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1987-1991 Parley with regards to your 1987 to 1991 Bonneville, Olds 88 or Buick Le Sabre Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

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Old 03-23-2005, 12:07 AM   #121
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Ohh and as for the timing, if it'* more than 30 degrees i'd be wary of goin over 9.5:1 too but that'* only comparing the engine to the L36.
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Old 03-23-2005, 07:37 AM   #122
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My ECU doesn't adjust timing.. if it does I have never heard of it doing so. To be honest, I don't see what my ECU does other than fire off the injectors and tell me something is wrong. But yeah.. I am still looking for some vet builders, but around here there aren't many.


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Old 03-23-2005, 09:36 AM   #123
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Oh yeah, and dude.. you have a helluva lot more knowledge than I do on this. If it weren't for you saying anything, I never would have thought of it. Nobody has mentioned this to me before.. so yeah. Better now than later.

I think I may be a little confused here. KR = Timing retard, right? My ECU doesn't do that. If it does, I don't know how, because I have yet to find a knock sensor. Trust me, if there was one, I would have found it by now. Well, I will be running 93 octane fuel, so I don't know where I am going to see detonation or anything like that. I'm not quite sure where I am going to see KR. And to be honest, my car may have been able to get out her own way, there is NO way that she will be slower than when I started. The tune up alone would make a world of difference. I want to push the envelope on what I can do. However, I still want her to make power. I know compression alone doesn't make power. If you had 12:1 CR but not the right fuel to accomodate it, it will be worthless. I really want her to perform, but who doesn't?

And in your opinion, I don't mean info backed up, or whatever, I mean blunt yes or no. Just would you do this, or would you not. Do you think the risk is worth it, the money, etc..

-justin
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Old 03-23-2005, 10:13 AM   #124
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The ECM in the 88-91 Bonnies does adjust timming much in the way that the L27 and L36 do.... But the programming for each is a bit diffrent... And you do have a knock sensor... it should be on the rear side of the block ... Look up between the trans and the block and you should see a knock sensor sticking out... I have seen my timming from 13-19 at idle on up to 30+ depending on driving situations... Even though these are the old school ECM'* now, they stilll did a good bit in the way of engine control... And if the ECM didn't know where the crank was or what cylinder is in what position via the cran sensor the car wouldn't start... If the cam sensor didn't work the ECM would not be able to fire the injectors in a true SFI pattern... And yes the Vin C 3800 is an SFI engine... So yes the ECM does a lot...

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Old 03-23-2005, 01:01 PM   #125
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Where I have a Long Term Fuel Trim, you have a BLM, Block Learn Modifier i think.

Where I have Short Term Fuel Trim, you have an INT, Integrator.

I posted links to those sorts of pages somewhere.... Google burning your own chip and you can find all kinds of pages about what it all does.
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Old 03-23-2005, 03:47 PM   #126
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Straitor dude.. long time no talk. You get those rockers ready yet?

I always thought the knock sensor was on the exhaust . But yeah.. I guess the ECU does do work. Anyways.. as you can obviously see my knowledge is surpassed greatly by other people here.

I guess then, that the engine can adjust timing in the case of KR.. I guess I see 95nasta'* point. But then couldn't that just be corrected with higher octane fuel?


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Old 03-23-2005, 04:34 PM   #127
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I am going to guess and say that with the 10:1 compression you will need somewhere between 89-91 octane... I'm not totally sure of what the ECM can adjust for with higher compression... Maybe later on down the road you may be able to get a Mem-Cal chip burned for your car... I just would like to see how well the engine responds...

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Old 03-23-2005, 04:57 PM   #128
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I thought for sure I was going to need 93 no questions.

After I get all the engine mods done, and probably the suspension mods done, I'll hook up with GM Tuners and get a custom chip. But, it won't be for a little while. I may need it sooner, but I want it to be last. You know how it is, just in case I run extra **** then the chip I have is worthless and needs to be re-programmed.


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Old 03-23-2005, 05:17 PM   #129
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If you use higher octane gas to compensate for increased cyl pressure, you will need to change the spark advance maps to compensate for the slower flame propagation rate.

Normally the ECM just retards from the maps and you will need more advance.

