Ziggy682

Yesterday she was riding with me in my car, when I got stayed on the gas up until redline. When the buzzer went off, she freaked out and asked what it was. So I showed her that it goes off when you hit redline. She told me not to do it because it is bad for my car. I got a good laugh out of that.

dre_2ooo

Shouldn't this be in the Lounge?

rico05

Funny story, but this needs to go in the lounge. This forum is for FC questions and mods, not cute stories!! Sorry man!!

scathcart

Laugh at her.... but your girlfriend is right.
Shifting at redline, so far above your power peak does nothing but excessive engine wear. It won't make you faster.
Sean

darkwaveboi

enless you have an safc

scathcart

S-AFC allows adjustment for fuel across the rpm range (as I'm sure you know).
If the engine cannot move enough air to be more efficient at higher revs, shifting higher will not make a difference. If you're not moving any more air into the engine, the SAFC will make more power, but the peak will be at the same point.
My point is: chances are this guy has never dynoed his car and is shifting too high and just wearing out his engine.
Thus, his G/f is right.
Sean Cathcart

Ziggy682

So your telling me I can't shift my RX-7 at 7000 rpm? The point of shifting at that rpm is to drop down into the fattest part of the torque curve for the fastest acceleration. And yes, my car will pull hard to about 6800 rpm, which is where I estimat peak hp is. Anyone else think running a rotary to 7000 rpm is particularly bad for it? I've red several places(Atkins Rotary comes to mind) where they recommend you take it to redline regularly to avoid carbon deposits. Just my thoughts.

Agent_D

iTrader: (2)

peak poer for 86-88 is 6500, redline buzzer is at 7000, shifting 500 over peak, the power hasnt even started to fade much, if its faded at all yet, remember rotaries power doesnt fade after peak like piston engines

Agent_D

iTrader: (2)

gotta make myself clearer lol, Rotaries peak power fades, but not as rapidly as a piston*

scathcart

yeah, and your peak torque is around 4000 rpm. Shifting at 7000 would put it higher than that.
Go ahead and argue, but you're not doing the engine any good, or your acceleration. You don't need to take it all the way to redline, only to the hp peak.
Sean Cathcart

darkwaveboi

scathcart:
bottom line is ur probably right about him wearing out his engine

edit: taking it to redline is good for dislodging carbon stuck in the housings, but we were talking about useless wear on an engine which has already seen its peak power.

Does anyone else here have a 'problem' where when you get up to 8000 (series 5) the shift **** starts shaking unbelievably harsh?

rico05

For a series 4, I must agree with Sean. No need to shift that high all the time. I shift my 91 that high (7700 RPM) because I have 0 emissions and mods that allow for power up that high, as well as having a higher stock redline than you. It is good to shift that high every once in a while, but not all the time. Save your gas, and you seals. Shift at 6500 unless you have mods. Put it on a dyno if you don't beleive us.

Ziggy682

Well, when I bought my car the 6 ports weren't activating from lack of use. The actuators are hard to push down, and the valves get stuck when you try to move them. I had to wire them open until I can pull the intake manifold and clean the valves. This effectively kills by bottem end torque. I also do have a couple of mods now, I just haven't updated my sig. Like I said, I can feel power start to drop off about 6800 rpm, but I have little torque down low. Because of this I can accelerate faster shifting at 7000 than I can shifting at 6500.

scathcart

What are your mods?

Ziggy682

Only a high-flow cat that eliminates the pre-cats with straight pipe, and a K&N cone intake. I know what you're going to say, I need to do exhaust before intake. Yeah, I know, I just got a good deal on it. Exhaust is coming next though(Unless I buy a Turbo II).

hyperdaddy7

when i race my car i shift out of first at 6500, then i drive second all the way to redline and third gear all the way to redline (usually the race is just about over by then and shifting would just slow me down). I can feel the power drop after 6500 in my car too, and i usally pull the most on cars in second so i like to get into that gear as quickly as possible but with a lot of power.

Mark S

iTrader: (1)

When going for max acceleration, in 95% of cars redline is the best place to shift. What you're trying to do is maximise the ammount of area under the horsepower curve, and unless you're curve is extremely irregular, thats going to happen shifting at redline.

I've been told this by instructors at my local driving school, and it's also in "sport car and competition driving" by paul frere as well as several other books I've read.

Ziggy682

AMEN!

Poindexter10thae

iTrader: (2)

The peak power point in a N/A Rx7 is around 7200-7400 RPM, anything past that is really pointless. Plus, if you are shifting beyond that pint, that is time you are losing by not shifting and accelerating even more

Agent_D

iTrader: (2)

86-88 n/as make 146bhp@6500rpm, and 138ft lbs @ 3500, and between 100-115 of that torque is maintained all the way to redline at 7k, and the hp usually drops off by like only 2 or 3hp. shifting at 7000rpm you get set back to 5000rpm, where peak torque has only dropped slightly and where a good chunk of power is made, so it has balance when shifting at 7000rpm, a balance between torque and hp on the next gear.

peace

Ziggy682

I actually did a little experiment today. Shifting from 2nd to 3rd at 7000 rpm drops me down to about 4600 rpm. Shifting from 2nd to 3rd at 6500 rpm drops me down to about 4200 rpm.

So I wanted to see how long it would take me to accelerate from 6500 to 7000 in 2nd, and from 4200 to 4600 in 3rd. (I know this sound kind of confusing.) Basically this will accelerate over the exact same speed, which is somewhere around 60 mph.

Anyway, it took about twice as long to accelerate from 4200-4600 as it did to accelerate from 6500 to 7000. Most of this is due to gearing, and not to hp or torque.

Conclusion: In my car, I can accelerate faster shifting at redline than shifting at 6500. Anyone see any flaws in this?

Agent_D

iTrader: (2)

a *quick* shift will put the rpm's at 5k shifting at 7k

RX-7Impreza

I agree with Ziggy's last post..... peak power doesnt really matter at all. what matters is if you have more power hitting the ground at 7000 in second or 4200 in third. there is no point in shifting at your peak power point because you still have power after that. and probably more power than you would if you dropped it into the next gear at 6500

lamens..... you just wanna keep on the top of the torque and power curve as much as possible and shifting early will put you further back

Justin

MaxRX7

yup

yes
maybe they want to sell you a rebuilt engine after you blow it nah, they will never do that

Agent_D

iTrader: (2)

today i went out and checked rpm's, i shifted at 6500 and it sent me to 4800rpm, and 7k sent me to 5200rpm, but *I sHiFt MaD qUiCk Yo* lolol