Was wondering about how far the stock digital tach on an '89 lags behind. I am playing with the trans governor and want to get it to shift automatically at about 6000 or maybe 6200. It is now shifting at about 5800 on the stock tach for the 1-2 and the 3-4 shift. I'm thinking that is about where I want to be. Does anyone have a good tach installed and the stock tach and ever witnessed about how far behind the stock one lags? I don't want to install a tach in my car as I don't bracket race or anything and once I get the governor set up I'm done and won't need it.

Use Datamaster. The digital tach isnt behind by a given consistant amount.

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Ya know, that's not a bad idea. Why didn't I think of that option? I already have a laptop, I could just buy a cable and download the software, right? I don't plan on doing any tuning because honestly once I start it would consume me, I know for a fact I'd blow my engine up making 100s of passes trying to get it perfect. I would like to look at things tho. Never thought of making the pass then looking to see what the max rpm was.

I was just looking at all the stuff you can see. Cool. Never played with this yet. Was looking at WinALDL also.

Just ordered an aldl OBD1 cable to USB. Downloaded WinALDL. It took like 10 seconds to download, but I installed it and it seems like it is all there. Gonna be cool to datalog. I do it on my Hemi truck with a superchips flashpaq, but there is nothing to it with that. As a side note, I run my truck on 89 octane and even if I have the 87 octane tune loaded it still gets some knock retard, as much as 4 degrees. It is always at very low rpm when I'm on the gas some going up a hill. Once it shifts it is all good. Sorry about getting off topic. Can't wait to use the new cable and software!!!

Thanks for the idea Casey!

No worries mate, but if i were you, id also give Datamaster a go too, its a very good program

Another plus with this method is that you dont need to look at anything while driving, its all recorded and you can view it all later.

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Not to hijack your post but I'm really interested in knowing the details on how you got it to shift close to 6000 automatically. I have been procrastinating about doing this Mod.

John

First I bought a "double diamond" weight governor from ebay for like $22, it is exactly the same as my stock governor. That way I kept my stock governor intact so if I screwed up I could put the stock governor back in. I then bought a B+M governor recalibration kit from summit racing. The governor is on the drivers side of the trans, near the back. There is a cup that looks like the bottom of a pop can kind of, it pops out with a screwdriver or crow bar. The governor then pulls out. You have to cut the "nails" off and remove the pins, then the weights come off. You then remove the inner weights and springs. The directions with the B+M kit are very detailed and very easy to follow. I tried going with lighter springs and lighter weights because I wanted to raise the part throttle shift points (springs) and the WOT shift points (weights). After about 4 tries, I discovered that the 1-2 shift will not happen at WOT with lighter than stock springs. Also, I ended up not even using the B+M weights, I ended up using a dremel and cutting a little off the inner weights that were on the stock governor. After I went back to the stock springs and weights with a little shaved off, it was shifting at about 5500 on the digital tach. I pulled it out and shaved a little more off, then put it back and ran it again. It now shifts at WOT at about 5800 on the digital tach. Once I get the Datamaster or WinALDL set up and working, I'll see exactly what RPM it is shifting at and will adjust accordingly. I am wanting a WOT shift at about 6200 but I'm not sure how far the digital tach lags behind. I've been told about 200, then I've been told that in 1st gear accelerating hard it is as much as 500 behind. I am close enough for now till I get a better tach reading than the stock tach gives.

The hardest part of the governor swap is getting the governor cap back on. There is no good way to get at it to hammer it on with the trans in the car. Don't hammer it in the center or you could bend it. I ended up using a 2lb hammer and a combination of crow bars with about a 90 degree bend on the end, like used for pulling nails. The bottom is easy to tap on, but I used the crow bar nail puller to get to the top, then it levered against the exhaust pipe using the exhaust pipe as a fulcrum. After a couple of removals it got easier. I can now pull the governor, take the weights out, grind on them, put them back, and reinstall the governor in about 25 mins. (Giving that the X brace is already off as I have a vert.) PeteK gave me some good info in getting started with this. The only surprise to me is that the springs are to adjust the part throttle shifts, but going with even 1 step lighter than stock springs won't allow a full throttle 1-2 shift at all. My suggestion to you is to adjust the weights to where you want them for WOT automatic shifts, then try messing with the springs for part throttle shifts, but I doubt you will be able to change the springs with success. The outer weights stay the same, the inner weights are what you change out or shave weight off of. Make sure you keep the weights about the same weight on each side, which is why I ended up grinding material off of the stock weights.

