Minus 7 port turbo
Turbo Mini Forums

Well that sounds like an eventful RR session,

None too shabby on 15 psi either! that torque does seem to roll off more than i'd expect, presumably due to the restriction you mention. is it feasible to add some tapped holes so you can get a pressure gauge on a few points next time? ie turbo out, intercooler in, intercooler out, just to check its not pressure drop across the core.

I cant see it being the exhaust side, as youve not done anything different to normal, unless its a wastegate issue, but youve run this setup as 5 port right?

solid effort id like to get on with mine however things have put it back i just need the space and time

i think that you'd be surprised to see how crap plumbing can be before killing power ie angles of pipe joints

not sure if anyone watches sloppy mechanics on you tube how ever matt is quite proud to show how cheep and nasty a build can be and still make stupid power from a 4.8l ls i believe he pushed the 4.8 to 1000+hp spending crap all and hack jobbing the lot super low buget builds is his thing along side doing what manny say cant be done

yess the modern ls v8 is way different to the old cast a series we use however i think air is air and all we are doing is moving air with hp as a result

I'm no expert, but the power is at a very low RPM. Maybe you need a more exciting cam. Your bottom end should be good for 8k, and rpm = bhp:)

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

www.twin-turbo.co.uk

It was a bit scary! I could of done with a bit more notice to get some proper Wheels sorted. Although I would of still used these probably, Pirelli tyres so not cheap nasty ones.

Joe: you can really see it drop off in the graph. That’s quite a good idea. I’ll see what I can do.

Exhaust is a Matty manifold/downpipe then 2 inch back.

Turbo this: I’ve not watched those videos I’ll check them out. Simon and Matthew who mapped it definately thought it was exhaust or inlet. I should if got a picture of the intercooler. Everything else is nicely done for flow except this one point, it’s pretty bad.

Wil: What Cam would you suggest? I definately wanted to keep reving it up. I’d settled on going to 7000 but it’s not worth that as it is.
It’s currently a ph2. Maybe I could time it up to suit more top end.

Edited by jonny f on 29th Apr, 2018.

Maybe double check the cam timing, and drop it back a couple if degrees to push peak took up the Rev range, (that is the right way isn't it??)

Ph2 should do the business up to 7k. So could be cam timing, or the other restrictions you've identified.

Considering how it drops off, it could well be a restriction. I'd expect the torque to be much more level after the peak, rather than dropping sharply.

Edited by wil_h on 27th Apr, 2018.

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

www.twin-turbo.co.uk

Cam is definately at 108. It was checked with two sets of eyes a few times.

I’m going to leave it as it is for now and then see what I can do next winter. I’ve got a fair bit of work to do with a new subframe so no point getting a nice intercooler in and it not fitting around the new frame.

Really wanted to get out in it today but it’s hammering it down :(.

Well done! Some nice power there. Will the marks from the tyre buff out?

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

Yes, they came out easy :).

It has however damaged the wing along the top. It’s blown the GRP, it can be fixed but will need painting.

A good result for 15psi.

Re. it tailing of early, lambda seems a bit low to me. Personally I would be looking at 0.85 for maximum power, maybe even a bit higher as it's an alloy head. Did they do any "tuning" or did the tyre failure end it prematurely ?

And re. the tyres, quite a few years ago the same nearly happened to me with Pirellies (not on a Mini but a FWD car), they didn't actually fail but they were getting a bit low on tread and when I looked a bit closer they had a circumferential split all the way round between tread and sidewall I could see from the "outside" and when the tyre place took them off, the inner face was the same. It extended about 8-10mm in under the tread both sides all the way around. I've never touched Pirellies since.

Schrödinger's cat - so which one am I ???

Thanks Rod, I’m very happy with it.

I think there was a reason why it started to go richer at that end. To do with the restriction potentially.

Perhaps Pirelli are not all they cracked up to be .
These were pretty old and spent there life in a mini boot.

Edited by jonny f on 28th Apr, 2018.

Nice going.. are the 12's needed for the rollers or is that what went on after the blow out?

Good effort in getting the engine ready so soon! As you, I have a feeling there’s much more to come from switching to 7 port EFI. Does the SC ecu measure IAT’s? Given the very rich mixtures of 0.75 - 0.8 lambda, air density @ 15psi is bound to be much lower than what Will’s was set up for.

