[zedboy]

Hi Guys

Looking to squeeze a bit more out of the 1.3 in my sierra. It seems to have quite a bit of back pressure even at idle.
Can feel the exhaust gasses at almost a meter back on the standard exhaust, not sure if this is normal but I think it is due to the standard 20yr old system.

Now the extractors I'm looking at on ebay are 1 1/2" primary, 1 3/4" secondarys and either a 2" or 2 1/4" outlet.
Plan to continue the exact same pipe diameter through to the rear with mandrel bends, hi-flow muffler and no cat.

What would be better the 2" or 2 1/4"? Just want some more in the mid-range 2500-4500 rpm, can defenitely feel it choke out in the higher rpm range.

Below are the two options im looking at.

Anyone have these extractors? Feel free to let me know what your setup is.

Also the standard head is a square exhaust port yet I believe these are round? Would this cause a significant turbulence/restriction?

http://www.ebay.com.au/itm/SUZUKI-SIERR ... _750wt_940

http://www.ebay.com.au/itm/SUZUKI-SIERR ... _687wt_940

Thanks Matt.

[droverdave]

zedboy wrote:

Hi Guys

Looking to squeeze a bit more out of the 1.3 in my sierra. It seems to have quite a bit of back pressure even at idle.
Can feel the exhaust gasses at almost a meter back on the standard exhaust, not sure if this is normal but I think it is due to the standard 20yr old system.

I'm confused by this. what do you mean you can feel the exhaust gasses at almost a meter back on the standard exhaust?

[zedboy]

As in whilst its idling if you stand behind the exhaust at that distance you can still feel the exhaust gasses coming out with a bit of pressure to it - could it possibly be a collapsed muffler?.

droverdave wrote:

zedboy wrote:

Hi Guys

Looking to squeeze a bit more out of the 1.3 in my sierra. It seems to have quite a bit of back pressure even at idle.
Can feel the exhaust gasses at almost a meter back on the standard exhaust, not sure if this is normal but I think it is due to the standard 20yr old system.

I'm confused by this. what do you mean you can feel the exhaust gasses at almost a meter back on the standard exhaust?

[Gwagensteve]

That's not really evidence of anything. A collapsed muffler won't have any bearing on the velocity of the gas coming out of the tailpipe.

Some people claim a significant difference in performance once they fit extractors, others claim very little. There's unfortunately not much hard evidence either way, but it certainly won't hurt. I'm a bit confused about what you want to achieve though- extractors will do less at lower revs, where there is less gas flow, than at high revs. As you're looking for increases from 2500-4500 rpm, thee light not be much to show for your $$. There will be more gain in the upper reaches of the rev range.

2.25" is too much pipe for a 1.3 Sierra. It will just add cost and noise and to little or nothing for power. 2" is more than enough.

Don't delete your cat. A generic 2" cat will be doing nothing to hurt power, and they aren't even very expensive. The only reason to delete one would be due to the idea that catalytic converters are good for the environment and therefore must be bad for performance, and that's silly. It's very illegal to remove one and the fines are HUGE, should you get caught.

Through all of this, just remember that the gains from extractors and exhaust are very small.

Steve.

[zedboy]

Ok thanks for that. 2" it will be if I get an exhaust fitted.

In terms of rpm was just a general range I gues its were the majority of the time the engine is at, try to avoid north of 5K as that where I can feels to choke out.

Gwagensteve wrote:

That's not really evidence of anything. A collapsed muffler won't have any bearing on the velocity of the gas coming out of the tailpipe.

Some people claim a significant difference in performance once they fit extractors, others claim very little. There's unfortunately not much hard evidence either way, but it certainly won't hurt. I'm a bit confused about what you want to achieve though- extractors will do less at lower revs, where there is less gas flow, than at high revs. As you're looking for increases from 2500-4500 rpm, thee light not be much to show for your $$. There will be more gain in the upper reaches of the rev range.

2.25" is too much pipe for a 1.3 Sierra. It will just add cost and noise and to little or nothing for power. 2" is more than enough.

Through all of this, just remember that the gains from extractors and exhaust are very small.

Steve.