azvolfan

So Jon, given the datalogs I sent you what would be the first move you would make?

Looked to me I was still a little rich in a few cells.

azvolfan

By the way, I have had a couple of people say that the track was not in great shape that night. I ran slower, Tony ran slower and Chris also ran slower. So it may not be as bad as we thought. But I still think I'm a little shy on power.

azvolfan

Jon I never did ask you, after riding in the car and felling how it ran, what time did you expect it to put up?

Dewey316

I do to, although I'm in the 20psi range for FP with them.

I hold a dead steady 12.8/AFR according the the LM-1.

dimented24x7

iTrader: (2)

Ok, so thats the new curve? Looks much better. I was under the impression from you taht you didnt do much work at all with it. Thats what I had in mind to start with. I knew they had the PE enabled, but you disabled it. Also, I was under the impression that he was running the stock 0 degrees called for by most of the later tbi cars. It looks like you did all the things one would do for starters.

As far as teh track goes, even with wheel spin it should at least get decent trap speed by the end of the track and your shifting at around 5k. May not be perfect, but it should be good enough for 15s flat at the very least. Both the track times and the trap speeds are indicative of the car just not having power for one reason or another. It could be fuel. Doing a WOT run and checking the plugs afterward may at least give you some idea of where it is. If that looks ok, then Id look very closely at the car mechancially. Somethings way off, and I have a feeling its more then jsut the tune. You radically changed the params at WOT, and still came up with the same results.

RBob

iTrader: (1)

Hi, I've been reading this thread for a while now. And IMHO (azvolfan) your engine is performing up to task. The '92 L98 is rated at 245 HP which is 0.7 HP/ci. Your engine at 226 HP flywheel is 0.74 HP/ci.

For the most part the engine is using stock GM pieces. An L98 cam, 416 heads (ported?), stock 1-11/16" TBI w/68 #/hr injectors, stock fuel pressure, same as stock intake manifold. Then good exhaust and a decent air cleaner assembly.

I don't believe an L98 cam is a good choice for a TBI engine. The reason is that an L98 cam is matched for a TPI setup. Which falls flat in the 4,000 RPM range. The 1.6 rockers will produce more lift, but not that much more duration.

The Edelbrock Performer TBI intake is basically the same as a stock GM TBI intake.

I know you aren't asking for recommendations, but food for thought. To add some HP a different intake manifold, and a different cam is required. Those two pieces are the current bottle neck. Of course once they are opened up additional fuel will be required (increase fuel pressure) and possibly a larger TBI unit.

On the quarter mile times the 60 ft is lacking. It may be time for a higher stall convertor.

RBob.

90RS305

Wow, I understood this thread up until about 10 posts ago, lol

dimented24x7

iTrader: (2)

Just my

I would think that times on the order of very low 15's with 90+ trap speeds would be what Id expect for that setup. People have done this, and 14's as well, with unmolested LO3 longblocks. The only thing that really makes the L98 cams undesirable the large LSA they have. While the duration/lift isnt stellar by anyones standards, the L98 cam is set up to make peak torque around 3600 rpm. Without the TPI, they can probably rev to around 5k and provide reasonable power.

Another thing about the L98's, and a few LB9's, is that they can run high 13s with decent trapspeeds close to 100 mph with bolt ons similar to what he has along with posi, gears, etc... So that motor can make decent power, but on the flip side the TPI highly reinforces the torque around 3600 rpm, so that helps bolster the torque power output in the mid rpm range.

JPrevost

I was expecting high 14's at low 9x mph.
The funny thing is that the impression I got usually had a laptop in my lap and my feet bunched into the corner of the floor. Hence my impression of the cars actual speed was just me holding onto the door and looking at the speedo.
The gears in the rear give a false sence of power at low speeds. One thing you should do is set the lash if you haven't done it yourself.
Also, I didn't ask you this but does your air cleaner have that dumb silencer ring removed? If not, remove it.

That's good news that everybody was slower that day. That means we did find more power, although how much can only be determined through calculating to ideal conditions. Do you have the baro/humidiy/temp of the track conditions for both days?
As for the L98 cam, it's very similar to the Lt1 cam. Either way I feel the air cleaner is one restriction (70's design, designed for a 190hp engine), and the cam is another. An lt1 cam with the tighter LSA might have been a better choice.
Do you have any flow data on the heads? You said they did some exhaust porting and that's usually 90% of the battle with SBC heads.
Dim, the timing was too far advanced. Even now he's getting some pa3 msb counts so I'll give him another bin to try out. I think the humidity we had when I was there had something to do with getting far fewer knock counts than he's getting now. Because of my short visit I was trying to move very fast and didn't consider the "normal" conditions of Arizona weather. When I was there it was low 60's into the 50's in the evening, humid, and raining during most of the tuning.
I've got another bin for him to try out and then it's a matter of him moving the PE AFR values up and down.

azvolfan

So what are you saying Jon, another trip to AZ is in order?

