Shifting

[LOUDCRXSi]

I have a 90 CRX Si...I know to the V8 ppl it aint much but anyway. When i bought it i talked to my friend that had one and he was sayin when i race i could let it go alil past redline (around 6700 RPM and redline is at 6500RPM) to get better shifts. He explained how just the lil bit over redline will start to decrease dramtically so when i goto shift i will hit the next gear harder. When i went to the track i experimented. I would run how he say for a few times and then at redline a few times. But when i looked at my papers the times when i shift past redline were A LOT better then when i shifted at redline.

Now could it of been the track conditions that made the difference or has anyone else heard anything like that? I mean i dont like to run it a lil past redline but if it will make my times faster on the track....WHY NOT.

[Ridenour]

That could be the way your torque curve works. All cars have different torque curves. If you don't know how the torque curve / "power band" works, let me explain. Your engine makes more power at different RPMS. That's why, it may be slow off the line, but really push you back into your seat once you hit higher RPMS. And then it may boggggg down after you get to a certain point. All engines have different torque curves, and all have ideal areas for keeping the RPM's - The power band. It's the range of RPM's where the most torque is produced. So the idea is to try to keep the RPM's in the power band as much as possible. For example, in my Grand Am, the "power band" is between 4500 to about 5500 RPMs, and the "torque peak" is 4800 RPM. So when I shift, I try to rev-match in order to keep it in that range. My car doesn't redline until 5800 RPM, but anything past 5500 in my car is lost power, I can feel it, adter 5500 it's just like bwahhhgg..........

So your CRX's torque curve could work in a way that a good chunk of the power band is past your redline. In higher spinning engines, it's often common to have the torque curve be at much higher RPM's then higher displacement engines.

Your best bet is to do some research online, and find out exactly where your engine's power band / torque peak is at. The idea is to shift out at the top of the power band, rev match, and try to land the RPM's back in the power band as much as possible.

But it deffinately sounds like your torque curve goes past your redline. Redline's are often under-estimated by the way.

So if shifting past redline helps get more power out of your power band, I'd say go for it. I just wouldn't do it on a regular basis, due to the fact that it's probably pretty rough on that engine. I mean just save it for when your racing.

[kingpinn]

Ridenour your a smart man

[Ridenour]

LoL thanks Kingpin. I acclaim most of that to all the other brilliant people here on AF from whom I have absorbed so much knowledge LoL

[LOUDCRXSi]

yeah good looking out on that man....I was gona get my car dyno'd after once i get tires on. Then ill have the torque curve. Thanx a lot.

[Ridenour]

No problem. You'll probably see a torque curve that starts off low, and gets really high in the high RPM's, keeps going up after redline, and then suddenly drops off a couple hundred RPMs after redline.

I've always wanted to get my car dynoed, but unfortunately I can't find any friggin places around here that can do it. Have fun with yours.

[LOUDCRXSi]

are that how most honda's are? or you just assuming? nothin wrong with that.
Where do you live?? i know around my way theres a good bit of places that dyno.

[Ridenour]

Well that's the way lots of high-revving, low-displacement engines are, so I'm just making a logical assumption.

I live in St. Johns Michigan, and there's no places around here that do it. There might be some in Lansing (30 miles from here) but I haven't checked into it.

[tr0ike]

My Golf's stats are (I believe):

115hp @ 5200 rpm
122 lb-ft @ 3000 rpm

I don't like revving my engine past 4,000 rpm anyway, but people seem to say that going up to redline (6k rpm, limit @ 7k rpm) is essentially useless, esp. since the power kicks in @ 3000 rpm.

[Threeyearitch]

Originally Posted by LOUDCRXSi

are that how most honda's are?

Yep. Small displacement (sp), light flywheel, high revving engines. They live in the 6k to 7.5k rpm range.

[drftk1d]

with my engine basically powe output rises with rpm, but revving my shit to 9000 rpm isnt going to do anything (redline is 7000, i shift at 6700). if i had bigger ports i could go higher. i have 150hp at 6500 rpm and 138 ft-lbs at 3500, but it really kicks in at 3800 (thats when the secondary injectors and aux ports come on and its sorta like vtec but better)

[lamehonda]

I noticed that my accord kinda starts to lose power at like 6000 rpms which is 250 under redline. I heard that the VTEC on the car will not operate above redline on my car. I don't know if this is true or not though.

[LOUDCRXSi]

well im about to goto the track within the next few weeks and ill try shiftin rite b4 redline at redline and rite after redline and ill let you know what happened. depending i have 3 good runs like that or have time to do more.