shifting question

[KkiepCcaSsau]

i just got a 90 240 Couple with exhaust and intakei just wondering when is best to change gear (RPM) ?i'm driving stickshift not very long ,

[ilovedrifting]

i usually shift around 3,000, but i don't know if that is the best time to shift or not

[Dattebayo]

DO you mean for racing or what?Around town would be 3-4K i guess. But if you are racing it or just on the freeway, i would go with about 5-700 rpms before redline so you drop back in the next gear right into the beefy powerband.

[KkiepCcaSsau]

i have a prelude si automatic and when i drive 240 i feel likeit much slower. 1st and 2nd gear i feel like loosing alot power .my cat coverter is not tight up , could it be the problem ?

[Axel Grungy]

i dunno it shouldnt feel that way, maybe its just you lol. off the line 240s have lots of torque so it would be faster. but then again something COULD be wrong i dunno. if you get a rotten egg smell your cat conv. is gone. but i wouldnt think that would be the case for it being slow.

[Thee 240sx Owner]

could be many things.. bad fuel filter, fuel pump, clogged injectors, bad spark plugs, mechanical timing is off, ignition timing is off, running cheap gas, bad MAFS, Air Temp senor, Coolant temp sensor, O2 sensor (which all controls mixture) so you have to be a bit more specific in your statement

[elbles]

When I'm just driving normally, I'll shift anywhere from 2500 RPMs to 2700-2800 RPMs or so. And a 240 should feel plenty quick down low . . . it's a torque-filled motor. :-)

[KkiepCcaSsau]

i dunno it shouldnt feel that way, maybe its just you lol. off the line 240s have lots of torque so it would be faster. but then again something COULD be wrong i dunno. if you get a rotten egg smell your cat conv. is gone. but i wouldnt think that would be the case for it being slow.

240 have alot of torque , i'm not so sure about that

[Fenvy]

i shift at 3k for normal driving and 6k for trying to go fast. for some reason I dont feel the power after 6k so I dont even bother to redline it

[Dattebayo]

youre not sure if 240's have tourque?

There must be something wrong with your motor then cause you dont hear anyone else having doubts about it.We would not give you some line about "our cars are better" cause we know they are relativley slow. But for sure they will rocket you off the line cause they DO have mean torque.

I cannot tell a lie...

edit: wait a minute... just how big is your exhaust?

[KkiepCcaSsau]

i know 240 have good amount of torque for 4cycl . '' Axel Grungy '' he said '' off the line 240s have lots of torque so it would be faster '' to me i think prelude SI is faster and more torque

my exhaust i would say average , because i see other exhaust are bigger than my .

[KkiepCcaSsau]

i bought the car with it . what branch it is , i don't really know

[zdude]

good thinking 2bn, if your exhaust is too big, you will lose torque, but i think gain high end?? or lose power overall

[Dattebayo]

well the exhaust thing is one.

But the real deal is that prelude SI's have less tourque than even 240's do because they are a short stroke motor with less displacement than 2.4 liters. I need a dictionary definition of torque here people. Roughly described it is how quickly you can apply maximum rotational force to the wheel. Its a form of mechanical advantage and time. If you dont believe it, than look at the stats.

'87 Prelude SI -- 110hp, 114 ft-lb (stock), weight ~ 2800.

'91 240SX SE --- 155hp, 160 ft-lb (stock), weight ~ 2800.

[KDashy]

Wow, even with the rear wheel drive power loss, The prelude can't make up for 46 foot pounds. not to mention the torque curve on a 240 is pretty flat.

[KDashy]

And I beleive he has a 92 Si, which is a gen up. 160 HP@6000 / 148 TQ @5000

[Dattebayo]

if your 240 is SOHC than that could definately be the issue.91-98 had a DOHC that is beefier in every way.

SOHC 240's suck in my opinion, even to your supposed 2.3L prelude.

