fiestaturbo.com

by **MIK3Y** on Fri Jul 04, 2003 1:55 am

Same BHP produced on same engine?

Is it the same amount of air forced into the cylinders?
Is it the same amount of petrol needed?
Is it the same BHP & torque?
Is it the same inlet charge temperature?

Only difference being deliverly and lag? :-?

Thanx

by **MIK3Y** on Fri Jul 04, 2003 10:51 am

Does a bigger & better intercooler affect fueling, mapping, etc.

I know it'll increase power but does this require the chip to be re-mapped to get the best out of the timing and fueling? :-?

by **Stoned** on Fri Jul 04, 2003 12:25 pm

Pressure of the air is the same, but due to it being a small turbo less air is flowing

Imagine a small desktop fan compared to a large one and you get the idea.
Larger fans always take longer to spin up...

by **Ian C70T5** on Fri Jul 04, 2003 6:59 pm

But the 10psi in a T3 will feel much more powerful than the same in the T2, my FRST had a T3 and that ran 13psi to start with, it felt more powerful than the T2 at 16psi

by **Fezzy Turbo** on Fri Jul 04, 2003 10:22 pm

A bigger and better I/C can effect fuelling as in the fact that there will be more air entering the cylinders.
Get it checked out on a rolling road.

by **xrsi** on Fri Jul 04, 2003 10:37 pm

biger turbo will flow more air!

more air = more fuel needed to stop runing lean and detting!

bigger intercooler will cool the air down to make it more dense so again more dense air needs more fuel!

also the bhp from a t3 fiesta should be more than a t2!

by **MIK3Y** on Sat Jul 05, 2003 2:02 am

Fezzy Turbo :A bigger and better I/C can effect fuelling as in the fact that there will be more air entering the cylinders.
Get it checked out on a rolling road.

Do u mean denser air causing faster combustion meaning u need different fueling?

When RRd, do u mean get a mapped chip set-up?

by **Fezzy Turbo** on Sun Jul 06, 2003 1:36 pm

Yes i meant denser air, as it will be cooler.

You wont need to get your chip mapped again, all a tuner will do is make sure the fuelling is ok, then adjust the fuel pressure regulator if needed.

by **IanRST** on Thu Jul 10, 2003 6:20 pm

I had a T2 running 10 psi then had a T3 conversion running 10 psi much more power in the T3, down side though takes longer to wind up but when it does it pulls much better and a cool sound.

by **Rolls** on Fri Jul 11, 2003 7:44 am

not again

go on to pasionford mate- there is a post about this on there,expained in depth

rolls

by **andymac** on Wed Jul 16, 2003 12:34 am

Not that I'm disbelieving you guys at all, but if a turbo can maintain 10psi of boost while the engines running surely thats the end of the story ? A t3 vs t25 vs t2 will make the boost (albeit at different points in the rev range) so it should all be the same unless people are feeling the boost kick in later on a t3 and because of the map at that point it makes it feel more pokey than it was ?

Any thoughts ?

by **Project** on Wed Jul 16, 2003 1:02 pm

One point - James (xrsi) - you use far too many exclamation marks :rolleyes:

by **Excursion** on Wed Jul 16, 2003 7:35 pm

It's the CFM that's important not the pressure -a good engine makes power with the SMALLEST amount of boost possible.

PSI is merely a measure of pressure - not the volume of air passed. The T3 has a greater area/radius atio therefore flows more air for the same given pressure (this is also determined by the inlet tract to a large extent but we will assume they are identical in this case).

Imagine a standard garden hose at 10PSI then a 2" hose at 10PSi - which oen will flow more water?

by **Sparky** on Thu Jul 17, 2003 5:55 pm

hmmm........ interesting, never really thought about this before.

A larger turbo may flow more air at a given pressure but where is it going? through the inlet tract and into the engine.

This will have the same resistance to flow no matter what turbo is bolted onto it.

