Dave B

I was just curious if you guys had determined the top speed of the 5 speed equipped Max with the MEVI/JWT with the typical bolt-ons. From what I've read, the 95-96 5 speed SE was tested to run ~141-142mph. Most of us with the MEVI/JWT are pushing about 18% more power with substainial gains after 5400rpms. As most of us car gurus know, you can't simply take 142 X 1.18 and figure your topspeed is 168mph because you've got 18% more power. It's takes exponetial power to add topspeed power because of increased drag. My guess is the 5 speed MEVI/JWT is probably capable of ~147mph.


Dave

JeffesonM

iTrader: (5)

I'd like to know the same number for some of the supercharged/turbo folks around here.

Stephen Max

iTrader: (59)

Power to overcome aerodynamic drag is proportional to the cube of the velocity. So if you have 18% more power than your velocity will increase to (1.18)^.333 X 142 = 150 mph. Neglecting other forms of drag that might increase with speed.

A supercharged Maxima making, say, 325 hp at the wheel, compared to a 96 Maxima with 175 hp at the wheel that can do 142 mph, will top out at about

(325/175)^.333 X 142 = 175 mph

Nismo87SE

Topspeed with a JWT ECU + MEVI is shown as 148mph @ 6300rpm in 5th gear. To get over 150mph there has to be at least 200whp @ 6400rpm to reach it. Now a 5th gen VQ30 could do it but it needs to drop 70-150lbs + make 200whp to reach 150mph. All you need to do is find a way to keep the power from falling off i.e. 5th gen IM would be perfect for this. However it appears that the only way to reach 150mph is to either make 200whp @ redline or get curb weigh to 2600lbs!

Stephen Max

iTrader: (59)

Good point about needing the power at redline, which a MEVI may not provide, but where does weight come in? Top speed is a steady state condition that does not involve acceleration (aside from the need to accelerate to get to top speed, but you know what I mean), and if acceleration does not enter into the equation then mass doesn't either.

Confused

iTrader: (4)

Me too but we need more speedometer for that

ivelweyz

Think of a fat dude and a skinny dude running against each other. The fat dude will be slower and won't be able to run as fast either, yet he's stronger than the skinny guy...

Stephen Max

iTrader: (59)

Okay, I'm thinking. I'm thinking of a fat, strong guy and a skinny, weak guy. They're both running into a serious head wind. By some miracle of nature they both have the same aerodynamic coefficient. The fat strong guy is pulling ahead because he is strong and can overcome the head wind. The weak skinny guy is almost being blown backwards. He is weak. He stumbles and falls. Fat dude wins.

ivelweyz

Damn you mofogger...

Stephen Max

iTrader: (59)

ein zwei drei vier funf sechs sieben acht neun zehn

krismax

iTrader: (15)

Yes this does make sense but explain why a 4000lb m5 with 400hp , with speed limiter removed, can reach 198 mph, when a viper of the same year with 450 hp and weighs 3300lbs can only do 185.

MrEous

iTrader: (11)

Simple gearing differences
there is also a bigger difference in downforce...a Viper would be creating more downforce (my opinion) than an M5...causing it to have a lower top speed.

I think everyone is comparing oranges with oranges. (i.e. Maxima with Maxima)

Dave B

Concerning the M5, I'd have to see that verified because I don't buy it. From what I've heard, the M5 without the limiter was capable of about 170mph. Even the non-AWD turbo 911 GT can only do about 200mph. How could the M5 come even close to that?

Why can the Viper only do 185mph? Because it's aerodynamics are horrible. If I remeber correctly, the first gen Viper hardtop had a .44 CD which is really bad. The car has a ton of frontal area.


Dave

krismax

iTrader: (15)

It was in a max power about three years ago , they wondered what it would do with the top speed limiter removed, so they went to germany to find out .I dont have that mag anymore but at that time many people didnt believe it. I showed that mag to many people.

ivelweyz

Wow you can count in german. Back to what I said. I was right. Why would you include a wind strong enough to knock over the little guy. The wind resistance for running does not have the same effect as it does on a 1.5 ton car...

ivelweyz

a 2k1 zo6 can do 200mph+ and it has 385hp with about 3200-3300 lbs...

Dave B

Sorry bro, the Z06 is gear-limited to around 172mph. It actually has less top speed than the normal C5.


Dave

Jeff92se

iTrader: (82)

Two guys at the speed of running would not matter. At over 120mph, wind resistance is a BIG consideration.

Soon2BMaxed

Dave, a JWT/ECU'ed maxima is definately going to go PAST 145mph. remember that race with a WRX i told you about? on I-70 about a year ago? if i didn't hit 150 that day then it was DAMN close. my speedo needle was touching the "H" on MPH (go look at your speedometer)

i know the speedo is "off" somewhat afet 100mph but i can't believe it is off that much.










btw, as you know, this was with intake/ypipe/suspension/clutch/etc.

no mevi or ecu.

Jeff92se

iTrader: (82)

Speedos get more inaccurate the faster you go. ie.. 5% @ 10mph is alot less than 5% @ 110mph. Also you have aftermarket wheels/tires? What size are the tires? If it's 235-45-17 the speedo will read slightly higher and if it's a 245-45-17, it will read slightly lower etc...

Stephen Max

iTrader: (59)

I included a strong wind to make your somewhat nonrepresentative example relevant to what we were talking about, i.e. the top speed of cars. Top speed of a car is limited by wind resistance. Period. Weight doesn't enter into it because, by definition, there is no acceleration at maximum speed. If no acceleration, then no resistance due to inertia (mass, or weight divided by gravity). I was just being silly when I made the wind strong enough to blow over the skinny guy.

The same thing happens with cycling. It's not the skinny, light weight riders who are best when fighting a headwind. They do great in the hills because of their strength to weight ratio, but when it comes to a headwind its the bulky, strong guys who pull ahead because they usually have more leg strength than the skinny guys, and when fighting a headwind their weight doesn't matter. It's a matter of absolute strength vs specific strength.

KsuMax

Just go and buy a gsp unit that you take with you in your car. I took my parents gps unit with me on a trip to colorado. It had the mph readout. Not sure how accurate it is, but I wouldn't think it would be that off.

Soon2BMaxed

stock wheels/size tires.

i know the speedo is off but where my needle was, would be where the 155mph would be if the speedo kept going past 140. so i have to believe that it's around 145 or so.


p.s. i caught up with the guy in the WRX a couple monthes later and he said his speedo said the same thing


makes me wonder exactly how fast i was going

Nealoc187

iTrader: (23)

Cartest using requin6's dyno and my car's weight shows a top speed of 150mph.

I've GPS'd my car at 146 on a closed course and the car didn't have much left in it... maybe 1 or 2mph but it was going nowhere fast.

As for the M5 thing I would never believe an M5 would be capable of 198mph stock (with the limiter removed) with ANY gearing, no matter if its stock gearing or gearing to make it have the highest top speed possible with stock power levels. Another thing that strikes me as strange is why in the world would a british magazine like Max Power publish a top speed in MPH when everything over there is KPH. Doesn't make sense to me and smells fishy.

Z06s aren't touching 200 or whatever was claimed, just like dave said they have a slower top speed than a regular C5 hardtop because of gearing.

Dodge Vipers--The R/T 10 had a .55 cD which is like a semi truck, the GTS coupe has a .35 cD which still sucks, ours is .32 for instance, and thus limits the GTS to only 177mph.