200+ MPH in a C900?

[Crazyswede]

you could go really deep and based on your gear ratio, the weight of the vehicle and the effects of drag, calculate the needed torque at that speed/rpm.

[SwedeSport]

There is a reason I put pictures on tee shirts,.... my math skills SUCK. you guys baffle me with all these numbers sometimes. I only begin to understand any of it when I see it in practical use.

I shouldn't have bagged math class so much.

[Geoff]

That guy in Sweden with the '69 99 with the 600 or 700hp SAAB turbo engine mated to the Audi 100 quatro system did 145mph in 1/4 mile. That thing had no visible aerodynamic changes. It must feel funny at that speed.

I had my '85 SPG (with whaletail) up to 120mph on a track and I could feel it getting a little unsettled.

What's the drag coefficient of a C900? That makes me wonder what the lift coefficient is...

[Rallyho]

I like this thread!

I think it would be intersting to see how fast you could drive a stock engined spg with only transmission and aero upgrades

Swap in the highest chain/R&P ratios.
Fit the largest and narrowest diam tires.
Block/smooth holes on front of car.
Build a smooth underbody tray.
Pizza pans screwed to outside of alum wheels.
Remove/smooth mirrors
Remove wipers.
Tape all body seams/door handles.

I bet the thing would go faster than we think...

[Geoff]

That sort of reminds me of Chang Ho Kim's car


He got 120mpg in it!

With a stock C900 and a #8 primary I'd guess you might run out of power before you ran out of gear.

[DeLorean]

I feel like the train conductor when Doc brown asked if there was any possibility the steam locomotive would do 90 MPH.

I'd say...

#8 primary drives, or custom drive
Solid lifters W/ a T7 head, capable of revving WAY out
Megasquirt or T5, properly tuned
Holset, proper FMIC, with 500+ HP
lowered slant nose car, possibly with an airflow kit with all the undertrays in-tact

and I'd say maybe it's not impossible to do 200! I have been to 150 MPH in a 900 (GPS indicated), it takes a LOT of power to get there, and it's exponentially harder to go faster and faster, but I would never say never... You might also need to figure out a better way to mount the front turn signals, reinforce the headlight buckets and glue on the bumper extensions

[SwedeSport]

Throw streetability out the window. Lighten the car however possible. Fab a 1 piece front end that is lighter and smoother, and quite exaggerated in favor of wedgy aerodynamics. Make the panel fitments super tight, and tape over anything that can't be reworked.

I read that he drag coefficient on an early c900 is .37 and the airflow cars reduced to like. 32. That's really not that bad.

[Crazyswede]

Or just buy a car that is already shaped appropriately and go do it for a lot less. I'm in the boat that says if you are going to go crazy modifying the car to make it capable of 200 mph...at some point the car is so drastically different then anything that it used to be that it kind of defeats the purpose.


Another tidbit for thought. There is a motorcycle shop out in Boise Idaho called Big Twin. They have two bikes there that they ran on the salt a number of years ago. I think both were turbo charged one was a suzuki and one was a BMW iirc. Both got to about 200 mph and could not go any faster. When I asked if they had run out of power at that point the shop owner told me that they had plenty of power but no traction. So at 200 mph they were spinning the rear wheel on the salt.

[Crazyswede]

When I was out at the Salt Flats in 2005 I saw a relatively stock looking Pantera hit 200 mph. There were also those old school lake bed racers that were doing around 200 mph...running big block engines and very little else.

[SwedeSport]

I made up a rendering of what I see. Chopped top, raked front windshield, raked hatch, 1 piece front end. Spoilers are not as much for downforce, but to hold vertical fins to help give the car some stability. There are small fins on the roof and front cowl to help manage the air over the car. Larger diameter tires and wheels, with moon discs. Bodywork extending down to the ground. All the lights and turn signals can be done in a digital wrap to make it resemble a Saab C900.

Even with all the changes to the body I still think you could determine its a Classic 900.

[Jordan]

Where are the submachine guns?

[SwedeSport]

The rocker panels flop down to reveal the spud guns. I guess it does have that Spyhunter vibe.

[DeLorean]

Apparently 165 MPH is totally possible, even with the standard jetronic system. I was reading some old threads over at SC, and on one of the Aussy's airport "track-day" runs, there was a flat fronted notchback with a TD04 & fuel chip that maxed out at 165, drag limited apparently. The calculation he made was that with about 50 more HP, he could have broke 175. I'd say an additional 25 MPH at that speed is a long way to go however... You would probably needed another 200 HP & 1000 RPM's to break a legitimate 200 MPH with no other modifications. If someone did it, I would like to see it.

[SwedeSport]

It is theoretically possible to make the kind of power required to achieve 200. Also seems that minor gearbox mods coupled with tall skinny tires, would put gearing within range. Really the only thing holding back the car is stability at speed, and aerodynamic drag. It comes down to the chassis and body mods. Start with a stock 16v turbo 900, gut it out and reduce weight. Then before anything else, add your roll cage and safety equip.

Next do the trans mods, see where it gets you. Next slam it and put the tall skinny rolling stock on it. At the same time modify the wheelwells to fit the new shoes. Modify the rocker panels, and shave the handles etc. By now this thing is going to already be faster than you think. Replace the nose of the car with a 1 pc hood, fenders and nose cone. Smooth out the tail section, and leave provisions for the diffuser and belly pan. Start playing with adding some fins to add straight line stability, and tweaking the downforce to keep it planted.

At this point, you still have a stock roofline, and a stock engine. I wouldnt get too carried away with the suspension. But I would want good brakes on it, and a parachute. This would be the time to build a new engine, and replace the engine management. Once you have (for the most part) exhausted your ability to go any faster on the stock engine, add power.
I would think to leave the roofline alone until you cant go any further. That would be the biggest challenge to build this car. Chopping tops is no small feat. Add to that the front/rear rake adjustments. The rear wing would serve to stabilize the thing.


It would be interesting to see how fast it could get before changing the motor. Doing it in steps would really show what is working. Most good race cars evolve as opposed to just happening.

[Crazyswede]

there is a 50cc streamliner bike that has run the salt and is capable of 100+ mph.