hinds90

Why is it that alot people want to have a higher redline to make a higher peak power at for example what makes a car that makes peak power at 7500rpm and redlines at 8500rpm better than a car that makes peak power at 5500rpm and redlines at 7500rpm.


Modified by hinds90 at 2:38 PM 10/15/2006

B18 CYA

a car that makes peak power at 5500 rpm must have a small turbo and spool up really fast. a car that makes peak power at 7500 will have a bigger turbo and more lag on the street.

Schister66

Hondas rev high, why not utilize that to make more power??

I would much rather have to rev my car out higher and make a lot more power up top rather than having a car that redlines at 6300rpm and makes peak power quickly.

In FWD, lag is traction....

Boner_Ben

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Schister66 &raquo;</TD></TR><TR><TD CLASS="quote">

In FWD, lag is traction....</TD></TR></TABLE>
Until the turbo spools up

z6

actually it is because a motor that peaks at a higher rpm allows you to use more gear, for example... compare two b18 motors,
the first b18 goes 125 at redline of 4000rpm in 4th gear
the second b18 goes 125 at redline of 8000rpm in 4th gear

what do you know about the two cars...the second has twice as much gear and therefore has twice as much torque after the tranny (assuming the motors are equal)

joppe

Torque + RPM = horsepower. When you know torque and rpm you can calculate your horsepower. I make it easy and you dont have to search your calculator.
http://koti.mbnet.fi/loge/linkit/power.htm
Pyorimisnopeus (r/min) = put your rpm here
Vaantomomentti = put your torque here
Then push "laske" = calculate
Tyhjenna = clear

ccivic

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by joppe &raquo;</TD></TR><TR><TD CLASS="quote">Torque + RPM = horsepower. When you know torque and rpm you can calculate your horsepower. I make it easy and you dont have to search your calculator.
http://koti.mbnet.fi/loge/linkit/power.htm
Pyorimisnopeus (r/min) = put your rpm here
Vaantomomentti = put your torque here
Then push "laske" = calculate
Tyhjenna = clear</TD></TR></TABLE>
Not going to add my input to the conversation-- only going to correct you: HP=(Torque*RPM)/5252

tokesGTR

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Schister66 &raquo;</TD></TR><TR><TD CLASS="quote">In FWD, lag is traction....</TD></TR></TABLE>

Not true at all. Vehicle speed wise, the difference between 4000 and 6000 RPM's with a B16/ITR trans in first gear is 12 MPH. You are not going to have drastically better traction travelling 29 MPH than you are travelling 17 MPH. A quicker spooling turbo that brings boost in much more smoothly is going to be a lot easier to modulate the throttle and get traction with, rather than a huge turbo that comes on like a lightswitch and is hard to control tire spin with.

In FWD, lag is the opposite of traction.

joppe

Yes sir i just didnt remember that formula. My original point was that hp is torque and rpm.

WickedHonda00

The best option is a big turbo tuned with boost at 6psi and 16psi (low&high boost for street setup). Ok, the 1st and 2nd gears are for 6psi, where your making no more than 250-275whp, then you switch to 16psi mid-way through 3rd and from that point traction is not an issue. Done. That way you have 1.6 60' and a top-end that can beat anything. However, I think gear ratios are the biggest factor other than the tire selection and displacement when talking about which is better than the other. Point is..if all your power is from mid-range to top-end...you can utilize gear reduction, meaning you can have 5.10 final drive and out accelerate everyone else that has 3.73 final drives and maxes out power 2/3 the way up the RPM band.

Tony the Tiger

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by WickedHonda00 &raquo;</TD></TR><TR><TD CLASS="quote">The best option is a big turbo tuned with boost at 6psi and 16psi (low&high boost for street setup). Ok, the 1st and 2nd gears are for 6psi, where your making no more than 250-275whp, then you switch to 16psi mid-way through 3rd and from that point traction is not an issue. Done. </TD></TR></TABLE>

If you run a larger turbo, for example, a T3/T67 or an SC61, you still won't get 6 psi until after 5000RPM. The turbo will not magically spool any quicker at a lower PSI. The engine is still going from roughly 100 WHP to 275 WHP at an instant, which means wheel spin on virtually any street tire. 1st and 2nd gear is still useless, or if it lags, it moves like a stock Civic DX off the line while it lags.

That's why I kill every big turbo Honda off the line with my current setup on the streets. Don't expect to touch any modded V8's off the line if you think lag is traction for a turbo Honda. You definitely want 350+ WHP at 1st and 2nd gear, and the only way you can put it to the ground on street tires is with a smooth boost transition and linear power delivery. You may spin a little when a small turbo hits at low RPM's, but a little pedal modulation will get it going and you can fully pedal the gas and maintain peak acceleration all the way. I haven't even got into launching the car because a small turbo does not need to peg on the 2-step and resulting in an abrupt launch that break the wheels loose. A small turbo allows a gradual clutch slip at 4000RPM or less and maintains traction after launching.

B18 CYA

Hey Tony, how much power is your gsr making with 10.5:1 cr, gt2871r @ 18psi, just out of curiosity. Looks like a pretty fun setup for the street

Tony the Tiger

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18 CYA &raquo;</TD></TR><TR><TD CLASS="quote">Hey Tony, how much power is your gsr making with 10.5:1 cr, gt2871r @ 18psi, just out of curiosity. Looks like a pretty fun setup for the street</TD></TR></TABLE>

383 WHP and 340 ft-lbs @ 18 psi