The Wife's 1988 Classic 998Cc Mini....supercharged!

[CHRIS211083]

Ok so I've decided to do a thread on the Wife's mini as I'll be doing alot of stuff to it and I have already done alot of stuff to it so should make interesting reading. Here is the latest episode on Cylinder heads for the 998 mini which I just wrote for the MINI forum.

 

Enjoy.

 

 

Ok my wife wants to make her mini faster and more reliable, so as the Mechanic husband I started by fitting Specialist Components 5 port injection kit.Which Upped power out put and reliability of our 998 1988 austin mini to 50.9bhp over the carb output by 5bhp with more torque. Here is the link.......

 

http://www.theminiforum.co.uk/forums/topic/235496-specialist-components-efi-5-port-kit/page__hl__%2Bspecialist+%2Bcomponents+%2Bport

 

However this was never the end, the final though is a supercharger which we will fit next year. However being more into Triumphs I didn't know the most cost effective way to go with heads etc. So after a bit of searching it turns out that the early 12G295 heads are suppose to be the mutts nuts. So for the wifes Christmas Present I bought her a Standard 12G295 head. This was a bit of a gamble as I can't find any evidence as to why this would be better, no pic's anyway. So before I fit the head here are some photo's and measures of the 12g and the standard late 998 heads. The Difference is MASSIVE!!!!

 

 

Obviously the one in green is the 12g295 and the one above is a cam4810 head.

 

So inlet ports:

Standard 998 Starts at 31mm but has a harsh taper closing the hole quite a bit.

 

The 12G295 starts with a 35mm recess with a 32mm hole which doesnt taper but instead goes into the port and gets wider at the valves. Massive difference over the late head.

 

Here on the 12G295 head you can see into the port and the is alot of space in there. Not how mucch of the valve you can see!!

 

 

And the late standard head, here is the taper and below the inner port. Note how much the chanber is reduced and how little valve you can see. It really is that different.

 

 

Then there are the combustion chamber shapes. the 12g shown below with a short chamber with rounded edges and unobstructed valves.

 

The Standard Head combustion chamber is totally different in that the chamber has a large ridge on the point of the heart shape and also the heart shape is much more pronounced than on the 12g head. Also note the steep and deep walls that are close to the valves and will reduce flow into the cylinder.

 

Next the spark plug holes, the standard:

 

and the 12G295

 

 

What a difference.

 

Finally the tops and valves. The 12G uses double valve springs with securing clip, the springs and caps are much smaller.

 

Then the standard heavy single valve springs.

 

Next is valve sizes, my measures are not accurate but you get the idea.

12G

Inlet

Exhaust

 

Standard late head:

Inlet

Exhaust

 

The Difference is very clear to see, so next job is to fit it and then Dyno test it. Changes will be just the head and see what difference it makes. This will happen in warmer drier weather so give it a few weeks but it will come.

 

Merry Christmas all 2012.

 

Chris.

 

To bring you a tad more uptodate below is the link to the EFI install.

 

http://www.theminiforum.co.uk/forums/topic/235496-specialist-components-efi-5-port-kit/page__hl__%2Bspecialist+%2Bcomponents+%2Bport

 

I've been intouch with http://www.vmaxscart.co.uk/ and I will be getting the SuperCharger kit from him and head work aswell. He says 90hp with the setup we are after so I think that will definitely be fast enough for the wife. However I have already bored out the original engine to +60 thou and it will be rebuilt by Minisport as will the gearbox with uprated clutch, cam to help the engine cope the best it can. The Idea at the moment is to mount the current EFI setup on the end of the inlet tube for the Super Charger just as the carbs do. Fingers crossed all will work fine.

 

Thats all for now so Merry Christmas all 2012.

 

Chris.

[James]

Hi Chris,

 

Do you mean putting the injector before the supercharger?

 

That's not the best idea as the fuel heats up — better you put it directly in at the head.

