Actually, I was talking to FrostByte. VE does NOT determine an engines reliability. What does determine reliable is how the engine is taken care of, the materials its made out of, and how the owner uses/abuses it. If you decide to run your 2.0 Beta at redline all the time, it will blow up. Why? Because it was never designed with that kind of abuse in mind. However, if you drive a ferrari like you stole it, it will last a LOT longer than a ferrari driven like a commuter car. VE is a byproduct of the factors that determine an engine's build and how you use it to be reliable. A High VE gives a good indication of where the engine should be used for best reliabilty, because thats where it was designed built to run. The more you avoid an engine's inefficient zones the more you avoid running it in the areas it wasnt really made to run in, since that'll shorten its life.

 

here's a few more items on torque/hp and shift points. i mentioned above to shift when the engine reaches highest torque.

1. i also surf some protege sites and asked over there about optimal shift points. basically this thread adds the idea of shifting to optimize your torque at the END of the shift, not the START of the shift.

http://www.protegemp3.com/vbb225/showthrea...&threadid=11872

2. i did a web search on "hp vs torque". this was the best article i found, which adds the idea of determining the torque curve in each gear, by multiplying the base torque (determined with a 1.0 gear ratio) by each gear ratio:

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


3. based on that article, i calculated my own torque curve in each gear. the conclusion is that i should shift at redline (6500 rpm)in each gear, because the torque at that point is higher than at any point in the next gear up. this is true in each and every gear.

since i've heard JRP is working on a chip to increase the beta redline to 7500 rpm, i wondered what the torque curve in each gear would look like with a 7500 redline, based on extrapolating the current hp and torq curves. the conclusion is that i should shift at redline in first gear, because the torque at that point is higher than any point in second gear, but the same is not true for subsequent shifts, meaning that some optimizing would be required.

[img]http://ca.msnusers.com/_Secure/0TAAMA*kXm78HB30FJDkuoGZXxcpbbzxOnRZGFu2ksMBJ0XGx* rrnbrcu6a4xWsEnFoVME0cTh8*7QUO
KIHgTKznGrnqiPjseKDYovhMxy2MCQ*XLQlgfig/torque_in_each_gear.jpg?dc=4675408002170885662[/img]

[img]http://ca.msnusers.com/_Secure/0TAAAAKEW7WZSGhK4X4HaGUflSDPrc7n9bJy9L4yz3bueyxuKD bjgS3Q8rL!QbuuwqhBwlUhWclgeu9s
H3SzOialAdRC!6mAWGw7i3Zlu7XVRBewbL7br3Q/hp+torque@7500rpm.jpg?dc=4675408008971680044[/img]


4. i guess with a 7500 redline chip, if my extraploation of the current hp and torq to 7500 rpm is valid, i'd need some other engine upgrades to boost the hp and torq at higher revs, to get the full acceleration potential out of the higher redline (headers, SAFC tuning, etc)

hope this doesn't sound too blah,blah,blah.

[ February 02, 2003, 11:05 AM: Message edited by: 99mini ]

 

no, it adds more info to the post. however, i do know that you get more hp and tq to the wheels in shorter gears, but are the calculations you did for torque? because in 1st at 5,000 rpms, you have 422 as the number. it can't be 422 ft-lb of torque.

 

yes, the torque hitting the road is 422 ftlbs @ 5000 rpm in first gear, basically because the transmission is a torque multiplier.

the dyno shows torque hitting the road of 130 @ 5000 rpm in fourth gear, with a 1.061 gear ratio.

the first gear ratio is 3.462, which is multiplying the 4th gear torque by a factor of
(3.462/1.061), so the torque hitting the road in first gear at 5000 rpm is

(3.462/1.061) x 130 = 422 ft lbs.

(the final gear ratio is ignored in all the calcs because it's a constant.)

BTW, not sure why, but the articles say the tranny is a torque multipier, but not a hp multiplier.

 

Because torque is FORCE.
HP is FORCE OVER TIME (WORK)

You can't multiply FORCE OVER TIME(work) with gearing, but you can multiply FORCE.

You are correct in your calculations, that with the beta engine, and the 5 speed, you should shift at redline for maximun acceleration. Not all cars are like this.

There is no point in extending the redline out on the beta engine. Do your calculations for 7000 and 7500 RPM using your extrapolated data. You'll see 6500/6750 RPM is still the optimal shift point.

For the beta engine, the only time the 7500 RPM limit might help is in racing or autocross, where the ability to get a little extra room out of a gear rather than shifting is important. Unless you somehow manage to modify the engine to move the torque peak closer to 5252 RPM or beyond.

 

My torque peak is at 5300 RPM, and peak HP is at 6450 RPM. This is the affect of the SR 2.0L Cam, combined with a good intake / exhaust. NEone who has the cam will have similar peaks at those RPMS.

-Steve

 

4g63t, also begin to drop off torque and hp after 5k.


But they still extend to 8k+rpms because with the turbo. You still have sufficient power.

So I would think an extended rpm would still be good in a turbo situation.

 

i wish i had a dyno graph for my G6AT. i know the peak torque is at 2500 RPMs, and i don't think there's much of a drop-off after that...all i know is i like not having to wait for a turbo and get the power at about 5k RPMs, but i wouldn't mind the power once i got it.