. The friction you are describing here is a difference in analyzing styles. I don't even know what glenn does for a living, but i'd guess he is some kind of engineer or technical person. He wants details to try to put things together, and when things don't fit, he vocalizes it because he's trying to get more information and see if anyone else can help him complete his thought.

Ski, you seem more like a hands on person. Rather than analyze the system, you're just doing what works for you without looking at the bigger picture. So when glenn is digging into what's going on with your set-up, you are taking it all the wrong way. While you are obviously very successful at what you are doing, you CANNOT assume that your success would be universal. Hell, you said so yourself that you painstakingly blueprinted the engine beyond belief, and the combo itself was all designed to work together.

Glenn is just trying to figure out whether or not your assumption is correct. Results do not necessarily prove much to an engineer/scientist. They must be repeatable.

And honestly, i'm seeing holes too. Like how was your buddy running almost identical times/mph with an off the shelf chip? If your method of tuning is so great, i guess the random guessing of formato is even better relatively.

Also, i see you mention 'dyno time' on both his and your car, yet i see no dyno sheets. And you didn't log any data when you were on the dyno either to give us simple pulse width numbers? Sorry but that makes no sense whatsoever.

And you built a solid roller motor to only turn 5500 rpms? Ever try to spin it to 6k+ or so like most solid roller motors. Maybe you did and it fell on it's face because you do indeed run out of injector but are leaving that detail out because it would complete the circle that the rest of us are trying to figure out.

Just trying to figure this all out myself so don't take it the wrong way. I'm not doubting the times you run, and even with absolutely no helpful input from you besides injector size and et/mph tim is doing a good job of proving your case for you. But until the rest of the blanks are filled in, it's all guessing. If someone just gives up dyno numbers and injector pulsewidths then this will ALL be over. Until then, the engineers in this post are going to sit on the fence and say, hmm thats interesting but it makes no sense so i have no idea how to apply this lesson to myself.

 

ED,

If you would have read this post and others that are linked to it you would see that I have infact been trying to get logs of my car. I logged every run at Keystone the other weekend, but the computer did not save the logs. I am new to this software and learning as I go. Never had it do that before so your guess is as good as mine???

The week here has been nothing but rain and I was gone all last week and weekend in St Louis. Tonight however as I promised I took some logs of my car, under WOT conditions. Very interesting getting the car out a nice neighborhood that is pretty quite. I had several neighbors come to the front yards to look.

Now I have the logs and as we all expected the pulse widths are way up there. But as I pointed out, the car is maintaining a VERY good 12.7-8 AFR and is well within the confines of tunable, sooo that leads to my exact statement that the injector pulse widths are skewed because of telling the injectors that they are different sized in the constants than they are. This was agreed upon before, so the reported pulse widths are those of calculation and really don't clear anything up.

As far as the type of person I am you might want to tred lightly here. And as a matter of fact I am an engineering manager for a large corporation - main supplier of cam caps to all GM Cadilac engines along with an assortment of other engines. Hands on, yeah I am not afraid to get dirty and be involved with what is going on. I easily could have ordered a lingenfelter 383 for $30k and been running mid to high 11's. Instead corky and I put our knowledge together and built this engine that will surely break into the 10's soon.

You did not read right about the dyno graphs. Corky had his done down at Carlise and I just got mine together, so I did not have any dyno time yet. I will provide an excel spreadsheet with his AFR data and also my logs of my car at WOT. But understand this data, as far as injector constants go are bogus as far the people that understand go. The fact still remains corky is pig rich and I am able to maintain my AFR to the point it needs to be.

