998 High Boost Head - Update
Turbo Mini Forums

An afternoon in the barn with a die grinder:



Its a 12G295 casting that I picked up for 20 quid the other week. I'm going to fit 33/29mm race valves and bronze guides.

The inlets are already opened up for 33mm valves. I've opened up No. 4 exhaust throat for the 29mm valves already, do the rest tomorrow.

I'll tidy them up once the ports are done and the seats cut.

My lads high compression unleaded 12G295 with 33mm inlets in the background for comparison purposes.

Edited by Paul S on 25th Feb, 2007.

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."

looks like a nice piece of work sir!

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

Thanks, Matt.

I thought no one was interested.

But then I should not have posted it during "Rawden Week"

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."

Looks like it should do its intended job nicely, well done that man.

-MINI CLUBMAN 1380 TURBO-

good on you axel , that should flow stonkingly in a 998 . i like the rawden week comment , he does seem to get people going .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

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."

Fantastic stuff, with those valve sizes will you have to pocket the block or will they be ok? Also, are you using 1275 valves or 998?

Keep us posted!

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

Edited by Paul S on 18th Feb, 2007.

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."

i think its amazing doing this work yourself, your either brave or skilled or both, either way i'm finding it interesting, i think i'll have a play with opening up an intake manifold before i'd attempt a head, what is the basic things to have a go at when doing a head, cheers axel, PM that info if you get the chance axel rather than me cluttering the thread, look forward to more pics of the work your doing

SKYLINES ARE LIKE CLITS, EVERY FLANGE SEEMS TO HAVE ONE: see this sticker on my silvia

the Search-section on this forum is blummin superb & simple to use, unlike some other forums, without the search-section & the help of this bunch of chaps on here i'll never be able to !!!Start the day with a 998cc turbo!!! :) i'm getting closer though!

Tom Fenton says: I have it all, make me an offer

One of these:

http://cgi.ebay.co.uk/SEALEY-COMPRESSOR-50...1QQcmdZViewItem
A big compressor.

And one of these:

http://cgi.ebay.co.uk/1-4-mini-Air-DIE-GRI...1QQcmdZViewItem
A Die Grinder.

And some of these:

http://cgi.ebay.co.uk/5PC-MOUNTED-GRINDING...VQQcmdZViewItem
Grinding stones - or you can use carbide burrs.

And a copy of the Big Yellow Book. Its all based on Figs 9.14 and 9.23.

I've pinched the de-beaked shape from Avonbar or Benross, depending on who did it first.

Oh, and I spent about 6 weeks of my engineering apprenticeship grinding out steam turbine nozzles to 0.001" tolerance. 30 years ago, but you never forget how.

Edited by Paul S on 18th Feb, 2007.

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."

Got the porting done this weekend, fitted some bronze guides and did the first cut on the valve seats.

Still got to CC the chambers and fettle the valve seats and generally tidy up, but it's getting there.



Nice big ports, the inlets were already done, just took out the guide boss. I've opened up the exhaust for the 29mm valves and removed the boss.

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."

Really looking like you have just bought it from a pro looking forward to hearing about the results.

Matt

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

Looks good, but get the valve seats cut properly, with at least three angles.

I'm far more interested in the turbo in the background.

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

www.twin-turbo.co.uk

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."

I might be!

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

www.twin-turbo.co.uk

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."

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

www.twin-turbo.co.uk

Do a search for GT17.

Robert started a thread last year about these. The conclusion was that as the compresor is identical dimensions to the GT2052, then that's the map to use.

I think Robert is using one on his 1275 - he posted a datalog plot showing it boosting from 1400rpm!

My calcs would give approx. 180hp on 20psi at 7000rpm.

Interesting comment about the 20773s - Lets hope the Megas are better.

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."

the 20 52 is not the same as the gt1752 unless its runnig a 55 trim wheel with 4mm wide blade tips .
the only 2052 maps i have found are 48,52,60 trims . fab did an interpolation on the gt17 thread that i had done also and its the best estimate we could make at the time , i feel that the tip depth may have a map raising effect not fully anticipated as yet though.!

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

What makes it more difficult is that Saab used 4 different versions of this turbo 452204-0001/3/4 & 5.

Mines a 0003 with slighly different A/Rs than the others - 0.53 compressor and 0.47 turbine.

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."

the 1 4 and 5 are the same a/r axel . they are all .53 on the inlet and .47 turbine housing , i just went and checked out the other two i have .they are a 1 and a 4 and i have the 5 on the car , incidentaly if you replace one of the lower nos garrett supply a 5 to replace the others .so i think they are all pretty identical .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

I came to the conclusion that the different part numbers related to different orientation and actuator fitments only.

The 20773s were in fact perfectly reliable on the 998 running 18psi with a T3, Still got the set I took out, perfect condition after nearly 4 seasons.

This engine only revved to just over 6k. The efficiency of the turbo was around 5% better with the T3 compared to the T2. I think this with the extra revs conspired to break the ringlands.

Edited by wil_h on 25th Feb, 2007.

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

www.twin-turbo.co.uk

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."

oooh ah knowww (frankie howerd voice )
still ...i like the exp test pilot role .!

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM