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How stable a 330ci at 170mhp (landspeed racing)

7K views 41 replies 29 participants last post by  djnekkon 
#1 ·
In my area we have the opportunity to participate in a landspeed race. I have 330ci 5sp with an AA supercharger kit. I have the impression that I could hit 170mph. The track is 2.3 mi long with an acceleration zone 1.4mi and a deceleration zone of 0.9mi. The track is an airport runway in concret. Joins are very smooth.

I was wondering if my engine would hold up 15-20 seconds at 6500rpm.

But I am esptially concerned regarding the high speed stability. How a 330ci behaves at this speed ?
 
#4 ·
It depends on your suspension set up, I had KW V2s on my 330ci it was comfortable at 130 but I never had the governor taken off. My M3 with KW V2s is comfortable at 150 and at 130 it is more comfortable than the 330
 
#5 ·
I am not sure the stock gearing will get you to 170mph.
Check oil and coolant. Your engine should hold up if maitenance has been kept up.
Make sure you have the correct rated tires for those speeds.
If you could add a M3 spoiler, that'll help stability.
Check tire pressures all around before the run. That'll help with speed and stability.
 
#6 · (Edited)
If it were me, I would go over every bit of my suspension first. I've been 130 in a car, but not even close to 170. Since things change exponentially with increased speed, saying a car is okay at 130 doesn't exactly mean it will be okay at 170.

Look at everything tie rods, control arm bushings, ball joints, tire pressure, everything. There is a very real reason why not every car is able to go that fast, (1) they don't have the mechanics to go that fast/stay stable/stop, or (2) they aren't well enough maintained. I would think that your car fits the bill for the first part, but make sure you're up to snuff on the second. It would really friggin suck to get wobble at 170... I can only imagine the amoung of ground you could cover with just a few degress of error.

What tires are you going to use? Are you having your wheels balanced for higher speeds? Hitting resonence at 160mph would be terrible for your lugs and hubs .

my $.02

edit: when i say exponential, I mean it. the equation of kenetic energy is 1/2(mass)(velocity)^2 ... you have about 58% more energy at 170mph than at 130.
 
#31 ·
Are you having your wheels balanced for higher speeds? Hitting resonence at 160mph would be terrible for your lugs and hubs.
While you're correct about the consequences of an imbalance, there's no such thing as balancing for a certain speed. A wheel/tire is either balanced or it's not, regardless of the speed. It's just a matter of having it done correctly and meticulously.

While I am fully aware of the damage that can be done if you hit a bird going 170 mph I don't think you should be attempting this if you're thinking about turning the wheel often at these speeds. Jerk the wheel to avoid a bird at 170 and we will be reading about you in some memorial thread.
Which part of him specifically stating he'd move the wheel 1/32 (3%) made you think he'd "jerk" the wheel?

If he's seriously considering this, his question is valid. He's looking for feedback from anyone else that's gone that fast in this body style. Did the car float? Did one end get light before the other? Did it feel darty and require a lot of input to keep it mostly straight?

Given that he's asking about the effects of such a small wheel movement makes it seem like he's acutely aware of the dangers involved in these speeds.
 
#35 ·
Which part of him specifically stating he'd move the wheel 1/32 (3%) made you think he'd "jerk" the wheel?

If he's seriously considering this, his question is valid. He's looking for feedback from anyone else that's gone that fast in this body style. Did the car float? Did one end get light before the other? Did it feel darty and require a lot of input to keep it mostly straight?

Given that he's asking about the effects of such a small wheel movement makes it seem like he's acutely aware of the dangers involved in these speeds.
Woah, easy there killer, lets calm down a bit. I never said his question wasn't valid. But lets make sure we are quoting him correctly before you go off on me again-

My concern is how the 330ci handles at 170mph when I move the steering wheel 1/32 to avoid a bird ...
Its the "avoid a bird" part that prompted my post. Moving the wheel 1/32 at 170 mph would not be enough to avoid a bird, the course correction would have to be much more significant, the results of which would not be good.
 
#37 ·
Woah, easy there killer, lets calm down a bit. I never said his question wasn't valid. But lets make sure we are quoting him correctly before you go off on me again-

Its the "avoid a bird" part that prompted my post. Moving the wheel 1/32 at 170 mph would not be enough to avoid a bird, the course correction would have to be much more significant, the results of which would not be good.
I'm perfectly calm, and didn't mean for you to think I was going off on you. Going off on you would have involved a completely different tone. ;)

I think you're making a lot of assumptions about how far away he is when he sees this hypothetical bird and whether it's standing still or moving when you say that moving the wheel 1/32 won't be enough to avoid it. If the bird or any other object is static and big enough to be visible from some distance away, a gentle and minor turn of the wheel may in fact be plenty to let the car move laterally to avoid the object. The yaw rate might be imperceptible, just enough to let the car wander toward one side of the centerline or the other before coming back on center on the other side of the object. He's doing this on a runway, which I'm assuming is pretty wide, so he's got some room to move around a bit.

None of that is relevant, though. My original point is that he never said anything about jerking the wheel, and the very fact that he's asking the question means he's aware that there's a limit to what he can and can't do as far as control inputs. So warning him about jerking the wheel would seem to serve little purpose.

What he wants to know is if anyone has any experience at 170ish in this body style so they can give him specific info about how the car will feel/handle/ride.

$0.02
 
#10 ·
how is your gearing going to let you do that? what kind of diff do yoiu have? 6 speed?

check over your suspension, and get z rated tires. and check your brakes as well, new fluid is a must. I have done 140 i9n my car. and it is super stable. but i am lowered, with wide sticky rubber. but the car was stable. i just ran out of redline.
 
#11 ·
First make sure your tires will handle that speed, Then make sure you balance the tires, Best to have a Road force balance. Then make sure your control arms and bushings are good, Make sure everything is tight, Check oil, coolant. Be safe good luck, Carry a fire extinguisher just in case.
 
#22 ·
So nobody really hit that speed with his 330ci ?!

To be ownest I was thinking about removing my side mirrors and wiper blades. Usually tires are not a big issue for a short burst run. A well balanced tire will stay stable at 60 mph and 200mph. I am more concerned about the wheels and tire size.


Suspension is not a big issue. It will just get 500lb more load. It should be able to handle it on a smooth surface.

My concern is how the 330ci handles at 170mph when I move the steering wheel 1/32 to avoid a bird ...

I have a 5sp tranny and an unlocked computer so at 6500rpm I should hit 160-170mph.
 
#26 ·
I have a 5sp tranny and an unlocked computer so at 6500rpm I should hit 160-170mph.
160mph is about the height of it with stock gearing and 6500-6600 redline. Your car will be fine at that speed as long as your tires are in good shape and inflated correctly. Mine felt fine at that speed and I only had sways at the time as far as suspension goes. Just make sure you give yourself room to slow down as it takes a WAY longer distance than from 60 or 100. Good luck.
 
#32 ·
A money shift and a blown tire at the same time would add insult to injury. I guess that would be the blown money shift.

I do have some high speed experience at Bonneville. I took a Ford Freestar out there and it was stable as can be. It maxed out at 105 mph and became really boring really fast. Then I decided to do some donuts. Just so you know, the salt flats have an amazing amount of grip and you can get a mini-van up on 2 wheels. In addition to that, I was completely lost and it took me about 30 minutes to find my way back. None of these problems had anything to do with that we (there were 5 of us in the van) were going from Sears Point to Miller (between two Grand-Am races) and we were.... let's say, having a good time doing some 12oz curls.
 
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