Current conditions are high 70's to low 80's. Would that be better?

BronYrAur

iTrader: (1)

I think checking almost everything mechanical would be the way to go with this. Like Jon said check your valve lash and things like that. It sure seems like it would have a good tune right now, at least enough to run it faster than that! I think something more than the tune has to be killing you.

My car, a ragtop weighing more, with just open element, flowmaster and 3.42's pulled the exact same time 15.72 but at 86.92 and that was with 118* track temps. There's no way you should only be like 1mph away from my car. Man, I was really hoping you'd come back with some 14 second runs. Keep workin' at it, you'll find what's wrong soon I think, especially with all these guys in your corner

DM91RS

I think that we all need a WB Is the LM-1 the best for the money? (Not trying to get off the thread too far with this!)

Dewey316

DM...

Truth, I don't really know enough about what the diffrences are. One of my good friends bought the LM-1, so I use it.

I would say any wideband, is better than no wideband.

BronYrAur

iTrader: (1)

John, What kind of outputs does your LM-1 have? I was looking at the site because I'm sure I'll need one down the line soon enough. It looks like the least expensive "kit" only is an air/fuel meter. Do you have to get other stuff to log rpm and map and other parameters?

Also, to kind of keep it on the subject of this post. Say someone is trying to tune a setup much like Az's or maybe a bigger cam. What have you guys that have tuned far from stock setups done to get WOT fuel down without a WB?

TonyC

iTrader: (1)

Bill, when we get a spare weekend, I'll hook my wideband up to your car, only problem is rigging up something to put in the tail pipe. I'd argue that the car should run into the 14's at around 97 mph with that setup. I put down a 15.6 with the same intake Bill has on + LT1 cam, no headers. Bill has headers and heads over what I had and it's at the same track so I see no reason why the car shouldn't be in the 14's. Last friday was a really slow day at the track, but their trap lights weren't working correctly for most of the night either. Jon, the weather's looking mighty nice out right now, come on, you know you wanna come down again

dimented24x7

iTrader: (2)

I took a quick peak at a datalog bill sent my way. Its definatly on the rich side judging by the stock O2 volts being >1 volt. If you dont mind sticking your neck out a bit, you could lean it out to around 12.5:1. Wont be able to hold WOT for more then a few seconds at a time but itll give better results at the track.

I also found the following in the one log I looked at... Below in the table, I plotted out the absolute pressure in the intake vs. rpm at high load. The lower the pressure, the higher the airflow. One thing I can say is that the stock tbi and to some extent the air cleaner are building some vacuum so theres a restriction there. Its like running at altitude.

More importantly is the shape. Your airflow is peaking really low. I would think it would be safe to say that as the pressure rises up at higher rpms, your making less power there and the lowest pressure probably ocurs around peak horsepower output. This means that your peak power output is likely below 4000 rpms. A tad low for your setup. Theres definatly something up. Something like a problem with overadjusted lash allowing the lifters to pump up (they WILL pump up at lower speeds if too tight), parts you got not what they where advertised to be, drowing the engine in fuel, etc.

azvolfan

OK, so too much fuel, not enough air and check the valve lash.

Well I can adjust the fuel, I can go to an open element and take off the dual snorkel, and I will check the valve lash.

Did you see anything else that I should check?

Dewey316

He has the basic one, no outputs. He is talking about getting the RPM input for it, so the LM-1 itself will log AFR and RPM.

Tuning with it was rather unscientific, it involved 2 guys, a car going WOT thru 3rd gear, one watching the tach, one yelling out changes in the AFR. It did the trick though. Luckily I was actualy pretty close without the WB, so I just had a few small changes to make.

dimented24x7

iTrader: (2)

yeah, id check the lash first. Looks like somthing just pulls the rug out from under the motor and it drops off. Set it to zero lash with the engine running if possible and then add 1/4 of a turn when your done. You dont need any more then that, especially with a roller as it wont wear as fast as a flat tappet.

as for the airflow, Id probably say its the small tbi more then anyhing else. People have run 13's through the dual snorkel to it flows ok.