As far as not tuning my system enough or not caring to dig into it to understand it, you couldn't be more wrong. There is more time spent on this engine and my 350 tuning and dicking around making sure everything was perfect that you could probably add up all the time you spent on your in the last year, including drive time...and you probably wouldn't exceed the total time. True with this tune I burned only two chips...with the first one the BLM were nearly all dead nuts 127-131, sure I will probably play with it, to get them maybe all there at 128, but my honest opinion is I won't be able to tell and it will be a waste of time. The WB02 is the key to tuning WOT and it makes it a breeze. Now what else do you suggest I do? Can I extend the proposal to ask what your engine specs are and what times you are running? You might want to ask yourself that before knocking someone elses abilities or comparing tunes. And as far as that goes, Corky ran 11.10@124 last year as a best ET/MPH, nothing against his setup, but he will tell you I am ahead of the game with a 11.147@123 the first time at the track. And that was with 5 WOT runs on that engine, do you think it will loosen up and get better? I do, and so does any honest person out there. Not to mention the valves are still not even to spec where they should be, for we left them a little looser for breakin. I would say that Corky and I are doing pretty good.

As for revving it to 6000+ with a SR you are wasting your time. That is why people go for the mini-ram or stealth ram.

Really though if your not gonna post anything of value and just point out the obvious, try to shoot holes in others setups (with no valid information) or contirbute to the discussion in any appreciable way. perhaps you shouldn't post.

 

Here is a shot of the log:



Here is a shot of Corky AFR through the run....And don't anyone be stupid enough to ask if I just pulled these out of my ars! The only reason I am in these discussions is to bring about a conversation that will hopefully end with a better understanding of these systems.

RPM AIRFUEL
2500 14
2600 14
2700 14
2800 12.5
2900 11.5
3000 11.1
3100 10.9
3200 10.9
3300 10.8
3400 10.8
3500 10.8
3600 10.9
3700 10.9
3800 10.9
3900 11
4000 11
4100 11
4200 11.1
4300 11
4400 11
4500 10.9
4600 10.9
4700 10.9
4800 11
4900 11.1
5000 11.3
5100 11.4
5200 11.5
5300 11.7
5400 11.8
5500 11.9
5600 12
5700 12.1
5800 12.2
5900 12.2
6000 12.3
6100 12.4
6200 12.4
6300 12.5

 

All i'm trying to say is that there seems to be a lot of miscommuinication in this post. N one doubts your times or set-up. I don't see it anywhere, and i wasn't trying to say that either.

You have a helluva engine, and your tuning method is great. A WB and moving the PE vs. RPM is a perfectly fine way to do things, everyone in this post will cede that much.

Your car is a freak. It's making everyone question the rules. But we need data. You're right, i guess i missed parts, but now it's all out in one place, and some more is coming in. Perfect. We just want to reconstruct your success so it can be applied. And figure out why it works so well. For example: Your observation that timing has little effect on et/mph. That is not universal. But the more we know, the more it might all come together. Low BSFC and timing irrelevence are probably related, but i'm just a circuits guy.

I'm taking mental notes, i might be tuning a MAF car on friday. No WB though, but i've been around computer controlled cars long enough to make good WAGs.

BTW, whats this about injector pulse width. I definitely missed that, what do you mean your pulsewidth isn't right because of injector constant? Pulsewidth is what the ECM is firing. Thats like saying your timing isn't right because of the injector constant being skewed. PW is a real number.

 

Just for the records..
I just happened to read this thread.
No,my car is not running where it should be right now!
12.27@110.8 also that was first run since install 4 days prior.
I do have a W/B and my a/f was 11.9 -12.1 = pretty darn rich
now got it to 12.8-13.0 probably still a little rich.
Secondly I am running canfield heads flowing only 239 @ .500
nowhere near the 280+ Airflows are producing w/comp. porting.
Thirdly my compression is only 10.2,not 12.0..
I run a hyd roller 230/230,not a solid 243/240 ect
And lastly my car weighs in a 3600 w/driver .
So I should be running better ,yeah I agree with that. but am I disapointed ? well we will see after i get another run or two.
Also the day I was there a few guys I know were running MPH
1-2 less than optimal.
If I hit 113 mph I will be where I expected to be.


I think I am buying AFR's comp.ported 195 real soon.

 

Please, let me enlighten you.Ski built a solid roller motor to be able to turn those jumbo egg cam lobes.That is why he is running so fast.Huge lift+matched valve springs+solid lifters=monster power.That is what I'm going to do to my engine.That is basic engine tech.

 

And 240'+ @ 0.050 ain't exactly a RV grind either. People have run 11s with 350s with a lot less.

