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Advice On Tuning An Spi


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#1 Minimax234

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Posted 23 May 2018 - 08:33 PM

Hi All,

The time has come to get a bit more power out of my jap SPI and Im looking for some advice as to what the best setup would be.

Only looking a do some simple bolt on mods and was thinking of a K&N pod filter, 1.5 HI lift rockers, LCB manifold and a play mini exhaust.

Is this worth doing and will I see any notable power gains?

#2 brivinci

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Posted 26 May 2018 - 03:35 AM

By bolt on do you mean engine-in jobs? If so, do yourself a favor and simply save up for an upgraded head. Where all those others might add a few extra ponies...at best...a Head is guaranteed major source of power. id say that and a cam. But a cam means the motor has to come out.

I know 1.5 lifters seem to be the norm for mods, I’d think twice about it. Search Keith Calver ST as he sells, and swears but the fact that 1.5s are just metal torture. He finally had his own set made to a much more usual ratio.

When I first bought my SPi, I soon hit a deer and while repairing, pulled the motor. I cleaned things up and installed a swiftune sw5 cam into a stock motor with 40k on it. Freshened up the deck and head surface. That, with a k&N, and a cat back manifold system it really add to the drive ability of the car. It changed the rev range/power band to be much better suited to actual driving.

When I then rebuilt and added a custom head, now that’s when I really saw a big change.

It’s just that adding the little things, you are going to get very little. The big limiter is the head. The rest add on to the head but add little without.

#3 ryomini

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Posted 26 May 2018 - 10:21 AM

Have to agree with br

almost any other add on mod is a joke.  How often do you drive floored, you will find you mini is faster then, take some weight off, carpets and junk that you carry around.

 

I think I would be right in saying that the biggest mod you could do without touching the head would be to change the FDR, but you will pay in highway comfort dearly.

 

Check some of the youtube videos on head work and it rapidly becomes apparent that all real gains are only made by starting there - and that will start to increase heat and reduce reliability and decrease mpg - is that what you really want.

 



#4 MiniAida

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Posted 31 May 2018 - 07:52 PM

I bought my SPi with a "stage 1" head so can't comment on how that improved performance, but did notice a difference when I added an LCB manifold.

So if you want a simple "bolt on", that's where I'd start. It's been a standard mod since the year dot & has good science behind it.

Be warned, it can mess up your emissions, so don't change it just before an MOT.

 

Keep an eye out for a modified head in the meantime - look for enlarged inlet valves as a minimum - as it's a simple fact; more air/fuel in, more power out.

 

MA



#5 brivinci

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Posted 01 June 2018 - 09:31 PM

Adding an exhaust and filter on a stock motor may increase performance, but only marginally. Sometimes, not at all. Adding them in conjunction with a head and a cam is when you really feel the difference. The stock exhaust system on the SPi Coopers is actually a very decent system and more then up to the task. It is only when you add a head with bigger valves and ports that you really need to think about installing something new. Now, will an exhaust and LCB make your Mini sound better/louder/faster? Sure, but it doesn't mean its actually any of those 3.



#6 Wiggy

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Posted 01 June 2018 - 09:41 PM

I agree.

A K&N is a waste of money, in my opinion.

A bigger valve head is where the extra oomph is.

Don't want to pull the engine to fit a new cam? 1.5:1 roller rockers will do a decent job.

#7 MR J

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Posted 02 June 2018 - 09:01 PM

One of the best things I did was to remove my cat, wether mine was blocked up as I couldn't really see through it but it passes it's MOT every year with it on. without the cat the car is certainly more drivable and smooth. Not saying it add's power by removal but it made mine a LOT nicer to drive.



#8 RooBoonix

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Posted 04 June 2018 - 10:52 PM

One of the best things I did was to remove my cat, wether mine was blocked up as I couldn't really see through it but it passes it's MOT every year with it on. without the cat the car is certainly more drivable and smooth. Not saying it add's power by removal but it made mine a LOT nicer to drive.


On the flip side, removing the guts from mine didn't make too much difference. Although I've just smashed the guts out and haven't made it a straight pipe through the cat body (yet) and I can't see this "expansion chamber" doing any favours in regards to exhaust flow..




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