JPrevost

**Click Picture To Enlarge**

That proves that something in the intake is restricting the airflow. 91kpa when baro was 99.
Also, you'll notice the SA is a little funny, it's because he's getting some knock retard with 33 degrees of timing. We need to take out more timing and DEFINATLY lean it out. The narrow band mv is pegged which is a good indicator of being too rich.

DM91RS

I agree and from what little I've read I would really like one that datalogs

RBob

iTrader: (1)

Jon, can you re-post that graph in a larger format?

RBob.

90RS305

click on it

RBob

iTrader: (1)

azvolfan, was a dyno graph ever posted? I don't recall one. The MAP vs. RPM graph that Dimented posted is quite interesting. I checked the ALDL stream and the MAP and RPM are output next to each other. This is important as there would be little delay between the two values.

Just trying to get some thoughts going. . . After checking the valve lash I would check the firing order, concentrating on the 5 & 7 plug wires. Those two are easy to mix up. If coming straight off the cap and over the headers they need to cross over each other to be correct.

Check that WOT at the TB is obtained when the go-pedal is mashed to the floor. Remove the air cleaner and operate the throttle by hand. Note the stop at the end of travel. Now standing outside the car reach in with the right foot and mash the go-pedal. Does the TB hit the stop?

On the dual snorkel air cleaner, are there pre-heat flaps? If so (there probably are) how are they setup vacuum wise. If not using a ThermVac switch is there a vacuum can to maintain vacuum at WOT? Just want to make sure the flaps don't go pre-heat at WOT.

Back to the cam, have you been able to verify what it actually is? (I'm just asking, and trying to get some thoughts going, nothing more).

In the tech section these are the cams as listed for a L98. The 'Vettes probably had a different cams. A Caprice wouldn't be an L98, nor would any 350 trucks.

I would also try shifting at a lower RPM. None of these cams are rev'ers.

What timing chain was used. Many of the grocery store chains have built in retard. Not good for power.

On to the SA, I have an '85 LG4 in the ElCamino with the 416 heads. This thing will ping at the slightest hint of heat/throttle. I've set it up with a TBI unit and manifold off a 5.7l truck. Code and calibration is all mine.

Even at 4800 RPM, 100 Kpa, the timing is 24° BTDC (in PE). During the winter I can run 89 octane. But summer requires 91 octane. Even at that after heavy throttle it will ping as I back off. The chambers build heat which makes it knock prone.

Previously I mentioned a convertor. If from a stand still the gas pedal is mashed, what does the convertor flash to before it hooks? The convertor is one item that can make or break a car out of the hole. Is it possible that it was replaced a while ago, and it isn't really the proper one for the vehicle?

I'm just trying to help out in getting the thoughts and checks going. Honestly, I'm not looking for posted answers to the questions I've raised. Just want this to be a thought session.

RBob.

RBob

iTrader: (1)

OK, got it. Wasn't easy but I have it, thanks.

Jon, didn't know you had a Lockers setup on Bill's car. All the difference in the world. At the initial pedal mash the O2 goes a little rich then drops lean. If using a '8746 (correct?) will need to add to the MAP AE duration. Decrease the MAP AE filter value at the coolant temperature in use. This will extend the MAP AE duration. If a '747 then can also extend the TPS AE duration. I prefer to work with the TPS AE before the MAP AE. Too easy to drown an engine with delta MAP terms (think low RPM). Don't have the same TPS AE cal's on the '8746 as on the '7747 ECM.

Tying into Dimented'd graph of MAP vs. RPM, the same can be seen in this graph. At about 3,500 RPM in first gear the MAP starts getting pulled down. This can also be seen by the RPM nosing over. Something bad is happening. I'd also check to see if maybe the air cleaner duct work isn't collapsing. Or maybe the duct scoops are being blocked by the hood structure (I don't recall how this is setup).

LIttle wheel spin on the 1-2 shift, cool, followed by a steady rise in MPH/RPM. Then again the MAP starts to drop off. I believe that Dimented24x7 is on to something here. For some reason the MAP starts to rise again. This doesn't make sense. First gear didn't do that. (And I don't want to hear from anyone that thinks Bill needs a 2" 2bbl TBI on this '305' ).

I am thinking that the engine is all out by the 3,600 RPM mark. Either the cam isn't what it is supposed to be, or it is timed incorrectly. The Edelbrock TBI intake doesn't help either. Can always swap off to the stock one.

With the MAP increasing after 3,600 or so, that means the engine stopped pulling air. Find out why and you have the answer. Hopefully this helps.

RBob.

azvolfan

RBob,

I appreciate your putting a littel gray matter to the situation.

