TrueSTI man

Having read the spec on the solberg rally car i have woken up to the importance of torque over bhp.

Cost of car $600,000
Top speed 120 mph
BHP 300
Torque 588lb/ft at 4000 rpm
0-60 2.6 seconds


I have a STI 7 pushing around 330 ib/ft how do I increase this having already added PPP+TSL333+TSL76mm reverse pulse exhaust. Some say replace headers but for what ?

Gutmann pug

equal length headers from power station in Cheltenham....

TrueSTI man

They say that the familar subaru burble disappears when you change the headers. Is this true ?

banny sti

iTrader: (68)

that is correct you will lose the burble

Gutmann pug

You cant have it all matey

TrueSTI man

Wish someone could explain how the headers make that luverly noise

TrueSTI man

i'd really like to hear from someone who has changed the headers on a sti7 or 8 and let me know how good the improvement was ?

chrisp

Basically, with a boxer config they are shorter on one side. So the air has less distance to travel on the shorter side. So you get 2 different air flows rather than one distance on an equal length header engine. ish

Dracoro

There are numerous threads that should show you what BHP and torque is. BHP is directly related to torque. Torque, as far as performance goes, is neither here nor there without knowing what the GEARING is as well as the revs is produces. The WRC cars are limited to 300bhp due to the rules. Who knows what it does to the drivability compared to upping the bhp. If you wanna whack up the torque figures but not affect the BHP then you'll need to do some serious changes to the gearbox.

marklemac

TrueSTI man,

I am having fitted in the coming weeks the GT Spec Gen II unequal headers to my MY02 STI.

I'll let you know the results

Carl2

How do you do that? As you said bhp is related to torque, if you increase torque at any given rpm, you have to increase bhp at that rpm too.

Dracoro

Not if you reduce the revs and change the gearing.

BHP is directly related to torque AND revs/gearing.

If you wanna improve performance, up the bhp (upping the torque somewhat if need be, but certainly upping the revs & changing the gearing). If you wanna improve 'punch in the back' then up the torque. I bet the WRC cars have a rather narrow powerband (probably making them unusable on the road)

Just as a matter of point. You guys with 300lb/ft torque have MORE torque than a Formula 1 car!!!!!!

chrisp

yep but I can rev my motor to 19,500rpm, I would need a bigger rev counter for a start, mine finishes at 9000rpm

Carl2

BHP=torqueXrpm/5252

Dracoro

Yup. Which means that the wrc car produces it's peak bhp at about 2750rpm. Peak torque at 4000rpm makes for interesting power delivery/power band.

Granby

iTrader: (5)

PMSL

ALi-B

iTrader: (1)

Torque is king. When you've experienced what 600lf/ft can do...even with "only 380bhp" you understand the importance.

On the flipside....190Bhp with 130lb/ft is complete pants on the road

Dracoro

Who's got 190bhp + 130lb/ft????

BHP is king When you've experienced what 800bhp can do...even with "only 250lb/ft" you understand the importance.

ALi-B

iTrader: (1)

Pretty much any Vetec style Rice rocket.

Considering how heavy modern cars are..you need the torque to haul those heavy ***** off the line. Perhaps when we all have carbon fibre family saloons we maybe able ignore the torque issue.