Small bore, small budget, small turbo (1098cc for now)
Turbo Mini Forums

Hiya i have been here on and off for a long time but never started a project page or turbo on the road. Well i thought it was about time to start a project thread fingers crossed it will keep me going and i wont shelf anoher project.
The plan is to build a small bore turbo around a gt1544 which seem to be common and that i got one cheap. The base engine im going to use (well at first) is an a series 1098. It is a good low milage engine i got cheap and started was going to tune up. I started by pulling it apart a check over then ground some pockets for a 12g940 head oh and decided to 11 stud it. This was when i was planning to build it into a normally asperated engine but as i was calculating for a decent compression ratio i though i dont really want to skim my cylinder head to the max so why not turbo it lol.
Im still collecting bits which will be slow as funds are limited so will be working with what i can get my hands on.
My planned spec is:

1098cc standard pistons with oil split but with ptfe buttons
8.5-1 or 9-1 compression ratio
zero deck
12g940 small valve 11 studded ported
1275 or turbo oil pump (allready modified for this)
Mg metro cam or similar spec unless i get brave and try something else
standard crank and rods new bolts
standard gearbox but with xpin diff and 3.1 ratio
Gt1544 turbo from 2l vectra(i think) on home made manifolds
metro turbo plenum carb and inlet manifold
will be using an intercooler but not sure on what yet.
Oh and i know its a bit over kill but i will be using an rts verto clutch setup

Any advise is welcome i will sort some pics.
Thanks james

Edited by jlay on 29th Apr, 2012.

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

this is the head i was going to use when it was to be a N/A engine but im going to use a small valve 12g940 instead.

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

I got a turbo head to work on but its in a very sorry state fingers crossed i will save it.


After a bit of a clean looking better but needs a few parts lol

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

Im working on the manifold bit by bit i bought a set of flanges from pauls ages ago. made the turbo inlet flange but need to get some stainless to make the exhaust side.
For the head one of the inlet valves had a pitted stem tip so not taking the chance i was looking for a second hand valve but benross came to the rescue with a full second hand set of stainless ones for a bargain price and Turbo phil to the rescue with some 3groove collet valve caps. Thanks guys

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

Some serious cleaning there. You would never think it was the same head

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

how did you do the pockets in the block?

Speeding is like masturbating, everyone does it, but not all of us film it and put it on the internet

[quote=fab,8th Oct, 2010]fuck off

hiya i did the pockets with a die grinder with a few carbide cutters and then some rolox wheels to finish the surface. Cheers james

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

Nice job so far. I reckon an 1100 turbo will make a great road motor.

If something is worth doing, it's worth doing half of.

me too

i hope so lol. Cheers

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

i sorted some more pics i got out in the garage at the weekend and machined up some new spacers for the clutch. got it all together yesterday thats one thing i can tick off the list for now (+ it was cheap to do lol)



Then i spun up a pair of ptfe button blanks to try out.


And this is where im at with the manifold at the moment. I need to get some more tig rods.

Edited by jlay on 17th Apr, 2012.

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

I like where you're going with the exhaust manifold.

cheers i might tuck it up closer to the inlet to give me more space to turn at the turbo inlet.

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

good skills!

as youve done and rts and are obvously a bit handy in the work shop... you should have a look at lengthening the clutch arm to give a lighter pedal, well woth the effort.

cheers for the tip i might give that a go. do you still use verto slave cylinder.

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

Yeah, although they are close enough in piston diameter either will work.

ok cheers i will have a think on that.
I got the piston buttons spun down today i was so surprised how off centre the gudgeon pin is in these pistons.

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

I got a little more done this week but not as much as i was hoping Oh well.
The first set of piston buttons trial fitted.

a little more on manifold had a bit of trouble getting symetry.



And as i couldn't find the correct abutment plate i ended up making one. I was going to mod one i had but i will sell it on instead.


I just gota sneak it in to the next plating batch we get done lol.

Edited by jlay on 26th Apr, 2012.

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

Good job on the plate mate i ended up modifying a non turbo one for mine looks a bit of a state but works... the turbo ones are hard to get hold of on there own

Yes i moved to the darkside

Instagram @jdm_brett

That be a nice torque but eco engine to build :) nice one!

maybe ill build a 850 turbo ;D

cheers guys i use my breaks at work for the fabrication stuff. I dont have a tig at home so have to sneak bits in when i can lol. Yeah why not ridinglow at least you will have loads of material between the bores

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

this should be really good fun to drive.

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

Cheers robert i do hope so.

Bit of an update the turbo carb i have looks like its been in the elements for many years i have been soaking bits in freeing fluid trying to get things loose.One of the most stubborn bits has been the needle carrier thingy a tried various things and stupidly put a little heat on it brushed over the nylon stop and killed it doh. So i dug it out and have spun a new one up as i cant seem to find the available just need to trim it down now.
Also bit more progress on the exhaust manifold and few bits are off the be zinc plated (sneaked in with batch from work lol).




I think i have left enough room for the webbing on the a+ block but i will try on one when i can. Its very tight to the inlet manifold about 3mm on the centre exhaust. but wanted to curve it. From memory i think the cast manifold is really close. Cheers James

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

love how the manifold is coming together now. how easy is it to re orientate that turbo as i know on the vaux they are fitted the other way up, so the oil feed would be at what is the bottom of yours now?

one day boost will be mine!

Cheers its not hard to reorientate the turbo it took a little patients to get it moving first but its all free now. when im happy with it im going to cut the old actuator mount off and work out a new place for it. Are you going to use a gt15?

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901