a scan with the stock chip would be fine. but it doenst even begin to solve the underlying issue of the timming tables being way off and the idle setting being to low. if you have a copy of the stock chip send it and the one i sent to you back to me. im low on prom carriers. plus those 2732b's are hard to get in quatinty's. send it al back but keep the chip your car was running on in your car cuase youll need it. ill get to work today on the new chip. ive gotta do some serious over hual of the tune. the one i sent was a stock based modded up 2.8 motor sytle tune. the one you need is gonna be completely custom from the first byte of data. ill need at least 1-2 days to get this finished. then to mail it. but yeah id lke some scans. please !! those would be most helpful.

 

Hey Redraif, did you do anything about the compression ratio? funstick will need that, to help figure out just how much pressure is there under low rpms...

 

The cam is a good bit lumpier than I've seen many go with on a 2.8, and honestly I overcammed it, but not as badly as some seem to think.Yes, it could use more compression. the powerband isn't that high, up to 6k or so max. The gears and convertor are going to help a lot, but surprisingly enough the stock computer had no real issues with this cam. It started on the first try, and has had excellent driveability to this point. Midrange and top end power have improved, and MPG has gone up a lot. Her motor had no bottom end before the cam swap, so I don't think its completely to blame here...at worst, its at near stock levels on the low end. The valvesprings are new, and matched to the cam.

Compression is stock, maybe slightly less due to the polishing of the combustion chambers. I'd be more likely to change the cam rather than put pistons in a 2.8, since there is so little return for the money spent. In all honesty, I think anyone who wants even 175 hp should seriously consider an engine swap. We have leads on an 87 GN motor/trans/computer, so any real expenditure will go in that direction.

 

Doward..no we did not do anything to the compression ratio. I realized that hurt its low end. Joe (lt1guy) never knew the car when it was running well and it did have a good bit of low end. That is definately gone, but my low end was initially lost with my 2 year drivability issues (distributor), but all that has been worked out... the car still has some pull... On the cam, We went Reed's sugggestion. told him about the car, what was done, what we wanted and this is what he thought suited it... big Question is will it pass emissions?

Funstick...here is what I will do...Sat morn we will go to pull-a-part & get as many proms as we can... then I will send then wtith your chip and the, fingers crossed, spare I have at the house. I pray its the same BCC...

Funstick we may have to have you burn an emissions chip too...hehe! I have to go in this month for the test!

 

Wow... yeah, the lack of higher compression is killing some of the low end... the timing with help bring some of it back, but not much....

Only 6k? The stock cam is only like 180 @ .050" isn't it? I'd really think that much extra duration would let the engine breath until 6500, at least... Perhaps a restriction still in the intake or exhaust? Those long tube headers should help the exhaust dept!

 

as long as your nox2 exxepmt i think i can make it pass. with all the timing you need to run correctly itll be tough. for it to pass emission id need to phciyscally have the car. i can try but i cant make a promise

 

Actually I was meaning a 2nd chip for emissions, hehehe!

The EGR was and is disabled and I managed to pass before on the no2 scale. That was before the cam though!

The intake has been gasket match ported and it has the ram air hood and set up from Suncoast. So the air coming in is free. I would say the manifold are holding it back, so I can't wait for the headers! Though before the cam the car would do that gurgle pop that said I did not have enough back pressure...now the gurgle is gone...

 

I don't know what you are going to use for a scan tool, but you can rent Diacom Plus from TPIS for $50/wk. Do lots of scans and e-mail them.

I am just suggesting this as I am not aware of what "freebie" scan tools will work with the MAF V6s.

With Diacom Plus, remember that it's the cables that are the secret, not the program itself. Heck you can even e-mail the Diacom Program to the other party to review it.

As for the "heads" glad you guys cleaned up the combustion chamber...it's one of those things that a lot of people miss and it's really critical to how much spark advance you can run.

 

well i just finished changing the scalar for the #6 maf table. thatll get back the airflow youve been losing. im gonna have to assume youve maxed out the code not the maf.

the stock code was limited to 150grs/sec and the best 2.8 without the type of work youve done ive seen to date has pullse just about 140grs/sec. i made that adjustment and put the curve back the way it was. the top 14 entrys were all pretty useless.

ive worked the spark table backwards from stock with your 15 base time. so the new chip has the 5= drgees as a global change across the spark table. i went and pulled some of the extreme values that were pushing well over 45 degrees after siad change and brought them back down to no more then 42btdc. i also went and borught some of the value that i felt were to low to optimize your cynlinder pressure up.

the spark map has been sort of flattned. but it had to. now im working on fuel. i need to know for sure that the injectors are 19pph @ x fp.

ive gotten my hand into the AE and PE tables and im making a boat load of changes in the hopes and prayers that this thing just want more fuel.

im sreu you maxed the code hence why its never had the power you expected it to.

ill try to make this one count. i think now that i have an understanding of the issue i can make it run.

its just gonna take a very concerted educated geuss to get on the right track.

