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Home > 998cc > Phase 2 - 998cc build turbocharged

Barrieri

289 Posts
Member #: 11231
Senior Member

Hi guys would an Avonbar Phase 2 cam suit a turbocharged 998cc 8.3CR ? Also what kind of lift does this cam have ?

Thanks


wil_h

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9224 Posts
Member #: 123
Post Whore

Betwix Harrogate and York

I tried one and it was terrible, boost threshold rose and the power was very peaky.

I use the MG metro cam (Kent KC500), I have over 180bhp, so it's not a restriction.

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

www.twin-turbo.co.uk

On 2nd Jan, 2013 fastcarl said:

the design shows a distinct lack of imagination,
talk about starting off with a clean sheet of paper, then not bothering to fucking draw on it,lol

On 20th Apr, 2012 Paul S said:
I'm mainly concerned about swirl in the runners caused by the tangential entry.


Barrieri

289 Posts
Member #: 11231
Senior Member

Thanks Wil, I will go for the Kent500 and save up some money for other stuff.

By the way, from the specs how should you know if a camshaft is good for a turbocharged Mini or not. I thought that it needs to have small overlap and large exhaust duration with high lift on both the inlet and outlet lobes. Or it isn't just that ? Yesterday I compiled a little info on possible choice of cams and compared them in the Excel sheet attached.


Attachments:


Paul S

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8563 Posts
Member #: 573
Formerly Axel

Podland

You missed the kent MD274.

Like a mini Ph2 for 998s.

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."


Barrieri

289 Posts
Member #: 11231
Senior Member

Yeah actually I knew about it Paul but I read somewhere on TM that it is not so good due to its overlap. I think for my build I'm going to resort to the Kent 500, but still not sure on the benefits of the Kent 266, the METBP255, the Phase 2 and the Minispares Camshaft Turbo Special over it. Any help ?


Paul S

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8563 Posts
Member #: 573
Formerly Axel

Podland

On the contrary, the MD274 has a high LSA which is ideal for turbo. Both the Ph2 and the MD274 have 112 degrees.

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."


Barrieri

289 Posts
Member #: 11231
Senior Member

The phase 2 seems to have very long exhaust duration which I think helps the turbo keep on spooling. On the other hand it has a very large overlap. With the Kent 500 I think I will be losing both the duration on the inlet and exhaust. On the other hand the Minispares Turbo Special and the METBP255 seems to be a compromise between the two.

However this is my first camshaft replacement so I'm not so knowledgabe on the matter.


Barrieri

289 Posts
Member #: 11231
Senior Member

Does high LSA mean small overlap Paul ?


Paul S

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8563 Posts
Member #: 573
Formerly Axel

Podland

LSA means Lobe Separation Angle. A high LSA means lower overlap.

There is a post titled "Lobe Separation Angle". Lots of missing graphs but I can PM you them as Pdfs.

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."


Barrieri

289 Posts
Member #: 11231
Senior Member

Yep, if you can I appreciate it. Currently I'm doing a lot of theoretical analysis before I start buying the stuff.


Paul S

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8563 Posts
Member #: 573
Formerly Axel

Podland

I've been having problems with my photo hosting, but now sorted so i'll post them here:



Edited by Paul S on 16th Oct, 2016.

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."


Barrieri

289 Posts
Member #: 11231
Senior Member

For what engine displacement and CR are these Paul ?


Paul S

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8563 Posts
Member #: 573
Formerly Axel

Podland

1020cc and 9:1, 0.8 bar boost.

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."


Barrieri

289 Posts
Member #: 11231
Senior Member

Thanks a lot Paul. So it seems that the 274 only lacks the lift of the Phase 2. However this week I emailed Kent and asked them what they recommend for a 998cc turbo and they actually said that the 500 is the best candidate. I'm quite confused. However I think that the camshaft selection also depends a lot on the specific engine specs, doesn't it ?


Barrieri

289 Posts
Member #: 11231
Senior Member

Does anyone have an idea of the quality of the Mega pistons from Minispares ? They are much cheaper than the Omegas. Any experience ?


Turbo Phil

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4336 Posts
Member #: 20
My sister is so fit I won't show anyone her picture

Lake District

They've been discussed quite a lot on here over the years. I think the general consensus would be to pay the extra and go for the Omegas.

Phil.

WWW.TURBO-MINI.COM


Barrieri

289 Posts
Member #: 11231
Senior Member

Hmm I will be a little bit limited on budget however. But lets see how things go.

My other concern at the moment is the crankshaft. I have at my disposal a 1275 A+ block and a 998cc block. I was thinking the other day if I should fit a short stroke crankshaft into one of these blocks, however I would need to stick below the 1140cc, as I don't want to end up in a higher category with the 1.4x multiplier (turbocharged).

My concern however is the fitment. I read that Paul had a hard time with machining the thrust washers, so that might be an issue. But what if I use the 1275cc block ? Or maybe I buy an 850cc block and overbore accordingly ?


Joe C

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12149 Posts
Member #: 565
Carlos Fandango

Burnham-on-Crouch, Essex

small bore cranks wont fit 1275 or visaversa,

998 and 850 swap is also a pain,

On 28th Aug, 2011 Kean said:
At the risk of being sigged...

Joe, do you have a photo of your tool?



http://www.turbominis.co.uk/forums/index.p...9064&lastpost=1

https://joe1977.imgbb.com/



Barrieri

289 Posts
Member #: 11231
Senior Member

So if I swap the 850 crank in the 998cc block, what would need fitment ? I only know of the thrust bearings yet


Joe C

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12149 Posts
Member #: 565
Carlos Fandango

Burnham-on-Crouch, Essex

think thats it, apart from skim a load off the top to get the piston flush.

On 28th Aug, 2011 Kean said:
At the risk of being sigged...

Joe, do you have a photo of your tool?



http://www.turbominis.co.uk/forums/index.p...9064&lastpost=1

https://joe1977.imgbb.com/



Barrieri

289 Posts
Member #: 11231
Senior Member

Yep. Anyone machines these type of thrust bearings ?


Joe C

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12149 Posts
Member #: 565
Carlos Fandango

Burnham-on-Crouch, Essex

nope, and thats why its an issue, it's be a custom job,

On 28th Aug, 2011 Kean said:
At the risk of being sigged...

Joe, do you have a photo of your tool?



http://www.turbominis.co.uk/forums/index.p...9064&lastpost=1

https://joe1977.imgbb.com/



Barrieri

289 Posts
Member #: 11231
Senior Member

But I think it shouldn't be sn issue if we design it in inventor and send it to be machined on a CNC.

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