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998 Turbos


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#1 Wil_h

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Posted 14 September 2007 - 05:35 PM

There seem to be a few people interested or doing this conversion, so I thought that I would offer some advice from my own experience of building numerous 998 turbos.

firstly, see here for my latest conversion As you can see you need no engine mods and it all holds together, done 1000 miles now, no problems http://www.twin-turb...IN_20_HOURS.pdf

This used a T2 from an R5 GT turbo, this a great all round turbo for the 998, it won't boost efficiently over about 12psi, and will make a maximum of around 140bhp.

Other turbos I have used include the T3 of a metro and a GT17. The GT17 will make bags of power (160 or more I suspect) I have 155bhp and 1/4 mile times to prove it!. The T3 is a pile of junk, old technology, high inertia and enormous. The T3 will work and make 140 bhp easy, if not more but at the expense of driveability, you will not get boost below 4k, ok for track use, but little else.

Edit: I put 100 miles when it should have been 1000.

Edited by Wil_h, 15 September 2007 - 04:42 PM.


#2 lemmingzappa

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Posted 20 September 2007 - 10:30 PM

Thanks, that PDF is handy for me ! ;D

#3 Big_Adam

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Posted 21 September 2007 - 11:12 AM

DAMN YOU WIL!

Now I've got ideas. Horrible expensive ideas.

:D

#4 james105

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Posted 22 September 2007 - 07:06 PM

same! could this same conversion/method be done to a 1100 or a 998 with an 1100 head, or a normal 1275

Cheers

James

#5 Wil_h

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Posted 28 September 2007 - 03:39 PM

same! could this same conversion/method be done to a 1100 or a 998 with an 1100 head, or a normal 1275

Cheers

James



Yes this will work on an 1100, you'll just need bigger chambers to get the CR low enough. It's also possible on a 1275 as long as you can get the chambers bigenough for the lower CR.

#6 Ollie180

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Posted 28 September 2007 - 07:43 PM

What head would you use on a 1293? would the head you use be ok? and could you make them bigger if i had to? ie maybe drilling them out a bit (on a machine ovcouse)

also is there thicker head gaskets?

Edited by Ollie180, 28 September 2007 - 07:56 PM.


#7 Wil_h

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Posted 29 September 2007 - 06:01 PM

No, you can'tr use small bore heads on large bore engines. You need a 12G940 as a base for a 1293.

I think a 12G940 with 30 cc chambers will get you close, but it depends on what cc you have in your pistons. Not ever having built a large bore engine I don't know what is standard fitment.

Also, there aren't ant thicker head gaskets. Jonseed and Vmax have decompression plates which could be used, but I don't like the idea.

Edited by Wil_h, 29 September 2007 - 06:02 PM.


#8 mike.

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Posted 29 September 2007 - 09:38 PM

Hoe reliable is that clubby of yours wil, the one in your pic? I saw that in miniworld/mag in the drag racing article they had abit ago. Its sounds like a beast!

#9 Wil_h

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Posted 01 October 2007 - 11:45 AM

How reliable is it?

Well, we've had good and bad years. Some seasons we've not touched the engine at all, otheres we've been through lots of head gaskets.

In terms of road mileage it's not been that reliable I supose, but some of the problems are just anoying things rather than it blowing up because we're asking too much. Ultimately its' a 155 bhp 998 that dos 1/4 mile in 13.5 secs and gets to 60 in 4.5 seconds. We are asking it to do a lot and trying something that no-one else (that I know of) has done before, as such I expect to break things.

It's never lunched its self, the bottom end had been 100% reliable infact, the problems are piston damage caused by det and head gaskets caused by chamber shape and a dodgy torque wrench. Hopefully all these are cured now.

#10 mike.

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Posted 01 October 2007 - 04:31 PM

Its sounds awesome! In the future i want to do a turbo project with my 998. I'd be more than happy with 120bhp from it but i'd be using it probably every other day to get about in. Could i make it resonably reliable? Obviously i'm not expecting it to as reliable as a modern car or a standard a series set up but on the other hand i don't want to be whipping the head off every week!

Another thing is by the time i'll be looking at a turbo set up my engine will be getting on for 90k. Obviously It'd be getting a full rebuild but is that enough? Or should i be hunting around for an engine with lower mileage?

#11 Wil_h

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Posted 02 October 2007 - 07:25 AM

At the moment, the car that I turbo'd that started this thread (not the red one) has around 80-90 bhp and has now completed around 1300miles with no (turbo related) problems. I think upping the boost to 10psi should net 110bhp. A fresh engine should be more than capable of coping with this for road use for many thousands of miles.

You won't need a new block for any rebuild, a +20 overbore and a 10thou grind on the crank will most likely be all that's needed.

#12 jcws_mini

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Posted 04 October 2007 - 12:51 PM

At the moment, the car that I turbo'd that started this thread (not the red one) has around 80-90 bhp and has now completed around 1300miles with no (turbo related) problems. I think upping the boost to 10psi should net 110bhp. A fresh engine should be more than capable of coping with this for road use for many thousands of miles.

You won't need a new block for any rebuild, a +20 overbore and a 10thou grind on the crank will most likely be all that's needed.


Hi Will,

Its Jonny, Brendans mate. I am lovin your turbo conversions Bren has told me about them a few times. If i ever get my mini goin again I will be very interested in getting this conversion, it seems the cheapest way of getting a decent amount of power from 998 (id be well happy with 80 bhp!). How much did it cost to get everythin together?

My mini has been off the road for 2 years now and is dying a slow death outside >_< , hoping to get it garaged and then start sorting it out.

#13 Wil_h

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Posted 04 October 2007 - 02:24 PM

Now then Jonny.

The Green Mini cost around £1k to do, the red one a poo load more.

#14 998_Tom

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Posted 04 October 2007 - 07:38 PM

Ok so im building a 998 turbo thanks to you(wil_h) for the idea. Im wanting say... 120bhp, is that managable with out an intercooler, well reliably anyway i dont want the engine to C**p itself after a few thousand ks(miles). Iv got an hif6(same as a hif44) carb i think off a late mg metro(correct me if im wrong).

Will a competint mechanic or carb specilist be able to seal it for me so i can use a blow through setup?
Or do i just have to settle for a draw through system?

#15 Wil_h

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Posted 05 October 2007 - 07:07 AM

Firstly, you won't get 120hp without an intercooler no. well it might be possible but not worth it.

A HIF6? I think you probably mean HS6 which is a 1 3/4" SU rather than the later HIF. Yes this can be converted, as I said in the twin carb thread, sealing is not the main issue, fuel pressure in the float bowl is.

By far the easiest way to carb-turbo a blow through system on an A-series is to use the metro turbo carb abd plenum, it solves so many problems.




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