[i2ice4m3]

torque is the product of force and distance from the point where the force is applied to the pivot point. so i guess a shorter stroke motor means a crankshaft with less distance from the point it connects to the piston to its axis of rotation. If the force applied to each piston in each motor were equal, the longer stroke motor would experience a greater amount of torque rotating the crankshaft.

[KkiepCcaSsau]

240sx is fun car to drive , my is not SE . i want SE couple front bumper and spoilder . there's a guy try to sell me his spoiler and Trunk for 100 $ . He also has a set SE rim for $ 200 no tire . u guys think is good price ?

[KkiepCcaSsau]

there was a mistake that '''KDashy '''' post dohc I4 2.3 160 Hp 156 Torque

http://auto.consumerguide.com/...tions

[eliterit]

240 has lots of torque.

i like driving it more than my b13 se-r because of the torque down low. The sentra is good for top end so its faster when you rev it higher, but around the town driving the 240 is so much fun to drive.

btw, it maybe because you have the sohc. that one only has 140 hp compared to the dohc motor which has 15 extra hp

[KDashy]

there was a mistake that '''KDashy '''' post dohc I4 2.3 160 Hp 156 Torque

http://auto.consumerguide.com/...tions

Sorry my bad. I was just trying to correct him because he listed the wrong prelude.

[Dattebayo]

torque is the product of force and distance from the point where the force is applied to the pivot point. so i guess a shorter stroke motor means a crankshaft with less distance from the point it connects to the piston to its axis of rotation. If the force applied to each piston in each motor were equal, the longer stroke motor would experience a greater amount of torque rotating the crankshaft. torque doesnt have anything to do with time (ie. how "quickly" it can be done). i believe that'd have something to do with horsepower.

horsepower is a function of torque, and both include time in their equations. Otherwise a function missing one variable could not be used to equate the other.

Time has everything to do with it.

[i2ice4m3]

horsepower is a function of torque, and both include time in their equations. Otherwise a function missing one variable could not be used to equate the other.

Time has everything to do with it.

i am sophomoric. you're right

[PhaneSoul]

good thinking 2bn, if your exhaust is too big, you will lose torque, but i think gain high end?? or lose power overall

http://www.nissaninfiniticlub....haust

some claim there is no loos at all, and instead gains up top. ive also seen a dyno on this site somewhere stating that a bigger exhaust lets the car breath better and yeilded like 15ish hp and about the same torque gains. ive searched for about 30mins now and i cant find that dyno, sorry. but think of it like this, if you have a smaller exhaust, then it takes more energy to push the exhaust out, however if its bigger, then it doesnt have to push as hard, making it easier for the **** to rotate. instead the big exhaust creates a small vaccume. thats why it backfires, cuz extra gas is being pulled out of the cylinder and egniting from the exhaust heat.

feel free to correct me if im at all wrong.

[EastCoast240]

i dunno it shouldnt feel that way, maybe its just you lol. off the line 240s have lots of torque so it would be faster. but then again something COULD be wrong i dunno. if you get a rotten egg smell your cat conv. is gone. but i wouldnt think that would be the case for it being slow.

This is wrong....if you smell rotten eggs it is simply sulphur burning in the fuel. Ever notice how some oil companies offer sulphur free gas?

[i2ice4m3]

so if you're able to smell it wouldnt it mean something is wrong with your cat. since it doesnt normally smell liek that?

[nab911]

i have a prelude si automatic and when i drive 240 i feel likeit much slower. 1st and 2nd gear i feel like loosing alot power .my cat coverter is not tight up , could it be the problem ?

If you are leaking exhaust before the cat and muffler it wont have enough pressure to open the egr valve and it will caust it to run bad. Get that exhaust leak fixed.

[KkiepCcaSsau]

i'll get it in the shop again to tight up the CAT. my friend try to sell me a set of rim 92 240 SE Couple for 200 $ and spoiler with trunk for 100 $ is it good price ?