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Contemplating A Turbo Build


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#1 Hpal

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Posted 03 July 2022 - 06:09 AM

G'day,

My mini 1000 is currently getting the paint touched up and I'm getting closer to dropping the engine back in and finally driving it again after more than a year off the road. I built up a nice little 1150 with a SC12 supercharger and fitted a 3.1 diff. Its a suck through HIF44, and I've got some work to do getting the carby tuned up nicely and getting rid of a terrible flat spot when putting the foot down, a problem I've heard is inherent to the HIF44 with no accelerator pump. Even without having driven the mini with the S/C engine for long, I'm already thinking of more power and going for a blow through turbo setup for more power and tuneability.

I've started collecting parts for a 1275 (1100s) based engine and think about 120hp would be a nice figure to get without going too mad with the cost of it. I am thinking of building the manifold myself. There are a few options and I don't know which would be best/easiest. Manifold for side mount (over the clutch) turbo, rear mount turbo (no bulkhead mods), or metro turbo style with a low mount setup straight into the plenum (no intercooler), not sure if the no intercooler idea would be feasible for 120hp but it sure would be compact. 

 

Also, now is the time to sort out the fuel line size and return pipe location as the fuel tanks have been sand blasted and I can fit the required pipes to it. I was thinking for simplicity making an 8mm ID outlet in the normal location on the tank and hose it down to the pump wherever that may be (boot or under car) and tee the return line into that before the pump. I just see that as simpler than returning it to the tank, it just goes back into the pump feed.

 

I've got a choice of two blocks, one is a 1100s auto which will need converting, the other is a 1100s manual at about 1360 once it's had a rebore and i plan to use this one in my deluxe as a nice N/A engine.

The head will be semi standard, maybe slightly bigger valves and some porting and I'll get the exhaust inserts done.

Maybe MG metro cam or something else suitable.

Thinking cast omega's or if there's and equivalent from minispares that's cheaper but still up to the job. 

Possibly lightened flywheel, might wedge the crank but either way will get everything balanced.

I've been recommended "maxpeedingrods" H beam rods available on ebay are very good and much lighter than standard ones.

Will a gt1544 work or would that be more for a smallbore turbo? Is a gt1752 more suitable or is it overkill?

 

Obviously there's many more things to consider but this is where I'm at for now, just seeing which direction to go for modest power increase with minimal hassles for a road car.

 

Cheers

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#2 DeadSquare

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Posted 03 July 2022 - 09:20 AM

That looks a neat job.

People often talk about the BHP of the engine, but it is really only important on a race track.  Its potential is very seldom used on the road, even when overtaking, when what you really need is torque.

Check and see if there is a passage from the oil filter to the gallery in the auto block.  If not you will have to plan external plumbing into gallery at the front of the block.


Edited by DeadSquare, 03 July 2022 - 09:41 AM.


#3 Midas Mk1

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Posted 03 July 2022 - 01:30 PM

I’d be getting to setup on a dyno before condemning it, there is no such thing as an inherent flat spot on a hif44… it’s bad calibration that’s the issue there.
What specs on the dizzy are you running?

Sort your fueling and ignition out first.

Edited by Midas Mk1, 03 July 2022 - 01:31 PM.


#4 mini13

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Posted 03 July 2022 - 05:31 PM

on an su the oil dash pot is the accelerator pump, thicker oil for more fuel when you stab the throttle.

most people make the mistake of putting thinner oil in, generally 20w50 works well

#5 Hpal

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Posted 04 July 2022 - 11:30 AM

I’ve done a bit of playing with springs, needles and dashpot oil with a wideband gauge, got it ok to drive but will get the fuelling sorted on a dyno when it’s going again. Have a standard dizzy at the moment, I should probably get something mappable for this engine and in preparation for the turbo 1275. Is megajolt the best current option?

#6 PoolGuy

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Posted 04 July 2022 - 11:49 AM

I should probably get something mappable for this engine and in preparation for the turbo 1275. Is megajolt the best current option?

My preference is for Polestar Systems, but I'd find out what your rolling road guy is familiar with, you can have the best system in the world but it's no good if you can't get it mapped.



