top speed run 3000gt sl

[hyper3000gt]

so I just got a 97 3000gt sl made sure everything was tuned up on it and good to go and then did a top speed run. I could only get it up to 135 no matter how hard I tried it just wouldn't budge anymore.

now I know something must be off because I used to have another car that would go 136 - 138 every run I did and it only has ~180 hp or so and the 3000gt sl is suposed to be 220 hp.

so can some one tell me what's up and how come my car isn't doing 140+ like it should be?

is the the car governer limited by any chance?

[IPD]

1. i hope you're not doing this on public roads.

2. top speed is a function of 3 key factors, nothing more. aerodynamic drag, horsepower and gearing, and power to weight.

3. if you're judging top-speed by your speedo, then you're doing it wrong.

4. your comparison is irrelevant because you provide no other factors besides approximate hp and alleged MPH.

5. manufacturers sometimes fudge numbers, and powertrain losses vary greatly between platforms (and sometimes within platforms).

6. there is no governor on a 3/s.

[hyper3000gt]

well I gave aprox HP because I can't be exactly sure what it was on my old car it was orginaly 170 hp but I gave it high performence sparkplugs and a k&n air filter so I figure 5 HP for each. my old car was fairly aerodynamic but from looking at them both I think the 3000 is more aerodynamic so it can't be that. and if there is no governer in the 3000 then I can only surmise the tranmission must not be as good or geared properly for high end. but this makes no sense when I see in many other threads people getting there unmodded 3000 gtsl's up to 145 - 150.

my only other tid but of info I can throw in is that mine has 170,000 miles on it, however I have to note that it was extreamly well maintained and garage kept most of it's life and under the hood is very clean. and I was pretty sure japanese cars last far longer then this when maintained well and will not have performence issues.

so what could it be? what is sapping away my top end speed?

[IPD]

rofl @ filter & plugs adding 10 hp without any other mods.

[sketch]

Why are you trying to hit 140?
Are you manual or automatic?

The FWD manuals are geared to hit ~110 in 3rd gear alone.

Edit: also, at 170k miles you should plan on doing a 60k service sometime soon (depending on how often you drive your car)

[i3igpete]

2. top speed is a function of 3 key factors, nothing more. aerodynamic drag, horsepower and gearing, and power to weight.

3. if you're judging top-speed by your speedo, then you're doing it wrong.

2. weight is only a factor in terms of rolling resistance. p/w only predicts acceleration, not top speed.

3. agree. use GPS tracker apps (they're free)

OP, new plugs and good air filter won't give you power. they'll bring power back closer to where it was from the factory, but no more.

[HilbillyHomeboy]

If you're only seeing 125 on the speedo, top out, either the speedo is way off or something is worn out. We did 145 on a 1G dohc back in 93 with 4 people in the car. We did the same in mid 91 with a dohc Stealth. Knowing the speedo is off by around 5mph in the 1G cars, we were pushing close to 140mph. These were brand new cars that my friends got for their 16th birthdays, so they were obviously perfect health.

Jeremy

[hyper3000gt]

2. weight is only a factor in terms of rolling resistance. p/w only predicts acceleration, not top speed.

3. agree. use GPS tracker apps (they're free)

OP, new plugs and good air filter won't give you power. they'll bring powemphr back closer to where it was from the factory, but no more.

well even crazzier then if my old car was more closer to 170hp then 180 and still able to do 135mph and my 3000 is only doing 125mph.

speedo testing not a problem because I double check the accuracy driving next to a frind all the way up to 90 and we both confirmed each others speed was 90 on both speedos.

[hyper3000gt]

If you're only seeing 125 on the speedo, top out, either the speedo is way off or something is worn out. We did 145 on a 1G dohc back in 93 with 4 people in the car. We did the same in mid 91 with a dohc Stealth. Knowing the speedo is off by around 5mph in the 1G cars, we were pushing close to 140mph. These were brand new cars that my friends got for their 16th birthdays, so they were obviously perfect health.

Jeremy

yea and with me it was only 2 people in the car so that's what I'm saying I really should be hitting 140 or better. what do you think is not right in my car? what starts to fail around 170k miles? fuel pump? throtle body? transmission?

[Street_Chally73]

Cool story, bro!!