[SuziBlu]

JrZook wrote:

tassie jeeper wrote:

i agree with steve on the 2" being a good size but cant understand how a 1 and a half in exhaust gives more torque...? not being cocky i just want to learn something new.

A strong reflected wave comes from the exhaust pulses entering a different atmospheric environments ie pipe diameter step/merge collector/end of the tail pipe into open atmosphere etc. When this reflected wave of negative pressure (vacuum) reaches the exhaust valve at the correct time it can effectively draw out the exhaust gasses and pull in fresh intake charge. Commonly referred to as exhaust scavenging. The scavenging effect actually exists over a broad RPM range.


Suziblu you have an 8 valve 1600? If so I say you could probably make around 100-110ish HP at the flywheel with those mods?? I doubt may factory cars that make that much power have exhausts bigger than 2". Something to think about...

I wil never understand exactly what a cam is all about, other than the obvious, too much to learn for such a thing that just does, let the experts deal with this.

Tighe have build me a cam, had a lot of conversations with them about weight, driving style, expectations, rev ranges verses gears and speed etc etc etc.

He told me what he will do, an I was like, (lift, duration, overlap etc) yea ok, sweet.

What I am getting is a cam with amongst other things a largish overlap, so from my understanding, IF i get the right size exhaust, a lot of scavenging, and it will produce extra power above normal, just by the fresh air/fuel mix, somewhere in my stuff I have collected and read was a write up on scavenging and the extra power it creates, and gives formulas to give theoretical % boost.

That started me down the road to try and find the "correct" dia and length pipe, it all gets very confusing, especially when two learned people write contradictory papers, quite in depth, but different outcomes.

The cam that has been built is expected to come on around 2,000rpm and maintain till 7ish, im expecting my play zone to be somewhere in the 4-6,000 range, and this is what I was looking for a "perfect" pipe for.

I have read that after the collector, its all a bit mute, as all the work is done prior, to small is good to large is good., a resonator early after the collector to break the wave, to a resonator way aft.
Im probably more confused now tan when I first started.

If someone could explain id be stoked.

[atari4x4]

people running 2.0l turbo's with 300+kw at the wheels only run a 3-3.5" pipe... as said you'll be lucky to have 85kw at the flywheel a 2" pipe will be plenty, end thread.

[JrZook]

SuziBlu wrote:

I have read that after the collector, its all a bit mute, as all the work is done prior, to small is good to large is good.

This is somewhat true as the exhaust velocity is higher due the the temperatures closer to the exhaust port. So unless you plan on designing your own extractor system (you don't wanna go there) I wouldn't go too far into it.

Pressure waves still have effect after the collector (not as strong as in the primaries/secondaries of an extractor system) so why not try to harness their energy since its just pipe size you are playing with?

To get a rough ball park of what your pipe size should be after the collector lets have a look at a common example:

Toyota 3RZ, its 2.7L and puts out 150Hp. Stock exhaust size is 2-1/4" I believe with some shitty triflow muffler as stock. If 2-1/4" can support a 150HP out of a 2.7L with the muffler most likely being the largest restriction would you kind of sit back and think that maybe a 2" system would be quite suffice for what ever you can get out of your N/A 1.6?

What are your engine specs/planned specs btw?

[SuziBlu]

lol excellent explanation Atari, my understanding is complete.

Engine specs, unopened except for cam and stronger springs, when home next, put on cam, measure inside room to see if I can fit a 90degree under dash Brake master so as to fit the big carbs.

I do want to find someone who can regragh the dizzy, and make it mechanical only, no vacuum advance, DCOE do not have a vacuum port.

Want to go electric water pump, maybe, not sure yet.

After i do the diffs and gears, see how power is, maybe open it and give it a port and polish, but thats all.

I run 98 with acetone to slow things even more, and help atomize the fuel better, approx 15 degrees BTDC initial timing, I think its 33 total.

[atari4x4]

sorry i'm not sure how else to spell it out, it's been said god knows how many times already in this thread... put a fucking chrome stack off a mack truck on it for all i care.

JrZook wrote:

SuziBlu wrote:

I have read that after the collector, its all a bit mute, as all the work is done prior, to small is good to large is good.