 

Cool, funstick, we really appreciate all your effort. The injectors are definitely 19lb injectors; they're Ford injectors, out of a 4.6 SOHC. They were cleaned and flow matched by Cruizin Performance. Ford runs their injectors at a lower pressure than GM (39 rather than 43ish), but the way I understand it they are rated at the same pressure as GM injectors. Hope this helps!

 

On the 42*...Glenn was worried about running much more then 36*total= 10* base and up to 26* added by the prom...Are you thinking 42* because of the cam overlap? Only trying you understand a bit more how it all works...

Yes...the injectors are 19Lb Ford iniectors....yellowish orange...I love Ford's color idea!

Cruzin Performance
http://www.cruzinperformance.com/injsteps.html
blueprinted and cleaned them prior to install. Here are the results of their flow test...Yes 8 are listed...we sent extras in case something was wrong with any of them...

Static flow comparison test:
Injector #1-100ml
Injector #2-94ml
Injector #3-98ml
Injector #4-98ml
Injector #5-96ml
Injector #6-96ml
Injector #7-98ml
Injector #8-98ml

Dynamic flow comparison test:
Injector #1-99ml
Injector #2-98ml
Injector #3-98ml
Injector #4-100ml
Injector #5-98ml
Injector #6-98ml
Injector #7-100ml
Injector #8-98ml

 

I am saying 36* @ WOT. Most engines, even IF they can hand more timing @ WOT, will produce max HP by 36* (or possibly earlier depending on other factors). I know guys that are producing max HP at 32* @WOT, even though their engine can handle far more than 32* @ WOT. It really depends on the motor.

During part throttle, you can easilly run more timing especially with an EGR. I ran 47* on my L98 when it was stock and in Highway Mode. In fact, I was running such a lean mixture that the engine needed the 47* to have decent throttle response.

I've had to tone it down a bit now that I am using a Miniram.

BTW, there's a discussion right now on the DIY Board regarding the knock sensor's tendency to go "deaf" by the time we hear it. It appears a few others are now discovering this.

 

Thanks for clearing that up. My head is going in circles trying to process all this! Tuning is all new to me...

 

Glenn, I have heard that the knock sensor provided with the LT4 corvette engine is the best on the market.

Supposibly it hears less false "knocking/vibration" for when you run headers, larger rockers, etc.

My truck has all these, and the sensor is closer the heads then the pervious engine. Plus it gets dragged/vibrated on the road and am wondering if it will be getting false readings.

Is this what you have heard, or can you ask on the board for me?

 

glen i dont know if i covered this before but the 1227302 ecm doenst have a knock sensor. dont ask my why but it doesnt. ??

as for the timing yes those 42 btdc load values are at cruising. ive found with here motor that at light load and fast PT postion change more then 42 btdc tend to cuase burts knock.

ive got it setup with about 36 btdc at wot. with a base time of 10 btdc. thats actually more then it had stock to be honest. even with the 5 btdc there were adding in it only came to about 34 btdc. ive also figured in the pe for that wot total timing.

im working on the actuall injector slew correction but i need to see a scan to figure out if it was fuel or spark cuasing the troubles. so until i get the scan im a bit stuck.

as forf redraif collecting chips please do i need those damn eprom holders. !

 

