Time to argue?! When to shift

Ok, now the last forum i was on i got a huge debate started over this one. And these were all domestic car owners so im interested to see your point of view.
Ok, i race often (not in the winter though) and can say i am the best five speed driver that i have seen in these parts. Not saying there isnt better of course but the one thing ive been told is that im impressive by shifting w/ out letting go of the gas peddle and not ever hitting my rev limiter. Now the BIG question is when do you shift?? Now stop and think before responding. My Cougars' peak HP is at 6400RPM, and my peak torque is at around 5400rpm's. I shift at my peak HP, sometimes missing it by 200rpm's but you get my point. My strong belief is that you shift at your peak HP. Some say you lose to much rpm's when you shift so you should shift near or on the redline. I say wisetail, if you can shift very well and shift at peak HP your torque which is just below your peak HP will bring you back up to peak HP(quickly), right?! I only lose 750rpms(+- 250rpm's) when i shift, so i stay strong in my belief that you should shift at or close to your peak HP when racing, and not to bury your tack at every shift. Now your thoughts.

[ford50forlife]

hmmm thats a good plan but when i race i usually dont powershift i have to let off the gas so i can make it home because my tranny always locks out gears (t-5 suprise) so i usually just use the race to see my shift points.... if im being pulled on (cause i always get off the line when i had posi) i use the race as an indicator when to shift, when i raced a del sol with gsr swap and turbo i was being pulled so i shifted @ 6200-6500 to compliment my granny shifts.

I say if you powershift then peak hp is when to shift so when you dab the clutch you have a little leeway before redline before you tach it overkill style and it wont be bad to build the gear again. if you granny shift like muoy you want every bit of rpm before you shift because the revs drop hard and have to build up more...

P.S. DO NOT ****ING TRY TO SHIFT A STOCK MUSTANG @ 6.5K or you will blow sumthing high rpm intakes help.

[ChrisCantSkate]

2rpms befopre fuel cutoff nah... it depends... some engines will make power past their fuel cutoff(h22 for example) others dont (single cams usualy dont) not letting off the gas pedel will fry your clutch. shifting at peak hp is bad, you want to get past peak hp... so you can keep the rpms up. and the stock peak hp and tq is different from your car trust me. preludes dyno at 5500rpm-tq and 6800rpms-hp but on my friends dyno he peaked at 3250 for tq (flat the rest of the way... but still), and 6650 on hp. i say you go till about redline. think of it this way... just numers from my ass...
4500rpms you make 135hp
5000rpms you make 150hp
5250rpms you make 160hp
5500rpms you make 170
6000rpms you make 190hp
6250rpms you make 185
6500rpms you make 180
redline/6700 you make 175

when you shift at 6000 rpms you drop back down to 4500rpms thats 135hp... not good... but at 6700rpms you drop to 5500 and your already back at 170hp. this is very very basic, but i think you can see... you want to keep the power up as long as possible

Oh ill agree this is all a bit defferent from car to car! The clutch thing doesnt bother me, ive been trying my damndest to fry the clutch so i can tell my wife i HAVE to get a new one. I LOVE racing, have always got into it and realize the damage that can happen to the clutch but thats just the downfalls of racing you have to get over if your in it to race and make a name for yourself. Well so far ive gotten two to somewhat agree, thats new! Oh, i dont drop that far in my rpm's when i shift, like i said around 750rpm to 1000rpm(on a bad day). I geuss i havnt ran into having to shift differently because of the type of car i was racing. The only difference ive ran into is when to dubble clutch, or not to dubble clutch at takeoff. I built the car to run w/ my cuisins modded 2000 GS-R and it seems to race the same from race to race.

[ChrisCantSkate]

just a questions... mind telling me how to double clutch in a strait line?

I get real bad wheel spin and hopping.

Oh, thought that was a statement not a question. Im heading off to eat dinner w/ the Fam, ill be back and explain. Later!

[Racing Rice]

You should keep you motor as close to your peak power as possible, atleast thats what I think anyhow.

i say somewhere inbetween peak HP and redline, but as little as i have raced with a manual tranny, the few times that i have and from chris's info type stuff that he posted a little ways up there. I say wait till you reach 6500 rpms (im using his chart thing) and then you should drop between 175 -185 HP (once again using his chart) therefore you will still be at around the max point of your HP but still with a little buidup so you wont miss it. That is assuming like Lucky said and drop around 750 RPMs but hey i dont drive a manual or race one mostly. So this is just from what i can take from minimal driving with a stick and assumptions made through this forum.