The B+M kit gives you new "pins" and c-clips that replace the stock "nails" and good directions, but the new weights they give you are numbered 1-6 and no 2 are alike. With the 700R4 you need 2 weights that are the same. I tried using a #4 weight and grinding it to be the same as the #5 weight (higher numbers are lighter). When I ran the car it bounced off the 6500 rpm rev limiter then immediately shifted so I think that combo will give about a 6600 WOT shift, which is too high for my stock bottom end to survive. If you are looking for shift points at or above 6500 you should give that a try. The #4 and #5 that you get are the same thickness, you just use a dremel to change the shape of the #4 to match the #5, it is VERY easy. If you are looking for shift points less than 6500 then use the stock inner weights and cut them to look like a triangle. Stock they look like a square with a slight triangular point. You will know what I mean when you see the kit or the stock weights. The whole process is much simpler than it sounds, like I said the hardest part is getting the governor cap back on with the trans in the car. The most time loss for me was making so many attempts and not having a 1-2 WOT shift only to find out I could put even the stock weights back in but still not have that shift because of the lighter springs. Nobody told me that could happen as everyone said the springs control part throttle shift points. You will need 1/2 to 1 quart of trans fluid every time you pull the governor out, make sure you put a drain pan under it when you remove the cap. A new seal also comes with the B+M kit and the new seal doesn't get damaged by removing and reinstalling.

Sorry about such a long post but I hope this helps. It is SO NICE being able to romp it and have it shift back to the proper gear and hold it up close to the new redline.

As a side note, I have a 2800 stall TCS converter, a trans cooler, a B+M shift improver kit and 3.07 gears. The weights I used and modified may not give you the same exact results because different mods act differently with the same governor setup, but it should get you close. Depending on how picky you are you might get it on the first try as long as you use the stock springs.

Thank you so much for the detailed explanation. I have been considering this mod for a couple of years. I rebuilt the trans a few years ago and under the advice of the rebuilder I attempted changing the springs in the governor. I also experienced the never upshifting from 1-2 under wot when I went with lighter springs. I never bought the B&M kit but I did purchase a new governor from GM so I have one I can practice on also.

Our cars are very similiar and we run similiar components. I have a trans cooler, a TCI 3000 converter, a B&M shift improver kit and 3.07 gears.
I also have a 383 now with Trickflow heads, a Holley Stealth Ram intake manifold and a NX EFI race nitrous kit..

Thanks again Dan!

John

Wow, our builds are similar, will be even closer if and when I can afford that 383 that you already have. I am running 113 aluminum heads that have been ported and coated and have bigger valves, and a CC503 cam. What cam are you running? I see you are running trickflow heads, I hear they are great. I hope to go with a forged 383 and a bigger shot of nitrous soeday but I want to keep stock casting heads just for bragging rights when I beat them at the flashlight drags!! Will be fun to laugh and say I'm running stock casting heads and stock bottom end.

If it weren't for needing the pins and c-clips you could avoid buying the B+M kit. Maybe you could take your extra governor to a hardware store and see if you can buy 2 little pins and 4 little tiny c-clips. Then all you would need to do is dremel some weight off of the stock inner weights and put it in. It is surprising all the more you need to shave off the weights to make a change. It sucks that I can't find a way to raise the part throttle shift points. At this point I'm assuming an aftermarket valve body that still retains automatic shifts is the only way to do that. I'm not spending any on that right now, I need to rebuild the savings for the inevidable part failures. The way this car pulls now and still running the stock trans and D-36 I'm sure breakage is in my near future.

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I am running the CC XR276HR. It's either the same as the CC503 or really close to it. It's too small for the 383. I actually ran the 113's with the bigger valves also. I still have the original long block in a crate in my garage, I bought the 383 short block from Golen Engine Service in NH. He does great work. I also have the original D36 with the 3.07's.
When I replace it I will change to a solid axle. Forget the IRS crap!

I may just go for the B&M kit. We shall see. So it sounds like you had to take alot off the inner weights to get it to shift at 5800RPM. Am I correct? I'll have to see what I can do. Did you find that the 2-3 shift is also around the same RPM or is it a little less?


John

I actually didn't have to take that much at all off the inner weights. The flat part of the weight that has the "spring seat" or little circular bump on it is kind of square shaped from the factory. I just cut both sides so it is now triangular shaped and comes to a point at the end, and I cut that little square bump out that was on the very end off. That is it, and I am shifting at 5800 on the digital tach for both 1-2 and 2-3. Sometimes it shows a little less than 5800 on the 1-2 shift but I think it is because the tach isn't keeping up. It is always 5800 on the digital tach on the 2-3, which is close to 6000 I think. I'll know when I get my aldl cable and datalog it. If it is shifting at 6K I might leave it alone. I was ultimately looking for a 6200 rpm shift for the 1-2 and 2-3 but running the stock bottom end I am afraid to push it up anymore till I see exactly where it is shifting now.

The CC503 seems to be the perfect cam for a street high performance 350, but when I go to a 383 I am planning on going with a CC306. I want to have excellent street manners (nearly stock manners with the exception of a little higher idle). I'll bet your build is very tame with tons of torque and still pulls good up top. On the small side is best with the cam, especially since you can spray it more if you want more power.

Excellent! That is what I'm looking for. I could probably pick up .1 or so in the 1/4 letting it shift itself!

Thanks again Dan!

John

Behind or not, it's impossible to use it. Mine would skip up so much in 1st gear... 3000, 3300, 3800, 4100, etc.. that I never knew when I was hitting the shift point.

So regardless of it lagging, it just didn't refresh often enough, plus the bar graph is useless and hard to anticipate. I put in a shift light in the dash vent.