29.9 29.9 29.9 29.9 29.9 28.8 27.1 25.0 23.2 23.2 23.2 23.2
29.9 29.9 29.9 29.9 28.8 28.5 27.1 25.0 23.2 23.2 23.2 23.2
29.9 29.9 29.9 29.9 29.9 28.8 27.1 25.0 23.2 23.2 23.2 23.2
31.6 32.7 32.7 32.3 31.6 30.6 27.8 25.0 23.2 23.2 23.2 23.2
33.4 33.8 33.8 33.4 32.7 30.9 27.8 25.0 23.2 23.2 23.2 23.2
34.5 34.8 34.8 34.8 33.8 32.0 28.8 26.0 24.3 24.3 24.3 24.3
36.2 36.9 36.9 36.9 34.8 33.0 30.9 28.8 27.1 27.1 27.1 27.1
37.3 38.0 38.3 38.0 36.9 34.8 33.0 28.8 27.1 27.1 27.1 27.1
39.0 39.7 39.7 39.7 39.0 36.9 34.8 30.9 29.2 29.2 29.2 29.2
40.8 40.8 41.1 41.5 40.8 39.0 36.9 33.0 31.3 31.3 31.3 31.3
42.2 42.5 42.9 42.9 42.9 40.1 37.6 34.5 31.3 31.3 31.3 31.3
43.2 43.6 44.3 45.0 45.0 41.8 39.0 34.8 33.0 33.0 33.0 33.0
43.6 43.9 44.3 45.0 45.0 42.2 39.0 34.8 33.0 33.0 33.0 33.0
43.2 43.9 43.9 43.9 43.9 41.8 38.3 34.5 31.3 31.3 31.3 31.3
43.6 43.6 43.9 43.9 43.9 41.8 38.0 34.8 31.3 31.3 31.3 31.3
43.6 43.9 44.3 43.9 43.2 41.8 38.0 35.2 31.3 31.3 31.3 31.3
43.2 43.2 43.9 43.9 43.2 41.8 38.0 34.5 31.3 31.3 31.3 31.3

 

above is the new table. i still have to smooth some things out. below is the old table from stock.

 

25.0 25.0 25.0 25.0 25.0 25.0 22.9 20.0 19.0 17.9 16.9 16.2
25.0 25.0 25.0 25.0 23.9 22.9 22.1 20.0 19.0 17.9 16.9 16.2
25.0 25.0 25.0 25.0 25.0 23.9 22.1 20.0 19.0 17.9 16.9 16.2
23.9 26.0 28.1 28.1 28.1 26.0 22.9 20.0 19.0 17.9 16.9 16.2
26.0 28.1 28.1 28.1 28.1 26.0 22.9 20.0 19.0 17.9 16.9 16.2
28.1 29.9 29.9 29.9 29.9 27.1 23.9 21.1 19.0 16.9 16.9 16.2
29.9 32.0 32.0 32.0 29.9 28.1 26.0 23.9 19.0 16.9 16.9 16.2
29.9 32.0 32.0 32.0 32.0 29.9 28.1 23.9 20.0 17.9 16.9 16.2
29.9 34.1 34.1 34.1 34.1 32.0 29.9 26.0 22.1 17.9 16.2 15.1
29.9 34.1 35.9 35.9 35.9 34.1 32.0 28.1 23.9 20.0 16.9 17.6
29.9 34.1 38.0 38.0 38.0 35.2 32.0 28.1 23.9 20.0 19.0 19.0
32.0 35.9 38.0 40.1 40.1 39.0 34.1 29.9 23.9 21.1 19.0 19.0
32.0 35.9 38.0 40.1 40.1 39.0 34.1 29.9 23.9 21.1 17.9 17.2
32.0 35.9 38.0 39.0 39.0 36.9 32.0 28.1 22.9 21.1 17.9 16.9
32.0 35.9 38.0 39.0 39.0 36.9 33.0 28.1 22.9 21.1 20.0 20.0
32.0 35.9 38.0 39.0 38.0 36.9 33.0 28.1 22.9 21.1 21.1 20.4
32.0 35.9 38.0 39.0 36.9 36.9 33.0 28.1 22.1 21.1 21.1 21.1

 

The LT4s use a knock module that goes in the PCM; that is where the sensitivity is different than LT1. LT1 guys routinely use it when they go to roller rockers; the knock sensor, which screws into the block, is the same as LT1. You can desensitize a knock sensor by warpping it in teflon tape, so I have heard. The LT4 route won't work for you.

 

Fun, yes, I gathered from your earlier comment that MAF V6s don't have a knock sensor. Not owning/having a MAF V6 on hand to confirm, I believe you. Nothing involving the General surprises me. Interesting enough, a 1982 X-body HO 2.8 (carb version) that I use to own did have a knock sensor. It was first year with an ECM.

The discussion of "knock sensor" that I was refering to on the DIY Prom Board was more on the "deafening aspect" of the knock sensor. I just thought you'd find it an interesting post as well as the others that are posting regarding the "knock sensor". I think that is a better place to post and discuss it.

I am more interested in assisting to tune this engine and improve it's throttle response. I would prefer to keep this post related to "tuning" a MAF V6.

I am a bit confused on the two tables and just wanted to clarify a couple of things. 1) The first table is the "new" spark table and the second is the "old" spark table - yes? 2) Was 2 columns dropped off by accident on the first table? It looks narrower than the second table. 3) Are these spark values (old and new) "with or without" the base? And is the base 10* for the first table and 5* for the second? I ask these questions so I can clearly see where you are on the spark. With different ECM (and even different versions of the TDFs) - the way spark is measured is different.

