First off I'm not implying sd folks not to read,thank you.I would like you to post your rpm redline.Then post your gr/sec @ redline.Finally post the 1/4 mile time and/or dyno results for your car.Info like weight and mods would be nice.Just gr/sec and redline rpm if no dyno or timeslip.Thanks for any info.

 

Redline is at 6300 rpm, was at 6400 rpm for the last dyno session, but I lowered it back down since I'll be shifting at 6100-6200 rpm. I think the engine was pulling 236-240 gps at redline, but I've maxed out the MAF a little above the horsepower peak at around 5600 rpm. My best 1/4-mile time is 13.058 @ 105.76 mph with a 1.911 60-foot time (Drag Radials are old and worn out) in humid 80-degree air. I've had a best trap speed of 106.25 mph in much cooler/drier air. My best dyno pull was 279 rwhp at 5200 rpm and 337 rwtq at 3400 rpm with the current mods. I killed some of the low-end torque with more fuel and less timing to fight off some detonation and help hook up at the track. Car weighs 3460 lbs. w/out me and 1/2 tank of gas, IIRC. Mods include a built-up 355 with TF 23* heads, LT4 HOT cam, Hooker shorty headers, SLP runners, and the usual stuff. You can see everything including the timeslips, dyno runs, and every mod at:

http://www.erols.com/gcwestph/IROC.html

 

I can understand your enthusiasm.
I really can.

But, you're really to the stage of needing to build an ecm bench to really see what's going on. So far you've just been looking at one end of the equation, and drawing results from one car. Which while they may be true, they are only true for one car.

If you were to look at things on a bench and make slow deliberate changes, some answers might just pop out at you.

This is kinda a single reply to a few of your postings, and just my opinion, no flaming meant.

The MAF is a wonderful devise, and GM spent a bunch of money getting the calibration right on it. The reason I started off suggesting the ARAP, was that the fuel lined up pretty well with it.

Now, the ecm is doing almost all the fuel cals based on the MAF. If you somehow change the flow thru the MAF then you'll need to recalibrate it, ie if you remove the screens, cut the heat sinks out etc.. Those mechanical changes to the MAF will mean changing the MAF scaler tables. Since they influence the actual way the MAF senses things. Changing the injector size, engine displacement, etc, have no effect on the MAF, the mechanical changes done to the engine, won't make a mechanical change to the MAF. If you change the injectors then it's injector characteristics that need changed. The new injector will in all likely hood have different rates of response for it's pintle/disc/ball movement so the battery voltage correction would need changed as a result.

On the issue of battery correction, it's primarily noticed at idle. At idle the injector has a duty cycle of 2-3%. The 10% change that a battery volatge correction might make is then .1 msec.. That same .1 sec at a pulse width of 20 msec isn't hardly noticeable.

If you want to continue changing the scaler values, fine, but, please realise you not making the corrects the best way possible.

There is a difference.

To answer your guestions,
with a stock MAF, I pegged it at 3,400 RPM, and by 3,600 was into MAF drop out. Stock turbo
With a rescaled MAF, ie late LS1 MAF, I can draw about 400 gms/sec.. Stock looking turbo.
With some tiny injectors I ran a string of low 13s using part throttle until 3rd gear.

Now, if you want to get a second MAF, do some data logging, and build an ecm bench I can probably help ya get some more resolution out of a stock MAF. The real trick is that the output is no where near linear (at least in my application).
But, you still have the restriction of drawing thru a MAF.

Undoubtably someone will take issue with the above. To that all I can say is, Oh Well.

 

LOL, it's taken about 3 weeks of me reading the diy archives and experimenting with my car to figure that out, and Grumpy sums it up in one sentence.

Combine that with the slow response rate of a hot-wire system upstream of the plenum, vs. the undampered, fast response of the MAP sensor, is why I'm going to use the 808 code to run my car.

I'm going to set it up so it's simple to switch back and forth, just make a 'test pipe' for the MAF while the MAP sensor is being used.