 

James

[Nick Jones]

Chris,

 

A good find as a decent, unmolested 12G295 casting is something of a rarity these days. Haven't worked out the numbers but it will have bigger chamber volume than your existing head. I guess this is good to an extent as you'll want to drop the CR for the supercharger.

 

Some numbers on here but dunno if they are right.

http://www.calverst.com/articles/Eng-Engine-998_tuning_further_options.htm

 

Would CC your chambers before and after any valve work before choosing your final skim. IIRC it's always worth CCing all chambers as being as cast in rather than post-machined (like Triumph) they can vary quite a bit in production form.

 

Nick

[CHRIS211083]

Standard Chamber 28.3cc in this head John. I wont be modding the head myself, http://www.vmaxscart.co.uk/ will be doing it and have alot of experience in modding the 12g295 head.

 

James, throttle and injectors will be before supercharger at the end of a long inlet to the front of the car. Just like the carb setup, the fuel will help cool the supercharger. Many carb setups work this way and so should the injection. Here is a pic:

 

 

Chris

[CHRIS211083]

Ok so today I called a company called MiniSpeed, they were very helpful and seem to have a better designed Supercharger kit. So why is it better.......Well ok the first thing that I like about their kit is it does away with the v belt and converts all the pulleys to the modern serpent type belts that practically never stretch and never slip. This is a big reliability bonus. The second bonus of this is that only having the crank pulley the standard width will mean that the Specialist Components crank trigger wheel setup will bolt on as per normal. Third is the Supercharger setup has been flow tested.....So both ports receive the same amount of charge and they have a better flowing manifold and a better inlet manifold to the charger which has been tested. This kit differs from the others as the charger is in a different place compared to the other setups. So all looks good but the iceing on the cake came when I spoke to them about the Specialist components 5 port injection kit I wanted to use. Here is a pic:

 

 

This is a very nice kit and its all complete in a bundle and I didn't want to have to mod it. My first thought was to just bolt it up like a carb type superchager kit (haveing the carb at the front of the car) however MiniSpeed said that the injectors have to be at the inlet to the superchager to be the most efficient and that they could easily make a custom inlet manifold to bolt the 5 port kit straight to the charger. They said this is a much better way of doing it but there isn't enough room with a carb which is too tall, this why they have the long inlet pipe to the front of the car. This should also mean that I don't need to lengthen any of the wiring for the throttle body which is a massive bonus, however the current air filter may have to be changed(but may not need be). This is not a problem as Specialist Components do what they call a turbo inlet which allows you to use a clamp on filter or attach tubing to a filter and yet have a good velocity stack inlet. So this will work out very well. The final bonus was when I asked them about the head, to port/polish fit larger valves and hardened seats its only £380. This would give the correct compression ratio for the kit and is cheaper than the others. The power figure they gave was the same as the others at 90bhp so I think this is the kit to go for. The final thing I like about this kit is that they get a compression ratio of 8.5-1 using a larger head gasket than standard, this means that if you remove the charger then all you need to do is replace the head gasket with a stock one and the ratio would be suitable for a N/A application if you choose to sell on or decide to sell the kit.

 

I've also decided that I'll be making another purchase from Speed hut for the mini. It has two guages at the moment but only shows speed and milage on the first and fuel/coolant temp/high beam and oil light on the second. My Idea is for a speedo/tacho/ mileage and high beam to be in the first and fuel/coolant temp/battery charge/oil pressure to be in the second one. Here is the kit I'm looking at.

 

http://www.speedhut.com/customizer.i?clid=191057

 

Because the speedo reads from the gearbox on the mini and the need of the different ratios for the supercharger the gps speedo will always read correct. It will also be very handy to know an accurate coolant temperature reading and oil pressure reading. The battery voltage gauge will also show us if the alternator ever goes tits up either no charge/uncharging or overcharges which is handy and the fuel gauge went tits up last month. I've changed the sender and its not the fault so the new gauge will correct this to. One thing that has always bugged me with this car is that there is no tacho. With the 5 port efi kit you can add a limiter which is really handy as before you would go to over take something and suddenly loose power which sounded like valve bounce.Where now the limiter is set (on the dyno) at 5,500rpm as at 5,700 we got what the dyno guy agreed to be valve bounce or just the engine not enjoying it's self. This makes a distinctive noise when the limiter kicks in and holds the power so you can just change the gear. Having the tacho will make life much easier, that and the new engine should be good for 7,000rpm rev limit.

