Fett

GREAT numbers! I love that Torque curve. It must be a blast to drive that monster! :hurray: :cheers:

scorp508

Well now that you've given it more fuel you can probably add a little more timing. :thumbs:

0ski_dwn_it

Dude, if I told you how much timing I was running you would :eek: you pants. The car is a freak :D Ans schleprock is probably holding me back another 20 hp, truth be known. :crazy: :jester

SBNova

Great numbers! I know your hunting for 10's, and I was looking at your graphs and noticed that your power did improve overall in your second graph, but your down a few ponies below 3300rpm from your first run. This could just be variance from run to run, but you may want to leave your fuel curve where it was on the first run from 3300 down and from 3300 up leave it like the second run. Also, you cant really tell, but your improvemets in the second run really only occured form 3300-3600 rpm. You may want to try altering fuel curves after that window and see if you ET or MPH change. My last thought is that your looking to pick up 1-2 tenths by HP increases and it looks like you have the top end covered. I guess by your signature that your not new to drag racing so remember ET is more about gearing and suspension and MPH is about HP. Id say your 10 second slip is waiting in deeper gears or suspension work, possibly even a looser converter. As far as lockup goes, I have a TCI 3200-3800 lockup 10" w/kevlar disc and I dont lock it up under full throttle . Its about two years old now and I can feel a decrease in its lockup firmness already. Good luck with your search for 10's, Im sure youll get it. We're all rooting for ya

Rays Vet

Man what a monster!!!!I 've been follwing your progress from 3rdgendiy to here and you have made a believer out of me on the maf limits.I may e-mail you later as far as your prom burning.But I will finish reading the post there
first(diy3rdgen).Low 11's.......who would have thought!!!! Congradulations again. :hurray: :hurray: :hurray: btw I also have a 3rdgen z28 with 406sm. blk,miniram,t.f.ported heads,cccam560/540,........but have only gotten to 12.12 e.t. with it but still burning chips!!!!!!

MrJay

Great numbers!
I bet it is fun to drive that car with all that power, now you got me thinking about getting a 406ci....... :D
Maybe one day I will get me one.

Jay

0ski_dwn_it

Thanks all for the nice comments! :cheers:

It does appear though after some more analyses, that my injectors could be maxed out. Since the HP never was altered in the upper RPM range with the fuel changes.

That seems a bit strange. I am all out of Toluene so I have to order some more before I can do some further testing. I have a way to see if the injectors are maxed or not. Test results from that will be posted this week. Maybe there is even some more power in this combo :thumbs:

scorp508

Jesse,

How much power do you think you would have to sacrifice in order to bring the timing down so that you could run it on pump gas alone and be able to take a trip with it? Just curious.

Beach Bum

Wow !! Great numbers Ski !! I bit more than I would have guessed.

On the flip side, with the 5100 rpm peak and that Solid Roller cam of yours, I think there is a restriction somewhere.... probably the SR, but dunno. I think your HP peak should be around 5500 rpm with that cam and a 406 with the SR.

In any regards, thats a great torque curve that will allow you to run low 11's or high 10's without needing a lot of stall or gear..... typical small block chevies need a lot of stall and gear and 6500-7000 rpm ability to run those #'s.

I'll try the TPIS solid roller cam you guys are running sometime in the future, but for now, I am going to experiment a bit and see if I can get low 11's out of the 219 set-up.

Great Stuff !!

cheers,
Beach Bum

0ski_dwn_it

Scorp,

I do run the car on 94 octane when on the street. I took it to a wedding this weekend it was a 2. hr trip either way. You just can't go past 1/2 throttle or it will ping a tad. But with 500+ ft/lb at the wheels you can give it 1/4 throttle and hit 100 mph in no time at all. With the street tires and full throttle your just asking to wrap it around a tree.

On the way up there on a straight stretch I had a camaro try to pass me when I was going about 65-70 already. I wasn't going to race him, but thought what the heck. I didn't even downshift the car, just left it in D and gave it about 1/2 throttle. I walked away from him like he was on the brakes, and trust me I'm sure he was WOT.

