lastchance88

So I'm not really one to excessively speed, but I like to have fun when driving my new TSX. I have a 5AT transmission, which I like to switch into sport shift mode when I'm first at a traffic light or something, and I was wondering how to get the best acceleration. What is the ideal RPM to shift into 2nd, 3rd, etc. without putting too much stress on the engine? And I've read things about possibly disabling the VSA? I know everything depends a lot on the conditions but just wondering if anyone had any thoughts. Thanks guys.

acn684

VSa won't make a diff much on or off maybe a little, especially more with other mods.

Shifting closest to redline will get u the quickest acceleration, and the car switches into high cam past 6k rpm.

Engines were designed to be safe, from a technical standpoint, beyond the redline limit providing that you maintain it well and keep the oil clean while also taking precautions not to over heat the engine. Enjoy!

sidssp

If you look at torque curve, you get maximum torque between 3500rpm and 4500rpm. After that point torque does a nose dive until about 5800rpm than it makes a V turn back up to a stable but reduced torque at around 6200rpm. That mean if you accelerate thought that V shape drop, you won't get much pull. So IMHO, I think the best shift point is at 4500rpm.

godfather2

^ "nose dive"?

esco718

shifting that early does not make much sense beacuse you are not even giving your vtec a chance to kick in at all......your vtec is designed to give you an extra kick at high rpm's and you will see some better acceleration for those few seconds.

Rpappi

when you balance out the torque drop with the gear ratio increase you will still accelerate faster in the lower gear. so rev it all the way up. your not going to hurt the engine. it has a rev limiter for a reason.

gdcwatt

Shift points depend upon a car's torque curve and its gearing. The torque at the road (the force which accelerates the car) in each gear appears as a distortion of the car's torque curve, if you plot it. Calculate the engine speed at which the torque at the road in the higher gear is greater than the torque at the road in the lower gear and shift at that point.

The greatest acceleration (rate of increase in speed) will always be greatest at some point in 1st gear. Don't confuse acceleration with the sensation of speed.

CarbonGray Earl

Its a relatively flat torque curve with the VTEC oomph at the end, so short shifting isn't going to get you the fastest acceleration. That being said, revving it up doesn't necessarily mean you're getting more and more torque, what its doing is landing you in the meat of the powerband for the next gear.

ChrismanTSX

Somehow, I think that acceleration once moving is linked closer to HP than to Torque. Since HP is a factor of torque * RPM, you get more HP through 4500-6000, regardless of the drop in torque.

Then the VTEC kicks in past 6K, and torque and HP increase dramatically. To get the best acceleration, shift at the redline.

Acurasrule

I would never shift at 4500rpm if you were trying to run a fast time or 1/4mile etc, this car comes alive at higher RPM's!

Reach

Hey, mine goes into vtec at 4850! If you're shifting before vtec, you're not pushing the car.

ChrismanTSX

VTEC starts at 6100K, according to most info I found. you do get a bit of a surge around 4500+, but I believe that's the torque/rpm combination that picks up....

aaronng

It doesn't increase dramaticaly
But yup, shift at redline to maximise torque when you are in the next gear.

For an absolute measurement of the best RPM to shift at, Take your dyno measure the area under the power curve for the RPM range that your gear uses. Shift the RPM based on the RPM that you want to shift at. The best RPM will give you the most area under the curve.

alucardx

Reach most likely has Hondata ECU flash. this makes the VTEC kick in at 4800

jlukja

Best acceleration is when you floor it and upshift at redline.

Reach

Best acceleration is after you get the Hondata reflash (yes, that's why i vtec at 4850)!