 

One thing I am going to look into is a way to cool the Supercharger to engine manifold. I've been told that it gets quite hot and have seen an idea of using the fuel return line to act as a manifold cooler. I'm still thinking of this but it seems like a good idea. I'll let you know more once i've though of it.

 

Chris.

[CHRIS211083]

Well I was asking questions about the supercharger kits on the mini forum and trying to find out info on different kits when the MiniSpeed guy came on and wrote this with these photo's.

 

Hi Chris, that's a good question with most of the suppliers prices being similar and all supercharger kits giving a power increase. Our kit really is the best on the market due to superior design and craftsmanship and while we do not normally reveal our trade secrets I think this is a good opportunity to see the main difference.

 

This is a photo of a BMW mini supercharger body mounted on one of our rivals inlet manifolds. You can clearly see the that intake charge (air/fuel mix) is squeezed into a tiny hole which creates unwanted pressure and temperature while massively restricting power output. http://www.facebook....&type=1

 

This is a photo of the same BMW mini supercharger body mounted onto our own inlet manifold. You can clearly see the massive hold matched to the supercharger output which is achieved by hand crafting tubular and sheet steel individually in house by our engineers. There simply is not a comparable quality item in the market that even comes close to the efficiency and power that ours produces.

 

http://www.facebook....&type=1

 

Very good response and clearly shows why theres is better.

 

Chris.

[CHRIS211083]

295 Cylinder head is off to MiniSpeed tomorrow for bigger valves, porting, hardened seats and a skim. Will be 2 weeks and then I'll find to the standard engine and dyno run it. Will post photo's of the run and the graph.

 

Chris.

[CHRIS211083]

Quick update, the 295 head has been worked and now has the correct 8.5 comp ratio for the Supercharger. The original gearbox was very worn so it's been rebuilt to like new and is awaiting pick up at minisport. The engine and gearbox will then be sent to joint the head at MiniSpeed where they will build the engine. Then in a month or two the engine, gearbox and supercharger kit should arrive. They recon 90bhp. Can't wait.

 

Chris.

[CHRIS211083]

Anyone ever driven a 2 cylinder Mini Before???? I did today!!

 

Driving along and sudden loss of power, but it was just drive able at about 35mph max. First thought was lymp home mode? But there is no edis on this setup. So I limped home and as soon as I lifted the bonnet with the engine running I could see an arking spark flash from the wiring loom to the bulkhead. It turns out that the wires to the coil pack had rubbed through.

 

 

A quick clean up.

 

 

And then some solder, followed by some insulation and the loom was wrapped again.

 

 

Unfortunately after a quick test drive the problem was not fixed. So with the engine running(badly) I pulled the plug leads off each plug one at a time and it was clear that one coil in the bosch coil pack had failed. Buggar, so what do I do now......

 

Well I have a spare coil pack in the Spitfire? and I also have a spare connector too. So time for a brand change.

 

The cheap Bosch coil pack:

 

 

The second hand Motorcraft coil pack with the matching connector. The Ht leads are the same type so were a straight swap.

 

 

This cured the 2 cylinder mini engine problem and has actually made the mini run better than ever with a more snappy response. The Motorcraft coil pack must be a much better item, the bosch you can buy for £40 new where the motorcraft coil packs are much more expensive. However you can buy them second hand off ebay for £10 delivered. So with the better performance from the new coil pack I've decided to leave it on and have just bought two more motorcraft coil packs to act as spares for both vehicles.

 

Job done,

 

Chris.

Edited January 17, 2013 by CHRIS211083

[James]

Chris,

 

 

I presume the ECU will have dwell settings etc — it's worth checking they match the coil — it could have killed the coil.

