what rpm should i leave at Jekyl? - Toyota Nation Forum : Toyota Car and Truck Forums

clem · 10-27-2005, 08:00 AM

Am gonna debut my jdm mr2 at the track this weekend and was wondering what rpm i should leave at? the lenth of our track is 1000 feet !

***MRQtwinturbo*** · 10-27-2005, 08:43 AM

every car is different and it also depends on driver skill....get a few practice runs in first before you can determine your optimal launch rpms....

JekylandHyde · 10-27-2005, 09:21 AM

Is this a basically stock turbo MR2?

A good palce to start is 5000-5500 rpms with clutch slip or else you will spin them.
What tires are you using? (tpye and size).
Is this a prepared track or street surface?

semi-charmed · 10-27-2005, 12:15 PM

so basically J&H you're saying, in general of course, a good way to start off the line is to rev her up between 5000-5500 rpms and then ease the clutch in as opposed to just dumping it?

also, when accelerating through the drag...where should your shift points be...i know this all depends on your car and your tuning setup...but let's say for a mostly stock MR2 turbo

JekylandHyde · 10-27-2005, 12:32 PM

Dumping the clutch is almost never ideal.

Shift points, this is a quote of me from the mr2oc.com:

Quote:

Originally Posted by JekylandHyde

***EDIT** There was an incorect gera ratio listed in here.
Teh correct 3rd gear ratio is 1.258:1

Please feel free to post anything that contradicts the following information. I am merely sharing what my research has found.
Nothing below is written in stone (As far as I know

)

Shift point information:

http://www.lingenfelter.com/shiftpoint.asp

http://www.allpar.com/eek/hp-vs-torque.html

http://realbig.com/miata/miata/1995-12/910.html

Using the formula on the third link, my car should be optimally shifted well beyond redline ... and I do shift at redline.

Formula:
Lower gear ratio / higher gear ratio X RPM at peak Torque = Shift RPM

Using the same formula for a stock CT26 MR2, I get shift points:
1st --> 2nd = 6595 rpms
2nd --> 3rd = 5643 rpms
3rd --> 4th = 5595 rpms
4th --> 5th = 4915 rpms

Hope that helps.

Notice how the following both have the peak torque at the same RPM?

276 HP CT26
http://www.turboforum.net/dyno/image...ns/dyno276.jpg

161 HP CT26:
http://www.turboforum.net/dyno/image...redmr2dyno.gif

Same turbo, same shift points

clem · 10-27-2005, 12:35 PM

i have hks cams 264`s on the intake and the exhaust upgraded exhaust a hks intake and i am running 10 pounds of boost!

onehotcamry · 10-27-2005, 03:17 PM

man, turn that boost up a little. Your car can take it. A stock mr2 can take it.

Piddy · 10-27-2005, 04:09 PM

Yea.... a good condition MR2 will run up to 12psi.... why are you limiting it to 10?

semi-charmed · 10-27-2005, 04:31 PM

I calculated the shift points for the N/A 5S-FE using the same formula above:

1st --> 2nd = 7374 rpm
2nd --> 3rd = 6523 rpm
3rd --> 4th = 5658 rpm
4th --> 5th = 5516 rpm

Just in case anyone's interested

glish_dreams · 10-27-2005, 07:03 PM

if you cant get ahold of a shift light.. if i was you.. id find out which RPMs you can speed shift..

you know what that is right.. shifting without the clutch.. doing that on drag strips give you good time...

other then that.. id just runn the gears out as long as you can.. pretty much go for the redline half way mark..

***MR2Jedi*** · 10-27-2005, 08:35 PM

if you go redline in every gear, you will miss your optimum shift/torque points..thats where the power is to pull you thru the next gear quickly.not to mention over reving the engine and shortening it's life.
clem, take the Doc's advice, there's a reason he takes home all those tropheys.

Piddy · 10-27-2005, 08:41 PM

Quote:

Originally Posted by glish_dreams

if you cant get ahold of a shift light.. if i was you.. id find out which RPMs you can speed shift..

you know what that is right.. shifting without the clutch.. doing that on drag strips give you good time...

other then that.. id just runn the gears out as long as you can.. pretty much go for the redline half way mark..

You are stupid...

***MR2Jedi*** · 10-27-2005, 08:46 PM

^

glish_dreams · 10-28-2005, 02:23 AM

well its the way iv always done it on my 4g63 mitsubishi motor . DOCH 2.0L 180-195hp 205tq
rpm0-9speed 0-145
boost -3 0 7 14
rpms 7red start
8middle----id shift right about here..
9last red line

never had a problem.. and i always won, even if i didnt on take off..

Piddy · 10-28-2005, 02:30 AM

Well I suppose if you have a 80hp advantage on the 4 door, single cam civic you are racing.... you can still drive like an idiot and win.

You should search around and get a feel for the forum before you go posting stupid comments. Especially when it is explained several times in the very thread that you are posting in as to why your comment is stupid. And if you think shifting without the clutch is faster and/or cool.... you are an even bigger idiot. Peel your eyes away from the movie screen..... we are real people... with real cars... that go real fast. Welcome to the MR2 section of ToyotaNation

Now lets get back on topic...

Quote:

Originally Posted by semi-charmed

I calculated the shift points for the N/A 5S-FE using the same formula above:

1st --> 2nd = 7374 rpm
2nd --> 3rd = 6523 rpm
3rd --> 4th = 5658 rpm
4th --> 5th = 5516 rpm

Just in case anyone's interested

Yikes!! I dunno about that. The redline on NAs is around 6,200rpms. Plus the 5sfe kind of falls off around 5,500rpms anyways. You might want to redo your math before you hit the strip.