i rev mine until it wont rev any harder.

yup - 1.5" for 1.3L, 2" for 1.6L...

and KEEP YOUR CAT CONVERTER!!!!!! Its illegal to run without it and the fines are HUGE.

A flamethrowing exhaust would be just the ticket!!! I want one, I want one now!! Perfect for the arsehole tailgater.

does this also apply to a jimny.

1.3L = 1.5" ?? i was thinking about extractors and exhaust but was gonna go for a 2" system.

my jimny likes to rev also, going up big sand dunes it would be around 6000 RPM, but on the road i like to keep it at or below 4000

Mine can do that, haha

Drive along at about 50, turn the car off in neutral.. Keep your foot flat to the carpet for 5-10 seconds, turn it on with your foot still flat!

Booooom, with a foot long flame
I don't think it's good for the car however

Your 100% correct.

I think the collector size on the extractors is a clue to the ideal exhaust size. I think for most suzuki extractors it's 2".

It's funny how the myth of small diameter exhaust building torque never really goes away. It's partially true for stock "log" manifolds (and I say partially true because manufacturers are quite good at making cat manifolds that flow these days - have a look at the G16A exhaust - by using twin engine pipes, suzuki effectively created a tuned length extractor stock- shame the manifolds crack), but for tuned-length extractors (and turbos) it's false. The optimum backpressure for exhaust scavenging has already been achieved at the extractors collector. (That's why they are called "extractors". Downstream of the collector, no amount of additional backpressure is an advantage.

If you have a 2" exhaust that's too noisy it's not because the pipe is too big, it's because you don't have enough muffler.

I've built loud and quiet exhausts - I built a system for a G13BB engined Sierra with mandrel bent extractors, 2" all the way with a 3" tailpipe and it's just amazingly quiet - it has a triple flow muffler in it and two hot dogs to take out resonance. It's half as loud as legally permitted. At idle, the loudest sound is the injectors ticking.

I'd normally recommend a triple flow muffler and one 12" hot dog (with a cat) Th car will have a nice note under full throttle, but won't drone or resonate.

My own 660 car runs a cat, and triple flow muffler, but it's 2.25" and is very short- dumping behind the cab. It's too loud - not helped by the fact the 660 is always on boost so it sounds like it's working hard.

Steve.

I've seen Sierra extractors available on Ebay alone with both 2 and 2.25 inch collector measurements. The set of extractors I have at home measure 1.75 inch... seems like too great a range of variation for them all to be optimal design for the same 1.3L engine.

So how to distinguish between extractor brands designed for performance, and those bung together with the surplus bits of pipe in the back the shop without any proper testing?


Maybe i'm not understanding this concept properly, but surely 1/2 an inch in variation in collector sizes (assumuing a matching exhaust size) will lead to massively different performance outcomes?

Optimal design for what purpose,

what you need for low down power isn't the same as what is needed to get power higher up in the rev range.

What you want to achieve with your engine might be different to what others want.

i rev mine until it wont rev any harder. i have seen mad kennys taco go past
the numbers and it is the sweetest running sierra that i have seen.

Yep i agree...
From what i understand, in a generalization -
A smaller 1.5in will give you more torque at lower RPM's...
A medium 1.75in will give you some torque at low, med and high rpm...
And a big 2in will give you alot of torque at high RPM...
But if you go to big, like 2.5in, you get a low exhaust pressure and you loose the scavenging effect, and loose engine torque and performance....

Correct me if i am wrong...