This is somewhat true as the exhaust velocity is higher due the the temperatures closer to the exhaust port. So unless you plan on designing your own extractor system (you don't wanna go there) I wouldn't go too far into it.

that's interesting, my old man built a few open wheeler hill climb cars + formula fords & clearly remember him babbling something about tuning home made exhausts & header pipe lengths/collectors on one of the hill climb cars with a line of spray paint down the pipe/collector... something about when the paint wasn't burning off the gas temps were too cool.

[SuziBlu]

lol yea, but not sure if she can handle the power from those stacks.

You can get wax pens for that now, work out by wax melt where your hot and cod spots are.

[atari4x4]

this was back in early 70's i guess, well before my time unfortunately.

stacks or 2" pipe, the ball is in your court.

[Rhinoman]

SuziBlu wrote:

I run 98 with acetone to slow things even more, and help atomize the fuel better, approx 15 degrees BTDC initial timing, I think its 33 total.

That's an odd timing curve. A stock EFI ECU runs 8degs at ide and 44 degrees at low RPM/low load and that'll work with something like 92 RON. Have you got the spec for the cam? do you have to pass emissions testing?

[SuziBlu]

sorry, its 44 degrees, i thought something was wrong

i prob if got pulled over, but coffins is a pretty little laid back town, and this car doesnt leave very often.

[SuziBlu]

not sure of the specs, he told me, but that was a fortnight ago, they will be with the cam wen i get home

[want33s]

If those flash new carbies aren't E fuel approved I wouldn't be adding anything like acetone.

[Fatzook]

http://www.mk5cortinaestate.co.uk/calculator5.php

2" mandrel bent pipe will flow enough to make 125fwkw. You will have NOTHING like this sort of power.

2" is plenty!

To put it in perspective, I'll be running custom headers into 2.5" mandrel system back to the cab, then into 2.25" tail and rear muffler for 200fwkw 2.0L supercharged motor.

[Marko_SJ]

More perspective lol

People with 6 litre v8s wrote:

Thread: Question regaurding exhaust size?

Question:

With the HSV VZ Clubsport R8 6 litre what the exhaust size(standard), does anybody know?.
--------------------------------------------------------------------------------
Reply

2.25 inch.Nearly big enough but not quite....

The OP would be fitting a the same or a larger diameter exhaust to his 1.6 than some people do with 6 litres.

[atari4x4]

big chrome stacks FTW

[sideways]

Yeah, except the Clubby runs twin pipes.

[Gwagensteve]

Each fed by up to 160kw and 3.0 of capacity.

76kw of 1.6 needs 2.5" though.

Steve.

[sideways]

Gwagensteve wrote:

76hp of 1.6 needs 2.5" though.

Nah, it needs a 3". Haven't you seen how fast all the Lancer coupes and Excels with 3" exhausts are?

[tassie jeeper]

Fatzook wrote:

http://www.mk5cortinaestate.co.uk/calculator5.phpI'll be running custom headers into 2.5" mandrel system back to the cab, then into 2.25" tail and rear muffler for 200fwkw 2.0L supercharged motor.

is that the 2.0 4cyl or the 2.0v6?

[JrZook]

tassie jeeper wrote:

Fatzook wrote:

http://www.mk5cortinaestate.co.uk/calculator5.phpI'll be running custom headers into 2.5" mandrel system back to the cab, then into 2.25" tail and rear muffler for 200fwkw 2.0L supercharged motor.

is that the 2.0 4cyl or the 2.0v6?

[Fatzook]

tassie jeeper wrote:

Fatzook wrote:

http://www.mk5cortinaestate.co.uk/calculator5.phpI'll be running custom headers into 2.5" mandrel system back to the cab, then into 2.25" tail and rear muffler for 200fwkw 2.0L supercharged motor.

is that the 2.0 4cyl or the 2.0v6?

Would it matter? Cubes is cubes

What Jr said.

[atari4x4]

has anyone suggested running a 2" pipe yet? i reckon a mandrel bent 2" system would be plenty!

[Rhinoman]

Fatzook wrote:

http://www.mk5cortinaestate.co.uk/calculator5.php

^This made me laugh.
MK5 Cortina - the default settings max. power = 0bhp, required power = 400bhp, that's how I felt about my father's old Cortina Estate :lol

These conversion utilities are all very well and good but there isn't any explanation of how they arrive at these figures, the software that the manufacturers use costs millions of pounds and need a lot more input data. The earlier post about conflicting information from reputable sources was a good one, is there actually a correct answer? The internet is wonderful but should be treated with the utmost suspicion at all times. Ultimately you need to pick a number, try it and see how it works. You would expect any company that manufactures an off the shelf performance exhaust to have already tried a few combinations and picked the most suitable compromise. Calmini and Janspeed both use Mandrel bent 2" pipe.