10psi into a CVH FRST is going to be flowing the same amount of air regardless of which compressor is used. The T3 will just be less stressed doing this than the T2.

whaddayafink?

by **Excursion** on Thu Jul 17, 2003 7:43 pm

Yeah that's a valid point Sparky - but the air also carries more velocity with the alrger compressor. More air fills the cylinders at any given time. It get's pretty complicated, many different factors and the maths for flow dynamics are hideous.

by **Excursion** on Thu Jul 17, 2003 7:55 pm

Forgot to add - the reason the air is flowing faster is due to the larger exhaust housing and different pulse.

Also the inlet tract has changed, ina big way - the compressor scroll is much larger and it makes a large difference believe it or not

by **Sparky** on Fri Jul 18, 2003 12:37 pm

.......but if more air fills the cylinders at any one time then the pressure must be greater (higher psi) 'cos the size of the cylinders hasn't changed!!

my head hurts!!! :-?

by **Excursion** on Sat Jul 19, 2003 12:27 am

as the air builds up in the cylinders the air pressure does increase, but nearing the final moments of the fill a slower charge will slow down, whereas the faster charge can 'pack' more air in during that final moment before the valve closes.

if that makes sense?

by **BUTRE** on Sun Jul 20, 2003 8:40 pm

hi ppl.. this is my first post on the fiestaturbo.com forum.
Finally the acount has been activated.

thanks adm whoever you are.

This is my thought about the subjetc:
the boost pressure is measured on the TB. So 10psi of boost done by T2 or T3 has got the some air.
What I think that differs is the heat. Since the work produces heat, the T2 to get 10psi boost has to spin faster (more work and by so more heat wich heats up the intake air) than the T3 to get the same boost on the TB.

Since air is more dense (and by so has got more O2) when cold, cold intake air = more O2 to be burned with the fuel.

Dont know if its right, but its the only thing right now that I can think of.

Sorry the mistakes... I'm Portuguese. Not that good typing in English. :/

by **MIK3Y** on Mon Jul 21, 2003 12:40 am

No1 would hav known u weren't English mate.

Good theory and i can understand that this subject is complicated but doesn't the velocity (speed) of the boost pressure @ the TB increase with the turbo size due to it flowing more?

That's in basic junior school physics language people. :wink:

by **BUTRE** on Mon Jul 21, 2003 8:39 pm

thanks. been talking alot with uk ppl for some years now. I guess it starts to pay nicely.

The TB size is always the same, no matter the turbo size. Knowing this I can only say that the only way to get more air flow throught it is by incrising the boost.

Spent the day (at work... sorry boss eheh) looking over this matter and the heat is the only thing I can remember.

anyone else?

by **MIK3Y** on Mon Jul 21, 2003 11:02 pm

So ur saying that the force & speed at which air goes through the TB is the same as the boost pressure reading taken from it?

I think there still is an explanation to why a T3 flows more air at the same psi though as stated by some1 above. :-?

by **Sparky** on Tue Jul 22, 2003 12:02 pm

Excursion :as the air builds up in the cylinders the air pressure does increase, but nearing the final moments of the fill a slower charge will slow down, whereas the faster charge can 'pack' more air in during that final moment before the valve closes.

if that makes sense?

Is this not a higher boost pressure?........ :-?

The turbo creates the charge, the rate at which the charge goes into the engine is governed only by how quickly the engine uses the charge ie. RPM.

by **Sparky** on Tue Jul 22, 2003 12:06 pm

I think the advantage of the T3 is due to its 'capability' to flow more air it can maintain a given boost pressure at higher RPM's

by **Phil Si** on Tue Jul 22, 2003 12:58 pm

been reading this and i still understand it that the pressure stays teh same, but the larger housing = more air...

fill a tube up with air... till 10psi.. one tube is 10cm in diameter, other is 15cm... the 15cm tube has more air but at teh same pressure.... do u see? :-?

by **Sparky** on Tue Jul 22, 2003 2:17 pm

Phil Si, I know what you are saying but what is the tube?

