What a difference
set it at 12 degree's on her 88 formula 350
it easily spins the tires now, way to easy

felt a little smoother too

also put the straight pipe in, and took off the gutted cat
nice idle sound.

it's so much easier to work around everything in the engine compartment with the air tubes off

the SLP CAI went in nice a smoothly, fits perfect

 

You went from 6 to 12 with no pinging?

 

i initially went 6, then 10, now it's 12
no pinging
i run 93 octane

fuel pressure is at 50psi
MSD6 ignition

only problem is the tires spin so much easier now, so i may come back down on it, as she will burn them up, i just know it

 

I thouth the time was controled via the computer

what am I missing?

 

it is
but if you disconnect the brown/black wire by the heater, set the timing, then reconnect

thats what i did

of course turning car off between connects/disconnects

i should get it out on the road more to see how the mid and upper is

i didn't hear any pinging and i was listening good for it.
i'll have to try the powerbrake test as well, to see if it detonates

she's not really gonna whale the throttle open, so if it's not pinging by these tests it should be ok

i do run 93-94 octane in it too

 

I still don'y get it?

The computer still makes timing adjustment. (when the wire is reconnected)

Can you explain how this works?

 

ok say ur base timing is 6* with wire off, if u set it at 10* with the wire off and resonnect it the ecm still thinks that its set at the 6* so it goes by that # all the time

 

Put a scanner on it and see how much knock retard it's getting. The computer only knows what it's told. If it's meant to be at 6, and you put it at 12, then all the timing will be an extra 6 degrees advanced (since you didn't reprogram the chip to tell it that the base timing is at 12). The computer will not know it's advanced that much. The computer only changes timing from where it "thinks" it is.
The knock sensor and ECU algorithm will remove timing when knock is detected, and put timing back in only up to the PROM's table values. It won't "advance til it pings, then back off." It just goes to it's programmed advance, and if it hears knock, it backs it off until it goes away, then brings it back.

Most of the L98s will have knock retard even with factory settings and 91 octane. Advancing it more will just keep the knock algorithm more busy. If the knock sensor fails, your girl's engine will be destroyed by the girl driving it. She won't know what the problem is, she'll just drive it home, and maybe remember to tell you it made a noise, but likely won't.

 

Roads - there's "Base" or "Initial" timing advance, and then there is computer controlled timing advance (vac. referenced advance in carb'ed cars) - BOTH make up your TOTAL TIMING.

Let's say you computer put's in a total of 14 degree's of advance (I'm just making up a number as an example) by 3,000 rpm. You have your distributor physically turned 8 degree's (counterclockwise) in "Base or Initial" advance of top dead center. That would give you a total of 22 degree's advancement by 3,000 rpm. However, you still have 8 degree's right at idle.

Look straight down at your ditributor, it should be spun slightly so the first plug wire is aimed closer to your strut tower, then let's say cyl. #1. The amount that is turned, is the amount of INITIAL timing. The computer control's the timing from there on.

In coilpack ignitions (no distributor - like grand nationals, and 89 TTA's), the computer controls all of the timing, base and advance.

 

Awwwwwwwww-soooooooo. I get it.

It did not occur to me that the ecm ran the timing from tables based on RPM. I figured it was all based on sensor input.
However, this makes more sense. Thanks

 

Yes you have to be carefull, I recently experimented with this on my 88 350 Iroc. Mine is stock and I took it for some baseline runs at the track and decided to play with timing. I brought a scan tool along so i could monitor the knock signal and play it safe. I had been driving the car with 8 degrees initial timing, only 2 degrees above stock, the car ran great but at the track I decided to bump that up to 10 degrees for the first pass. Keep in mind I always run 93 octane in my car and nothing less.
First pass the car pinged like crazy and ran 15.03 at 92 mph. I knew right away it did not like the timing. Back at the pits I knocked it down to 8 degrees and made another pass with no cool down time. It was still pinging but only on the initial upshifts and then it cleaned up and picked up to a 14.80 at 93 mph. I was keeping the engine warm with no cool down time on purpose to simulate real world driving conditions on the street. As you may know a very cool engine may not detonate until it gets nice and hot. By the end of the day my best pass was 14.60 at 94 mph with no pinging and I found I could not run the base timing higher than 8 degrees. Also as mentioned above, this changes the timing across the entire curve, not just down low because the computer does not see what you are doing. I still run the stock chip in mine, in the future I plan to start playing with chip tuning in which case you can change timing where you want it in certain areas and not have it in the other areas, a little more accurate, at this point I may set the base timing back to 6 degrees and start over from there. I would recomend taking the car to the track and do some real world testing and find a sweet spot for it. You have one more advantage than I did, you appear to have adjustable fuel pressure which I did not at the time. Wish I did, that would have been the next variable I would have played with to find a good setting. At the track is the only real way to know if you are heading in the right direction. When I had my base timing at 10 degrees on the street it also felt like you really gave the car a kick in the butt, would light the tires pretty good, butt,,,,,,the car was not being loaded that hard with the tires spinning, what made my car ping was a full run down the quarter mile and the trans shifting into second and then into 3rd and really loading the motor in high gear, that is where you may experience some detonation. Goodluck, hope this helps, Larry.