[Rhinoman]

SuziBlu wrote:

Who wants a turbo anyway, spesh when you can get this.
http://www.pulleyboys.com/store/product ... ductid=207

Calmini use to sell that kit around 10 years ago before Camden dropped it, I heard that they were bringing it back. I was looking into it just before it was discontinued, its US made kit and its not going to be a bolt on to an RHD as theres no room for the brake servo, you also lose the PAS which isn't ideal if you're running 33s. By the time you've made it fit you may as well have created your own set up.

[want33s]

Rhinoman wrote:

SuziBlu wrote:

Who wants a turbo anyway, spesh when you can get this.
http://www.pulleyboys.com/store/product ... ductid=207

Calmini use to sell that kit around 10 years ago before Camden dropped it, I heard that they were bringing it back. I was looking into it just before it was discontinued, its US made kit and its not going to be a bolt on to an RHD as theres no room for the brake servo, you also lose the PAS which isn't ideal if you're running 33s. By the time you've made it fit you may as well have created your own set up.

Suziblu has a Maruti.... No brake servo/booster.

[atari4x4]

want33s wrote:

Rhinoman wrote:

SuziBlu wrote:

Who wants a turbo anyway, spesh when you can get this.
http://www.pulleyboys.com/store/product ... ductid=207

Calmini use to sell that kit around 10 years ago before Camden dropped it, I heard that they were bringing it back. I was looking into it just before it was discontinued, its US made kit and its not going to be a bolt on to an RHD as theres no room for the brake servo, you also lose the PAS which isn't ideal if you're running 33s. By the time you've made it fit you may as well have created your own set up.

Suziblu has a Maruti.... No brake servo/booster.

he's already having to deal with LHD gear not fitting on RHD's with the twin DCOE manifold & carbs he bought from the US, fouls on the master cylinder & i believe he's looking into 90* swing under dash boosters/masters. then only to throw all the side-draft kit away to bold on a supercharger with a down-draft, it doesn't make sense... just like most of this thread.

[tassie jeeper]

Fatzook wrote:

Would it matter? Cubes is cubes

only reason i ask is u mentioned a supercharger and i wanted to put a MR2 supercharger on mine but was a little worried about the ecu's capabilities i know ill need bigger injectors but dont wanna fork out big dollars for a computer (as i have a mate that bought the supercharger for his 4x4 then decided to go v8 instead) hence i can get it cheap

[SuziBlu]

atari4x4 wrote:

want33s wrote:

Rhinoman wrote:

SuziBlu wrote:

Who wants a turbo anyway, spesh when you can get this.
http://www.pulleyboys.com/store/product ... ductid=207

Calmini use to sell that kit around 10 years ago before Camden dropped it, I heard that they were bringing it back. I was looking into it just before it was discontinued, its US made kit and its not going to be a bolt on to an RHD as theres no room for the brake servo, you also lose the PAS which isn't ideal if you're running 33s. By the time you've made it fit you may as well have created your own set up.

Suziblu has a Maruti.... No brake servo/booster.

he's already having to deal with LHD gear not fitting on RHD's with the twin DCOE manifold & carbs he bought from the US, fouls on the master cylinder & i believe he's looking into 90* swing under dash boosters/masters. then only to throw all the side-draft kit away to bold on a supercharger with a down-draft, it doesn't make sense... just like most of this thread.

Who is throwing all this away ?

I have yet to be told why this or that size exhaust is better, other than, she'll be right, just use this.

I have read lots of stuff that says so much conflicting date, have stuff from `dynos that tell of the very best for a 1.6l around 100hp is the 2.5" and also read a 1 5/8ths, and of course, giant Mack stacks.

I will shutup now, only getting shit for asking, as normal.

[atari4x4]

FFS it's not a race car, 2" will be plenty.

just thought you seemed keen on that supercharger kit & would need to ditch the dcoe's for it

[31zook]

Your asking, but not listening. Ain't nobody got time for replying to the deaf.

[atari4x4]

31zook wrote:

Your asking, but not listening. Ain't nobody got time for replying to the deaf.