#7 Hpal

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Posted 06 July 2022 - 06:53 AM

What's thoughts on the fuel pipe return? Replace standard outlet with larger outlet in tank and tee return in before fuel pump? Or 8mm(?) return into tank near current outlet or at top of tank??

 

Best turbo for 120hp on 3.1 diff GT1544 or GT1752, smaller one might be good for quicker spooling and low down torque?

 

Turbo manifold, side mount? rear mount intercooler? or rear mount straight into plenum like metro turbo? 



#8 mini13

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Posted 06 July 2022 - 08:36 AM

the absolute easiest ( and neatest) solution for the return is to fit a later MPI injection tank, if at all possible do that.

 

if your only going to 120ish hp then the gt15 is a good choice. however, boost is addictive. the gt17 wont have loads of "lag" anyway, i guess the gt15 will probably top out around 150hp, the gt17 can make 200hp


Edited by mini13, 06 July 2022 - 08:37 AM.


#9 sonscar

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Posted 06 July 2022 - 09:07 AM

My two pence,the costs are going to be large,buy a new tank and have two fittings welded on to take AN fittings and a fitting for a vent.run two 6 mm Id pipes front to rear.Fit a combined filter/pump at the rear.Do it once and cry at the cost for a few seconds then enjoy your new fuel system.
I did not do it this way and every time I see my bodge I am ashamed( it is not on a Mini),Steve..

#10 Northernpower

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Posted 06 July 2022 - 12:30 PM

What's thoughts on the fuel pipe return? Replace standard outlet with larger outlet in tank and tee return in before fuel pump? Or 8mm(?) return into tank near current outlet or at top of tank??

Best turbo for 120hp on 3.1 diff GT1544 or GT1752, smaller one might be good for quicker spooling and low down torque?

Turbo manifold, side mount? rear mount intercooler? or rear mount straight into plenum like metro turbo?

I would fit an mpi tank. The mpi pump is well up to the job. Put the pressure regulator in the boot and connect up to the standard outlet and return pipes on the tank thereby keeping it all in the boot and just run a single line from the pressure regulator to the engine bay for the fuel feed.

Edited by Northernpower, 06 July 2022 - 12:34 PM.


#11 mini13

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Posted 06 July 2022 - 02:09 PM

Interesting, that arrangment had never occured to me.

 

only thing with that is you'll need to run pipe back to the reg to reference it to boost.

 

 

 

What's thoughts on the fuel pipe return? Replace standard outlet with larger outlet in tank and tee return in before fuel pump? Or 8mm(?) return into tank near current outlet or at top of tank??

Best turbo for 120hp on 3.1 diff GT1544 or GT1752, smaller one might be good for quicker spooling and low down torque?

Turbo manifold, side mount? rear mount intercooler? or rear mount straight into plenum like metro turbo?

I would fit an mpi tank. The mpi pump is well up to the job. Put the pressure regulator in the boot and connect up to the standard outlet and return pipes on the tank thereby keeping it all in the boot and just run a single line from the pressure regulator to the engine bay for the fuel feed.

 

 



#12 sonscar

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Posted 06 July 2022 - 05:30 PM

Running a carb?Why do you need boost reference?I thought that was taken care of by boost referencing the carb float chamber.Could easily be wrong though,Steve..

#13 mini13

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Posted 07 July 2022 - 07:23 AM

Doh!

 

Yes sorry, no referece needed for a carb,

 

Running a carb?Why do you need boost reference?I thought that was taken care of by boost referencing the carb float chamber.Could easily be wrong though,Steve..


Edited by mini13, 07 July 2022 - 09:55 AM.


#14 Turbo Phil

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Posted 07 July 2022 - 08:56 AM

The regulator will need a reference to boost for a blow through install regardless of whether it’s a carb or injection. Otherwise how will fuel pressure be increased to compensate for boost?

Phil.

Edited by Turbo Phil, 07 July 2022 - 08:57 AM.


#15 mini13

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Posted 07 July 2022 - 09:56 AM

jeez yeah what am i thinking, its been one of those weeks i guess,

 

yeah, reg needs to be set to approx 3.5psi, then boost referenced.






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