Twin Turbo question
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Between crawling and running is the status known as walking.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Thanks for that insightful tidbit buddha! Lol. Let me pose a question to you Paul, if you were turbo'ing an 850cc motor, what would your choice be?

I'm pretty sure there is a turbo out there that will give boost on an 850 from 2k and still be efficient at 6k.

In fact the GT12 seems to be able to make boost from way less than 2k and go on to make 100bhp at 15psi at 6k.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

www.twin-turbo.co.uk

I'm thinking that you've used a gt12 turbo Wil? Is it really good for anything over 8? I read somewhere(can't for the life of me remember where) that it's only good for about 8 psi.

well providing you get hold of a gt1241
they look good for 20psi and 100+hp (2.4 pressure ratio and 12lb/min airflowon the map below)





have a play with this, set specific fuel consuption to 0.45 and VE to 80%, that should give fairly realistic no's

If it's good for about 20psi, then it's probably perfect for what I'm looking for, and I think, should I want more power, that the gt15 has the same output flange so it would just bolt straight up.

I hope this doesn't sound too dumb... Is boost compounding? Say you have two turbo's, independent of eachother, same size, boosting at the same time. If each turbo is set at 5psi, is it the same as 10psi?

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

No reason to be rude Paul. I was asking your opinion, not for an answer to what I'm doing. This thread has been helpful to me, yes, in that it's solidified what I'm going to do. But I do enjoy hearing people's opinions about what I'm going to do, or they will do, to their cars.

Yes i moved to the darkside

Instagram @jdm_brett

It makes sense. smaller turbo would make higher pressure. However, you're supercharging and turbo'ing, so you may be able to get away with a larger turbo. What capacity motor are you using?

1293 it will be just turbo first, wouldnt mind turboing a blower though, fancy being able to turn the charger off though and gear it for high boost down low and turn it off up top let the turbo take over

Yes i moved to the darkside

Instagram @jdm_brett

Yes i moved to the darkside

Instagram @jdm_brett

2 for the price of one

Edited by Brett on 23rd Jun, 2010.

Yes i moved to the darkside

Instagram @jdm_brett

This is how I would do it:



The smaller turbo would not create a restriction as it is handling much denser air once the large turbo kicks in.

There are some complex thermodynamics involved here. I'll post a spreadsheet of the calcs after dinner.

I still think that you're bonkers.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

were all bonkers thats why we are here

i think its all sort of clicked into place now, i was struggling to understand how the pressures change, but after running afew calcs and looking at a map it clicked, its not pressures its pressure ratios

Yes i moved to the darkside

Instagram @jdm_brett

I wouldnt do it like that becuase one the big turbo spools up itll blow the crap out of the small one.
Id have both Turbos running off the same exhaust manifold but seperate intercoolers and intake ports.
That way the small turbo produces boost from low revs and the 2nd turbo kicks in once the revs pick up.


in theory .... in my head... as i see it.

matt.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Attachments:

199.65kb

Yes i moved to the darkside

Instagram @jdm_brett

Just realised that the arrows are in the wrong direction on the exhaust side, but can't be arsed to fix it today.

EDIT: Should be fixed now.

Edited by Paul S on 23rd Jun, 2010.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

These are the calcs:


There are other ways of doing it, but this is mine.

I have all the parts to build this engine except the forged pistons. However, I seemed to have gained a little sanity recently and have shelved the idea.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

cheers Paul

Yes i moved to the darkside

Instagram @jdm_brett

Definite thanks Paul.