I never did post a dyno graph. I have one now from the chip the shop dynoed for me. I should take a snap shot of it and post it. I will also have one later this month as the PHX crew is setting up a dyno day.

As far as the thermac, they are still there and they are not being used. I do not know what postion they are in at WOT. I should probably disable them. There is not vacuum can.

I will check the 5 & 7 wires and make sure they are right.

I will also check the throttle body and make sure it is hitting stop with the pedal.

The cam is an '87 L98 cam the spec of the tech data page are:

404 .415 202 207 114.5 (115/-114)

I did notice that it was one of the smallest L98 cams out there.

The timing chain was just an off the shelf gear and chain kit for the local Checker.

I use 91 octane only in this car.

As far as the converter, it is the stock converter. The car only had 32K miles on it when I bought 4 1/2 years ago. Everything was original. The guy I bought it from was a family man and not into buildups. So I'm pretty sure it's stock.

I hope this answered everything.

If the rain hold back (yes it's supposed to rain again out here in the desert) I will go out to the track again and get another time. This time I will try Speedworld instead of Firebird.

dimented24x7

iTrader: (2)

Ive found that with the stock tc, it flashes around 1850-1900 rpm behind a decent motor. The stock TC is alot better then my junk TCI staturday night special. That one stalls higher, but feels like crap and wastes power. The difference is profound when the TCC locks up at 90 MPH+. The stocker should do ok with that cam. A better one would help the response, but at this point, figuring out why the motor is doing what its doing is way more important.

I was looking at the lockers and the plot of the rpms in first gear. It seems like after 3000 rpm, the rate of acceleration suddenly changes. The slope suddenly reduces. It reminds me of when I first got my 'Hecho en Mexico' 350. They way overadjusted the lash and at 3000+ it would nose over and get this awful roaring 'WHOOOOSSHHH' sound in the exaust as the charge rushed out during the compression/power strokes. Incidentally, I suspect it burned at least one valve. I have a loud pop/tick exhaust noise at the same speed as a single cylinder firing and the #6 exhaust primary will glow at the drop of a hat whenever something is amiss. Doesnt matter much to me, though, as there is a set of new vortecs due to arive at my doorstep soon.

Im not saying that the valve lash is the problem, but it rises pretty high up on the list of suspects when seeing the lockers data.

Ronny

iTrader: (1)

Quote: That proves that something in the intake is restricting the airflow. 91kpa when baro was 99.

this may be an issue for me as well. i have only tried WOT a fewe times with a load on engine. seems like the engine was starving for fuel or air. My WB showed about 13.2/1 and engine stopped reving at about 5000 rpms and seemed to break up/gurgle. if i WOT 1st to 3rd gear(manual) it reved above 5000 but as i said have not datalogged much due to weather in Nov 04. due to clearance issues i am running a drop base AC and a 14x2 inch KN. KN at their booth at drags said the 14x2 is insurfficient for my setup. the WB contradicted that as was lean WOT in 3rd gear(of 5). ign system is all new(accel). fuel pump is TPI. fuel pressure 12 lbs soon to be 15 lbs.

Dewey316

Ronny,

It sounds like you are running out of both fuel and air. The breaking up sounds like your going static to me. Have you used RBob's modifications, to get the ALDL stream to spit out your injector PW?

Ronny

iTrader: (1)

Quote: Have you used RBob's modifications, to get the ALDL stream to spit out your injector PW?

i am using winALDL and tunercat. 7747. i investigated that but am of opinion i cannot do with above? i checked into another datalogging program and they do not support 7747. i dont think fuel will be issue if i up FP to 15-20(80 lb injs). that AC may be coming off soon as it was temporary to get car running, on road, and into barn for storage. first order of day will be up FP and redo VE. we did not change FP during manifold/cam swap. i wanted to see how car ran with old tune(smaller cam/xram). ran better cept lean WOT and way too much AE.

Dewey316

Ronny,

Its actualy pretty easy. You just change what viarable is displayed in the PROMID fields for the ALDL stream.

in the 8746, the address that need to be changed are.

$414, $415, $416 & $417

Check this thread....

https://www.thirdgen.org/techbb2/sho...hreadid=210908

Here is the info according to RBob...

Ronny

iTrader: (1)

thank you. i will pursue that when car is back on streets. in meanwhile i will take a look at my laptop(winALDL) program. i cant believe how in the dark i would have been without WB02. it don'd lie.

Dewey316

No problem. I'm just relaying information I had stored up, from the Jedi Master himself.