In your analogy the tube should equate to the engine.

To get more air into an engine at the same pressure you would need a bigger engine!! ie. Higher cc.

by **BUTRE** on Tue Jul 22, 2003 7:13 pm

hum... I say again.. the pressure is mesured on the TB! the TB is always the same size.

The only way to get more air and get the same pressure is to get a bigger "runners" from the TB to the inlet valve.

There is no other way.

I still belive on the my theory. T3 gets cooler intake air at 10psi of boost when looking over T2.

by **Phil Si** on Wed Jul 23, 2003 7:37 pm

surely the moreair going in means the quicker it comes out? hence the big kick in the arse when it kicks in?

just a thought, i dont claim to know anything even remotely technical :lol:

by **Jockster** on Wed Jul 23, 2003 8:04 pm

Hopefully this will answer a few theory's

the t3 will provide more air at the same pressure as the t2.
e.g.
if you take a 1L bottle of coke and a 2L bottle of coke (the coke represents air)of the shelf they both have the same amount of pressure in them but the larger bottle has more coke in it i.e. more air

the inlet tract will not restrict the greater flow of air because pressure is felt equally throughout the system according to something called bernoulli's theory

heat is generated by the increase of pressure and flow therefore more heat will be generated from the friction of more air flow.

cheers Jockster

by **BUTRE** on Wed Jul 23, 2003 10:15 pm

well... Pressure is measured on the TB. So the TB is the "bottle of coke". Tell me now how can you put more air in but keeping the same pressure? Not possible.
btw, remember that the TB does not expand, so the only way to get more air is by geting the turbo to build more boost.

heat is generated by two ways in a turbo. Sudden increase of pressure (like Jockster says) and by the heat on the turbine of the turbo. On a turbo the heat from the exhaust on the turbine side passes to the compressor side.

Other thing: intake air must be cold down on a turbo engine because of two mainly factors:
- Hot air is less dense than cold one and by so has got less O2 so badly needed to be burned with the fuel. This when comparing 1 dose of hot air to 1 dose of cold air.

- Hot air can detonate the fuel. Not a good thing.

This is why Intercoolers exist.

I think the T3 can boost intake air at lower temperatures.

I hope that this is understandable. eheh

by **BUTRE** on Wed Jul 23, 2003 10:16 pm

btw, I'm here just giving my thoughts about the subject. I'm not saying that I'm right... eheh dont get me wrong.

by **Sparky** on Mon Jul 28, 2003 9:52 am

I'm with BUTRE on this one.......

by **Excursion** on Mon Jul 28, 2003 1:04 pm

your all forgetting one thing - the size of the compressor itself (more volume) and the change in the exhaust housing size. They all work together to make more power at the same boost comapred to the T2.

This is a basic overview only btw

by **andymac** on Mon Jul 28, 2003 7:27 pm

So you're saying because the rate of flow using a T3 is higher than the rate of flow attainable by a T2 when the inlet opens and air begins to move the T3 will be able to be able to not only fill the inlet tract more quickly but wil re-reach the boost limit as defined by actuator / amal / boost controller more quickly as it is simply able to flow more air ?

Or something like that

by **andymac** on Mon Jul 28, 2003 7:29 pm

I suppose in some respects this is somethign like a switch-mode power supply. It takes "bites" out of the air pressure so the turbo has to work to try maintain that pressure. A bigger turbo that can flow more will be able to restore that level more quickly than a smaller one would.

fiestaturbo.com

T2 @ 10psi same as T3 @ 10psi?

T2 @ 10psi same as T3 @ 10psi?

>

>

>

>

fiestaturbo.com

T2 @ 10psi same as T3 @ 10psi?

T2 @ 10psi same as T3 @ 10psi?

>

>

>

>

Twitter

Facebook

RSS Feeds

What is RSS?