your mate dave walker has a little rant in his column in practical performance car this month about cossies and ecu's. he's been reading your posts on here too much

 

 

lol

 

what am i missing? lol

 

You are missing Tabetha's take on cossie ecu's and why so many people still use them when in his opinion aftermarket ones are much better. i'm sure thats the gist of it

 

I am astounded by the amount of big hp cossies that have never had or have the capability of having a rolling road map.

A live map is a new thing yeah?

 

i have GOT to get me a copy asap

probably from tesco tonight then

 

Weber has been live mappable since it came out in 1984 mate. So hardly a new thing.

 

that is the gist of it

 

corner shop for me

 

 

He said WAY worse than that the month before!

"All the most powerful turbo cars make the power at 12psi or less" and then basically tried to say something along the lines of if you got 30psi boost but 29psi manifold backpressure you only really gaining 1psi of power, which is total and utter bollocks, as many top cars run over twice the backpressure as they do boost.

Totally lost all confidence in him myself, wouldnt go there.

 

Fpmsl

 

I guess he means without an external emulator.

 

you can't diss dave, he'll do jedi stuff to you

 

Wonder if Dave Walker thinks that Veyrons are chipped up Skodas as well?

 

"All the most powerful turbo cars make the power at 12psi or less" and then basically tried to say something along the lines of if you got 30psi boost but 29psi manifold backpressure you only really gaining 1psi of power, which is total and utter bollocks, as many top cars run over twice the backpressure as they do boost"


A pressure differential is a pressure differential. Pressure runs from high to low this is simple physics. Dave knows his stuff, no question.

 

pmsl

 

Physics that dont apply to engines im afraid.

 

i think stav is on baout the original bit that he quoted
the more air you can get in the more fuel you can ignite, so something running 24 psi will be able to potentially create a bigger bang than something running only 12 psi

and 12 psi in a 1.2 4 pot is different to 12 psi in a 2.0 4 pot, plus compresion ratios, compressor maps, etc, there's a lot more to it than just the boost the turbo is making

 

12psi on a 2.0 4 pot will be fuelling a hell of a lot more than a 1.2 4 pot running the same boost on the same turbo

 

so the 2.0 would make mroe power at 12 psi than the 1.2 yes?

 

for a given pressure, a higher displacement engine will be able to command a higher rate of air flow into the engine working on the basic suck principle and given engine specifications the same boost pressure seen on corresponding 1.2 and 2.0 engines should result in the 2.0 producing more power. Take a standard FRST producing about 0.6 Bar of boost that produces 130bhp. Then take Silvia 180SX that produces 220bhp as standard on about 0.6 Bar of boost as well.

No replacement for displacement

 

What a load of bollocks

How the fuck can you use that as an example, using totally different sized turbos, never mind completely different engine specs!?

Capacity is prob the least important of all the reasons those cars are those power levels at that boost.

You been listening to Dave Walker too?

 

that was the only thing that sprang to mind that I knew of running the same boost and different engine displacements. Its pretty hard to think of an example of an engine running the SAME spec with the SAME turbo and SAME boost SAME map but just differs in displacement.

 

as far as i understand it that toally depends on the engine and size of the turbo....

don't forget 12psi out a t4 is a shit load more air than 12psi out a t25.... if the 1.2 can take 12 psi out the t4, fuel for it and actually use it then surely that'd make more than a 2.0 running a t25 at 12psi?

 

that's another factor as described in one of Stu's articles that I was reading. A huge turbo running a small amount of boost due to the volume of air it can suck in may well be more than a smaller turbo running a very large amount of boost.

 

I think you ought to re phrase that Stu. Either that or i have just spent the last few days designing an inlet manifold totally the wrong way!!

 

engines in turbo f1 cars of the early 80's were heading towards 1000 bhp.. and were 1.5litre...go figure!!!!

steve

 

You are talking about a 1.6 8valve with a small T2 against a 1.8 or 2litre 16valve with a T25 or T28, none of em doing 220bhp and pretty sure neither running 0.6bar.

Couldnt get a more distant comparison if you tried.

Simple fact is capacity dont mean that much with regard to power in a turbo car, airflow does, and different turbos will give different bhp even on the same boost on the same engine, so what your saying is odd full stop.

 

BMW was 1500bhp, on an old road engine too.

 

Maybe I've just been putting my point across wrongly or badly phrasing it.

Given EXACTLY the same conditions bar the displacement of 2 engines, wouldn't you expect the greater displacement engine to be more powerful? I understand the principle behind airflow and fully appreciate what you are trying to say but I jsut wanted to point out a higher displacement engine running under exactly the same conditions of an identical smaller displacement engine surely warrants the higher displacement engine to produce more power?

 

from what i read into stu's articles, the amount of air flowed is different to the amount of pressure generated, so a bigger turbo will fbe spinning slower to provide the same amount of boost as a tiddler spinning like a whirling dervish maxing out at 12 psi, the capability of the bigger turbo to flow more air is the thing to look at

but back to this 12 psi thing, the smaller engine will have a disadvantage in that it won't be able to flow enough air to shift the bigger turbo as opposed to the bigger engine being able to generate more oompf at the same revs
if they were using a turbo designed for the 1.2 on both engines as opposed ot using a turbo designed for the bigger engine

yes?

over to you dave

 

Please explain??????

 

this has gone off on a bit of a tangent

let's get back to provoking tabetha

 

Theory and real life are worlds apart.

 

Tabetha = arrogant

 

the realilty is that i was tested and had an iq of 164 when i was 11

the theory is that i should be really really clever and shit like that, but i'm not

so, you see, worlds apart

the theory is that a 500 bhp car should do certain speeds, but the reality is that when they go to a set of rollers, something always breaks

 

Genius!!!




The quote from Dave Walker has been taken all out of context anyway. Do some of you write for the Sun?

It states that "high boost does not equate directly to high power"

The reference to 30 PSI boost and 29 PSI pressure in the exhaust is with regards to small turbos.

The quote regarding 12 PSI is

"The cars making the biggest power always have big turbos an do it on 12 PSI or often less"

 

Its not all about engine sie, take the busa turbo motors for example