Turbo Group Buy

[foggyjames]

Liam,

I was talking about *headroom*. If we're going to talk audio, you must surely know that you can drive a given loudspeaker with over 4x its rated power in certain situations quite safely. It's all about duty cycle. You're FAR more likely to blow up a loudspeaker with a power amp which is too small than one which is too large. Of course the audio analogy breaks down for various reasons that I'll not bore you with, but I was just trying to make a point in easy to understand terms.

The point is that (all other things being equal) a large turbo will not be working as hard to produce the same boost pressure as a smaller one. End of story. Whether or not that is significant in this case is the question. There's got to be a good reason why turbo upgrades are popular, and it's because they are more efficient (read: happier running) in higher boost applications.

My Dad's 940 LPT with 4psi has a piddly little Mitsu 13c...Doug Kauer's 242 with 30 psi has a Holset turbo from a truck. Not that I'd necessarily choose Doug's car as an ideal study into a perfectly engineered engine - it's a little too much boost, not enough flow for me...but it makes the point.

cheers

James

>The point is that (all other things being equal) a large turbo
>will not be working as hard to produce the same boost pressure
>as a smaller one. End of story. Whether or not that is
>significant in this case is the question. There's got to be a
>good reason why turbo upgrades are popular, and it's because
>they are more efficient (read: happier running) in higher
>boost applications.

That is nothing new though, and with that I agree. However, the fact remains that the stock turbo is still happy at various levels of tune.

Adam.

[foggyjames]

For the sake of world peace and actually standing a chance of finishing my dissertation, I'll agree :)

Of course if anyone wants to give me their old 15G...:D

cheers

James

[Traduk]

James,

We will not deal with the amp issues because I left my career long life in the electronics industry behind over a decade ago and electronics bore me rigid. I do not agree with your arguement but we must agree to disagree.

You are looking at turbo sizes and boosts in a linear thought mode. The reality is dynamic and whereas your statement is correct it applies only to a snapshot of activity. When a larger turbo gets the full flow of some real revs it has to have control and if none is present the longetivity of a bigger turbo is irrelevant if it destroys the engine. I saw the reason for a large turbo purchaser as stated as being because it would last longer than the old stock one. My thoughts were that without re-mapping it would probably outlast the engine, car and two year warranty.

James, I did not realise that a little bit of a flame war had started whilst I was outside and would not have posted. However I have seen many of your posts and know that much of your thinking reflected my tuning ideas right up until the program controlled era took over in a big way. In modern cars the re-mappers are kings and without access to the coding most of your tuning ideas are redundant unless confined to oldie goldies.

Liam

World peace it is! :) Good luck with your dissertation. I can tell you now, I'm glad I don't have to go through all that again, although good times were had!

Adam.

[foggyjames]

>We will not deal with the amp issues because I left my career
>long life in the electronics industry behind over a decade ago

I think we've just misunderstood each other, as I'm simply quoting some of the most basic power amp selection theory.

>When a
>larger turbo gets the full flow of some real revs it has to
>have control and if none is present the longetivity of a
>bigger turbo is irrelevant if it destroys the engine.

Almost any turbo will destroy an engine without boost control. How you control the boost is essential to engine performance, clearly. Or did you mean how the engine is controlled to 'react'?

>I saw
>the reason for a large turbo purchaser as stated as being
>because it would last longer than the old stock one. My
>thoughts were that without re-mapping it would probably
>outlast the engine, car and two year warranty.

Running standard boost, a standard turbo will last a good long time before it requires attention (200,000 miles seems a fair figure given average use, but I might be behind the times there). Running a turbo at a boost level off the top of its efficiency map will drastically shorten its lifespan. Period.

>However I have seen many of your posts and know that much of
>your thinking reflected my tuning ideas right up until the
>program controlled era took over in a big way. In modern cars
>the re-mappers are kings and without access to the coding most
>of your tuning ideas are redundant unless confined to oldie
>goldies.

No! The chip tuners are the kings if you want a quick, easy, and cheap solution to give a moderate power boost without changing other components. That's obviously enough power for most customers, but it's certainly not the be-all and end-all. Once you have uprated physical components you can go back, re-tune, and free up more power. However there is a limit (seemingly around 310bhp) where chipping a stock car runs out of options. Of course going and getting your friendly chip dealer to map your EMS is only one option...

I may be (currently) heading down a carb route with my own car - for authenticity (it's an original 300 series R-Sport kit) and insurance purposes, as I am one of those wreckless young drivers you hear so much about! Believe me, I'd have a 360 turbo T5-basher (power to weight ratio folks!) if I could insure it. However, the engine soon to be on the bench will have programmable electronic fuel injection. An engine is an engine - the whiteblocks don't have magical properties which differentiate them from what has gone before. There are some very powerful and fast whiteblock cars out there, likewise with redblocks.

All of the engine control techniques used on the whiteblocks can (and have been) applied to the older engine designs. Naturally engine management technology moves forward, so many of these advanced systems aren't present 'from the factory'. However some of the last redblock engines to be developed from scratch (for example the B204GT) have EMS almost as advanced as the whiteblocks, featuring ECU controlled boost, EGT, etc. Incidentally, the B204GT (2.0 16v turbo - not offered here due to the Brits being too conservative!) has almost exactly the same BHP figure as the similarly specced but alloy block T4 engine. Nothing much changes...

Need I remind everyone that the fastest Volvos in the world aren't whiteblock powered? There's a good reason for that too!

cheers

James

[foggyjames]

Oh Crikey....I missed the peace treaty while typing that....disregard my post!!!!! :D

Tell you what chaps - we'll settle this in a Chip vs Redblock deathmatch at Santa Pod sometime next year. A fun day out for all the family :)

cheers

James

[sholtby]

Adam,

When my turbo fails what replacement would you recommend? Should I just get another 15g?

Thanks
Simon

It depends if you want to alter the driveability characteristics of your car and if you are prepared to travel for a remap to make the most of it.

Adam.

[IC]

Let us all remember the purpose of this thread. Iain's message asking for people interested in a turbo group buy has all but been lost. Please start a new thread if you want to discuss other topics.