278 replies to this topic

[clipping_point]

i certainly think that the headwork has helped with midrange torque on mine...

Shouldn't it also provide better top end flow => power. Maybe the exhaust manifold is too restrictive? What kind of manifold does Rubber have?

[paulb]

The exhaust manifold is one bit that is still standard on mine. I think this is another area that could potentially benefit. It also has a standard plastic inlet manifold. I could look at changes to this but would rather put it in the bin and look at throttle bodies. Rubber's is also standard. I think one of the problems is that it is quite tight to get the exhaust round the boot without some tight bends which are not ideal. Ideally, it would be nice to have a 4:2:1 manifold, but I don't think there is room.
I don't know if there is room for bigger valves but that is another option to be considered.

For me, I'd like to see the end game for me being:

• Gas flowed, big valve head
• Race cams
• Direct to head throttle bodies
• 4:1 exhaust manifold
• Race cat and sports exhaust
• Lightened flywheel

With all of that, I'd be hopeful to get about 100 bhp/litre out of the car. It's a similar spec to the Elise Sport 190, but probably with a bit milder cams to retain a bit of low down torque.

Paul

[clipping_point]

The Regal one (manifold) is not much better than standard?

[PaulCP]

The Regal one (manifold) is not much better than standard?

How do you know???

[clipping_point]

Twas just a question to Paulb, his view. Dunno myself, tho it looks like it has short branches. I suppose if you have a ported/polished head you need to increase the flow in order to benefit from the reduction of pressure drop, either by increasing the revs or the cam lobe duration

[garyk220]

IME the Vauxhall stock exhaust manifold should be fine for most road-based applications. They are rarely the weak point on the exhaust side. The Gp A Corsa/Nova rally cars used the standard cast manifolds in preference to 4-2-1 or 4-1 tubular manifolds. They showed no benefit in peak horsepower at 6500-7000 rpm at the expense of mid-range torque. A 4-1 tubular manifold will help release top end horse power at high revs, but you'd need to be revving to near 8000rpm to see major benefits.

Edited by garyk220, 12 February 2004 - 03:32 PM.

[paulb]

I'm hopeful to be able to source a manifold that can have some longer pipes in it to ease initial flow from the engine. Not sure how it will work out yet but if I can't solve it, I may consider the Regal manifold.

[BradW]

I think people may be starting to take the table a little bit too seriously given the relatively few entries! Until we get a good number of entries with similar tune levels then it won't be too clear what we should expect. There is clearly a variation between the engines to begin with... The more RR results we can get in the table the better. I can't imagine the viper having no effect despite in one instance the table seeming to suggest this. More results of cars without the viper would prove that either which way...

[clipping_point]

Might be! However I've bought the Milltek this far and no induction system. Not until someone can show any effect . A before/after test would be nice

[DAZ]

I have k&n in/kit and had it RR just befor the bala meet I had 144 bhp@ 6120 rpm and 138 lbft @4500 rpm at the wheels I think this is prity good.

[clipping_point]

I have k&n in/kit and had it RR just befor the bala meet I had 144 bhp@ 6120 rpm and 138 lbft @4500 rpm at the wheels I think this is prity good.

What? 144 WHP meaning around 180 HP at the crank?

Bad news for Rubber I´d say....... all that money...

[DAZ]

U THINK IT GOOD THEN M8 cheers I THINK ITS 195.85 BHP AT THE FLY WHEEL.

Edited by DAZ, 12 February 2004 - 10:48 PM.

[rubber]

I have k&n in/kit and had it RR just befor the bala meet I had 144 bhp@ 6120 rpm and 138 lbft @4500 rpm at the wheels I think this is prity good.

no way, aint going to happen. BHP yes!!

Ian

[DAZ]

WHAT AINT GOING TO HAPPEN M8

[clipping_point]

Those K/N filters must add some steroids to the air. Yes I could very well believe you had 147 BHP at the car dealer and 144 BHP after the filter change. Seems reasonable, the guys at Opel/Vauxhall are not morons.

[rubber]

195+bhp from just K&N induction kit. Bogbrush on here has the same and is no way pushing anything like that out. Any chance you can post the graphs? Ian

[Turbo Head]

WHAT AINT GOING TO HAPPEN M8

No need to shout

[DAZ]

Will as soon as i can get my scaner warking i s*it u not m8

[BradW]

How are we ever going to get a table of reliable information?... Everybody will want to 'big up' their figures...and then there are trolls!!! K&N is not doing that...there is something wrong there...it sticks out like a sore thumb!... ...the more reliable results we get the more the b*ll*x becomes obvious!

[rubber]

Wasn't just me thinking that then Brad. Ian