87 Oldsmobile Cutlass Supreme

[olds87]

Hi ladies and gentlemen,

I have been a member for a while on this great site that find great information and ideas. Now about the car. This was my grandmother car ever since I was seven or eight years old. When turned 16, my dad and I decide to get car back from my uncle. I notice the paint was fading and missing a few parts. Took me while certain trim peices and other miscellaneous items, in high school.



About four or five years ago, my mom was driving my car on expressway here in Phoenix, all of sudden, the engine was shaking a lot and miss firing. It seems to be something internal that could be coming a part. My mom and I found this guy in valley use to modify Oldsmobile 307 engines to run up and down drag strip at Greulich's automotive. Sometime this week, he is going to take the engine out and see how bad. Here is old picture I took 10 years ago.



Over the time of having car, I have been collecting suspension parts from Marcus at SC&C, but I haven't put them in yet, because I need to get new wheels to go over 13" rotors upfront.

Has anyone with G-body put 18 x 9 on front of car?

[Olds502]

I'm running 18x8 with 4.25 bs, 245/45 tires. 1 1/2 drop hotchkis springs. on aggressive drives rubs a little in the fender well, full lock rubs the frame. Don't think 9s would work without body mods.

[jetsetw31]

Hey, I agree with Olds502, you'll need body mods to run that wide a tire. The '81-'88 Cutlass Supreme Gbody is the only one when lowered has issues with rubbing rims and tires bigger than 18 x8 with a with a 235 35 18 tire. 245s rub a little as said by Olds502. One reason is the squared wheel housing interferes with the top of the tire when lowered. The other Gbodies don't have this interference. With a 4in. bs up front with a 18 x 8 rim, you wont touch the frame. But with a 245 tire it will rub the fender. A 235 up front will just clear.
I'm going to be running a similar set up to Olds502's up front but with a 18 x 8.5 4in bs and 18 x 9.5 rear. i'm flaring my fenders with the FE3X kit and running a panard bar in the rear. Yhere are others running bigger combos on Gbodies forum, but not all are lowered.

[SSLance]

I run a 17x9.5 with 275/40/17s up front with no rubbing except just a touch at full lock on the frame.

[olds87]

Thanks for all your comments guys about front wheels. I am going to try take a stab of putting 18x9 wheels up front with front suspension I have from Marcus at SC&C. What I have so far is upper and lower Spc control arms, AFX spindles, Eibach springs and vari shocks. For the rear, I want to get Speed Tech control arms.

[SSLance]

The trick to getting a wide tire to fit G-bodies without rubbing the inner fender wells is to correct the geometry. If you get the suspension to gain camber under compression instead of losing it, not only will it not rub but it'll handle corners a lot better as well. Remember, it is not just about buying parts, although that is part of it...you need to find how how to set those parts up too. Good luck. Any questions just fire away. Always been a fan of the Cutlass styling.

[olds87]

Thanks Lance. I have always followed your progress on monte for while. How did you modify the cross member to fit t56 manual?

[SSLance]

Here's what we did to modify my existing G-Force to work with the T56. I was the designer while my friend John was the lead engineer and machinist. Thanks John...

The T56 transmission mount needed to be about 1 1/4" lower and and inch or so towards the front than the 200R4 mount was, so we cut a C-notch out of the front of the g-Force cross member.



Then tack welded plates to box the C-notch in and tacked a new mounting plate at the right height inside the notched part.





Then took it to the car and test fit to make sure everything was correct before final welding.







We got the height perfect. I removed the rubber bumper on the top of the T56 and the tail shaft height is now in just about the exact same height as the 200R4 was and I can fit a straight blade screw driver between the rear two cover bolt heads and the floor pan.

200R4



T56 on new mount





John finished welding it up and I painted it up and it was ready to go back in one last time.

[jetsetw31]

Good luck with that 9 on the front. If I was you I'd only buy 2 rims so you can try to fit them on the rear.
This car has 18 x 8s up front. Do you see the rub?

This is Olds 502's car before he put the 245 45 18s on front. He had 225 50 18s and was rubbing bad.

This car has 18 x 9.5s in front. It has a rounded factory fender flare just like the Monte Carlo and the Grand Prix.
I don't mean to sound harsh It is just my observation and to me there is no amount of suspension geometry changes to get 9 inch rims to clear the stock front fenders of a lowered '81-'88 Cutlass Supreme without rubbing bad. It's kinda obvious once you compare the 4 cars to each other.
If you prove me wrong without rubbing, Then i'll gladly recant that statement.
Again Good Luck.

[olds87]

I can see the rubbing on olds with torque thrust ll wheels and appreciate all the information from everyone. Just want to try fit the widest front tire, to rear of my car. My plan is to take it to some local autocross events, here in Phoenix area.

[SSLance]

Well, I guess everything is relative. With a ride height as low as that silver Cutlass above, you aren't going to have any suspension travel anyway so autocross ability will suffer.

Here is my car at ride height last spring. I've lowered the front about a half inch since then.





Here is is under hard braking and cornering on the autocross course.







The tire never even comes close to rubbing on the fender lip.

I realize the Cutlass fender is shaped differently but it also has a bit of a bulge to it. When the top of the tire tips in under compression, it shouldn't be even close to the fender if set up correctly.

That is a 17x9.5 with a 5.0" back space and a 275/40/17 tire.

[olds87]

My car is at same ride height as yours, Lance and I am going to try keep it same spot. Just need to find a used tire like yours and see how it fits.

[jetsetw31]

You don't need the widest tire for great handling. Your suspension set up right will get you that. It's not in the tire.
I pulled a 1G on a 200 foot skidpad A while back in my '81 Monte. My set up was poly bushings on the stock lower Arms in front, A '86 Trans Am WS6 Front Sway bar, A rear sway bar from a G body wagon. one inch lowering springs up front and air bags in the rear coils. My tires were small compared to what guys run currently. 235 60 15 front and 245 60 15 on the rear. The Monte had a cammed Chevy 400 motor and a TH 350 tranny with a shift kit. It was very basic. Sat just like SS Lance's Monte. My car cornered very flat. (Btw I like your ride SSLance.) The suspension made the tires work. On hard turns the tires made a lot of noise but i never lost traction. I imagine with some 45 or 40 series tires it would have been at a competition level.

I also once entered a clover leaf off ramp doing 80mph and exited it doing 60 never once hitting my Monte's brakes. The G forces was so hard that some pennies i had in a center cup jumped up and hit the driver side window during that turn. (Scared the crap out of me)
There are some evil Gbodies out there with relatively small tires and good suspension set ups that can challenge Exotics. Also bigger tires slow you down if you don't have a lot of power to make up for the loss of speed.

[SSLance]

To really get the maximum cornering grip out of a ride, you need balance between the front and rear. There are many ways to achieve that balance, tires, springs, sway bars, shocks, roll center heights...etc. Most G-Bodies need way more help up front than they do in the rear to keep them from pushing in autocross style turns. As wide of tire as you can get up front helps in this regard.

I ran 245s on 8" rims previously but wanted a square setup front and rear to help maximize grip and balance. Frankly I was amazed that I was able to travel and turn the front tires the way I do with no rubbing...but it works. When I ran just drop spindles and then with 2" drop springs and stock spindles, I always scrubbed my 245s on the inner fenders over large dips in the road. Since fixing the geometry that has never been an issue.

[olds87]

Here's an update on my car. The guys @ Greulich's in Phoenix, AZ have help with installation of Dakota Digital VHX gauges. Here is night time view.



Sometime later this month, I am going to check with Vivid Racing about purchasing Forgestar f14 in 18x8.5.

[monteboy84]

Going with what SSLance was saying, the stock front suspension geometry on these cars is garbage, to the point where the tire actually loses camber with compression, it's back-asswards. So, with lowering on stock geometry, you'll have more rubbing issues than with corrected geometry where camber is gained with compression/travel. If you give Marcus at Savitske Classic & Custom a call he can set you up with stuff to correct the problem. I ran his Stage II Plus kit on my Monte Carlo and it worked fantastic. Not sure if you'll fit 9's with that, but you'll at least be in the right direction and it will handle properly as well.

[olds87]

Hi Matt,

I had bought all of my front suspension from Marcus a while ago, but life got in the way and couldn't get them any earlier. He did say the biggest tire I can fit but have a little rubbing is 255/40/18 from inner finder. The smallest wheel that Forgestar makes, in style I like is 18x8.5.

[olds87]

Hi everyone - here is a little update on Olds. About a week or two ago, I brought MB Old School 17x8 wheels with BFG Comp 2 summer 245/40 R17 tires.
Sometime soon I installing UMI adjustable upper, SPC lower A-arms, Speedtech AFX spindles and Kore 3 brakes.
The only tricky part going to be removing old stock springs, with spring tenstioner goes on inside of spring.

[Wraith]

Nice update and it looks good!

[SSLance]

Nice update James... I have a coil spring compressor if you want to borrow it for your spring removal. Just found it today in fact while still unpacking...