24 replies to this topic

[Screwdriver]

Greetings all,

 

I own a 96 JDM Spi that came with a Stage One kit installed (HKS filter, heat resistant wrapped headers and a centre exhaust). I've read through several JCW conversion threads on this forum + the YouTube Videos and was hoping you could share your actual user experience on the following :

 

1) Drivability - Will the 1.5 Roller Rocker + Cylinder Head combination improve high end power AND low rpm torque or just the former? 

 

2) Fuel economy - Has anyone measured the before/ after impact to economy? A better breathing engine should theoretically yield more economy...

 

3) Reliability - Installation/ teething issues aside, have there been any concerns with your conversion 6+ months after installation. Again, this is meant to test the reliability/ compatibility of the new mechanical components and not quality control issues like the rust of the exhaust.

 

Given that JDM Spi cars have aircon and a larger alternator setup, I'm guessing won't be needing the oil cooler. Which begs the question is the 1800 quid worth it for an improved head, a really cool set of rockers and the 12 bhp they'll likely bring? 

 

Cheers! 

[timmy850]

With the John Cooper kits you're really paying for the sticker kit and the badge. If you have an exhaust and good condition filter already I'd buy the head (and rockers if you think you need them) somewhere else and save lots of money...

[Screwdriver]

Thanks for the suggestion! I'm aware that I could save by piecing together the kit but if I do this, I would only be interested in an official conversion. (Plus I really like the rockers!). I'm hoping that JCW owners will be able to answer the questions above that will help me decide whether to stay as is or go for it. 

[minidaves]

dont fit the rockers and it will be lovely and reliable with good grunt, 

[absx2]

It is known that Hi lift rockers cause increased wear on the camshaft so if long term engine life is your priority you need a little more research.

 

A better breathing cylinder head will reduce pumping losses on the exhaust stroke meaning it will take less energy to expel the gas thus improving economy but on the flip side a better breathing head will give you more power that you will use and that uses more fuel.

 

The best performance and economy gain for money spent was to change the diff ratio to 3.44:1.

This was done for friend after a blown diff on his SPI and the ratio change was not intentional just a used gearbox swap.

The car changed from a thirsty slug to a rocket powered roller skate :) The fuel consumption when from 30mpg to 35mpg.

 No motorways in cornwall though.

[Carlos W]

You could see far greater improvement for your money if you're not paying for the sticker

[r3k1355]

It's a period correct mod which is what most people are interested in, having said that I'm not sure if it was available for JDM Mini's so might in your case not actually be worth it.

 

What is quite interesting is the stage 1 kit your Mini currently has, having old school Japanese tuning bits on your JDM Mini is pretty cool, speaks to the history of the car and it's something you don't really see everyday.

I'd stick with the current theme, early 90's Japanese market stuff, it'd be a really interesting car!

Edited by r3k1355, 04 May 2017 - 09:40 AM.

[greenmini1275]

Buy the kit, take out the cylinder head, the stickers, cross member plate and certificate and sell the rest, at least then you can make some money back. As for the rockers, as others have said don't fit them, besides it doesn't matter how cool they look, you can't see them.

[Screwdriver]

Fascinating range of responses here. I'm curious where the aversion to the rockers stems from, as I've always believed that high lift rockers combined with a uprated CAM leads to wear and not just the rockers in isolation. 

 

It's unlikely that the JCW will sell me just the head, which means that I'd have to spend 700 quid at Minisport. Probably best to keep it JDM stage 1 after all, just as I found it. At this rate, I'm almost afraid to share that I fancy the JCW 8.4 brakes too!

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Edited by Screwdriver, 04 May 2017 - 10:18 PM.

[Midas Mk1]

The head is just a Minisport head painted blue.

[absx2]

Fascinating range of responses here. I'm curious where the aversion to the rockers stems from, as I've always believed that high lift rockers combined with a uprated CAM leads to wear and not just the rockers in isolation. 

 

It's unlikely that the JCW will sell me just the head, which means that I'd have to spend 700 quid at Minisport. Probably best to keep it JDM stage 1 after all, just as I found it. At this rate, I'm almost afraid to share that I fancy the JCW 8.4 brakes too!

 

Its taken me too long to realise that sometimes its best not to ask questions and over analyze things, it has left me with a lot of regrets and I should haves.

 

So go with your gut, it seems clear you want it so if you want it and you can pay for it have it.

 

So what if it wears out a little quicker and costs too much to start with. Life`s too short 

[Quincy Sparks]

I'm sure you've found it, but the folks here would hopefully be able to answer your original question about the everyday drive-ability: https://www.facebook...?ref=ts&fref=ts

[minisilverbullet]

You will find that the "coopercarcompany.com" are actually Minisport

 

I understand minisport manufacture / retail the parts. 

 

20 pounds difference for essentially the same parts: 

 

https://www.minispor...r-calipers.html

 

http://www.coopercar...r-calipers.html

[Steve220]

You will find that the "coopercarcompany.com" are actually Minisport
 
I understand minisport manufacture / retail the parts. 
 
20 pounds difference for essentially the same parts: 
 
https://www.minispor...r-calipers.html
 
http://www.coopercar...r-calipers.html

No essentially in it, they are the same kit! That's a weighty price for a name and a slightly remastered mini sports calliper!

As said, minisport now do the engineering for the cooper garages. Their heads are the blue painted Ines under the cooper name. However, you can get the same head or better from other venders!