Also, have you looked at the fuel? Made any corrections? If so, what table and how much?

 

those tables are total with base included. ie the table add 22 +10B = 32 total in the table. or subtract the base 32T - 10b = 22 added.

as fr the fueling its goofy. it uses a lv8 vs inj pw table similar to the $32b but it doenst have rpm just lv8. its a 2d table. there is no injector constant and as always the maf table only return the incoming A/D signal into a grm/sec conversion for the ecm to use for its calculations.

i did however fix a lineraity issue the gm pulled to limit the amount of fuel the ecm could use. in maf table 6 the scalar was set to 150 which limited the max the maf could input to 150grs/sec

i goto thinking about here combination a bit more and it would only make sens that the reason even with all the timing etc that the engine wont make any more power is due to the fact that the ecm cant fuel it over 150 grsm/sec.
so i rescalaed table 6 and used the old curve but reploted the last 10 entrys to properly represent maf flow. ive done this before and it works fine.

i did change the spark adders around i added more cold start timing and a bit more pe timing. i also lowered the PE a/f ratio to something more appropriate to this combo. being its so low compresion i figure a bit more fuel and alot more spark might be better then less spark and lean. even though low compresion engine tend to run better lean.

i also tapped into the AE table and added a good chunk more AE fuel. this way even with more spark itll stay away form lean,

for the lv8 vs pw table all you need to due is figure the % difference between a 13pph and a 19pph injector.


13/19 = 0.68$%$&$#&

so just multiply old inj pw by the .68 and you have your gross correction.

but the kicker was that she would have been way overfueled at anything over 150grsm/sec but then again she couldnt use the table entrys over 7.8 msec. ahh

so i did some things i hope they work. this is where i am based on what info i got. i changed the AE multiplier to a big cam friendly 1.50 from 1.0 which was nessicacry with my buddys S-10 mpfi MAf setup when we put in his edelbrokc cam.

i also richedn up the cold start open loop tables and a few other things. all in all i think ive gott a much better rough tune now then i did last time. i really primarily left the spark table alone.

i also added some highway spark mode based on what they were already running to help the gas milage out.

all in all i think this new chip will get it close enough to run pretty good.

 

Wow, I'm glad you guys understand all that!

Well I called yesterday to try to get to dynolab to do a scan. He can't scan, so Joe (LT1GUY) is going to try to call his buddy who tunes and makes chips for Grand Nationals and see what he can do...if he can't help then there is another tuner we know. He tunes LT1s. So hopefully I will have an idea where to take the car for a scan by the end of the day!

On the spare chip I had...it did not even have a silver sticker! Its from the philippines. The chip is plastic, unlike the others, they feel more like a stone type material. It has delco on it though. I think it is a HRL 5535. Definately different then my stock chip.

We will still get some chips this weekend and try to get that scan!

 

see how much the GN chip guy would charge to just brun a BIN onto a blank chip. i could email the binary file to you and he could just burn it saving an imense amount of time in shipping.

 

Hes out of the office today, but should be back tomorrow. Hopefully we can have the chip out to you by Monday!

 

I will check that out with him. Maybe if I let him use that spare chip of mine, he will go for it! I will grab more chips from the junkyard in the chance that idea will work! If its less then or around shiping it will be the way to go!

Also would it help you if we had him copy the bin off my stock chip to email to you. Then you would have a copy of that chip, since the spare turned out to be different!

Then I will also get him to do a scan of the car with the stock chip, so you can see what is going on with the settings we have and my mods!

 

sounds good.

i like this idea

itll do more then just cut down on shipping costs. itll speed the procces up if he can just brun them for you. also if your gonna be mailing stuff. send back the chip i sent !!. those 2732b's are hard to find and im running out of them.

see if the dude has email.

 

Well Joe contacted the GN guy, but we never got a call this weekend, so no scan yet. See Joe's dad is having some work and we think he thought Joe's dad called and not us. Anyway... Joe is going to try to get him on the phone today.

At the junkyard we got 11 proms...one has a different plastic carrier. We found them in Fieros, Cutless cruisers (big wagons), Transports, Regals. Only one came from a S10... Most of the usual others were snagged...Birds, Camaros, S10s, Blazers...
As soon we get to talk to the GN guy and figure out the costs, I will either send all the proms, or some...depending on what we are going to do. I will definately send yours back!

So I figure we will get in touch wth the GN guy and see if and what he would want to burn the chip if we bring it or email it to him, and that we would supply the chip... Normally its around $35. But if I bring the chip and program...we will see...I will definately check the scan costs and if he can do them...

