What RPM Do You Shift At?? Options

[Curvie Roadlover]

This topic came up on the other BBS and I read lots of interesting opinions. I'm wondering what are the thoughts of the folks on this BBS. It seems to me I have been shifting too early and cruising in too high a gear. I was cruising at about 2400, maybe I shoulda been down a gear and running a higher RPM. Also, on a stock 2.0 at about what mph on the freeway do you take 5th gear? (IMG:style_emoticons/default/driving.gif)

[need4speed]

I've always heard that the traditional school of thought for aircoolds is that you want to cruise on the mid to high end of the RPM range, to keep more air flowing over the heat fins. Makes it a bit of a gas hog tho.
(my Ghia with the stock 1600 dp gets 36mpg freeway).

driving with neither a tach, nor a stereo, I've learned to listen to the music of the engine. For a while, I drove with no speedo either - and I could tell roughly how fast I was driving by the engine tone, and gear.

I really can't wait until I get a teener. :loveletter:

[SirAndy]

yepp, no numbers to tell. i drive by listening to the engine.
have not looked at the RPMs in quite a while.

but i did remove the RPM-Limiter within the first week of driving the car,
so i must hit the 5000 frequently (IMG:style_emoticons/default/cool.gif)

[Curvie Roadlover]

I used to shift by sound as well and never really paid much attention to the tach until just recently. I was riding with other people and thinking, man, these guys really run up the rpms before shifting. Then I started thinking maybe it's me whose not running the rpms up enough! So that's when I started watching the tach. I'd like to know what people think is a good range rpm-wise for a given gear.

[SirAndy]

i suppose that very much depends on your engine setup and the gearing of your transmission. i remember that brad had some dyno charts that showed RPM/HP ration on a stock 2.0L ...
damm alzheimer kicking in, but somehow the number 4600 comes to mind to be a good shifting RPM. you want to be OVER the top HP for that gear when you shift up so you hit the HP peak for the next higher gear right away ...

anyone here with the real numbers?
Andy

[Bleyseng]

ask and you shall receive, Andy.

[SirAndy]

ask and you shall receive, Andy.

thank you sir,
sooooo, 4600 seems about right ...

Andy

[Bleyseng]

I try to shift around 5000rpms when AXing, to keep in the power band. My motor is non-stock so that dyno is alittle off for a stock motor but still close. Running a motor to 6000+ is a waste of time.
Geoff

[Joseph Mills]

This topic came up on the other BBS and I read lots of interesting opinions.

I think this is a good topic. Being a relative newbie to 914s, I probably have way too many observations (read Obsession).

For both the street and AX, I usually shift by ear. When the engine sounds happy, I shift up. However, having said that, with my new 914, I have started taking note of tach readings and have started making adjustments, both for the street and AX. Here is what I have found.

For the street I usually short-shift before 3k - I like to semi-bury the throttle for 2nd and wind it a little higher - kinda fun. For 2nd & 3rd I go to 4k+. I usually cruise down a street at 4k. Keep the air flowing. It's noisy. So what.

For me the freeway is a chance to let it breath. Coming off of on-ramps I usually take it towards 5k and then slow down and merge left with traffic. Keep it above 3k and when needed, shift down for slower highway traffic. For me, 5th gear on the freeway @ 70mph is about 3300rpm.

For AX I usually short-shift 1st gear - strictly for launching. 2nd gear depends on the course (depends on the first turn). Sometimes I go to 6k (my car is not stock & winds freely to 6k). However, I know the T4 is not a high winder - it's all about low and mid range torque. Recently I have started forcing myself to short shift all gears for AX, and I'm seeing an improvement in my times - even though we all know the penalty of shifting a 914 in an AX. It's called 4 feet of linkage. Early shifting may not work for you - works for me. I'm installing an adjustable rev-limiter and shift light to help me shift before 5k instead of 6k.

I guess for the street, I'd say don't lug it around - wind it higher than you think you should. Cruise at 4k.

For AX, I say shift the damn thing. You'll go faster.

my 2.0L cents

[Lawrence]

Running a motor to 6000+ is a waste of time.

Might be a waste of time, and a waste of fuel... but, damn, it feels good.

While puttering around town, I probably shift aroun 4000-4500. During spirited driving, 5500 or so... once in a while I tag the rev limiter. (IMG:style_emoticons/default/smile.gif)

-Rusty

[Bleyseng]

Rusty, you are driving a 6 which is way different! No fair!
Geoff

[Lawrence]

Anytime you want to drive it, Geoff... all ya have to do is ask.

I'm pretty free with the keys.

-Rusty

[Joe Bob]

I shift when the rev limitter won't let me go any farther..... (IMG:style_emoticons/default/blink.gif)

[Joe Bob]

Off to the kids first communion....beautiful day in Santa Barbara.....

[Bleyseng]

Nice pic of the girls! which one is the artist? which one wants to drive at the AX?
which one is daddys girl?


Rusty, next time I am near your neck of the woods I'll take you up on that. Hey, maybe you could get stationed at Fort Lewis! Only 30 to the AX course at Bremerton.

Geoff

[Brad Roberts]

We shift the 2.0 cars at 5K when on the track or AutoX. Typical race people say to shift 400-500 RPM over peek torque. I shift the cars at 3500 when beusting around town.

Anybody notice the date on Geoff's dyno run ??

9.16.00


B

[Jeff Krieger]

We shift the 2.0 cars at 5K when on the track or AutoX. Typical race people say to shift 400-500 RPM over peek torque. I shift the cars at 3500 when beusting around town.

Anybody notice the date on Geoff's dyno run ??

9.16.00


B

The owner's manual for my '73 2.0 says that max. torque is 105 lb*ft at 3500 rpm. Shifting 500 rpm over peak torque would be about 4000 rpm. I'm no expert but that does seem a little low.

[Bleyseng]

I think they mean peak torque is just before the torque curve falls off which is at 4500rpms if you look at the chart. The torque curve is really flat from 2000 to 4500 rpms without a spike that you could call "max torque" unlike the hp curve.
So I shift at 5000..........
I lost the newer dyno chart so I posted the old one. 95hp at the rear wheels is the best my car has done.
Geoff

[Brad Roberts]

Correct.

We are running a nice header and free flow muffler. My torque curve is not the same as the factory on a 100rwhp engine.

B

[Bleyseng]

How do you get more hp above 5000 to 6000? Impossible due to the Djet? the cam?
5300 rpms and then it drops like a lead zepplin!
Geoff