[ebpda9]

it all depends. i've seen cars that run out of ger even before hitting 3000 rpms. i have an automagic and i run out of gear after it passes 5500 rpms, right when it makes some beasty 125 hp

[ShagginJet]

I'm lost, but keep the it coming.

[Wren57]

Yeah yeah I know I have an auto but have gotten dang good at a friend's 5spd manual civic... I have found that when you shift right before you bounce of the rev limiter, it keeps your RPMs up, which is where most Hondas/Acuras make their useable power. I have the perfect solution to let you know exactly where to shift, but the exact equation uses calculus, so I will make a quick explanation... if you have your dyno graph, and know how many RPM a high RPM shift causes you to lose, plot it on the graph with a line representing your RPM loss under the peak HP point... let me make a graph real quick and post it...

[Wren57]

forgive the crappiness of this quick drawing, but I think you will get the idea...

[nonovurbizniz]

my car starts to loose hp after 6.2k or so and if I shift before it does then I'm stuck like 1-2k away from vtec in the next gear so for me I HAVE to rev out the gear to the redline otherwise I take to long to get back up into vtec.

So to simplify I'm with chris... if you shift at your peak your dropping into dung usually but if you wring it out a little more you end up closer to you peak in the next gear.

Originally posted by highlander
forgive the crappiness of this quick drawing, but I think you will get the idea...

So judging from your drawing you would want to shift before you hit the rev limiter (obviously) but AFTER you have passed peak HP?

So hypothetically, my Civic redlines at 6,800 (which is where I assume the rev limiter kicks in) but is at peak HP at 6,500. So my ideal shifting point would be around 6,650 or thereabout?

Is that accurate in comparison to your drawing?

If so, you might as well make it simple and say "shift before redline."

[Racing Rice]

Originally posted by Ty's Si

So hypothetically, my Civic redlines at 6,800 (which is where I assume the rev limiter kicks in) but is at peak HP at 6,500. So my ideal shifting point would be around 6,650 or thereabout?

That sounds about right to me.. The best way to really tell is to dyno your car so you know exactly where the power peaks at.

Originally posted by Racing Rice
That sounds about right to me.. The best way to really tell is to dyno your car so you know exactly where the power peaks at.

Never done that. I'm a n00b around these parts. That's why I'm at these boards...How would I dyno my car?

Anyhow, I was just going on the Honda specs I have read for my car and trying to put his drawing into more practical terms.

So I guess the conclusion is to do what seems normal. Wind it until just before redline and you should get the best performance.

[Racing Rice]

Well best way to do it is, find a local shop that has a dyno and schedule some time to get it checked out. It will give you exact HP and Torque ratings this way there is no guessing, you know exactly where your car makes power.. And where it doesnt make power. Its especially a good idea to dyno your car if you do some major engine mods that way they can tune you car to make the most power by adjusting Air, fuel, spark, etc..

You may want to make sure they are a reputable dyno shop, that way calibration is correct.

[silver]

you are forgetting about gear ratios as well. my car's rev limiter is 6250, i make peak torque at 2500rpm, peak hp at 5000 i believe(that one is a guess). When I shift at the rev limiter it drops me to around 4800, I am almost out of my peak hp, therefore I am losing hp by passing my peak and taking to the rev limiter, then I only get 200rpm's of peak hp. Therefore in my instance I cannot say take it to peak(this is all to back up the shift before rev limiter idea). But, by shifting at 5200 let's say, it will drop me down to 3500, well past peak torque which means that if that is a shift into second gear i lose. So every vehicle is different, based upon where the peaks are and the ratio of the gears.

"do you here that, our son is going to hit his peak"
"doug, if you're gonna hit your peak, do it in your room"
-who knows what movie?

Originally posted by Racing Rice
Well best way to do it is, find a local shop that has a dyno and schedule some time to get it checked out. It will give you exact HP and Torque ratings this way there is no guessing, you know exactly where your car makes power.. And where it doesnt make power. Its especially a good idea to dyno your car if you do some major engine mods that way they can tune you car to make the most power by adjusting Air, fuel, spark, etc..

You may want to make sure they are a reputable dyno shop, that way calibration is correct.

Thanks Rice. I'll check that out. I have a good friend who knows his stuff and is going to help me make some modifications hopefully in the near future. I'm just trying to get up to speed.