JPrevost

http://www.moates.net/files/3)%20Bin...DL%20patch.zip

I made that up a while ago. It'll make modifing the aldl datastream a lot easier. The zip has the ecu file and the commented ram so you can output whatever you want in place of anything else.

azvolfan

Made it out to the track tonight. I went back to Speedworld. The same place my car previously ran a 15.5.

And the new is worse than last time.

azvolfan

Race 2

azvolfan

Race 3

azvolfan

and Race 4

azvolfan

I'm going backwards.

BMmonteSS

As stupid as this sounds, this is a good thing. This means that whatever is wrong is getting worse, so it'll be easier to diagnose. How did it feel this time? It looks like it just crawled off the line, and then fell over after the 1/8th.

azvolfan

It felt sluggish. No power in the uppper rom range. The really strange things is that it feels great just driving it around on the street. It feels like it has plenty of power at part throttle but when I got to the track it does nothing.

If you notice in the first race I beat the guy off the line pretty bad and was leading him for a while, but then he just blew by me like I was standing still. I didn't have an answer for that. He was running a 4th gen camaro. I don't know what he had in it.

azvolfan

oops. Forgot, I didn't show the other guy's times.

BMmonteSS

There's deffinately somthing up. When it lays over does it make any funny noises, or sound like a misfire? Or does it just get a nasal sound and just fall on it's face? This kinda sounds like something ignition related, but it could be fuel related. Your gonna have to catch it doing it while datalogging. I had a module start breaking up on me, the knock sensor went nuts when it broke up above 4000 rpm. If it's something like the fuel pump dying, you have replaced the pump right?, you should see the O2 swap over lean when it falls over.

dimented24x7

iTrader: (2)

Bill, your datalogs showed this. After ~3000 rpm, the engine is rapidly falling off. You can see it in the screenshot that JP posted. The big question is why.

It could be fuel related, or it could be some sort of ignition problem causing a weak spark, or even some sort of a mechanical problem. Any of these will slow the car down in a big way. As far as the ignition goes, if you still have the stock module, coil, etc, it wouldnt be a bad idea to replace them. Theyre around 12-13 years old by now if youve retained them so a fresh module and coil from A/C Delco would be good peace of mind. You never know when the module will fail and leave you stranded.

I just learned the hard way that its not always the case . The spray pattern looked good, the O2s could go >.95V, the pump sounded fine, but the motor ran like dog crap in certain areas. Put a new pump in and it made all the difference in the world.

azvolfan

The pump has not been replaced. It's still the stock pump to my knowledge.

I will check out the fuel pump and ignition.

I will have to say it did not feel strange at all at the track. Just no power at WOT.

We have a dyno day here in PHX next week. That may help track down any problems.

JPrevost

wow, something's not right!
I'd also say fuel pump at this point since that is a wear item. When my pump was stock I ran a 13.9 with it dead-headed (no fuel in the return line because the pump was so weak at 16psi), then after a few months the times slipped into the 14's and then would go high 14's, low 14's back to back runs nothing changed.
The o2 sensor will also show rich when you've got a misfire induced by spark and/or lean fuel mix too lean to combust. It sounds like a fuel delivery issue at this point. We should have brought that fuel pressure regulator over to Snuf's place. The increased fuel pressure would have magnified a pump delivery problem.
I can say with 99% certainty that it's not the chip . You got me worried at first but with it being a stock pump... since 1992, well... yeah, been there done that and when an engine feels great at part throttle but falls on it's face above a certain RPM but is "smooth" it's fuel. If it's spark it usually happens with load, even at low engine speeds the car just would feel really ruff.

Dewey316

You car still has the cat on it correct?

when I had my cat go bad, the car was a dog above 3k, eventualy is started missing so badly over 3k it was almost undrivable.

JP, was Bill running exesivly rich prior to your tuning? the rich condition will do a number on a cat, in a hurry.

One more thing to add to the 'potential' list.

azvolfan

It has been running rich since the original mods a little over a year ago.

BMmonteSS

Ok we all had bets on how much power this thing was going to make, now lets bet on whats wrong with it!

I say it's probably the fuel pump, but the cat does sound like a very liable source of the problem if the car was running way rich for a long period of time. If you can get your hands on a fuel pressure guage that has a hose long enough to tape to the windsheild that would be the way to go. I wouldn't spend anymore money on track or dyno time till you get this figured out.

With that said, I'm putting 10 bucks on a snake crawling up your exhaust and dying. NO really I've seen it happen. The guy droped a full .5 tenths after a head swap and couldn't figure out what was wrong. He finally got pissed off and make a glorry pass shifiting at 7000 rpm and on the 1-2 shift a snake carcass blew out the exhaust! He found his missing power.

90RS305