is it just me or do 240s have horrible highend power?

[babowc]

well.. since i fixed my car and all, i took my car out for a joyride.. and i was on a straightaway in 5th and i WOT'd it.. i thought to myself, "wow, this car has NONE highend power.."

its really fun in the lower gears though.. very fun.

anyone confirm this?

[BadMojo]

Not just you. See below...

zerothread?id=133838

[babowc]

i didnt mean rpm wise, im @ 2.4~2.8k rpms when im in 5th WOT.

just doesnt accelerate after the fourth gear as well..gears 1 2 3 are fast enough for me, 4 and 5 isnt just what i expected though.. considering i was driving a v6, i guess im used to the power on the v6.

[1991S13]

Yeah, if you are in 5th gear around 2.5k you're not going to get anywhere in a hurry unless you downshift. I don't mind it though...I sit right around 3k at 65 mph so that's good enough to pass someone without needing to downshift.

[babowc]

oh.. lol i see.. im gonna go try this then

[Bigvinnie]

well if you own an s13 a couple of problems will make you feel that your not getting enough high end power.First the s13 KA's come with secondary butterfly's, good for atomizing air to fuel at lower RPM, but horrible for the higher RPM HP numbers, makes it a little less aggressive in higher RPM numbers.The 5th gear to the KA has a pretty wide gear ratio, it wasn't really meant to get you moving quickly, but it was more of a conservative gear ratio to save on fuel economy. If you reprogram the ecu "not" to run on the speed sensor or the 4th and 5th gear sensors, you can install a z20s transmission and it will make the car much more jumpy and off the line. The gear box will mount right upto the KA bell housing. If you have a digital hud you may run into speedo problems, so try to keep the speed sensor, it was also used as an emissions device to conserve fuel...

[Bigvinnie]

Sorry to repost here are the gear ratio's. Z20s transmission 1981 ONLY1st: 3.321, 2nd: 2.077, 3rd: 1.308, 4th: 1, 5th: 0.864

Z22s transmission 1981-831st: 3.592, 2nd: 2.246, 3rd: 1.415, 4th: 1, 5th: 0.813

Here is where I got my info from:http://www.gracieland.org/cars....html

[InsanityInc]

i didnt mean rpm wise, im @ 2.4~2.8k rpms when im in 5th WOT.

just doesnt accelerate after the fourth gear as well..gears 1 2 3 are fast enough for me, 4 and 5 isnt just what i expected though.. considering i was driving a v6, i guess im used to the power on the v6.

The problem is that at that low of an RPM your engine is barely putting out enough power to oppose the frictional/aerodynamic losses at that speed.

[babowc]

yeah.. i guess i need to get over driving a v6, very different two cars.

[Bigvinnie]

You can also use the nissan pathfinder transmission from 1997- 2004.

Nissan Pathfinder 1997-2004 Transmission number FS5R30A1st: 3.580, 2nd: 2.077, 3rd: 1.360, 4th: 1, 5th: 0.811

Nissan 240sx 1989-1998 Transmission number FS5W71C1st: 3.321, 2nd: 1.902, 3rd: 1.308, 4th: 1, 5th: 0.759

The pathfinder transmission bell housing is a direct bolt on (FS) suffix is a direct fit to KA engines.The first gear to the pathfinder transmission will drag out longer than the 240sx transmission. 5th gear from the pathfinder transmission will be more jumpy than the 240sx 5th gear.
Modified by Bigvinnie at 3:10 PM 9/6/2005

[babowc]

ally ou need is just more power, it'll feel a lot better than :P

[gumby]

i dunno this is the fastest car ive had yet. maybe its the intake/exhaust mods but i have no complaints. my other one has a drop in K&N filter no resonators and a crappy crush bent 2.25" cat back. huge difference in accelaeration so i see your point. they are very restrictive stock.

me thinks its time you invested in a sytem.

[Bigvinnie]

ally ou need is just more power, it'll feel a lot better than :P

But changing your gear ratio frees up HP at the wheels :P

[InsanityInc]

But changing your gear ratio frees up HP at the wheels :P

Uh... no it doesn't. Horsepower at the wheels is always the same regardless of reduction gearing. Reduction gearing multiplies torque by the factor that it divides rpm, and since horsepower = torque*rpm/5252, if you multiply torque by x and divide rpm by x, your result doesn't change, because the Xs cancel. Shorter gearing will give you better acceleration because it will keep the car in the powerband much better after a shift. Well, usually, anyway. You can obviously go to short and actually slow your car down, but you'd have to go reaaaaly short for that to happen.

[Bigvinnie]

Uh... no it doesn't. Horsepower at the wheels is always the same regardless of reduction gearing. Reduction gearing multiplies torque by the factor that it divides rpm, and since horsepower = torque*rpm/5252, if you multiply torque by x and divide rpm by x, your result doesn't change, because the Xs cancel. Shorter gearing will give you better acceleration because it will keep the car in the powerband much better after a shift. Well, usually, anyway. You can obviously go to short and actually slow your car down, but you'd have to go reaaaaly short for that to happen.

HP increases acceleration does it not? Less frictional, and smaller rotational mass that incurrs heat would increase HP numbers at the wheels. Reducing the 5th gear is freeing up numbers. It takes more power to drive larger gears, hence having a slower car in fifth gear. But I see where you are coming from.

[Bigvinnie]

You can always optimize your gearing to increase your 1/4mile times, but that doesn't mean that you will reach a higher top speed. Implementing a larger ratio 5th gear will increase acceleration, but it will make your car lose what ever top speed it once had. Your giving up top speed for a faster 5th, but the margin in numbers lost in top speed wouldn't be that much, to give up for a faster car.

[InsanityInc]

HP increases acceleration does it not? Less frictional, and smaller rotational mass that incurrs heat would increase HP numbers at the wheels. Reducing the 5th gear is freeing up numbers. It takes more power to drive larger gears, hence having a slower car in fifth gear. But I see where you are coming from.

It doesn't take any measurable amount of power to drive a larger gear. You're talking a difference of MAYBE .5hp, and also the difference would be felt in all gears even if you only reduced one becase the transmission is always spinning all of the gears, even if none are locked to the output shaft.

The reason why your acceleration gets better isn't because you've gained horsepower, it's just that you're maintaining your power better after a shift, so you aren't accelerating at a lower power level. It would be like the difference between shifting first gear at 3000rpm, and then accelerating all the way through second gear and running first gear out to 6500, then running through what's left of second gear. You'd obviously accelerate much faster in the latter case, even though you didn't really gain any horsepower, you're just driving your engine in a more optimum range, same as lower gearing will do.

[Kenrik]

You're in the wrong gear for power you will not get any power in 5th till 80mph+ stay in 4th and rev her high but it will cut down on your MPG BIG TIME! when i'm trying to save gas I shift into 5th at 45mph but if i'm going for passing power I shift it up around 80mph

[SilviaS14KA24DE]

Exactly. In 5th gear at 2.5 you won't move. if you really want to feel a pull at 5th at 2.5rpms, down shift to 4th. If you want even more, downshift to 3rd then to 4th when you know 3rd is about to run out.

[sean8564]

just get a RB20 or 25 and you will be happy I can Give you a ride in it. if you come down to Southern fried Slide.