Power output and diff pin
Turbo Mini Forums

Just planning my turbo build and getting parts together now. The plan is to refresh my current 1330 and build it back up as a turbo motor. This will be the spec - unless any one can advise me better? The plan is for a high torque, high mpg motor running 2.76 FD - capable of being a daily driver.

1330cc using new 21253 pistons (replacing current 21251's)
MG Metro unleaded head (35.7*29)
9.5:1 CR
Turbo HIF44 + Plenum
GT15 turbo (possibly the larger GT1548)
Home made manifold
Megajolt
Reasonable size intercooler
Possibly 7/8psi boost
Morspeed phase 2 cam (unless there is a better option)


Roughly what power should I be looking at? I was guessing around 110bhp?


Also, the gearbox is being rebuilt and having a 2.76 Final Drive fitted. But, what diff/diff pin do I go for? Is swapping to Minispares performance pin enough, or do I need to look at the 4 pin diff at ~£160.

1994 Mini Mayfair, 1330, Mspd Ph2 cam, Benross turbo head, 9:1, GT1752, TT Intercooler, MegaJolt, BMW M3 leather seats.

I won't speculate on power but just go for a x-pin for piece of mind

bit of a no brainer imo £160 is pennys compared to what you would potentially loose

Yes i moved to the darkside

Instagram @jdm_brett

x-pin it!

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

I've seen a diff pin out of a standard engine that was terribly worn, so running one in a high torque, high final drive engine isn't going to end well. Just buy the minispares x pin and forget about it.

Power wise, I'd have thought you'd made a little more than that, but power isn't really your main concern from what you have said. First thing you do needs to be to get it on the rollers and have fueling and ignition setup to your requirements. Be that a big number on the print out or a reliable tune.

http://www.turbominis.co.uk/forums/index.p...tid=469104&fr=0

turbo's a bit small for good economy, too much back pressure , I would use the gt17 ,comes in early enough but flows more on the turbine.

id use a mg metro cam or a stock cam for better economy and low down power .

cross pin wise , my stock diff,with a competition hardened pin , ate its roll pin ,and the pin and planet gears were welded together ,that was on 5 to 10 psi.

regards robert

Edited by robert on 27th Mar, 2014.

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

As above, any measurable. Power around 110 to 130 HP it will fail above that extremely fast.

Thanks guys, cross pin it is then. Don't want to start throwing money at it all over the place but if the competition pin isn't really up to it then no brainer!

Interesting comment about turbo size. I was thinking a small turbo would be good for the low down boost for economy. On my engine spec when can I expect it to come on boost with the GT17? Want to avoid lag as I'm planning on going MPI FD.

1994 Mini Mayfair, 1330, Mspd Ph2 cam, Benross turbo head, 9:1, GT1752, TT Intercooler, MegaJolt, BMW M3 leather seats.

GT17, phase 2 cam, very well spec'd head. No real lag.

https://www.youtube.com/watch?v=IkF4ysjnNcs

Not sure a turbo coming in low down will help with economy? I run a big t3 on mine, it can be driven normally using light throttle below 3k without the turbo making boost.it acts like a std mini engine at this stage bar the heavy clutch. Also it cruises at 60-70-80 with light throttle control, no boost, afrs of 16 plus. So driven carefully it provides very good fuel economy. When you boot it though its extremely fast, and economy isnt so good at all when this happens!!

yeah as above turbo's lumps are generally ok on fuel as long as you dont go too low on the compression ratio, and get them set up well.

OK thanks sounds like I'll go GT17 then.

When you say Phase 2 cam, do you mean avonbar or Morspeed?

Does 9.5:1 sound OK on the compression side for economy?

1994 Mini Mayfair, 1330, Mspd Ph2 cam, Benross turbo head, 9:1, GT1752, TT Intercooler, MegaJolt, BMW M3 leather seats.

Avonbar. The upside down skip wad 8.3:1, but we used to run 25psi +. 9.5 is too high for any more than a few psi imho.

Even looking at 7psi with good intercooler? How about with water injection at 5+psi? Don't want to lower compression too much as I'll start losing torque and economy.

So what cam would be best for my application:
Standard
Mg metro
Morspeed ph2
Avonbar ph2

1994 Mini Mayfair, 1330, Mspd Ph2 cam, Benross turbo head, 9:1, GT1752, TT Intercooler, MegaJolt, BMW M3 leather seats.

Go 9:1 and stick 12psi down it's neck. It will be about 120bhp and will be lovely to drive.

Dont rely on w.i. What happens when your wat runs out unexpectedly? Pop.

for economy and really good rd manners I would stick with the stock cam or at most the mg metro cam .theres a graph in the gt17.. thread showing onset of boost.

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

12psi? Would the 21253 pistons be ok with that?


Re: camshaft, the Morspeed phase 2 is quite a mild cam - similar to 266 but with more lift (and supposedly better economy). At the moment, it idles really smooth, and pulls well from 2000-5500. Economy wise, it does 37mpg round town/traffic; 40mpg motorway (too low geared); and 45mpg on good A Road runs.

Would I still be better off with a standard, or MG Metro cam?

1994 Mini Mayfair, 1330, Mspd Ph2 cam, Benross turbo head, 9:1, GT1752, TT Intercooler, MegaJolt, BMW M3 leather seats.

ah yes your right ian , I was thinkning you meant the avonbar ph2 turbo cam , that mrspsd cam looks ok.

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

If you've got a 266 I'd just leave it in, saves buying something for little gain tbh

yup,as carl says, if you have a 266 already.. use that , and if you want an upgrade in the future just fit 1.5 rockers.

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

Ok cheers! Don't the 1.5 ratio rockers tend to move the power further up the revs? I.e. reduce bottom end torque?

Also, what are the thoughts on 21253 pistons running 12psi?

1994 Mini Mayfair, 1330, Mspd Ph2 cam, Benross turbo head, 9:1, GT1752, TT Intercooler, MegaJolt, BMW M3 leather seats.

Nick on here ran over 20psi on his machines 21253's so don't worry too much about them as long as your fuelling and timing is good.

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

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

Haha, maybe. Although I want to keep this as a nice torquey motor, that can be driven daily and return some good MPG. Boring I know!!

I think all this is going to do though is convince me to put a bigger turbo on my daily hack though!

1994 Mini Mayfair, 1330, Mspd Ph2 cam, Benross turbo head, 9:1, GT1752, TT Intercooler, MegaJolt, BMW M3 leather seats.

You need to read the tm 10 commandments. You're currently at odds with them.