1380 T2 or T3
Turbo Mini Forums

Hi,
I'm currently running a N/A 1380 100lb-ft /120bhp. I want to go turbo, I'd like a T2 so I don't have to meddle with the bulkhead, or do I need a T3 for the extra engine capacity? I want to run about 9.8:1 and 10psi of boost and a T2 cam. I'm road going so I'm aiming for lots of low down torque. Discuss................
Cheers,
Gavin. :)

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Hello Bat,

Sounds like quite a quick motor

Have you read the all you need to know bit on this site ?

Anyway first thing, your pistons will need to be cast or fordged, other wise they will just fall to bits or melt as soon as you start using a blower....You should be using a nitro carberised crank and rods also...alternatively just start with a turbo engine !

You don't need a big displacement to get big power from a turbo engine and a + 20 bore will be more reliable than a 1380 motor in the long term and the pistons will be nearly 1/2 the price !

Also if you want to increase the boost from the standard 7psi you will have to reduce your compression ratio, around 8.25 : 1 is a good figure. This can be achieved by using pistons with a sufficiently deep dish or by grinding out your head chambers.

You should also be using sodium cooled exhaust valves or equivalent.

Interms of the turbo to use you will have to cut the bulkhead, unless you use a T2 on the mirage motorsport manifolds, check out their web site. Alternatively you can use the automatic front sub frame and just have a small cut out to perform.

Once you have got all this sorted then I would worry about the cam...the avon bar phase 2 is a favorite or the MG Nat Asp.

BTW - I took my buddy VTEC Pete out for a spin this weekend, and even though I am running her in, he gave it a name, the "Brocket"...cause I'm a brocket maaannn, nah nah nah nah nah nah nah nah nah nah nah....

Build thread - http://www.turbominis.co.uk/forums/index.php?p=vt&tid=7483

Katy Mini Owners Club Thread - http://www.turbominis.co.uk/forums/index.php?p=vt&tid=505552

Let's make sure you embarrass at least one VTEC MINI today !

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All this "automatic" subframe talk is nonsense IMO.

Yes it will bring the engine for by about an inch but you can do that on a standard subframe by re drilling the holes for the engine mounts.

If you do use an auto subframe you then have the problem of bodging up an engine mount as the frame is about 1 1/2 inchs wider on the radiator side between engine mount hole.

Moving the engine forward you then ofcourse have less room for intercoolers/oil coolers/dissy caps etc..also in theory it will make the car understeer more as weight over the front provokes this.

Turbodave might even have a view on the driveshaft angles to!

So basically you want to fit a turbo to your 1380 without cutting the bulkhead, and you want to run 10psi with a CR of 9.8:1.

There are a few options, but I think the simplest is as follows:

Buy a Mirage manifold an a T2 (easiest way to fit a turbo without modding the bulkhead). Then fit a decent intercooler and a well mapped ignition.

Personally I think 9.8 is a bit high CR, but if you retard the ignition enough it'll probably be ok.

As for cam choice the Avonbar PH2 or an MG metro cam will be a good bet.

Wil

Edited by wil_h on 8th Dec, 2005.

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Hi All,
Thanks for the replys. I know Turbo Hogster has been running the same set up with a T3 (don't know what cam) He says its got plenty of low down torque. I was wondering if the T2 would spool up quicker, while still flowing enough air and not causing too much back pressure? I'm using Millers VSP (has octane booster built in, and mapped ignition already. I won't know what pistons I've got till I pull the head off though!
Cheers,
Gavin. :)

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T2 would spool up very fast on a 1380 with the c/r your planning on running, as you say hogster has been running similar c/r-boost with no problems. Does your mapped ignition system have a map sensor as to allow ignition retard as the boost comes in??

-MINI CLUBMAN 1380 TURBO-

Hi Tone,
Not yet, but the wiring is there waiting for me to fit one. Also there's an air temp sensor, which I can map to retard timing if intake temps go up aswell. So I've got that bit covered, I just need to sort everything else!
Cheers,
Gavin. :)

Edited by Bat on 8th Dec, 2005.

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Sounds good, i think you will be amazed at the torque you will get from this set up:)

-MINI CLUBMAN 1380 TURBO-

I'm no ignition expert, but I thought that the minimum you need for a mappable ignition system is a MAP sensor and an RPM reading?

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

You can do mapped ignition on RPM only or RPM and TPS, but on a turbo that is useless and you might as well have a dizzy.

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Having used a T3 almost 10 years in a 1380 I can say that it is not bad, that 100 cc extra helps a lot. However, it is an "ancient" design and a T2 should give better results.

Remember that a 1380 will give more torque to begin with and turbo will emphasize that. Most likely with a fast spooling turbo you can run less than 10 psi boost for nice results. Do you have any idea what your CR is at the moment ?

1380 is not that unreliable if it is assembled carefully and set correctly up. It is true that good pistons cost more and you will have certain limits to CR achieved. Also, if you get bitten by the bug (read more and more boost) and you eventually will 1380 may not be the optimum size.

Hi,
@ Ben H You can do mapped igintion RPM again MAP if you ve got the right system....
@Jukka. I ve got Powermax 20659 pistons which have a 10cc dish, so hopefully not too high. I think for Turbo Hogsters figures for his 1380 should do me just fine. Would an Avonbar 10psi carb needle be a good starting point or not?
Cheers,
Gavin. :)

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mine worked out with a 14.5 cc total volume of the piston to deck , 21.3 cc head and 3.4 cc for the head gasket which came out at 9.8 :1 cr.

used a fixed 24 deg advance, intercooled set up on the rollers using det cans.

ran 10 psi on the last run 140 bhp at the flywheel, and when driving went like stink with very little lag but when on boost pulled like a train.

only 8 bhp short of my best of 148 bhp using a chambered 30cc head running 15 psi on 30 deg fixed advance.

i worked out i lost 15 bhp running same psi with the different heads

eg 10 psi with modified chambers on 10 psi was 125 bhp as to 140 on the standard chambers.

always looking for them bigger bunches of bannanas

I have no first hand experience about Powermax pistons, I have bought some project engines with old flat top Powermax pistons (dating back to 80´s) that had most of the ring lands broken off the pistons. Maybe someone can comment on the pistons. At least the dish is good news. A lot depends on the rest of the assembly, are the pistons flush or down at the bore at TDC, what is the chamber size in the head etc...

Needle is a difficult thing, I doubt that avonbar 10 psi needle suits your engine since it is most likely a 1275/1293 needle and 1380 may require different fuelling. Remember that EACH engine is different. I once had a BCA needle that was supposed to feed the engine. It did at top end but lacked at low revs. So, how about getting into needle modification business ?

hi bat,

millers VSP is shite compared to this stuff

expensive though but worth it!

http://tetraboost.com/

Bat,

I know you can do ignition with rpm against map, that is the only real way to do it. If you dont have MAP there is no point IMO.

Re-read what I said, I think we agree.

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