FEW 200R4 ?

[kraused]

I have a 87 Gn with 200r4 obviously,it was rebuilt 2 years ago.Worked fine with stock motor, till I moded the car this year more.I added heads,cam,intake tb,alky etc.Now i took it to the track ran it and with combo I don't know where it should run but 12.02 at 107 seems slow to me.Am off in thinking with what I have it should go faster.I have looked at the logger,also had some who has been doing buick stuff longer look at it.And he thinks something with the govener and weights in my tranny is fd up.I am no trans expert but i beileve him.I know the trans was rebuilt but i don't think when it was rebuilt they used the correct stuff.I put in a billet servo to stiffing up shifts didn't really change how it shifted.If i manually shift it on the street it is a totally different car then if leave it in drive.I want to get into fixing the trans myself but everyone I talk to or artical I read says take it to a pro (ck,jimmies,jarnis etc)Is it really that difficult or what? I am a mechanic day in day out ,i take apart alot of stuff that I never went to school for and repair etc. I called the local tranny shop's here and they tell me junk the 200r4 put a 700r4 in it,be much happier.Which I don't want to do.I have seen plenty of 200r4 's handle the abuse of much more power, then my lil 6 can put out.I have done everything on this car since I bought it ,to save my cash for the next mod..Is this something I should get a pro to do or what?

[Orlando_87GN]

Post your data file from the logger and lets see how the transmission looks. You can pretty much tell from the shift points, drop in rpm and how quick it shifts whether or not it's healthy. Hopefully you have a powerlogger or direct scan file to share. A recorded run from the track would be best.

[kraused]

I have some from the track in fact .This is from this last friday night at the track,leaving it in drive.The one pass were it drops real bad at the end had it od went to bump to 4th and it was in fourth so hit neutral,dum azz me.so here they are , hope this works

[Orlando_87GN]

What you need to figure out is why at 5093RPM you are going 93 miles per hour. What rear gear, tire size and torque converter do you have? The transmission shifts look fine so I think you've got another problem.

[kraused]

3.42 27560r15 rear tire and a 2800 boss hogg converter from poston

[Orlando_87GN]

How is the transmission fluid? Does it look red or brown? Does it smell burned?

[Steve Wood]

1. Tranny signaled switch to third gear at 4750 rpm at 51 mph. I am assuming that the speedo gear has not been switched to match the 28" tires in your signature.

2. Engine reached 4914 rpm before the shift began to occur.

3. Shift began to take hold at 59 mph and 3963 rpm.

4. Converter is listed at 2800 rpm and the shift point is low which puts the shift point back into the area where the converter is still slipping excessively. Slip is showing 49% at this time, but, this number would be off if the gear has not been swapped in the tranny as the mph is 7.6% higher than the vss is reporting...still it is relative in error when compared to the higher rpm.

5. Slip is shown in low 20 %s at top of third gear.

6. Indicated shift into 4th at 5040 rpm at 93 mph.

7. Rpm drops to 4000-4100 in 4th and flatlines. Converter slippage stays in high 40s.

8. Shift out of 1st appears to be around 5040 at 29 indicated mph.


Now, the car has a roller cam and the power band probably begins around 4600 and goes to about 6000 if it is like mine.

The current shift points are dropping the car out of the power band, and back into the inefficient zone of the torque converter. The shift to 4th demonstrates this well.

Add the lousy 2-3 shift, low shift points, the sagging wot tps voltage, etc. and I come up with a tranny that needs some work. Makes me wonder if this is a brf valvebody

[kraused]

i know it is a brf valve body because it had brf written on the side of the valve body,when had pan off.Fluid is perfect red color,no brown or burnt smell.But when the trans was built what did they change in side of the valvebody is my ? ,did they take everything out and replace it all or what things I don't know.And the shop that built it don't remember that was 2 years ago,so know what do I do replace the valve body with known stock brf or ?. i did not switch gear or anything for 28 inch tire is this something I should do first or not. Like i said car runs great if manually shift it,no 2-3 bobble etc,works great.In drive it is a slug....

[Steve Wood]

Right now, when your speedometer reads 100 mph, your car is going about 108. Does not make a real difference as long as you know that when it reads 70, you are actually going about 75 and may be close to a speeding ticket. I put the yellow driven gear in mine and made it closer to right.

As you state, you don't know what was done inside your tranny. If the valvebody has brf on it, then it is the right valvebody....but you don't know what, if anything, was done to it. Further, you don't know what kinda clutches, plates, etc. were put in the tranny.

Many of us have found that shops that are not specialized in Buick 200-4rs usually mess them up and they work worse than they did stock.

Different guys have different ideas as to what should be modded in them as well. When you start mixing parts and suggestions from various places, it often does not turn out well either.

At a minimum, the governor needs to be modded to shift at higher rpm so you get the benefit of the power band of the cam....that does not address the tv problem, the soft shift in drive, etc...

[Orlando_87GN]

Seems like the most important thing to figure out first is if you are really experiencing that much slip. Figure out if your speedo gears in the trans are correct. Figure out if you really have 3.42 gears (jack the car up, spin the drive shaft, count revolutions of the tires) and if everything checks out sounds like you'll need a new converter. I say it's most likely the converter because if the transmission itself was slipping that much your fluid would be burnt. If the slip is coming from the converter, I would change it out with a better one and maybe most of these shifting problems will go away.

I have a 210/210 PTE roller cam in my car and manually shifting is the only way to drive it at the track. I need to manually shift the car at ~6000rpm for it to run a good number. Relying on the trans to autoshift nets a bad run because it will shift on its own around 5200rpm. I've documented before that there is a 8mph and .8sec difference in manually shifting my car vs. leaving it in drive. This was in a very different car, might not be that extreme in your situation.

[Steve Wood]

Have your governor modded, Mike (Orlando)

Mike Kurtz did mine long ago for the same cam

[Orlando_87GN]

I've thought about it, but I've since switched from 4.10 gears to 3.08's and haven't been back to the track since. No idea what's going to happen now.

[Steve Wood]

Kraused, the other Mike brings up a good point...you may not know what gears are in the rear end of your car.

Have someone drive a steady 70 mph in front of you while you see what your speedometer is reading. If yours has 3.42s, you should be reading about 65 with 28" tires on the back.

[kraused]

It has the 3.42's in counted it after reading all this,I will take it down highway tommorrow and see what scanmaster says tommorrow and report back on it.I know it has a flair from 2-3 if leave in drive real minor.But if manually shift at same rpm no flair,could this be the crappy converter.till tommorrow that is all i know..

[Steve Wood]

I doubt it....sounds like a crappy tranny rebuild to me...