 

Some engines are able to handle more timing because they are worn out (low cyl pressure). I adjust my timing with the knock sensor disconnected. I advance the timing till the engine pings then back it off and reconnect the knock sensor. When I get home I disconnect the four wire connector behind the dist. and check the timing. It was right on 10*. I use 92 oct. and the engine has 10.3 to 1 comp. and 12% leakdown.

Auggie

 

i also run a 180 stat, and have the higher fuel pressure too
not sure if either of those are stopping it

i'll see how it rides when i get it on the road
since she uses it really around town, the advance will help her in the aspect (slightly better mileage, better lower end response)

as soon as the weather clears up, i'll try some seat of the pants feel from 6-12.
timing is trail and error, and even equipment used can make a difference in reading

i'm also sea level too

 

Yes the cooler thermostat should help, I run a 170 degree in mine and also have the fans coming on a little sooner also. Problem for me was, since I didn't give the car any cool down time plus starting and stopping in the staging lanes etc....my temp was always between 190 and 200 by the time I made my runs according to the scan tool I had hooked up. As long as I am cruising down the road and getting good air flow the temps would come down nicely and the fans wouldn't even run. So actually at the track the car was running slightly warmer than it does on the street, give or take a little. I am sure if I took the time to cool the car, spray the radiator, ice the intake down etc....I could have knocked another tenth or two off of my times but that wouldn't be real world testing in my book for a street car.
Also cam profile, gear ratio, stall converter, combustion chamber design, and even how heavy the car is will all play a role in how octane sensitive the engine will be. Part of the problem with mine also is the tall 2.77 rear gear in mine coupled with a tight stock torque converter, it really lugs the motor in 2nd and 3rd gear and makes it work harder. With shorter gears and maybe a looser converter I believe I could have gotten away with more timing also. You have an advantage over me though, Fuel Pressure. If I had an adjustable fuel pressure regulator I may have been able to cushion some of the detonation I was having and therefore squeeze another degree or 2 of timing out of it. As I am sure you know a lean engine will also detonate. That will be a big help for you. Everything I have read here suggests that the 350 tuned port cars perform better with higher fuel pressure of around 48-50 lbs. even the stock cars do. Mine is still stock at 44 lbs. So with that said, I can only test and see for myself if my car responds to that or not. I plan on doing that in the future along with other mods one by one and have real world results from the track. Anyway, goodluck, experiment and let us know. Larry.

 

An adjustable fuel pressure regulator is only good if you have a scan tool to see what difference the changes are making to your fuel curves.

With 3.42 rear gears and an RV type 2500 rpm stall converter I was still getting pinging at 10* with a ZZ4 cam and 9:0-1 compression. I was still getting it with my 9.5" 2800 rpm converter. You have to make changes in your timing tables to eliminate the pinging. By backing off the timing in some areas I have increased my power by not prompting the retard to kick in.

I have a PROMinator which really helps in tuning my car quickly. I have eliminated my pinging, quickened my throttle response and increased my gas mileage. The car also seems to have much more top end pull as well. This on 91 octane Vs. the 93 octane that was available when I first put the engine together. I'm just getting started with the tuning as I have much to learn. Do a search on the DIY board and you will find lots of information on how to tune whatever computer you are running, and lots of opinions on which computer you should be running.

I am upgrading the original bin file with the changes made to the fuel curves and the increased injector sizes so I can try the extra timing with a couple of gallons of 100 octane unleaded added to the tank..... Hope to have the car back on the road later this week after the installation of a new fuel pump/relay.

