# Reving question



## Loki (Jan 12, 2004)

hey guys im just wondering what can be the highest i rev my car for drags ( yes its in a track) i usually shift it at 7k.....my engine is a bit old like 202k miles on it.......i have hot shot headers, injen intake short ram (soon cold air) apexi n1 exhaust with full 2.5" straight piping......a stage 3 clutch, stock plugs and ngk iridiun IX plugs. Engine responds perfect on everything....the thing is when i take it to 7k i feel it can take more, im just wondering if i should do it or leave it as is....what do you guys think?


P.S.... its not an every day thing when i do this , maybe like Fri, Sat, and only 5 runs at the most.

Also adding the cold air extension...how much hp would i gain extra?....3 maybe?

thanks in advance


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## Loki (Jan 12, 2004)

21 views and no one has an answer? oh come on!


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## ckykm (Apr 22, 2003)

you really dont need to run it up to 7000rpm..the KA runs its top power at about 6000rpm


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## ckykm (Apr 22, 2003)

but it might be different with all that stuff you got on it...but im not sure...the cold air might add about 5-8 hp


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## Loki (Jan 12, 2004)

ckykm said:


> but it might be different with all that stuff you got on it...but im not sure...the cold air might add about 5-8 hp


thanks......hope some one around there has a similar set up...and might know what it should be best...im gonna try shifting from now on at 6k instead of 7k....this way i save time.


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## CA18FASTBACK92 (May 26, 2004)

If I were you, I would never rev it past 6200 rpm or so. The ka24 runs out of air above 6000, and all you are doing is making noise instead of power. By the way, what kinda times are you running?


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## Loki (Jan 12, 2004)

CA18FASTBACK92 said:


> If I were you, I would never rev it past 6200 rpm or so. The ka24 runs out of air above 6000, and all you are doing is making noise instead of power. By the way, what kinda times are you running?


thank i will try that to see how it goes.......well...i havent timed myself yet, i want to do a dino first , also want some suspension upgrade....im really not sure what time i would get on a 1/4


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## lshadoff (Nov 26, 2002)

NPM has a dyno chart for the stock KA24DE. The HP max is at 5200rpm. For the best results in drag racing, you want to shift at an rpm which will put you below the HP max in the next gear. That way you run through the max in each gear. 

The gear ratios in the 1994 FSM are:

1 - 3.321
2 - 1.902
3 - 1.308
4 - 0.759

1 -> 2 = 0.5727
2 -> 3 = 0.6877
3 -> 4 = 0.5803

Looking at the dyno chart, if you shift at 6800rpm:

1 -> 2 you will be at 3894rpm
2 -> 3 you will be at 4675rpm
3 -> 4 you will be at 3946 rpm

All of these are below the HP max. If you shift at a lower rpm, the engine will be in a lower portion of the power band in the next gear. The only gear you might gain by shifting at a lower rpm is the 2 -> 3 shift since you are shifting to just below the max when you shift at 6800rpm.

Lew


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## fugiot (Jun 27, 2003)

There's a certain way to figure this out but I forgot how. The idea is to have each gear start at a distance(rpm wise) below the peak power and end at roughly that same distance above the peak. Leaving the peak roughly in the middle of each gear. But it also takes the torque curve into account somehow, so I'm not really sure how to figure it out.

I know on SR20DEs, the optimal shift points are:
1>2 - 7500rpm
2>3 - 6800rpm
3>4 - 6300rpm
4>5 - 6100rpm

But that's a completely different power curve.


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## bridrive55 (Aug 26, 2004)

Wow, an impressive 120rwhp on the KA24DE. Ouch.


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## Loki (Jan 12, 2004)

lshadoff said:


> NPM has a dyno chart for the stock KA24DE. The HP max is at 5200rpm. For the best results in drag racing, you want to shift at an rpm which will put you below the HP max in the next gear. That way you run through the max in each gear.
> 
> The gear ratios in the 1994 FSM are:
> 
> ...



Thanks Lew your awsome! but im a bit dumb so let me see if i got this straight... i usually rev to 3000 - 3500 for my launch...so than i should shift to second at about 5800........than to 3rd 6900 and 4th at 5800...... that is kinda what i understood, i hope i got it right. since ive always shifted at 7k....and i mean ALWAYS.........looks like ive reved it in vain, since it was lacking power on those high revs....


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## lshadoff (Nov 26, 2002)

Loki said:


> Thanks Lew your awsome! but im a bit dumb so let me see if i got this straight... i usually rev to 3000 - 3500 for my launch...so than i should shift to second at about 5800........than to 3rd 6900 and 4th at 5800...... that is kinda what i understood, i hope i got it right. since ive always shifted at 7k....and i mean ALWAYS.........looks like ive reved it in vain, since it was lacking power on those high revs....


Shift at:

1 -> 2 6800 rpm
2 -> 3 6300 - 6400
3 -> 4 6800

This will put your engine at about the same power level as before the shift in each gear.

Lew


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## Loki (Jan 12, 2004)

lshadoff said:


> Shift at:
> 
> 1 -> 2 6800 rpm
> 2 -> 3 6300 - 6400
> ...



Thanks LEW!!! ore no Sensei!!!! oyajii!


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## Sixways (Jan 12, 2005)

what happend to racing by feel ay? (no one laugh now) but when I "drag" my pulsar I shift when I feel the power start to fade, this is at about 5,500rpm. wow that's really sad to see it writen out. anywho that's my solution.

To add to the question, CA18FASTBACK92 said that the KA runs outa air above 6k, would a turbocharged KA act any differently? or would most people use the same shift points? just trying to cover all bases thanks :cheers:


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## bridrive55 (Aug 26, 2004)

I push mine all the way to 7 every gear. I run a T04E on my 1997 S14 KA.


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## bridrive55 (Aug 26, 2004)

Loki said:


> Thanks LEW!!! ore no Sensei!!!! oyajii!


Sensei ni naru no muzukashikunee naa...


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## Sixways (Jan 12, 2005)

Loki said:


> Thanks LEW!!! ore no Sensei!!!! oyajii!





bridrive55 said:


> Sensei ni naru no muzukashikunee naa...


............................... k


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## bridrive55 (Aug 26, 2004)

Nihongo wakaranee no ka? Choubaka da naa, omae!


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## Loki (Jan 12, 2004)

bridrive55 said:


> Nihongo wakaranee no ka? Choubaka da naa, omae!



urusee naa kasuyarou!....temee ha baka :fluffpol: 

ore no nihongo ha chotto.... lol

temee no nihongo ha yabe!


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## Loki (Jan 12, 2004)

ok so back to topic!.......... so im guessing i will take Lew's advice on this one.... unless any one can proof him wrong....highly difficult.....he is after all......the ROBOMOD! :hal:


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