If you cut the weight IN HALF, a stock NA Crossfire would still be aerodynamically limited to no more than approximately 160 mph. To get a Crossfire to 200 mph would require well over 400hp.

Even claims of 155 mph for a stock NA Crossfire are ambitious since in theory you need a little over 200rwhp to get the Crossfire to that speed. Photos of speedometers at 155 are impressive but they don't verify that the vehicle is traveling on level ground or wind speed/direction.

 

Smaller wheels would equal less angular moment of inertia. The weight and diameter of the wheels make them harder to spin. The NA Crossfire cannot launch very effectively because of the large wheels; it doesn't have any resulting wheel spin and bogs down since rpms aren't high enough to be where they need to be on torque curve for best acceleration. Even if the diameter of your tires on the 18" wheels is the same as the 19" you would improve the launch because the wheel mass would be less, and the mass would be closer to the axis of rotation. I don't know if the 3.8% speedo difference results in any issues with ABS or TC.

 

There's now way we're aerodynamically limited to 155, Mag-wags and the new Porsche Panorama sedans go about 170 and I know our aerodynamics are better than those. And wouldn't smaller wheels reduce our top sppeds though?

 

Weight has a lot to do with acceleration. With top speed, not so much. As the vehicle goes faster and faster it is air resistance that amplifies. Weight remans the same.

As for redistribution, the car is fairly well balance,. Far better than most. I wouldn't redistribute it too much. You would gain nothing but a very loose rear end. Our cars don't drift. Save that for the ricers.

As to making those high speed turns, you have the wing creating down force. Without it your just a Dodge Omni going off into the woods.


roadster with a stick

 

Thing is I would change the wheels before I went 45 miles to the track. I assume I wouldn't have a lot of trouble. The question is, would it be worth the trouble.

Teck9,
Top speed is not the goal of drag racing the 1/4 mile. Acceleration is. Smaller rear wheels should help.

 

I like the little wing....I call it the "bikini spoiler"

 

Theory is one thing. Reality another. I guess I need to find 3 miles of Bear free, Deer free, deserted, straight, highway.

And satelite positioning unit to validate my speed

And witnesses who can withstand waterboarding interrogations

And one of them needs to be someone onehundred80 will believe.

Otherwise, we will never really know how fast one of these NA's will go.


roadster with a stick

 

I think the smooth, enhanced torque of even a 1998 naturally aspirated 4.3 liter Mercedes V8, I think 200 is possible. But I also think that with a good chip tune, lowering kit,and other mods that are purely physical like perellis, cola air intake, etc. nothing complicated. I think doing **** like that with a total cost of a grand, the 180's are likely very easy. we already handle like ferrais thanks to our wonderful lord, Mercedes Benz.

 

Franc,

Right on!

By theory I mean the top speed possible, assuming no wheel slip, based on drag coefficient, frontal area, weight, and rwhp.

And don't forget, you have to measure your speed at the same location while making a run in the opposite direction, and take the average of the two.
According to my calculations you will need at least 228 rwhp to reach 160mph. That's certainly doable with some modifications. You'll need at least 272 rwhp for 170 mph, 322 for 180, 377 for 190, and 438 for 200.

 

Do you think that 438 can be attained with a naturally aspirated V8 from a W210 platform (1998-2002). If so, what size would be needed and if any mods are needed, what are they. Also, by your calculations, what would a 650 rwhp Crossfire do?

 

Yes, way!

The Panamera has 400hp and a claimed drag coefficient of just 0.29 - that's why it can attain 170mph stock.

You are confusing aerodynamic resistance with aerodynamic stability. To go fast you want as little resistance to forward motion as possible. The more drag, the more power it takes to see a gain in speed. The Crossfire coupe has a drag coefficient of 0.37, which is higher than many cars, and actually in the realm of crossover vehicles/SUVs. The boat tail design isn't the most aerodynamic (though it was considered sleek half a century ago). The Crossfire's art deco sheet metal is the car's unique feature. But..... it takes lots of work to move this work of art.

In the case of handling, the Crossfire is quite stable because additional down force is added via the spoiler. But the compromise there is that to make the rear wheels stick to the pavement drag has to be added. Cars that are better designed strictly from an aerodynamic standpoint than the Crossfire are able to attain both higher down force and lower drag at the same time.

Yes, smaller diameter tires/wheels would lower the top speed.

 

I don't know if it's possible or how it would be done but it would take many expensive modifications to even get close. Probably wouldn't last very long either.

Crossfire with 650 rwhp and no wheel slippage, 229 mph, in theory. Reality probably sets in about 210 when the spoiler breaks and you are cleared for takeoff.

 

Would a lowering kit reduce the drag coefficient and also allow less air under the car for less wheel slippage? And how much do tires effect the top speed? I mean good ones like racing slicks or perellis. I think a good chip tuning and racing tires are all we need to do the 180's. And how does our cornering compare to the competition. Another member is working on a v8 conversion and it bolts right to everything. i just dont know if the trans and everything else back to the rear wheels can take it. I'd like to try to get up to 350 HP with only an engine swap with a w210 e430

 

I think the fastest I have driven a car was in my Crossfire - hit 240km/h on a nice dry, deserted bit of highway - although I was wondering if the moose would come out and tromp me ! . . . anyhow, that being said, the best place to drive (in my humble opinion) the Crossfire, is on a road course.

I took mine to Willow Springs a few years back, during spring fling. I had a BLAST !!! I mean, driving 1,600miles one way, then spending the day on the track (used 1/2 tank of fuel just on the track) . . . was about 35mph FASTER at the end of the day, after learning the car, the track and better driving from the instructor ! Was fun - had a buddy that brought his 06 Hemi (5.7) Charger . . . I had him in the corners, but he could pull on the straights !

I am not a tiny guy (6ft, 230#) and found the car comfy (cozy mind you) on the trip. But have to admit, I got a major thrill going thru the turns at speed ! Sure going fast or drag racing is fun, but get it out on a road course where the car can really shine. Having another 100hp would be great on the road course too !!! . . . oh the best of both worlds . . .hmmmm . . . SRT6 roadster in my future ???????

Mark

 

None of this debate matters. Once Lantana TX paves the way for us to learn the Mercedes V8 swap, the Crossfire's potential from its Mercedes blood will be realized and the realm of 200+ MPH will be child's play. All of Italy and the rest of Germany will be brought to their knees.

 

The best I have actually seen is 139 and I quit before the car did my feeling is it will quit around 150 flat out not much more beyond that due to drag but with mods who knows what you might achieve but then it is not stock so box stock auto in my case is around 150 to 155 my guess or SWAG as a few people say it.

 

I've had my 07 6-spd coupe cruise at 135 down the freeway, very stable and smooth.
Haven't had an excuse to go any faster than that. Traffic was a ***** and I was late for a funeral.
maybe another day...

 

I had mine to 140 in 5th gear, had to get off at my exit so no 6th but it was still pulling. New GY F1's all the way around kept me planted and smooth.