So I guess what I am trying to say is you can still have plenty of fun with just the 94 octane, you just have to have some self control. Also I am thinking about doing a special chip that has a bunch of timing retard available and just let the car pull the timing like it was designed to. I'm sure the performance will still be unreal, even if its pulling timing.

Beach the injectors are the weak link I think now. Here is why I think they are and the car is not making bigger power up high. The fuel in those graphs and several others were changed ~10% to richen it up. While the lower end picked up then fell off as I contiinues to add fuel the 4000+ HP/tq stayed dead nut the same. This leads me to believe that the injectors are dumping as much fuel as they can at that point up, and the reason the tune changes to AFR never effect the upper RPM HP/TQ. :crazy: :thumbs:

mean8t

WOW, I gotta get me one of those :thumbs: :thumbs:

mike89z

Just wondering what fuel pump you have and if your pressure really wasn't dropping in the higher RPMs. I looked on your website and didnt see anything. It does seem like the top end might have a little bit left in it. Whatever the case, that motor is awesome!!! Good Job

Wadoka

I don't know why anyone would want to badmouth the MAF system. Chuck Probst's fuel injection book leads me to believe that the MAF system has it all over MAP/chip systems, because the MAP/chip is all calculated guessing and has to be changed every time you make a significant engine change, while the MAF/O2 sensor combo just calls for more fuel if you're pumping more air, to the limits of the fuel system.

0ski_dwn_it

MAtt,

Its a bit more complicated than that. Let me first say this. MAF will take to mods much better than any other system will. It will run and run decent with little problems and little tuning, but will need tuning, so don't get me wrong.

SD need to be right or it will have major driving issues. The tune is entirely bases on efficiencies and manifold pressures. You know what happens to manifold pressure when a big cam is put in. Major changes.

The limit everyone is talking about with MAF is more of a resolution problem, but when really looked into its not as much of a problem as many think, or its made out to be.

Here is why. Let me try to explain this for you all. The MAF is setup to read a max of 255 g/sec in closed loop. Once it gets past that point it will not be able to make corrections for 255+ g/sec. With that being said let me explain why you can make this system work for you, even with a big power maker like mine. Up till recently with all my harping on this subject many of the better tuners adimently disagreed with me, but now more and more of them are starting to realize that it can is IS being done. Here is why.

When you have a smaller motor <350 ci it will be nearly impossible for you to max out the MAF, 255g/sec in anything but WOT conditions. With that being said the computer is 100% able to adjust fuel curves to manage the system. When you reach the point of 255+ g/sec by then you are well into PE power enrichment mode, which is great since now the computer has already switched modes and is running PE parameters, which in this case is just a given set of values the computer runs for fuel. It doesn't care about the MAF meter at that point. Just the values in that table. The table is called. PE % change to AFR vs RPM.

Now lets take it up a stage to a bigger motor like mine that can easily max out the MAF. Keep in mind that when I say max out the MAF, I mean in terms of resolution (255g/sec), not max airflow ~750 CFM. That is where many people get confused they are VERY different units. WIth that being said, let get back to the bigger motor.

Now with a bigger motor, you have a huge benefit. That is you can make major power with very little amounts of throttle. FOr example for me to pass a car, I only need to apply about 1/4 throttle and I am screaming like an F-16 past the other car. Since I can make tons of power with very little airflow, I can too keep my airlflow under the 255 g/sec for cruise conditions. This doesn't mean that you have to tiptoe around on the street either, just like when the smaller engine envokes PE, my engine too at 60 % throttle engages PE and jumps to those PE fuel values.

Now the die-hard SD people will try to tell you that you lost your resolution from 60%-100% throttle, since what will happen is you will go a tad rich till you go actually WOT. SO what that means in my case, is that I am only probably making 400hp at the wheels instead of 437hp.....do you think I miss that 37 hp? :rolleyes: Not a chance. And besides that, when you have that much power, you seldomly even come close on the streets to using it. I drove my car more this weekend than I have since I put it together. One 2.5 hr trip each way, and tons of cruising with my dad in his new vette, and I have to say I never went past 1/2 throttle and we did some serious spirited driving through some major mount roads and some long straightaways. In every case I could easily leave him behind. On the long trip I had a camaro try to take me on a straightaway. Held it at 1/2 throttle and walked away from him like he hit his brakes when I hit the accelorator.

