32 replies to this topic

[Gr4h4m]

If you want a Fast and reliable mini, it wont be cheap.

If you want a fast and cheap mini, it wont be reliable.

My old tutor told me that, and so far it has been true, although I am sure someone will prove me wrong

Time, cost, quality triangle. You can have two of the sides but not all three...

[liamharries]

not really any poing modding 1litres they cost so much for roughly the same as 1275 best thing to do wouldd be to get a 1275 or 1380 then mod that after.

[BritishRacingGreen]

not really any poing modding 1litres they cost so much for roughly the same as 1275 best thing to do wouldd be to get a 1275 or 1380 then mod that after.

Very true, if you don't look at the whole picture... My turbo 998 is about as quick as any highly tuned large bore, yet much more driveable because it doesn't need such a wild cam. And when you include insurance in it, especially for the younger drivers like myself, having a 1275 with similar power is far more expensive...

[Andi-p]

I would suggest listening to some of the previous comments about going from 998 to 1275. If you don't fully understand the principals of forced induction don't do it. I have a friend that works on Skylines and Supra's that sort of car. He is a wealth of knowledge but I wouldn't ask him his advise unless I understood it all. I am a mechanic and have still read books on turbocharging engines and with the information from my friend I would say that with what I have learned from it all is overlook one thing and the engine is just a ticking time bomb.

[crock]

One thing to throw in on the topic of supercharger vs turbo is that it is far simpler to set up carburation/injection/spark timing on a supercharger than a turbo. When I used to set up cars on a rolling road, it would take about two hours to set up a supercharged car, and several days to properly set up a turbo! The problem with a turbo is that at any RPM and throttle position you can have any amount of boost as you pass through the transient stages where boost builds up. This means that the spark timing and mixture have to be correct or detonation sets in. If you try to tune the car conservatively with extra rich mixture or retarded timing you have thrown away so much power you may as well have done something else. In my humble opinion by the time I could get a turbo street engine performing at near 100% of its potential, the engine was pretty well knackered from abuse on the dyno. At least you got a good map for your next engine build! I brought this concept up on another forum a few years ago and one of the people insisting that there was really no issue setting up his turbo mapping said that he had his project on the road for two years and he had his map almost sorted out.....I had to laugh. No insult to the brave souls with their 200 hp turbo Mini's, but they have a lot more patience than the average enthusiast. That they can they keep these monsters rolling shows a lot of dedication.

Edited by crock, 18 February 2013 - 02:00 AM.

[welshdan]

a cheap reliable 1275 turbo motor can be built very cheaply with carfeul selection of parts. my current uses a low mileage metro bottom end that cost me £50, a second hand swiftune cam (£40), a second hand (turbo phil modded head - cost was under £200).
along with the metro turbo gubbins, 2wd cossie intercooler, megajolt etc. it currently puts out 130 bhp with 130 pounds of torque at 10psi. so very good results for an engine that has been built on a shoe string.

[pdaykin]

I haven't had any real experience of turbos - looked in to it previoulsy but was put off by the expense and the constant need to "experiment" to get the most out of it.

But it is a very subjective issue - particularly cost. After 30 years of playing with minis, £3k doesnt sound that expensive for reliable hp to me. But I wouldnt want to pay for it - the extra few horses that gives over a £1.5k rebuilt/tune doesnt make sense for my uses.

I dont wish to dismiss anyones comments on here, but how you can build a reliable turbo motor on a budget that I would call cheap is beyond me. I accept that you can get some bargain parts - but they tend to be few and far between and take a long time to collect. If you dont know what you are doing, you will just end up with worthless, unreliable junk - most of it is so old and knackered by now that it will need a (professional ?) rebuild.

Unless you can do everything yourself, getting more power is an expensive job. Even the bulkhead mods required for the normal turbo is expensive if you cannot do it yourself. When you add up the cost of all of the anxilliaries (radiators, diffs, carb, dizzy/ignition, manifolds, brakes etc) it becomes quite frightening when originally you only expected to pay a few quid.

Admittedly, my n/a engine came to many thousands to get a decent amount of reliable hp. When you are looking at more than 110 (ish) hp in a reliable/usuable format turbo/supercharging seems to have advantages.

Now (and if I could persude my Mrs), I would probably experiment with turbos as my minis are just play things - in my younger days they needed to be a lot more reliable.

But unless you have that luxury (and it isnt a track car), my own experience says follow the following list:
1. Get a 1275 motor - even as standard you feel a big improvement over a 998
2. Rebuild it so that it is solid and reliable
3. Proper rolling road tune
4. Overhaul the handling
5. If that isnt enough, add a quality head, cam and bigger carbs.
6. Peg any aspirations at 90 hp (ish) to ensure that it is useable - even that will start to expose/wear the diff, gearbox, cooling, etc

Bar horsepower is only any good when you are at the bar. If you are constantly rebuilding/feltling what is the point - Minis are only any good when you are driving them.

[Turbo Nick]

they can be built reliably and cheaply if you are willing to do the work yourself and do some research.

I killed my engine (on purpose) last year as it was worn out and needed rebuilding. But it had done 8 years and well over 40,000 miles..

I built it originally with 120hp in mind which i got on 10psi with a T3. Then i swapped that for a T25 and ran 15psi which gave me 165hp. As soon as it wasn't a daily drive any more i fitted a GT20 at 20psi which ran 200hp....All on the same bottom end with a std crank, rods and AE cast pistons.

[mini*mad]

reliability cheap powerful

you can only really have two of the above

[welshdan]

That quote makes me smile, its not true...

[Alex_B]

That quote makes me smile, its not true...

care to elaborate ?

[welshdan]

a cheap reliable 1275 turbo motor can be built very cheaply with carfeul selection of parts. my current uses a low mileage metro bottom end that cost me £50, a second hand swiftune cam (£40), a second hand (turbo phil modded head - cost was under £200).
along with the metro turbo gubbins, 2wd cossie intercooler, megajolt etc. it currently puts out 130 bhp with 130 pounds of torque at 10psi. so very good results for an engine that has been built on a shoe string.

i ran a cheaply built, 130 bhp turbo motor. it cost peanuts, was 100 % reliable. with some careful thought to parts, put it together properly very good results can be had.

you dont need to spend thousands to get good results.

[pdaykin]

Welshdan - could you give us a better idea of costs, when it was built/bits purchased, exactly what you did/what professional work was farmed out and how many miles you have done so that we can have a better concept of what you are referring to.

[mini13]

a rebuilt bottom end (that means bored +20 and using something like cast omegas, powermax's etc) std ish cam... normal 1275, mg metro, 256, 266, sw5.... lightly ported head, in good condition, and thats all you need engine wise for 130 hp with about 10 psi boost,

[mini*mad]

What about a turbo fella? Lol