But at $35.00, I'm not sure if his burning the proms will be worth it. It really would not be any faster. So at that cost, plus going all the way to his shop, over an hour from my house, unless in rush hour, then its 2.5 hours. Plus I work 9-5 (m-f), same as his hours, so with traffic, I could not make it there during the week. I would have to wait till the weekend, anyway. Thats about like shipping it.

Who knows though he may give us a good break, since Joe's Dad is having work done there right now. So until I, or Joe, talk to him, its still up in the air...

 

well the check you sent is still sitting on my desk, iu havent cashed it yet. get a scan and mail back the extra proms and the chip i sent. email me the scan results. i just wanted to know how close the fuel trim was. the timming i got it figured out.

anyways ill sit on that check till its right or spend it on shipping back and forth. with a good scan i think i can nail that pupy. dont you know anybody with a laptop PC ?? if not you should invest in one. and with Joes Lt1 he should have one to.

 

Well we are going to see about a lap top. Its just with so many projects going, time is always the factor. Glad you got the check. i was wondering if it got lost.

OK we talked to the GN guy. He is not sure if his stuff is compatible. We have to go see him and he will see what he can do. So later this week, maybe I can get a scan done. Man this is frustrating!

 

as long as his erpom programmer is capable of readings and programing 2732a 2732b 2732 eproms then hes fine. all he needs to do is open the xx.bin file read it into the programmer and program it like any GN chip. the GN uses a 2732a eprom so itll be fine. id be glad to send the .bin file to him or you for programming. as for scanning got a power inverter ? if you have one strong enough just stick a desktop pc montior and mouse in your car and run the winaldl program. the cable i super easy to build. youll need a 10ohm resistor between the jumper pins you normally use to flash codes. if you not sure how to hook up the cable drop me an email ill build a cable and ship it off to you. there stupid simple to build.

 

Redraif, why not just get the burner yourself? Think about how many tanks of gas, travel time, "co-ordinating time" so you are both available, etc you waste. Trust me, getting a good chip takes more than only "one or two burns". You can burn 100 eproms for your engine and STILL find ways to improve it.

Get a burner and you'll be in contro on your side. Then, consider getting Craig Moate's Flash Prom Adapter (and Flash prom) that allows you to run multiple 2732A bins and switch from any of them.

Then you'll get much quicker results. Heck, at that point, all you'll need is a Bin Editor yourself. Then you can use funstick for "tutoring".

 

That ia a good suggestion. Believe me I have thought about it. I guess it seems like such a big deal right now cause its something I have not even seen done once. Most of the guys who we know that tune these cars take them to Dyno labs. I don't know a soul here who does this stuff themself. I don't have a lap top. Heck the home computer just died. So I'm a bit technology impared right now. But I will get to see my uncle at Easter. He has been working on my computer and he may have access to an old lap top I could get for cheap. So I plan to research this route and may be headed in that direction as well. Until I get an idea from the GN guy on cost, I'm not going to jump ahead of myself though.

 

Read Tim Sifford's (aka Traxion) article on Prom Burning.

https://www.thirdgen.org/newdesign/tech/promintro.shtml

To start, especially with Fun's help, all you would need is a "burner" and Craig's adapter with an AT29C256 Flash Prom (or two) so you can burn "instantly" and don't need a UV Eraser like you do with the 2732A eprom. Also, a Flash Prom last virtually indefinitely while an eprom like the 2731A can only be reprogrammed about 25-50 times. Plus the cost for a Flash Prom is not much more and readily available.

A used Laptop is relatively cheap. It only needs to run W95 and no faster than 100 mhz. I picked up a Toshiba 75mhz W95 machine at a "Thrift Store" for $50 (Canadian) and it can handle all my eprom burning. But, you only need the laptop IF you plan to scan.

 

Awesome! Thanks for the info! That would save a ton of time. Joe and I will put our heads and $ together and see what we can come up with. It will probably pay for itself this go around!

 

im flexiable either way. check www.ustr.net for a prom programmer the epromer5 is nice. that adapter isnt a nessecity but by the time you buy a eraser the adapter paid for itself.

 

That's my reason for recomending it. That, and the fact that you reprogram a Flash Prom in seconds and last for thousands of burns versus only 25-50 max for the stock eprom. And, as you reburn the stock eprom, you need to keep increasing the erasing time until, one day, it doesn't reprogram no matter how long your erase it.

But for people using 2732As, it solves a problem of supply AND you can burn 8 test bins at once, if you are so inclined.

I won't use anything but a Flash Prom now.