Not a big change though I'd probably back off on the DFCO at bit and drop the fan turn on speeds to align with a 180F thermostat. Only other issue would be if you start exceeding the MAF limit (170 gm/sec) but that usually takes boost.
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Old 03-23-2005, 08:28 PM   #130
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*Sorry, this is gonna be a long read*
Yeah, i didn't see a distributer on there so i know the computer had to be doin something.
Dude, honestly i would just go closer to 9.5:1 compression, after that you can advance your timing at WOT if your not seeing any knock to begin with. The knock sensor has to sense the knock first before it can stop it so you still can be damaging your engine before the computer has a chance to react. I am keeping in mind that you would use at least 91 otcane.
If you want my opinion i'll tell ya but you should really talk to an engine builder.
Make sure you don't fall short of doing everything right which would include the valvetrain geometry being really close or the same as before, check the sparkplug spacing, and the playdough test is really making me worried the more and more i see the word playdough, it should work in theory but you should really try and borrow someone'* venier calipers or maybe an outside micrometer. I'd do measurements at least like 10 more times with the calipers or mic, write everything down and take the average. you really can't be too carefull, something i'm sure you know but i'm just stressing it.

When i went to go and see how much a local performance shop would charge me to mill my heads, he broke out the calipers and a straight edge right away and measured the spare heads i had, he told me that i'd only be able to take off .030 or .040 at the most. That info only took him 10 minutes to tell me. and could have saved my engine if i had decided to just send them to a shop to have x amount milled off. He was also telling me that he would be able to calculate if there would be any interference between the valve and the piston(due to the milling), no problem at all. and that was all free, engine saving info.
You should have your valve springs checked to see if they have the proper force still, that should be able to be done for free too. and if there not the right force, you can just get shims for the springs, i know those are like only 20 bucks. These are real important cause if your springs aren't pulling your valve back as soon as they should (especially in higher rpms) there is more of a chance of the piston smacking the valve plus add teh fact that you'll have milled heads.
I'm assuming your installing new valve seals, and replacing every single gasket you took off, with the exception of the metal exhaust gaskets, if you have them. And put dabs of RTV in the corners where your lower intake manifold gaskets meet.
Umm back to the compression, i'll stick by the 9.5:1 just because it seems safer to me. I mean say you go to far on terms of compression and higher octane gas isn't going to cure your knock, you'll have to pull timing, and i think for every degree of WOT timing it'* roughly 3-5hp so if your knocking and it pulls or you have to program it to pull 5 degrees(a pretty conservative #) that'* 15-20 hp loss. That would suck real bad. Take into account that 1 point in compression will net you around 5-10 hp. Now say you go with 9.5:1 and your not experiencing any knock, you'll be able to increase your timing a few degrees to gain more hp.
As far as gm tuners goes, i can vouge for the customer service and quaility of thier work. Your going to need to hook up a scan tool to your car(maybe someone in your area can let you borrow one?). Once you get everthing together, you'll be able to see if your BLM/INT values (how much your fuel has to adjust) Damemorder was talking about are close to 0% or 128, see if your throwing any codes, and if your experiencing any knock during idle/cruise/WOT. gmtuners will work with you till you are satisfied with the custom burn, that means if you have to change something, it can still get changed, free. I've gotten like 3 chips already, each one getting closer to what i want and a couple others trying to do new things like adjustable timing/removing the maximum 6500 rpm rev limiter/ and adding performance shift. These few others trying new things i haven't gotten a chance to fully test due to the winter weather. Also i took a break from data collecting and getting new chips because of the winter months(no sence being out of tune when the summer comes around). I'm still going to get more chips and finish later this spring or possibly in the summer when i do more work to my engine/tranny. Did i mention i only paid about 55 bucks so far including shipping? That'* hot. If all that data stuff seems intimidating, believe me, it'* not. I'm sure either i, someone else on here or ryan from gmtuners will be able to walk you though what you need to record.
I'm kinda getting ahead of myself but, yeah that'* what i think. I might know more than you but i'm no where near a pro at all this. Get more opinions!!!!!!!!!!!!!!!!!!!!!!!
Shoot me a pm if your not sure about anything i'm talking about.
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