That is basic engine tech.

 

87_TA,

There is no doubt you are not running anywhere near where you should be. There are 350 combos going 110-115. There is no reason you shouldn't bein the high teens. I saw all your other posts of the problems with hesitation etc that you are having. Not to get back into this agruement, but my setup ran with no problems like hesitation etc, even with the 350 tune, granted the BLMs etc were not on etc, but it never hesitated or anything. I would imagine that you can switch back to MAF fairly easily right? If so it would be a neat experiment to see how much closer and quicker you would run with a simple switch back. Not saying that you can't tune the SD to get to the same point, or visa versa. Take one for the team and do the experiment, and be honest about it. My bet is .25-.50 sec better first return to the track, with some slight tuning for WOT, to get AFR back to around 12s that you reported on the current SD system.

Also my heads are stock out of the box AFRs 190, so are Corky's. This is kinda funny, actually Corky has a mismatch of heads on his. One is 190 and the other is 195. LOL.

I really need to get mine to a dyno to get some more proof of the AFR etc. I wish I did not have to travel so far to get one or I would have just done it within this week. Not only that, but I am itching to see the numbers.

Trax good information you posted on the injectors. Keep it coming and lets sort this thing out.

 

Exactly. I'm glad somebody pointed this out because I have been sitting on this comment for awhile now

IMHO - this is one of the biggest reasons that Jesse is making some good power numbers. I've always always held it close to me that solid rollers are where it's at. People just don't seem to use them that much anymore. However, if you want serious power then go solid roller. You can run some really nice lift numbers and have incredible area under the curve. The only reason I have a hydraulic roller in my car is because I couldn't afford the full solid roller setup.

Tim

 

What springs are you running? Did you get their spring upgrade when you purchased those heads? Are they the 'out of the box' AFR competition port or just the 'out of the box' standard head?

I'm trying Which scan program is that picture from? Also - the TPS% indicates that you were feathering the throttle. I take it that the data was from a street run and not from the track?

Tim

 

There is no doubt that a solid setup is the way to go for major HP numbers. I will never look back again, and the valve setup and maintenance nightmares you hear of are from the uninformed and people that probably never ran one before. IMHO they are MUCH easier and EXACT than the hydr. lifters. They are positive and no chance of accidently compressing the lifter when setting them.

Trax the spings I am running are K-Motion 800s Good to .700 lift if I remember correctly. I did the valve upgrade to the AFRs from AFR when I was running my 350. The stock AFR springs are only good to .540 lift and I was with 1.6 RR and the 219 cam at .560. Those are sitting in a box with ~1500 miles on them if anyone could use them..........

They are out of the box standard AFR heads, No competition port what so ever. I ported my SR myself and naturally gasket matched everything. You can see the entire combination go togehter in several post in the CorvetteForum. Just do a search on my username in the archieves. I think there were like 6 big posts, pictures etc. Wonder what I would be running with the Competition heads???

Those scans are from Ease, it an AWESOME program....graphs every parameter in second and you can zoom into areas like I did there to isolate certain parts of a run.

Feathering the gas, yeah, like I said it was on the street with the slicks etc, open headers and in order to keep in under control I had to keep the gas under control. The thing is rediculous powerful. It literally pins you HARD against the seat the ENTIRE run. There I did not run a full 1/4 because I don't like going that fast on the street....the track is the place for that. In hind sight I shouldn't even have done that with the slicks on, headers etc. I can just imagine what the fine for that would be

Have you ever taken out hard in a boat from a dead stop, I mean in a really fast boat, how the front comes way way up.....Well that is what this thing feels like, but the forces are about 10x that of a boats launch. Kinda weird to compare a vette to a boat, but that is what it reminds me of. LOL.

Crunch the numbers man, crunch the numbers!

 

No real numbers to crunch until you get the WOT scan with 100% TPS and the MAF pegged at 255. But, as soon as you have that scan I'll crunch away!