Right now the big drawback is the 808 code that has TC and WinBin support isn't very good. No EGR or VATS from what I can see. After I get the 808 stuff going, I'll look into some of the later bins that can do EGR and VATS.

 

Figure the guestion out, and ask.
Sometimes figuring out how to ask to get the info you need is as hard as actually experimenting enough to analyse the problem.
BTDT.

 

quote:
--------------------------------------------------------------------------------
Originally posted by Grumpy

Changing the injector size, engine displacement, etc, have no effect on the MAF, the mechanical changes done to the engine, won't make a mechanical change to the MAF.
--------------------------------------------------------------------------------

I understand that but the reason of this post is to see some results from a maf system.How far it can be pushed and such.This might shock you boys but I'm looking into the swap to sd.The maf cost $150 at the parts store.I'm sure the swap can be done under that.My maf is at least 10 years old.It's time to get things lined out.After I swap to 1:6 rockers I'll be done modding stuff,for a while(I know not a big change).I guess I'll read up on speed density.I would still like to hear actual results FROM you maf users(cough,cough).

 

Well i hav'nt done much WOT tuning,only a little timing due to no WB o2 and hitting duty cycles of 110% at 6000.(new inj.on way)
but on that ill setup i ran 12.65 @ 106.4 and @ 6000 my highest
gps was 243 (modded MAF,SCREENS,FINS) and have never been to dyno but guessing 320 flywheel.

 

TuneRight now the big drawback is the 808 code that has TC and WinBin support isn't very good. No EGR or VATS from what I can see. After I get the 808 stuff going, I'll look into some of the later bins that can do EGR and VATS.

If you need anything extra for the 808 that tunercat $5D doesnt have give me a yell , I have it .

Vats isnt a issue as its not used on 808 code and 808 has full egr although not used or desired in our application

What engine are you going to run it on , I can send you a base calibration that should start and then its time to tune it to your application.

 

Thanks, someone uploaded an ECU file for WinBin to the diy site, but I haven't been successful in getting it to run. Disappointing because it looks like it has a lot more stuff than Tunercat. Edit: Never mind, IE sucks. Used a real ftp client and it worked. I always get bit by the ascii/binary thing. Sigh.

You're right, VATS isn't an issue, because the VATS module still controls the starter enable relay.

I'd like to keep my EGR, for emissions purposes... I didn't see it on the 808 wiring diagram though, it was listed as N/C. Maybe I was looking at the wrong application?

The other thing I noticed is that it doesn't control the AIR pump. Maybe a temp sensor could control that...

Anyway, I've got an 89 Firebird, auto, with 5.7L TPI. It looks like ASBX9285 is my best bet? Spark reference angle needs to be changed to 10*. If you could send me a base cal, that would be awesome!

 

Thanks Grumpy, I did'nt think it was a flame.One thing that made me realize things,about maf was looking at the code(what little I understand).There seems to be "tables" that converts the sensors from vdc to useable terms,like coolant temp.Now I understand the maf tables are converting vdc to gr/sec.Not a "tuning" table,plain and simple.


Yes changing the maf cal will work to richen and lean.I'm sure I could "trick the ecm" other ways to cure a lean idle.Your method, batt correct table(explained well now) does seem to have the less negitive effects.


I did'nt go around changing alot with the maf tables though.Just tweeks here and there.There seemed to be no ill effects from changing a point or two for idle though.Your right,that worked for MY engine.But I have realized my maf is 17 years old.


The only way to acurately recalibrate the maf tables would be to flow bench it,or measure actual gr/sec vs vdc before and after the mods.I guess it could be done with a ecm test bench w/ two mafs?


So from this point on I will do as you suggest,Grumpy.I have looked at my post as a newbee under a different user name.You have always gave me solid advice.I was just to un-aware to use your advice.It's kind of like telling sombody something and they dont listen.But without UNDERSTANDING why they can't compute the advice.I think thats why things get rehashed.It takes awhile for it all to sink in.So Grumpy,do I have it right,now?