EXHAUST SYSTEMS. diameters and performance potentials?
Turbo Mini Forums

hiya guys, ive been trying to work out wether to have a exhaust fabricated. i currently have the 2" turbo systems available.

i know that more hp can be gained by machining out the exhaust elbow, but my queary is over the diameter.

on my brothers ex mini (choppos mini as seen on ultimate mini extreme) produced 170hp, and on idle (up to 1000rpm) his mini would produce high exhaust pressure, realy alot, esp compared to a standard lump, (turbos gereraly speaking run low pressure on idle) now when the engings boosting, surely the exhaust restricts flow, and hp.

my SRE built engine is a revised version of what my brother had, but with mig spec ofset valves, 36/32 so ive gone for a high flow system.

i was thinking of fabricating a 2.5 - 3" bore system, based on my existing dimentions.

now, it will be expensive, and hang down another inch. and is it realy worth it?

i know ive gone on abit, but appreciate any of your views.

HAPPY CHRISTMAS TO YOU ALL

the paint master! D

how long is a piece of string, what works for some engines might not work for others. you will affect the Turbo Lag as well as any power gain/loss.

The only way is to make one up and test it on the rolling road. most people seem to keep with the 2" system as it seems a good all round size.

Edited by Miniwilliams on 30th Nov, 2005.

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

THE 2" system is well up to the job for our power outputs of 200bhp TO 250

the only problem there is don’t use a middle box

the rear one make sure its a straight through one

and nothing else!

like say you can see daylight through the back box of 2" dia

i used a system a maniflow back box for a N/A engine and only the back box

this systems flow rating was 125bhp alas it was useless! to say the least. and strangled it so much ! a milk float passed me

i turbo is like a muffler exhaust

A rotary muffler

you need NO! flow restriction at all on a turbo engine or you will suffer power loss and tail pipe back pressure and heat leading to detonation.

trust me !!!

Would there be any point going any bigger than the exit (or whatever you call it) hole of the turbo?

Its only a bit of metal. If it blows it blows!

http://www.putfile.com/mini300bhp

has anyone ever run a full system wih no boxes at all? just curious as to how loud it was and any effect on power....

Pete

And on the 7th day........... God created turbochargers!

no benefits much to speak of.

here is the back box i run i call it my taliban rocket launcher
2" inlet to 2.5 inch internall 3" barryboys exit!

i know, i know i have posted it it a thousand times

the sound of a straight through pipe on a turbo would be 30% louder than this box TRY IT !???

i sketched this up faxed it to maniflow and had it made 85 quid
mind you it was 5 years ago! this cuts the harmonics down a tad so you dont get pulled by the police & get scorned at by the neighbours.

this does the bizz.

Edited by BENROSS on 30th Nov, 2005.

This is what I first had on my car........




.........but later took it off due to noise complaints. Sounded the bolox though.

never taken it to rr so cant comment on power, but it did feel slightly more lively without the box.

Its only a bit of metal. If it blows it blows!

http://www.putfile.com/mini300bhp

thats the way! yes the noise

my only Criticism is you bolted it solid to the subby NO GOOD!

it needs to have some give in it

better with some exaust bobbins through fitted.

Yes, I know ben, but chears for the advice. My engine is solid mounted, so no movment there, but as it heats up it expands enough the keep making my exhast blows, so will use your advace after all.

Its only a bit of metal. If it blows it blows!

http://www.putfile.com/mini300bhp

Picture below is a metro challenge pipe before all this noise regs non sense.

I have seen a beetle with a "zorst" straight off the turbo about 10 inches long, it was pretty quiet on the hole.

Cool pic JF!

It's a little excessive to use as a doorstop though isn't it? Maybe an old conrod, or pebble would suffice?

I'd contact maniflow, they'd be best placed to give advice. I was understanding that the general rule of thumb (on turbo cars) was the bigger the better as reduces backpressure? I'll have to re-read Vizzy's bible to see what his views were.

I remember Neil Slark jovially (is that spelt right?) saying to me that a straight pipe's best (like gallioflys).

Choppo

Hannibal: There are two ways we can do this: the easy way and the hard way. In a few minutes my friends and I are going to come down on you like your worst nightmare. You're gonna wish the Earth had opened up and swallowed you whole.
bad guy: What's the easy way?
Hannibal: That WAS the easy way.

thanks john just show us us all! & confirms what we have discussed.

those big weights john what you use them for ????

Edited by BENROSS on 1st Dec, 2005.

I love the cat in the picture lying there thinking "What the fuck has he bought in the house now??"

LOL

The cat is chilling, i don't have a Mrs that lives with me that gives a fook about be bringing car bit in the the house, i live 50 metres from the pub and i have lots of cars with turbos on!...

So true.....

Sex on tap and car parts in the house so sadly don't mix................

Would there be any point going any bigger than the exit (or whatever you call it) hole of the turbo?


well, the turbo exhaust outlet is around 2.5" then the cast elbow goes down to 1.75" approx, so i was thinking of a 2.5 system all the way through.

the paint master! D

giallofly: Picture below is a metro challenge pipe before all this noise regs non sense.

I have seen a beetle with a "zorst" straight off the turbo about 10 inches long, it was pretty quiet on the hole.




see, this is where im coming from, for example drag cars rin tiny large dia pipe, i know im going wide of the mark saying that, but the first stage of any tune up an a turbo car is a large dia pipe. take a subaru for example.

the paint master! D

tom fenton... Sex on tap and car parts in the house so sadly don't mix

.. well they do in my house, can promice you that!.....

the paint master! D

double vision

Edited by Mini_Andy on 1st Dec, 2005.

Soooooooooo

to sumerise, a good system would compise of a 2-2.5" pipe to single silencer then bigger tailpipe(anything from 3" to X")

or im i off target with this shot

Bigger the diameter the better, need to get rid of those gasses as quick as pos, best solution would be to go straight off the turbo and out the side, but a bit difficult on a mini.

16V project underway

im currently fabricating at work a 2.175" Diameter elbow, which will fit and replace the cast item, then im going to weld a rolled pipe, 2.175" to 3"

maniflow said they sort me out with main pipes,

im planning on puting the remote selector inside the car, so i can run a strait 3" pipe to the back box. (fit better, and wont hang low)

the paint master! D

I think for a road car you need a box or to, not for the loudness, but to help cut down the droning at motorway speeds on long journeys.

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

matt, no i didnt mean a strait pipe tp the rear of the car, im going to run a back box, (preferable as muffled as poss. i dont want noise! didnt want strait cuts, but i had too! but ive got loads of sound proofing to help a bit, and its only a weekend car.

just cant wait to get the thing up and running, my engines cling film wraped up, just got to paint my shell then its all systems go!

SRE 1293,omiga 15cc forged pistons,ulta light steel flywheel,phase 3, 36/32 offset valves, 16/17 psi actuator, antilag boost valve,large flow charge cooler& plenium, polestar maped ignition, and large diameter zorst, ex turbo challenge t3 =a whole big bang!

the paint master! D