Cool deal on the AFR spring upgrade. That was my only mistake when I got my AFR heads. So - now I am stuck trying to find a 1.437" spring that will fit into the AFR pockets (no way I am pulling the heads right now just to get the seats cut). Nobody makes a 1.43x" spring with the numbers I am looking for. The closest is the Comp 987 springs but the fully open lift seat load just isn't enough for my tastes. I'm in the process of obtaining some interesting Crower springs that are 1.440" lift. If they fit the stock pockets then I am golden. I gotta rev my motor to 6500+ so I need good springs.

Tim

 

Will any of those "tapered" springs work for you?

 

Trax, the 14.336 is gonna be a pretty good indicator of Max throttle under heavy load. I held it way past where I normally shift. I think I hit About 6200 RPM. I have another graph with the RPM overlaid on the pulse width, Also I had it to the wood for 1st gear until it hit ~6000 grand than I had to feather it and then for the latter part of the run in 3rd onceit hooked you can see it was held up there at WOT. My voltage always reads around 4 volts for WOT, I questioned that a while ago, and was told that as long as it was envoking PE and the blades are open all the way not to worry.

I don't think your gonna see anything above 14ms for the injectors. What does that equate out to?

I am gonna head to the track tomorrow and try some more logs. I hate to have the extra weight in the car. What do you think an acceptable injector pulse width would be. I will admit I have never really tried to figure out the duty cycle etc of my injectors. Just never really had the concern since like I said my AFR was where I needed it to be, therefore I figured I was not going static. Here is my log behind the static situation. If I were static and by luck getting an AFR of ~12.8 then when I tried to increase the fuel ratio or decrease it, I would not see any changes in the reported values until I fell below the pulse width that the injectors were not static correct?

 

Here is some more food for thought, in regards to the injectors going static.

If the injectors were going static, which means they do not have time to close between firing, wouldn't the pressure in the system drop WAY down. Think about it. The FP comes from a force feed of fuel into the fuel rails, the pressure is only released when the injectors open, if the injectors were open say though the 4000+ RPM range of the runs, I would see a HUGE drop in my FP guage. Right?

It eccentually would be the same scenerio that you would have with a stuck injector. Keep in mind, I don't have some MONSTER pump in the car its the stock unit.

Also if they were static and the pressure dropped, I suspect the car would fall flat on its face like it did the first run, when the gas moved away from the pickup.

The achievable/controlable AFR, and now the thoughts on FP are all telling me without calculation that the fuel system is well within its confines for effective use.

When I nail the gas the FP stays Rock steady though the entire run till I let off.

What do the calulations say I should be at with repect to the information provided thus far?

 

I second that motion,87_ta.You are correct,your car is not like ski's.I don't think you'll break into 11s with that combo.It's a nice setup,dont get me wrong.In fact I will be running a cam close to yours(solid though).But if you switch to maf it could'nt hurt.Just look at ski's timeslip.It would be useless for me,I have no timeslip.I'm pulling my engine/tranny soon,it's parked right now. I have to drive my freaking V6 camaro,at least she's maf. lol.

Ski,you have some log data??

 

Yeah I posted it on the other page, page on of this post....

Here is the one that has the RPM graph overlaid in the injector pulse width.....upon further inspection I see that I was near 4000+ RPM through the entire run, and maybe even up to 6500 on that first shift. This should be good data to see what the injectors are doing.



Please comment on my FP discussion I made, I think that tells the tale more than anything, thus far.

 

I definitely need RPM vs. PW to run any numbers. The graphs are cool but I need the exact numbers - tabular format. However, with that said, we should be running numbers for where you know the AFR. No point in running 6200rpm numbers unless you are sure the AFR is still acceptable at 6200rpms - thus showing that fueling is still good. Make sense?

Depends on the RPMs. Here are the various DCs from 3500rpms until max DC at 4300rpms for a 14ms PW.

http://www.celligent.com/tim/misc/14ms_DC.JPG

I have personally worked with SVO 24# injectors and at a 93% DC I was still able to supply more fuel. So, I know that 93% is acceptable. I never tested the limits of the injectors. Honestly, I'll say what you have already said - combining it with what Glenn said:

If you still have control over the AFR then your PWs are acceptable. However, keep in mind that very high DCs are known to increase the wear and tear on the injector. I'd hate to see a nice motor go boom because an injector crapped out due to abuse via high DCs. Now, with that said, I have never ever seen an injector crap out due to high DC abuse. Personally, I like to keep DCs to no more than 90% ... and that is 10% higher than the 80% norm. I'm currently running 30lb SVOs because the 24's I had were giving me 93%. I now have about a 78% DC - plenty of room for growth.