 

yeah, my car also liked alot of timing.... I have it at 13* BTDC

 

Yep I have a scan tool that monitors everything but I also use the track and watch the MPH which is a great way to make changes. I have seen alot of TPI cars with adjustable regulators that make a difference in performance. I realize it fattens up the entire fuel curve, I will just have to try it and see how it works for me until I am burning my own chips.
When I said cars with gears I meant gears in the 3.73 to 4.10 and more. I know these TPI cars don't generally like that much gear. I am very old school so when I see 3.23, 3.42, that is not alot to me, I am used to running cars with 4.56's. Unfortunately they would not do me much good in this Iroc Oh well.
I realize that the proper way to tune is in the chip, I could fine tune the timing curve in certain areas accross the board. I was talking about just playing with base timing on a stock L-98 car trying to find a happy spot. Eventually I will have the equipment required to burn my own chips and really dive into tuning this car and hopefully see some real changes. I am just playing with simple things on the car at the moment to get a good baseline on a stock L-98 and sharing what I have found on my car in hopes of someone else being able to use the info to help them in someway. I plan on posting in the future with other changes such as headers and Y-pipe kit, then maybe a cat back, adjustable fuel regulator, 1.6 rockers etc.....and go back to the track each time and post some real world results whether good or bad. I have been combing this board for quite some time and cannot really find any info like that, most people use there butt dyno etc...and mention, "oh ya it has more power" but I would like to see some real track times. Hopefully I can squeak the car into the 13's without getting inside the motor. Should be interesting. Of course we have discussed this on other posts so I won't go into that. Larry.

 

well ill have to say it all depends on the condition of the engine the fuel and what not i have a stock tpi and im runnin close to 15* advance on 89 octain with apsoutly no pinging and little knock retard to none on 50 psi of fuel the leaner u go the easier to detionate also so i like to stay a lil rich but it all depends on the condition of the engine and the type of fuel eg joe blows gas station will detonate easier then exxon or mobles 89 or 93 octain

 

Yep I agree, I think your fuel pressure is helping you quite a bit. That is one tuning variable I do not have at the moment so I could not throw more fuel at it. Wish I did, I may have been able to get away with a little more timing. Larry.

 

i'm interested in this scan tool thing
have to see if we have one at the shop
would like to see how it's acting in normal type of driving
since she isn't (yeah right) dropping the hammer down on it all the time
i think it's gonna be fine
again it's mainly to help the lower range and mpg's

 

yeah to the original question as long as you run super 93 it is hard to ping. I have mine set @ 15* which would be 45* total, or at least what the timing light says.

 

Back when I played around with TPI cars a lot (late 80s) one of the first things I did to ANY TPI car was bump up the timing to 10* initial. Most ended up at 12* eventually and a few ended up at 14*. 10* was a pretty safe bet as a starting point, though.

Remember I'm talking about a stock engine run by a stock chip and, of course, these engines were practically new back almost 20 years ago.

 

How much hp, if no pinging obviously, does going from 6* to 10 or 12*?

 

Not alot. ET wise I can tell you I found about 1 tenth after playing with mine and finding a happy spot where it didn't ping, for me that was 8 degrees. Keep in mind, I am still running a bone stock 350 tuned port with 50,000 miles on it. I could not play with fuel pressure etc...because it is still running the stock regulator obviously. I am also just playing with the base timing on a stock computer chip. My testing was mute since other things are going to be changed on the car anyway, I just wanted a good baseline before anything was changed.
On some cars it may be worth more, depends on the car as most are not stock anymore. Actually as mentioned in an earlier post, the best way to play with timing and fuel is in the chip programming, you will see more gains in there. I was just experimenting with mine for the heck of it. Larry.

 

there is some good info here
again each setup will probably be different.
and some equipment might give different readings too (almost like different compression gauges)

my goal here isn't to get max et or speed, just overall everyday street driving improvement.

when i first started the car back in April, it was at -2
why? i have no idea. was hard to start, idled a little rough, and floated from time to time at idle.
went to 8 and immediately improved.
so i just went to 12 and felt a slighter improvement too.

hopefully i'll be done with the car next weekend so we can get road time on it.

motor is stock, tranny stock, stock 3:42 rear
just slp cai, fuel pressure was at 50, removed air pump, installed pulley, and has a test pipe, mds6a, good wires, cap, rotor, and usuall tune up stuff car has about 80k on it, in real solid condition too.

man... i'm gonna be buying her alot of tires, i know it. hope she can use it in the snow as it's her daily car.

 

Hey You all what scan software are you'll useing. I'm starting to tuning on my car. I got the moates USB OBD1 cable just need the right software for it. Seems like it's a challange becasue i'm using USB and not serial port. Anyhelp would work. PS I know this is not the right place to post but theres a lot of talk about scanning.
Thanks in advance

 

I used a snapon scan tool that works for all cars 82 through 2004 or somwthing like that. It is pricey at $1,000 but works awsome. Unfortunately all you can do is monitor everything and check for codes etc...if you want to do some real tuning like changing parameters on timing and fuel, burning chips etc...then you will need the moates software that you mentioned. I have been to his website and talked to him for a while, nice guy. He told me he would set me up to burn chips with everything I needed and it was only in the $300 range, I already have a laptop, that would be an added expense for someone without a laptop of course. Check out his website and shoot him an e-mail, he will set you up and walk you through it. Hope this helps, Larry.