Yes, by lagging I basically meant not refreshing fast enough. With the TPI it seemed to keep up pretty good, usually was at 5000 or 5100 when it shifted 1-2 and always 5000 on the nose for the 2-3 shift (automatic). With the TPI and spraying a 150 shot it still was 5000 for the 2-3 but it pulled hard enough that it would sometimes show like 4700 then shift 1-2 but I know in reality it was about the same rpm as not spraying. Now with the new combo (and the governor is changed) I have seen it show 5100, then shift 1-2, then show 5900 then quickly drop. It actually gave a reading AFTER the shift. It is so slow refreshing that the shift happened before the display. The 2-3 shift always shows 5800 or 5900 now. That is why I am going to datalog to see where it is shifting but I have no need for a tach or shift light in the car because I want to set it up to shift automatically and let it do so even at the track. If I had a stick I would probably steal your idea and do that shift light. I'm trying to keep my interior stock looking (sans the subwoofer and 15lb nitrous bottle in the back). I really don't want a tach or any aftermarket gauges in there. My car is a car that the wifey and I use to go out in once or twice a week, drag racing for me is just a side effect of having the perfect cruiser with the ability to run hard.

I will say that I experienced similiar results but mine would climb during shifts similiar to a neutral state. i.e. 5800, 5900, 6000, 6200,6100, 6150, 6100,6200, 5900,5000, 4800. Kinda weird.
I know for a fact that my car is quicker if it shifts itself. Like .2-.3 seconds faster in the 1/4! Once I modified my car without modifying the governor I had to manually shift to get the RPM that high. I am looking forward to modifying the weights!!!

Cheers!
John

Good luck. I am happy I did mine and may adjust again once I find out exactly what RPM it is hitting at the shift points. Any questions you have or help I can give let me know. Keep me posted. I am surprised at the number of people who upgrade but then have to shift their automatic manually to get the revs out of their new setup. I'm glad to hear you are with me on making it shift automatically. I don't feel so alone now!!

I tried datalogging with WinALDL. Seems to work ok but it idles up a couple hundred when hooked up and the car cuts out or misses a little while hooked up and data is streaming. Don't know why. Also the tach is behind in the software too. Probably because so much information comes thorugh the same wire on the ALDL connector in the car. Sometimes it would show the 1-2 shift at like 5200, other times up to 5600. I think it is higher than that. It shows the 2-3 shift at 5650 while the tach in my dash shows it at 5800. The dash tach and the software tach are always right together during normal driving or mild acceleration so I now trust the tach in the dash for the 2-3 shift. I think it refreshes fast enough for the acceleration rate in 2nd gear, or at least close enough. I cut more weight off the inner governor springs so now it is showing 6000 for the 2-3 shift so I figure that is somewhere between 6000 and 6100. The 1-2 shift usually shows 5600 on the tach but I think it is higher than that, just that neither the software tach or the dash tach can refresh fast enough.

I was wondering when you'd get to this point. I should have said from the start, but WinALDL was designed for early C4s that communicate at 160 baud only, so I sort of figured the software would be worse than the dash itself. Later C4s (87-up) can run in 160 baud or 8192 baud. The faster speed is what you need for tuning, but I'm not sure even this will actually keep up spot on with actual engine speed at high revs, but will be better than the dash. You need something like TunerPro to be able to run your ECM in 8192 baud mode.

Thanks for the info!! I am going to take Case's advice and try Datamaster next but I did just discover something. The "Max Values" choice in the Winaldl software is where I was looking at the tach reading. I just went to the saved data notepad document and loaded it to an excel spreadsheet. On the saved data for the run it shows the RPM to be 6000 at the speed where the 1-2 shift happened, then at 5925 for the 2-3 shift. If that is right then I was correct originally in assuming that the 1-2 shift is a little higher than the 2-3 shift, and that the 5800 reading on the dash for the 2-3 shift was a little behind. Now that I changed the governor again my dash is reading 6000 for the 2-3 so I'm pretty sure (or sure enough) at this point that my 1-2 is happening at about 6200 or 6250 and my 2-3 is happening at 6100 or 6150. Right where I want to be.

UPDATE: I took your advice, Case, and tried Datamaster. It works better. It is showing the 1-2 shift at 6150 and the 2-3 shift at 6000. That part is right where I want it. I am picking up detonation, bad enough to hear it, from 5500 to 6000 rpms. I talked to Alvin and he basically said when I get a couple good full throttle runs and a nice long normal drive datalogged and saved to send them to him. He is going to go over the tune. He had me set the base timing at 6 degrees originally and he had the tune done for a 100 shot. I had the base timing set at 4 degrees and still got audible detonation at 5500, and it gets some spark retard and knock counts if I am driving and floor it and let it downshift itself. I'm not sure there is a way to get rid of that. Doesn't happen if I launch and make a full throttle run from a stop. I told Alvin when get the datalogs and send them to him I want him to tune for no nitrous. I'm going to add a timing retard box to use when I spray.

I was looking into doing my own tuning but I don't want to invest in a chip burner and chip eraser. I think Alvin will get it spot on with a couple of tries. Datamaster should give him the feedback he needs.

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Excellent! I like what I'm hearing!!!