I would go a step further, simplify it, and say that if you were static then you wouldn't be able to decrease the AFR (richen the mix) via using the PE %Change to AFR table.

Tim

 

That looks like you just might be stactic....

 

No. If your fuel pump can supply enough fuel at a given pressure than the pressure would not go down. You would have to back calculate the amount of fuel being demanded and compare to the gal/hr pump rating.

Nope. You are ignoring the fact that the Fuel Pressure regulator is returning a substantial amount of fuel back to the tank via a return line.

Yea - but you are running it at lower pressures. The pressure is what taxes a pump. The stock pump often supplies LESS fuel at higher pressures because it just cannot keep up with the demand.

Can you be more specific about what numbers you want me to run?

Tim

 

Can you give it to me in tabular form? I need the exact numbers because small changes make big differences.

Tim

 

Trax, that is what I have been saying....LOL.

If there was a way to open the injectors manually all the way to simulate static, and you turned your key on to activate the Fuel pump, what would the pressure be? Probably nothing. The same thing would happen at WOT if I was static and the car would not be able to run! Again lets not make it harder than it needs to be.

When I fill my tank with the rockeet fuel I drain out the tank via the shrader valve on the fuel rail. The first time I did this I was really for the hose to be whipping all over the place from the pressure, instead I was surprised to see the fuel just litely trickling out of the hose. The system's pressure works off the fact that there are no leaks or decreases in pressure. If the injectors were static for any period of time the pressure would decrease almost instantly. I have done it with the shrader valve. My car will hold pressure in the rail long after its shut off. I have decreased the fuel rail pressure with the guage I have, it has a button on it to release it. The instant you touch the button, even with the pump still going, the pressure decreases to near zilch and the car will start to run funny, even at idle, because the injectors themselves as we all know, really on the pressure for spray patters.

Again lets not dismiss corkys AFR readings. That was at 36 psi on the rail to boot.

Crazy stuff here...

 

See the spikes in the maf output at the end of the run.I'm trying to remember what that means.You have some underlying issue with that.

Listen,I'm going to try and get this injector thing figued out.There seems to be one way to really see how much injector ski has left.Ski would need to set his a/f ratio rich to the point of loss of control.Once he cant go richer,then we know how much is there.This is the easiest way to see if ski is out of injector.But is ski going to do that?We don't have a ecm bench here.But as I learned you don't need one to tune IF you have a maf car.

 

You drawing vac in your intake tract?Have the stock air ducting?

 

I don't want to get caught up in a fuel pressure discussion but what you just said is incorrect by both formulas and by real world experience.

I've run 22lb injectors totally static ... I mean totally static as proven by both pulse width measurements and via scoping the injector wires. My fuel pressure was rock solid. Others have seen the same thing. That's the reality. Now let's go to my old friend called math ....

Gas weighs about 6lb per gallon.
Let's assume your injectors are flowing 26lb/hr.

1 gal / 6lb * 26lb/ 1 hr = 4.3333 gal/hr
Multiply by 8 injectors = 34.6667 gal/hr

Your injectors are supplying 34.7 gal/hr while the stock delco pump can flow more than that at 45psi.

Even fully open 26lb/hr injectors can't outflow the stock in-tank pump (unless I am wrong about the rating of the stock in-tank pump).

Now - can we get back to the real questions?

Tim

 

The maf was not straight pegged.That goes against the rule of thumb,hmmm very funny

 

What are you talking about and who are you talking to?

Tim

 

Trax is right,the ONLY way the pressue would drop(as I see it) would be w/ bigger injectors.The 8 faucets you have might not exceed the volume of the pump.I have precribed a method for finding out how much injector is there.