All in all, what I want to people to realize is that MAF is not a restriction and anything under where I am at is fine for making power.

Hope this clears up some things.. :cheers:

hookedup

Jesse,
Great numbers :hurray: , hook that beast up and you're in the 10's! :D

Dave :thumbs:

Wadoka

So, if someone marketed a heavy-duty MAF - one with heavier wires and/or more power (heat) in the wires - it would be able to 'see' mass flow greater than 255 g/sec, and you could program the PCM to deal with the new calibration?

I'm asking "Is it MAF in general that limits out, or is it just the design capability of stock MAFs?"

I understand hot-wire anemometers...

Hmm...1994, 1995, and 1996 cars have a MAF *and* a MAP as backup...hmmm...

Great post, BTW - you just transferred knowledge, a great gift!


[Modified by Matt Black, 10:40 PM 5/26/2003]

0ski_dwn_it

MAtt,

Well actually its both. Some people have developed translators that use that increase the resolution to 512 g/sec. The power that can be made and dealt with using MAF is well at least to the point of where I am now. Somewhere the meter will become a restriction, but who knows.

The reason that some manufactures are running both MAF as primary and SD as a secondary is the emission restrictions and mandates. But it says quite a bit for MAF being the primary choise. My guess is they have much fewer customer complaints with the MAF system than SD. Hence the reason that SD is the secondary system.

USPRIDE

If you don't mind my asking, how much does a 406 set-up cost? Thanks!! Outstanding numbers!!!!!! :thumbs:

0ski_dwn_it

:confused: :confused: Quite counting last year. I saved a bundle as much of the work was done by myself with Corky and Dads help.

Its up there though. Just the tranny 1500.00 + Rear 1200 + TC 750 = $3450

Then throw the heads in there another 1500 ....ahhh I am not going to go much further.... I would say that 10 grand would get it done if you did everything yourself......and double it if you have someone else do it.

Sorry I would not want to spend the money on the cage ~1300 + fuel system upgrades and many other items I don't even care to think about in the next month if I added it up. Sorry, but I would rather just forget about it all, sorta like a bad accident. LOL

Someday I will add it all up and then think if I had invested that money I would have about 50k for some real nice toy. But when I get in the car and take it for a ride, all that is forgotten. Especially when your at the track and you light that second staging light. Its just pure adrenaline :smash:

I would really have to add it all up. I have some of the parts price listed in my website, but its all the little stuff that adds up like the million trips to Autozone I made. Now when I go there they just throw me free stuff, like ball hats and other assorted items. I don't think I paid for any bolts in the past 4-5 trips. They are nice people, but they get their money in the end!

:cheers:

AquaMetallic94LT1

The MAF works in open and closed loop mode. The addition of the O2 sensor put the ecm in closed loop mode and is used by the ECM to fine tune the fuel mixture because MAF is not accurate enough to keep the fuel to air ratio close to stochiometric for emissions purposes.

The MAF is still used at WOT. PE mode is the same as open loop. The computer goes to PE mode above a certain preset throttle percentage and stops trying to maintain the stochiometric air to fuel ratio of 14.7:1. In PE mode, the computer uses the AFR vs RPM table and the AFR vs Temp table to calculate the final air to fuel ratio. The ECM then looks at the MAF reading to figure out exactly how much fuel is needed to get the computed air to fuel ratio and sets the injector on time. Once the engine air flow exceeds 255, the ECM will still use the MAF (which is stuck at 255 at this point) and and PE table values to compute the injector pulse times but the actual air to fuel ratio in the engine will be leaner than the values programmed in the PE tables. Its possible to tune around the 255 g/s limit by making the air to fuel ratio richer in the AFR vs RPM table but the air fuel ratio will change as air density changes.

The 86-89 MAF will actually read above 255 g/s but the ECM only has one byte in the table for maf values which limits it to 255. Its possible to recalibrate the maf translation tables and then adjust the injector constant to allow for higher MAF values but the rest of the tables using the MAF will have to be adjusted and other functions of the ecm may not work properly. The fuel consumption calculation will be completely wrong at this point.