With all things else being equal this can be either down to excessive pressure drop between turbo and plenum and/or intercooler adiabatic efficiency. In other words the turbo has to work extra hard to bring the plenum up to 15 psi, which creates loads of additional heat, heat which the intercooler is unable to get rid of.

Acceptable pressure drop over the intercooler would be in the range of 2-2.5 psi with adiabatic efficiency of around 70%. This would give you post IC IAT’s of around 45C at 70% compressor efficiency and ambient temp of 20C.

With triple that pressure drop (6-7 psi) and IC efficiency of only 55% this quickly becomes 70C post IC IAT. This in turn leads to ((273+46)/(273+70)) = 93% of ‘ideal’ air density. 175 Bhp/93% = 188 Bhp true potential.

Now let’s say Will’s engine was mapped to give 12.5 : 1 AFR @ 15psi MAP , the 11.5 your engine shows suggests 92% air density compared to Will’s or 190Bhp true potential. Pretty close huh? Which goes to show you can pretty much calculate towards any given answers you want

But on a serious note, if intake temps are below 50-55C you need not worry too much about the intake side. If well above 65C there’s some real world gains to be made.

Edited by Evoderby on 29th Apr, 2018.

Schrödinger's cat - so which one am I ???

I am not sure this setup uses IAT and associated tables....?

Schrödinger's cat - so which one am I ???

Anyone else remember the 2010 rolling road day? Nonsense torque curves. Wasn't that the same make of dyno?

We concluded that the dyno was setup for average Joes hot hatch and gave inacurate numbers for low inertia, high powered turbo minis.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

On 29th Apr, 2018 Evoderby said:
Good effort in getting the engine ready so soon! As you, I have a feeling there’s much more to come from switching to 7 port EFI. Does the SC ecu measure IAT’s? Given the very rich mixtures of 0.75 - 0.8 lambda, air density @ 15psi is bound to be much lower than what Will’s was set up for.

With all things else being equal this can be either down to excessive pressure drop between turbo and plenum and/or intercooler adiabatic efficiency. In other words the turbo has to work extra hard to bring the plenum up to 15 psi, which creates loads of additional heat, heat which the intercooler is unable to get rid of.

Acceptable pressure drop over the intercooler would be in the range of 2-2.5 psi with adiabatic efficiency of around 70%. This would give you post IC IAT’s of around 45C at 70% compressor efficiency and ambient temp of 20C.

With triple that pressure drop (6-7 psi) and IC efficiency of only 55% this quickly becomes 70C post IC IAT. This in turn leads to ((273+46)/(273+70)) = 93% of ‘ideal’ air density. 175 Bhp/93% = 188 Bhp true potential.

Now let’s say Will’s engine was mapped to give 12.5 : 1 AFR @ 15psi MAP , the 11.5 your engine shows suggests 92% air density compared to Will’s or 190Bhp true potential. Pretty close huh? Which goes to show you can pretty much calculate towards any given answers you want

But on a serious note, if intake temps are below 50-55C you need not worry too much about the intake side. If well above 65C there’s some real world gains to be made.

Edited by jonny f on 29th Apr, 2018.

If it helps. My car was running massively rich on the RR. But as we started leaning it we had a problem that could not be resolved so that's how it ended.

It will make more power if it's leaner. This was a 'safe' setup.

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

www.twin-turbo.co.uk

Interesting that two like it that rich for peak power.
Maybe some idiosyncrasy with the design of the head ?
Personally I wouldn't like it that rich, it washes the oil off the cylinder bore walls.
Or maybe it's something to do with how the SC ECU deals with the AFR readings.
I've never seen one of these SC 7 port heads close up but there are some strange comments about spark plug location in this thread at least...
But if running that rich works, I guess it's OK at least for the short/medium term.

Schrödinger's cat - so which one am I ???

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

To clarify. As we started leaning it, power was increasing. I don't imagine that this head like a richer mixture than any other engine.

I'd expect peak power at 12ish . Ours will hopefully be back on the RR later in the year.

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

www.twin-turbo.co.uk

Well, been out pottering in it today.

Verdict, it’s lively and lovely! Diff is going to take some getting used to.

Starts on the button.

Feels a lot more refined just cruising around.

Blyton Park this weekend will be the proper test.

Impressed you got this all together, and working well. Be good to see some in car footage at Blyton.