 

 

 

James

[CHRIS211083]

Don't think so mate, more likely the arking out to the bulkhead from the rubbed through wiring.

 

Just in case james what figure should I be looking for??? The ECU dwell setting and then what??? By how much???

 

Chris.

[James]

Good point about the rubbing

 

It's just something to be sure of — coils vary and may need different dwell. If it's really driving better now then I expect the numbers are more likely to be right now than before.

 

I have no idea what numbers you need for the Motorcraft coil. With the Bosch there is likely to be a datasheet if you Google the part number (that's how I found the numbers for mine)

 

It may not really affect everything too much — but it's good to know you have the right numbers in there.

[CHRIS211083]

I'll check the numbers today but it was all set by specialist components who provided the coil so it should have been right. I'll have a wee scan.

 

Chris.

[CHRIS211083]

Found this on dwell.

 

http://www.extraefi.co.uk/dwell.htm

 

I has brief numbers so I'll just take a look at the ECU.

 

Chris.

[James]

Ok — you should expect it to be right with the Bosch coil then.

 

Just be sure to check it's still right with the new coil.

[CHRIS211083]

Well I plugged in the laptop to the Ecu and here is what I found......

 

 

Battery voltage x engine speed. So is it running correctly??? I honestly dont know but as this map shows, the lower the voltage the longer charge (dwell) time the coil takes naturally. However maybe this coil is different to the last one? It also seems to tail off as the rev's climb. Will call Sc on Monday to see what they say.

 

Chris.

[CHRIS211083]

OK if you want your head to implode then read this article on dwell timing....

 

http://www.dtec.net.au/Ignition%20Coil%20Dwell%20Calibration.htm

 

Ouch, need to have a lie down now.

 

Chris.

[James]

You need to find a datasheet or spec of the coil you are using to make any sense of anything— that's where you can start getting the numbers from.

 

Here's something that's easier to read from the Megasquirt manual— http://www.megamanual.com/ms2/configure.htm#dwell

 

I don't want to make a big deal out of this the main point is make sure the numbers are right when you swap components about if you want everything running 100%

[CHRIS211083]

Hi James,

Glad you brought this up. Apparently the best way to set your dwell is to set it in the car start at 3.0ms and lower it by 0.2ms at idle until a miss fire occurs. Then increase by 0.2ms until it stops misfiring and then add a further 0.2ms then try this at low load (cruising lean mixture) driving rpm. If its a Zetec coil pack then 2.0-4.0ms is ok. For more info see this article below. Or the one I posted earlier.

 

http://www.extraefi.co.uk/dwell.htm

 

Chris.

[CHRIS211083]

Well, the time has come. I'll be sending the engine away next week to be rebuilt. However the Wife and I have decided not to Supercharge the MINI!!!! Instead we will keep it N/A and just have a fast road engine built. The head is done and so is the gearbox, so just the engine needs doing. Should take 2 weeks to get built and then In the car it will go.

 

Chris.

[CHRIS211083]

Thought it was about time to put some pictures of the wife's mini(Chunky) up.

 

 

 

 

 

 

Chris.

[pomwah]

Nice!

[Nick Jones]

Looks very tidy for an '88

 

Nick

[CHRIS211083]

Well engine and rebuilt gearbox arrived at Minispeed end of last week and is being built this week and should arrive early next week. Its final comp ratio is 10.7 and it's fully lightened and balanced with the 12g295 flowed head and a minisport CA3 cam. This should make it a really lively, rev'y engine but i'm sure the wife will love the extra go. Also to be ordered later this month is the Speed hut Gauges. Still deciding if we should go for a single speedo/tacho combo with a quad gauges in the second hole or to go for a separate speedo and tacho with smaller Aux gauges in the center of the dash. The second option will mean dash replacement but the current one is scuffed anyway. I'm leaning towards the separate ones as I think it will look more sporty and cool. Will have a think about it and let you know more once it happens.

 

Chris.

[Aar0sc]

Clearly a relative of my mate Charlie's: