1 2 3 4 5
GPz11 (Forum Supporter)
GPz11 (Forum Supporter) Reader
6/17/20 7:09 a.m.

In reply to asphalt_gundam :

Do you need a crew member?

No spectators allowed yet. I'm just up in Aurora.

asphalt_gundam
asphalt_gundam New Reader
6/17/20 7:26 a.m.
GPz11 (Forum Supporter) said:

In reply to asphalt_gundam :

Do you need a crew member?

No spectators allowed yet. I'm just up in Aurora.

I'm already full up on my allowed crew.

asphalt_gundam
asphalt_gundam New Reader
6/17/20 8:10 a.m.

Ok, some more details and pictures.

If it isn't obvious already a major part of the modifications over last winter were chassis stiffness. Getting one tire 15" in the air before another came off the ground was little better than a wet noodle. So after all the boxing, notching, gussets and doubling I decided some cage work would be even better. Though the cage may have more to do with only a lift and 90+mph through the "kink" at Road America and the car wanting to take it flat out on a 225 street tire while simultaneously delaminating those same tires......

I started with working out the main hoop and rear supports sticking to NASA and SCCA specs. This will not be a wheel to wheel car but they probably know a thing about safety. Was able to remove it from the car for welding the top. Then back in to weld to the frame.

Harness bar is high enough to meet rules on belt angle with my current seats while placed low to handle any seat changes (which will all be lower position for helmet clearance) if I decide to jump into Time Attack. 

Door and sill bars I added for both more chassis stiffening and side impact protection. I may have seen too many videos last fall of cars sliding into a barrier/wall end via the door. Must have been 6 of them in a few days...

The sill bar ties in directly above the forward body mount. All solid aluminum body mounts now too by the way. And the door bar lands on the sill bar and directly on top of a stubby tube on top of the center body mount.

Now since this is still a street car. Several hundred miles already this year, many of those beer runs. Ergonomics and aesthetics are important. There is zero conflict getting in and out of the car. I didn't want to worry about a helmet on the street by having the overhead/halo bars. 

I finished out the backseat area with some plywood and carpeting. These bottoms are flip up compartments for the aforementioned beer!

solfly
solfly HalfDork
6/17/20 9:07 a.m.

this is outstanding, love the older cars brought up to track spec.

any reason you didn't go with a different spindle and a unitized bearing on the front?

jfryjfry (Forum Supporter)
jfryjfry (Forum Supporter) Dork
6/17/20 9:39 a.m.

You might make more power by taping up the vertical air cleaner element and just pulling through the top one.  
 

Based on a pretty comprehensive youtube comparison video

Snowdoggie
Snowdoggie Reader
6/17/20 9:50 a.m.

and you kept the cupholders. laugh

asphalt_gundam
asphalt_gundam New Reader
6/17/20 11:29 a.m.

In reply to solfly :

Cost.

The unitized bearing "pro-touring" setup runs over $4k by the time you have spindles, bearings/hub, ball joints, steering arms, brakes, lines, etc. Top of the line NASCAR and TA2 road race cars all run a spindle setup. Cost is very low by comparison and customizable in any way you can think of. I would have gone with the big snout spindle setup but didn't want the 5x5 bolt pattern. If anything I'd rather go down to 5x4.5 (114.3) for the competitively priced wheel options.

As for the benefits compared to my stock spindle they're not much now that I have a tall spindle (the tall ball joints), big brakes, high quality bearings, and if I switch to a 3pc spindle deign I can switch Left/Right steering arms for Ackerman.

In reply to jfryjfry :

Doubtful. The top lid is very close to the hood. I'm not sure what was compared in the video but I've spent a few hundred hours on the dyno with various engines and several that were just test mules. As for air being drawn from the sides (and as a whole) the air cleaner base is by far the most important part. A large radius base leading to the carb/throttle body will make more power than no air cleaner or a tight radius "fit to carb" one. 3HP more than no air cleaner and 12-22hp more than a tight radius "fit" cleaner on a 450ish HP big block Olds. In my particular case the throttle body top design is holding it back more than anything. The Holley sniper doesn't have a radiused top like the Terminator throttle body or most performance carbs. Taking the grinder to it and fixing that has been on my possible mods list.

In reply to Snowdoggie :

I had to make the cup holders in the first place.

Kitsbeach
Kitsbeach GRM+ Memberand New Reader
6/17/20 12:08 p.m.

Awesome build...I'm building an 80' Malibu for autocross/street/maybe track so you're helping me a lot...especially the cage which is similar to my plans for all the same reasons (stiffness and easy in and out).

I'd like to see a picture of the Vintage Air hot rod heater installed as that is what I plan too.  Mine is a no A/C car, plus I like the look underhood of the block off plate.

Here is a pic of mine...it sat under a tree for 16 years and I cleaned it up with CLR and scotchbrite pads (which were a little too scratchy btw).

Snowdoggie
Snowdoggie Reader
6/17/20 12:25 p.m.
NOT A TA said:

Great thread! I like that you've kept it Olds powered.

I had an '88 Cutlass Supreme 307 4V 4 speed auto. Car guy friend of mine ordered it for his mom late in her life. Went to bank, grocery, Dr's, and church in good weather and stayed inside otherwise. Had 42,000 miles on it but nooo power haha. I had a bunch of cars and some had to go so it got sold and became a donk. I've still got another G body though, '81 Malibu.

My Mother had an Cutlass Supreme Brougham that my Dad bought for her new in 1980. It was a pretty car and a good cruiser, but I never really thought it handled particularly well. I even autocrossed it once when Mom wasn't looking. I remember seeing them in NASCAR back in the '80s as well. I love seeing one of these as a Pro Touring Car. 

asphalt_gundam
asphalt_gundam New Reader
6/17/20 12:27 p.m.

In reply to Kitsbeach :

It also saves a lot of weight. My guess was over 20lbs. Takes some plastic epoxy and cutting but I molded it back into my factory vents too. Glove box is un-touched and functions. I needed to make a new center dash plate anyway as it was broken, cut, and mount points were gone. Its just some 1/8" thick aluminum with the vintage air controls swapped onto from the plastic bezel they came in.

Snowdoggie
Snowdoggie Reader
6/17/20 12:44 p.m.
asphalt_gundam said:

In reply to Snowdoggie :

I had to make the cup holders in the first place.

I like what you did with the interior. A cage and racing seats and carpeting and cupholders so it still looks somewhat civilized. I'm not sure if that is a Pro Touring thing. I am doing the same thing with my Miata. Full cage, hardtop and racing seat, with carpet and cupholders for street and track. I don't want the car to look stripped out. 

 

asphalt_gundam
asphalt_gundam New Reader
6/17/20 1:22 p.m.

In reply to Snowdoggie :

It is a Pro Touring style, but my reasons are for me. I've been down the road of building a car and so focused on the performance side that it reach the point of not wanting to drive it...that then makes it not get driven and then it sits. I want a finished interior, cup holders, no problems with getting in and out so that it continues to be a car I want to drive. Even now while making repairs and waiting on some parts I'm disappointed I didn't get to drive it on a cruise last weekend or make the Friday autocross I signed up for weeks ago.

Kitsbeach
Kitsbeach GRM+ Memberand New Reader
6/17/20 4:59 p.m.

In reply to asphalt_gundam :

Great pictures.! This was exactly what I was thinking of doing, and hadn't seen anyone else yet.  Thanks.!

Racebrick
Racebrick New Reader
6/17/20 9:40 p.m.

Maybe I will get a chance to see it in action another time.  Grid life is not allowing spectators, so I guess I won't be out there.

ClemSparks
ClemSparks UltimaDork
6/17/20 10:19 p.m.

I LOVE it!  I'm quite fond of G-bodies (and have 2, currently) myself.  I really appreciate your sharing what works (and what doesn't)!  

I'm subscribed and will be happy to see further development.

asphalt_gundam
asphalt_gundam New Reader
6/18/20 12:27 p.m.

Another important thing on these cars is cooling.  A good radiator and fan w/full shroud only gets you so far. The v-belts suck and the power steering system was never meant for sustained track use.  Good fluid and a cooler are a must for the power steering. (Mine lasted 3 20min sessions on track) 

I utilized Jones Racing Products parts and designed/built my own brackets. This upgraded me to a cog belt system, type 2 pump, and race alternator. An inline cooler and AN power steering lines made the system bulletproof.

To address the coolant temps climbing past 220 on track even with a good aluminum radiator and dual fans. I fabricated cooling plates/block off plates to make sure air passed through the radiator instead of around. At the same time I added hood vents to let some heat out.

This proved effective to the tune of 10-15 degree lower temps both on track and while cruising. 

Today I plan to build an air dam under the radiator support (factory ones all seem to get destroyed and or missing) to further improve cooling. While under the front I'll see about making some undercarrige covers to try to keep some air out from under the front end too. It might pay off big with reduced lift on the front at speed. 

asphalt_gundam
asphalt_gundam New Reader
7/1/20 2:01 p.m.

Update: Post GridLife @ Autobahn

Changes pre track weekend:

Switch to carb just to make it (ecu woes, shipping, bla, bla )

Dropped upper front A arm to lower holes (3/4" drop) this increased camber gain during suspension travel

New alignment Camber 3.4 Left/3.2 Right, max Caster at 6.5 both sides, Toe at 1/32 out

Air Dam under the radiator and a belly pan back to engine cross member behind that.

Results:

Compared to Gingerman where the Record holders in Street GT run almost the same lap time as Autobahn I gained 4 seconds!!! I was slower than the record at Gingerman by 20.55 and Cut that to 16.53 at Autobahn. Not a perfect comparison but the same guy and car set both new records.

The air dam worked amazing. Never once got above 185 degrees on track, even in 90+ temps and humidity.

Hard to tell what the belly pan did but for Sunday I added the rear one to cover up the gapping area between the fuel tank and rear bumper. Didn't get a faster lap but in some areas of the track the data suggests MPH was up .5-3mph. Though no faster laps they were all within 1sec of the fast lap Saturday. 

asphalt_gundam
asphalt_gundam New Reader
7/1/20 2:06 p.m.

Some pictures from the weekend. Credit to NVUS images for taking these.

asphalt_gundam
asphalt_gundam New Reader
7/1/20 2:17 p.m.

And this was exactly one year ago. Car has come a long way.

crankwalk (Forum Supporter)
crankwalk (Forum Supporter) GRM+ Memberand SuperDork
7/1/20 5:21 p.m.

Stick shift G body with Forgelines. smiley

 

Keep doing you sir. 

asphalt_gundam
asphalt_gundam New Reader
7/2/20 7:15 p.m.

Just mapped out the rear suspension geometry for roll steer. Looks like significant counter steer right now. I can cut it in half by going to my lowest drop bracket hole. Will have to get modifying the chassis or upper rear end mount to get neutral or with the corner steer. Both things should add traction.

Anyone been playing with rear steer enough to give me a heads up on what to shoot for or all out avoid?

NOT A TA
NOT A TA SuperDork
7/2/20 9:27 p.m.

The air dam under the radiator is important on G-bodies. That's why they came from the factory with them and why you noticed a big difference.  Hood vents probably help also. Have you done any tuft testing with the vents in place?

asphalt_gundam
asphalt_gundam New Reader
7/2/20 9:31 p.m.

In reply to NOT A TA :

I did the vents and top/side plates at the same time. Good for 15 degree drop

rustomatic
rustomatic New Reader
7/3/20 9:49 a.m.

This is a great build--definitely respect the focus on safety, durability, and research.  The fact that you took the time to realize that the diagonal in the roll bar must precede any horizontals puts you way ahead of countless six-figure "pro-touring" builds I've witnessed.  On the durability side, I've actually exploded an alternator on track, so kudos to you for addressing such possibilities.  The car looks very well-sorted in-situ!

asphalt_gundam
asphalt_gundam New Reader
7/7/20 9:43 a.m.

Some more photos from Gridlife @ Autobahn. The girlfriend took these and several others where I could zoom in and focus on the tire contact patch. This was the first event since I started doing autocross and track days that I had anything close to full use of the contact patch on the front tires in the corners. I suspect largely from my alignment changes after Gingerman. Its still not quite where I'd like it to be. More on that in a bit. 

First and last pics you can notice just how much camber i'm getting by looking at the reduced contact the inside tire. First photo we grey scaled to zoom in on the outside tire and looks planted and tire wear confirms. Its crazy to see the tire deformation at mid corner between the inside (at full height) and outside (crushed down)....just look at the 3rd photo. 4th photo you can really see the affects on just the outside rear. The way the rear tires were wearing if I just keep tracking them they'll wind up being camber cut...which should help go faster. In all seriousness though a floater rear axle with camber/toe snouts is going to be the way to go later down the road. I may do some changes with the mounting of the rear sway bar to increase effectiveness and see if it help. Rear bar mounts to the lower control arms factory and mounting to the axle housing and adding links to the chassis will make it more effective. That may or may not make the car faster I've seen setups that work well both with a sway bar or none at all on the rear. I think I have just a hint more rear roll than I want/need so it's a low budget thing to try. Plus it should free up movement of the lower control arms as the sway bar is a built in "bind" at the moment.

Those side side shots really show how much air is still under/getting under the car. Side skirts/ground effects are on the list of ideas to try out this year.

1 2 3 4 5
Our Preferred Partners
Uc3aZx9Ig0so1JayKnMP0yceHDsaWOCJdOz0u5zR7HOysptOUZSc9PG1TVpmnKN2