Yes there are two different ways to "double-clutching". One would be used for actual "road races" for downshifting, the other is when you have my problem and that is real bad wheel spin or hopping. Check out the attach file. If you need details let me know. All i know is if i dont double-clutch ive lost the race from the getgo. So far though i agree w/ evryone on where to shift. I wouldnt axcactly say i shift right at peak because i end up about 200rpms past peak HP, but for you V-tech guys i would use a deserted road and test how much rpm drop you get when shifting and do your own V-tech calculating on where to shift. But dont be like some and think you need to tack it out to keep on the powerband. Remember, the amount of time your burning on going to your redline could be longer than shifting right after peak hp then having the motor revving back up to peak hp. Get out your timer, ive done some testing on MY car and have found its better to shift at or a little past peak than to go to redline just to keep your rpms up. But once again my peak torque is just below my peak hp which helps me jump back up to the "powerband". Well, that probably made no since but i tried. Thanks!

Where's the attached file? Or am I missing something...

sorry it didnt work, just search "double-clutching" and it will pull up a bunch of info on it! Sorry.

[Spazum888]

redline the *****!!!!

at 2000rpm

why?

To get better gas mileage

[Addict]

I think I'd have to agree with ford50, it depends on the race.

I usually shift at about 7900-8000 RPMs. My redline is 8200, but my MSD 6AL cuts spark at 8000 RPMs. Peak TQ is at 7200, Peak HP is at 7600. I shift higher to account for the drop in RPMs. I don't consider myself a "great" stick driver.

I gotta go along the lines of what Silver is saying.

Highlander, when you drew that wonderful power curve did you mean the RPM lost to shifting is due to gear ratios or time? If it's gear ratios then I'd say your chart is the way to go, if it's time then the chart isn't so useful.

If you lose 500 RPM due to gear ratios or 1500 RPM then it'll change where you want to shift. The idea is to maximize the usage of the power band as Highlander's chart shows (assuming the blue bar is due to gear ratios). This will vary from car to car. Swap the tranny and you may need to adjust your shift points. Also if you put in a lighter flywheel you will either need to adjust your shiftpoints or learn how to keep the revs high enough you don't drop too low on the tach when you engage the next gear.

b

Gear ratios dont play a part in where you shift as much as your saying(manuals only). It does, but not to the extent your saying. Alot of it plays in where your cam lobes are ground to. Not sure if any of you come from a background in old school 350"s and 302"s but going beyond your peak hp to far is not good. My 1971 Chevy truck has a nice 350 4bolt main that runs like a bat out of hell until i go to far into the rpm range and the cams begin to "float". This can and will happen if you go to far up the tach. Another words you are wasting time being up to far in your rpm range because your not gaining speed(you are but not as much). I dont know, it all really depends on so many variables you cant say specificly where to shift. Thanks for the info, this just proved to me the Honda Forum has alot less motor head gods that think everyone else is wrong but them. Thanks for not banning me

Originally posted by Civic_Addict
I think I'd have to agree with ford50, it depends on the race.

I usually shift at about 7900-8000 RPMs. My redline is 8200, but my MSD 6AL cuts spark at 8000 RPMs. Peak TQ is at 7200, Peak HP is at 7600. I shift higher to account for the drop in RPMs. I don't consider myself a "great" stick driver.

Maybe this coming year you can head up w/ me and a few friends to Kilcare and practice the "slam shifting". You are the one that lives in Dayton right? Wheres the big "cruise fest" gonna be this year? You should come to Eaton for its big car show, slowly but surly the shows turning into a sport compact show. Right around 500 cars last year.

[ChrisCantSkate]

gear ratios play a decent part... i dunno how far your rpms drop between gears, but when i shift at 7500 i drop almost to 5100

[Addict]

Originally posted by lucky
Maybe this coming year you can head up w/ me and a few friends to Kilcare and practice the "slam shifting". You are the one that lives in Dayton right? Wheres the big "cruise fest" gonna be this year? You should come to Eaton for its big car show, slowly but surly the shows turning into a sport compact show. Right around 500 cars last year.

Yeah I'm game for that.

Looks like Cruisefest is in Chillicothe this year. May 9th, 10th & 11th. I'll be there.
http://www.cruisefestnationals.net/

What's the name of Eaton's show?

Originally posted by ChrisCantSkate
gear ratios play a decent part... i dunno how far your rpms drop between gears, but when i shift at 7500 i drop almost to 5100

I dont drop off that bad. Maybe 1000rpm's on a bad day. When i get my car out of the shop ill double check what im quoting here on rpm's.