998 Twinky Turbo - Advice Needed
Turbo Mini Forums

After having bought the kit of john a couple of years back for doing a K Head conversion ive finally got round to welding it up and prepping a block, I was going to build a 998 supercharged engine for the marcos but after a couple of mates having issues with there kits from a reputable specialist I thought about going 998 K Head, then I thought what about a 998 turbo twinky.

Ive been doing a lot of reading up and looking round with RobH giving me some good pointers and It looks as though a T2 or GT17 could be the weapon of choice?

Im gonna need a bit of help as ive not had much dealings with turbos as ive always had N/A A series minis and especially with using the K head i will have to design and make a nice plenum and manifold for the job! Im currently doing the machining at college doing a motorsport night course as they wont let me do anything interesting at work :(, So what im looking for is some good pointers and possibly some ideas on designs for the plenum and manifold and also what spec the engine should be!

The engine is to be for the mini marcos and im not wanting a total screamer of an engine but something that I could describe as a good GT engine something i can cruise on the motorway with but also give it the beans at a track day or sprint as i can keep it in the under 1400 class.

Cheers
Gaz

What head do you have 8v or 16v?

at 998cc I think the GT17 will have too high a boost threshold for road use, I only get away with it because I have a 4.1 diff. It will however give you the most potential power, but from what you say, 120 tro 130bhp will be enough.

There are lots of turbo choices, but you need to crunch some numbers for your application. I'm currently building a 998 with an IHI RHF4, I'll report back soon. The T2 would be a good choice, but the the GT1548 is a more efficient similarly sized turbo.

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

www.twin-turbo.co.uk

Alrigh Wil, Ive got a 8v but ive also got a 16v sat in the workshop but the 8v is all welded up and ready for machining.
I meant to say GT15 in the post, I was speaking to some other people about turbos yesterday and got confused.
Apart from the Reanault 5 where are T2s commonly found?

audi 80 tdi's use t2's

Drives
-Ford S-max Mk2 Ecoboost
-Rover 100 VVC #2 - track project

Searching is all you need on TurboMinis

theres a few t2s on ebay at the mo, which all need rebuilds which isnt surprising, so will try and get one cheapish and rebuild it at work unless someone has one to sell?

Quick update, i got a free T25 from a lad at work which is in very good condition with very little float in the shaft and the usual crack in hte housing :) I was going to use this to mock up the manifold but i now have a suitable T2 from a Renault 5 which i will use.
Progress on the machining is a bit slow but hopefully once ive paid a few bills on the house i can drop the head and block of at the machinists.

Whats the most suitable pistons to use? ive heard good things about the Oz oversize pistons?

I use the Mega pistons from Minispares, been quite reliable. The Oz hypertecs have slotted oil groves, which may not prove relaiable in a higher revving twinky engine.

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."

Well that's better news then. why have they slotted the smaller ones I wonder?

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

www.twin-turbo.co.uk

Schrödinger's cat - so which one am I ???

I will have to figure out what oversize to go for, it seems as though the 80 thou is good but may need to have deeper cutouts for the valves, got a bit of calc and dry building before order them.

I decided to go for +0.120" in the end.

Miniboo still had to relieve the block at 0.080"

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=183796

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."

alright paul, with the 120thou overbore how much wall thickness is between 2/3 cylinders?
Can you also send me a copy of the cad file? cheers

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 the file mate, Ive copied it into catia and will start measuring up, after looking at the pistons i realised robh was selling a set! and luckily i won them on ebay, so all i need now is a crank, rods and jackshaft and i cant start doing the maths! :)

Hey gaz, you finaly joining the 998 turbo gang......told you at imm 2008 that was the way to go......guessing for the pick up? ;o) Just starting to build mine for next year, liked the turbo way to much last year ;o) Tho mine isnt going to be 8v tho ;-(

hey mart, no its going in the marcos :) once its restored! got the maguire running so taking it to avon in a couple of weeks.

[quote=pickmeup,13th Jun, 2010]
Progress on the machining is a bit slow but hopefully once ive paid a few bills on the house i can drop the head and block of at the machinists.quote]

Gaz - looking forward to seeing the MM progress! Can I ask - where do you get your machining carried out?

Edited by Cooper1999 on 28th Jun, 2010.

alright mate, im using bowdens in bristol, propper little machine shop and hes ex rolls royce and a mini fan, i think he races in historics.

nearly a year since ive done anything with this :( ive had a kick up the arse after looking at my mate nicks homemade K1100 engine, hes running it on honda carbs and a dizzy and it seems to run well.
So ive pulled apart my spare 998 and got the crank and rods out of it which were in pretty good condition.
Im going to have a chat with a couple of engine builders about the costs of the machine work to dry deck and offset bore the block, any reccomendations greatly welcomed as bowdens are really busy at the mo.

Everyone is really busy, well anyone that's anygood that is!

You're better off getting the pickup finished through the summer and building the engine in the winter when people quieten down a bit!

That way you'll have a working mini to cone out and play in!!

yeah thats the plan, but if i can have a chat with them and get an idea of the money to do the machining i can buy a few of the other bits like the SC box and drop gears as well as spending the important time finding a suitable turbo

Turbo is easy, buy one and get it rebuilt. You can't take a risk on an engine like that, I know I wouldn't. There are plenty of scrappies by Craig and myself, if you want to come for a ride. I personally wouldn't bother with an sc box for the power your aiming at, drops maybe bit still not a requirement. People on here are running 200bhp plus with almost standard internals. Diff is the main thing. Save yourself money and get it on the road quicker...

I recommend Brett for engine build (contact details below), he built Gooony's new engine. But like everyone else he's really busy right now

http://www.brettsimsmotorsport.co.uk/

Couple pics of his work

http://www.chippers.me.uk/gallery/gooon/10...10/SDC11369.JPG

http://www.chippers.me.uk/gallery/gooon/10...10/SDC11372.JPG

http://www.chippers.me.uk/gallery/gooon/10...10/SDC11367.JPG

Edited by Ratty on 14th May, 2011.

alright ratty! good to hear from you, hows tricks?
I will give brett a call and see what he says, I wont be getting anything done until the winter once i have saved up a bit of cash.