FAQ: What are differences between '96 and '97-99 SC Rivs?

Can someone please tell me why the '96 Riviera is different than the 97 -99 versions?(engine wise)

Shipping to me now is:
Autolite 104's, 8mm Accel 9046 Extreme Heat Reflective Wire Set, 108* Intense Performance thermostat, Intense FWI kit w/ 9" K&N filter, and an Intense 3.40" MPS

I'm getting very frustrated because no one seems to have any mods for this year.
My next mod should be a programmer or scanner at the least and I can't find dick on either of them that supports the '96.


If I can't find a programmer/scanner can I take it to a dealer for a scan/program tune-up?

I'm sure the other '96 owners will point out the differences, but any OBDII scan software should work. The tuning software is more specific. I believe DHP supported '96 Rivs before they stopped selling the PowrTuner, but HPTuners hasn't yet seen the need to write the software. They should eventually. It took DHP a while, too.

So can I just take it to the dealer for a tune up?

The '96 has:
-Smaller rotors
-Older transmission (Cannot be tuned the same as the '97s on up)
-Different suspension
-Lacking the newer electronic torque converter (probably covered by the newer transmission)

Basically, the '95s and '96s are the suckiest years to have. Hoorah...

96's also have vac controlled trannys making them easier and cheaper to "tune" for firm, quick shifts.
metal seatbelt buckles
a different suspension, but one that is supported by KYB. (unlike the 97's)
smaller front rotors for less rotational weight.
our vac lines are arranged slightly different than on any other L67, but just different not better/worse
we dont have the option for a passenger heated seat or on-star.
96's are more rare than 95's or 97's (s/c 96's are even more rare)
i'm sure there are some other small changes i forget, but i certainly wouldnt say its one of the worst years
i'd say the 96 and 98's are the 2 best years. 98 being slightly better.

the dealership's "tune-up" consists of spark plugs, wires, air filter, etc. not a engine tune. they will not and can not do that, unless they have a dyno. like AA said, DHP supports 96's HPT does not. anything that will work on the L67 GTP,regal, riv, etc will fit the L67 in the 96's. the vendors like zzp dont list a 96 year b/c all the W-body cars didnt have L67's until 1997. the riv and bonnie (i believe) had it in 96. we are too small of a group for the vendor to add just "1996 buick riviera" to the list


...and it's Ooh Rah!

Also the 96s should hook up better in theory as our front suspension uses less aluminum therefore creating a more forward weight bias for better traction , albeit at the expense of some handling i'm sure.

Speaking of the different years, I saw a poor Riv at a dealer lot and I went to look at it. It was a nice pretty black, except it had some nice big spots of clearcoat coming off on the roof, hood and trunk. I was sure it was a '95, being they're the most common and most abused years. Surprsingly enough, it was at least a '96. I didn't see a year on it or a price but it was supercharged. It was several rows back behind a big Tahoe so it's almost like they were hiding it or something. I wouldn't trust them though, all their cars are usually junk.

Engine wise:
Supercharged:
96 and 97 were both the L67 similar to the 98+ L67. Although slight differences in head casting has been found to have small cracks when magnafluxed. Although one would never know otherwise. Due to the shape of the valve spring seat they require the use of 105# springs, whereas 98+ can use LS6 or 105# when replacing the cam or rockers.

96 had a painted Gen 3 M90 supercharger with a vacuum tree by the throttle body. 97 was an unpainted Gen 3 M90 supercharger with the vacuum tree by the throttle. 98+ was a similar Gen 3 M90 without the vacuum tree. Instead they had a slightly different vacuum routing.

Naturally Aspriated
I know much less about the NA motors, however to my knowledge the head castings should have changed like the L67 from 97 to 98 and otherwise the motor should have remained the same until approximately 2000 when the LIM manifold would have received a smaller diameter EGR stovepipe as GM made efforts to stop the UIM's from rupturing and filling the motor with coolant.

Transmission:
96 L67 would receive the 4T60HD transmission, controlled via vacuum from the TB. 97 L67 cars should have received the 4T65E HD trans which is full electronic control. 98+ received a slightly different diff, however it only affected the diff, sungear and shaft it sits on.. In 2003 GM made many updates to the 4T65 transmission whether HD or not that included a hardened 4th gear output shaft. (commonly known to cause the loss of 4th). Also along the line the diameter of the pan bolt changed to a smaller bolt.

I'm unsure on when the NA motors got the 4T65E in Rivs.. Bonne's got it in 98.

The differences between a 4T65E and a 4T65HD are the diff, sungear, and output shaft (long shaft that runs the length of the trans).

PCM:
96 and 97 share the same basic pcm and architecture. 98+ are a slightly different looking PCM with faster bus rates and some added parameters. Some of the differences are digital knock filtering vs analog, pinouts.. etc.

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It is assumed that since GP's got the 3800 in 97 with the 4T65 trans that is why HPT does not support the 96 year for the Rivs and Bonnies.

Overall minor changes in vacuum lines, head casting, pcm and transmission really don't make a huge difference when looking at the drive train.

Montaniera wrote:

So can I just take it to the dealer for a tune up?

Not the kind of tuning you could do with a DHP Powrtuner, no. The dealer will change plugs and filters/fluids, perform routine maintenance, that's about it. Stuff you can do on your own and save labor charges. They will not make changes to your programming.

That's some good info Bill. Can't we sticky this or put that somewhere people can see it?

Good idea. It's now in the Series II FAQ thread.

Mr.Riviera wrote:

96's also have vac controlled trannys making them easier and cheaper to "tune" for firm, quick shifts.

Can this be done without a tuner? How do you do it?

Montaniera wrote:

Mr.Riviera wrote:

96's also have vac controlled trannys making them easier and cheaper to "tune" for firm, quick shifts.

Can this be done without a tuner? How do you do it?

see this.

Thanks for all the info!

my trans-axle has a vacuum modulator but it says 4t65 e on the pan .what gives?

96blackriv wrote:

my trans-axle has a vacuum modulator but it says 4t65 e on the pan .what gives?

A quick Google search shows that both transmissions use the same pan... only the bolt diameters are different.

quick question for the gang..

Is the s/c on a 96 series 2 the same as a 97-99? I'm thinking it's time to get a used one...mine is making a noise I can't get rid of...I think a bearing is out...not in the snout, but perhaps the needle bearings...

anyway...there's a few on ebay, but before I bid,I figure I'd better make sure they are the same.


thanks!!!

Nate

They are not the same, the '96 SC has an extra vacuum port for the 4T60E transmission. However, you can easily make a custom vacuum tree setup with a '97-'99 SC.

where is the extra port? I see a 3-vacuum hook up tree on mine...I'm at work but will take pic...of what I think you mean when I get home to verify..

If anyone is reading... I took the snout off (third time) and checked it..tight as a drum...the two impeller gears seem very firm with only a very small amount of forwards and back movement...they don't rattle when I try to move them side to side... HOWEVER when I put it all back together, double checked vacuum lines...it sounds like a bunch of BB's in a tin can spinning around...not really a loose rattle sound, but a hissing bearing type sound..... I have no idea WTF...I can only suppose the impeller gear bearings are worn...

eBay has some good deals, but i don't want to buy and discover it is mssing a part (or has an extra!!!)

Gracias amigos!

I just bought a s/c off eBay for $150... says it's got new coupler and bearings (I'm assuming needle bearings)...

I plan to swap with what I have, but if there is a difference in the vacuum positions I guess I'll be getting with you guys to help..

i'll clean it up and make it pretty before I put it on... and I'll document it all for the gang.

still have my 96 blower for sale. with new coupler and nose seal...
has all the right port and its port and polished so you have less KR and run safer.

Hi y'all. What are the differences between the different year last gen Rivs? Aside from the obvious change to Series II in '96 and all supercharged in 1998, are there major changes to the underpinnings or specs?

Do all years use aluminum suspension components? Are door panels all the same? Dashes the same?

I'm specifically interested in the differences from the '96 to the 98 models.

Rock auto lists aluminum control arms for the 98 I had, but no listing for the 96. I'm guessing they are different? Can a 98 control arm be used in a 96? If so, do other parts have to be changed to work with it? Just curious.

There are many subtle differences in the electronics, emissions parts, some of the suspension and steering as mentioned. Most notably the transmission completely changes in '97 to the 4T65E-HD from the former 4T60 (non-E)
Panels and all that are the same aside from the seat movement buttons updated in 1998. Passenger door from '98 up likely has a heated seat button. The dash trim is changed at '97 but all cross-compatible from '96-on. That's all I can think of right now

You part swapping or somethin?

Thanks. Not really swapping, per se. Just want to know where I stand with respect to the new car. Is the '96 trans still OD? Is it a good trans? Is it a lock-up converter?

The car is supposed to be delivered next Saturday. I've seen it before, but it has been stored for a year or more, so I can't recall much. I will have the front and rear glass reset so the terrible-looking molding is replaced and a rear window leak is fixed.

What's different about the dash trim?