My First Turbo Build
Posted 20 June 2017 - 08:36 AM
I have been reading various mini forums for quite a while now to decide what engine I want in my 1981 clubman estate. I was set on a VTEC conversion but after speaking to quite a few people at shows I have decided to stick with a mini engine. In the hunt for more power I'm going the route of a turbo over a high reving 1380 as from what I have gathered the turbo cars are easier to live with round town as the have much more low down power.
I finished my restoration a few years ago and just finished redoing it all again (resprayed interior, cage, bucket seats, harnesses, perspex Windows, I'll put up photos if I can figure out how) the engine in my car seems to be shot as it overheated last summer and I can't seem to get it running properly again. So it's now time to build my first engine!
I have a 1275 engine in the shed that will be the base of my turbo build.
The parts I think I need are as follows.
Turbo - gt17 or T3?
Manifold - fustion fabs, gt1752 manifold set.
Head - I'm not sure on. Have seen benross heads mentioned a few times?
High capacity oil pump - minisport
X pin diff - mini spares
Cam - NA MG metro 1275/ Kent 500?
Pistons - some kind of omega(lots of people seem to mention them)/ AE21253?
Carb - I think you can mod the normal carb with a turbo carb repair kit?
Diff ratio should be 3.1?
Metro turbo inlet manifold
Metro plenum chamber
Some pipes and bits and bobs.
Rebore to 1293
Right I think that's the full list so far, I know I'll have missed some stuff as I don't really know what I'm doing haha. Dose this sound like the right kind of parts to build a 140ish bhp engine?
Posted 20 June 2017 - 10:32 PM
Also turbo Phil on here does great head work too, not that Benross dosent,
Posted 21 June 2017 - 02:49 PM
Ok thanks! ill have a look into both.
Is there a one stop shop i can buy all the mg metro turbo bits from or are they all parts you have to hunt down used on ebay and places like that?
I have also seen a kit (HOTEK1293T) from from avonbar racing that is as follows "1293 +020 Forged Pistons,The HOTEK 1293 Kit has been the base for many of our 180bhp-200bhp conversions.The additional specification for the HOTEK kit includes the following. 18cc lightweight forged pistons, phase 2 camshaft,steel duplex timing kit,Lightened Polished Con Rods ARP Rod bolts,Ultra light steel flywheel, Billet Steel Backplate and AP clutch. We will also supply the Hi-boost carburetter upgrade kit that is necessary to complete the conversion.
" which has a lot of the parts i would be getting in it so im interested. Have any of you guys used this kit?
Also do you have to get your crank machined or will the standard one be ok?
Any info or thoughts on anything is helpful!
Posted 22 June 2017 - 11:29 AM
Please correct me if I am wrong, but the standard bottom end should be fine, as turbo engines are not required to be high revving like a N/A engine with a wild cam. That said, the bottom end of mine has been lightened and balanced, with a wedged, drilled and nitrided crank (but that was what I already had in my 1380 engine with a 296 cam).
Posted 22 June 2017 - 12:55 PM
Oh ok thats good. what is a realistic cost of the whole build of a 140bhp turbo engine? also how much harder/more expensive hah is it to get say 160-180bhp as if its not that much more expensive i might as well do that hah.
I have heard that I will need to upgrade my gearbox, But im a bit confused do i need to buy a whole new gearbox or do you just buy some gears and swap them into your gearbox? i know i want some kind of straight cut gears but from reading there seems to be two sets of gears that you can have straight cut (drop gears and normal gears? I might be complexly wrong) which gears is it that need to be stronger? sorry if that made no sense hah.
One last thing, how do i find out what size pistons i want if have a 1293? do they say they are for a 1293 or is the a certain width/OD i should be searching for? or just a part number would be perfect ;P
Thanks for the help guys!
Posted 22 June 2017 - 02:39 PM
140hp can eb done with a largly std engiine, just pgrade the pistons to cast omegas and a bit of head work, 160-180, your looking at a fairly fancy head and a decent cam.
in terms of gearbox, you NEED a X pin diff, 140-150 hp is around as far as you can push the std gear kit ( the stuff in the bottom of the box). standard drop gears ( from the engien down to the gear box) should survive ok up to about 200hp.
Posted 22 June 2017 - 02:53 PM
Thanks for more helpful info!
So the avonbar racing kit and a fancy head should be enough to give me over 140? then i need to change out the std gear kit to sccr set to take the power? Time for another nooby question! I have heard of a gear set(not sure what they are called) where fourth gear is quieter is this because gears 1,2 and 3 are straight cut and 4th is just the std gear? would this be okay or do you need them straight cut?
Thanks for the help!
Posted 22 June 2017 - 04:34 PM
Most people go for the miniatures evolution gearkit.
Edited by mini13, 22 June 2017 - 04:35 PM.
Posted 23 June 2017 - 12:36 PM
Do you a link for that gear kit i cant seem to find it?
Posted 23 June 2017 - 12:54 PM
Minispares evolution gearkit.
Making the power is all about running enough boost without breaking anything. Get yourself the biggest intercooler you can squeeze in and keep the compression ratio inline with the boost you plan on running. The turbo gearbox was 95% identical to the non turbo version, it's debatable if the bigger spigot bearing makes any difference. Use an uprated diff and just make sure the rest is in good condition, pay particular attention to the transfer gears - or go straight cut if you don't mind being deafened.
Total cost can vary hugely, but expect it to be more than you thought, there are lots of little incidentals in plumbing in a turbo motor and it all adds up.
Posted 23 June 2017 - 03:21 PM
I know he has a fresh engine build ready to go out that he hasn't advertised yet. And that will be capable of the 180 if you get him to sort you the head. Top bloke.
He has always built my turbo and na motors.
Posted 26 June 2017 - 08:29 AM
Good news! I managed to(well my dad did) get my current engine working again so im not in such a rush to get the new engine. So i now have time to do a lot more research and hunt down exactly what i need. From what i have read up on so far i think im just going to aim for 180 bhp now not 140ish bhp because i dont see the point in buying lesser parts and buying the better parts down the line, might as well buy the better parts now and just do it the once(until stuff starts breaking hah). I will probably over build the engine as i would rather have a reliable car then a stupid fast one that never works.
My current engine is so loud past 60mph anyway as i have no sound deadening or carpet that im used to it being loud, thats what earplugs are for right? So i dont mind going SSCR, I need to do my research and make sure i learn more about gearboxes.
Thanks for the help with the gearkit info!
And with the built price its always about 2.5x what you price it up to be so im trying to add up all the little bits and bobs to because there is always loads of £££££ that gets forgotten hah ;P
burchy35 did you just buy complete motors off of him?
Thanks for all the info guys, really helps!
Posted 27 June 2017 - 03:05 PM
He knows what works with a turbo motor. He is always on the other end of the phone for advice and support.
Posted 03 July 2017 - 08:35 AM
Still on the hunt for parts, Where do you guys get your turbos from? Im looking for a new gt1752.
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