13 replies to this topic

[Alice Dooper]

The early kits had a few things different than the later / current kits. For example the janspeed exhaust instead of the manifold and the ‘crimped with a set of pliers modified’ fuel pressure regulator instead of the power boost valve.

But the early kits came with a modified inlet manifold, I think it involved some minor grinding back of a radius inside and stamping some letters somewhere on the outside. Anyone know what it was they done?

I know that there was a modification sometimes done to throttle bodies to allow the butterfly to fully open - they just ground the end stop back a bit.

Was there any other differences apart from the air filter?

[Fast Ivan]

The inlet manifold was opened up a bit so that it matched the now larger ports on the worked cylinder head (I have one somewhere)
The mod to the throttle body was, as you say quite simply the removal of the restrictor that stopped the butterfly from opening up fully, I also have one of those somewhere. I’m not convinced this mod produced any additional power though

Edited by Fast Ivan, 08 June 2019 - 06:49 AM.

[FlyingScot]

One of our club members removed the restrictor that prevents the butterfly opening. It had zero effect on power. Modifying the air box however did make a difference.

FS

[Fastorq]

[quote name="FlyingScot" post="3602128" timestamp="1560095735"]One of our club members removed the restrictor that prevents the butterfly opening. It had zero effect on power. Modifying the air box however did make a difference.

FS[/quote]

One of our club members removed the restrictor that prevents the butterfly opening. It had zero effect on power. Modifying the air box however did make a difference.

FS[/quote[quote name="FlyingScot" post="3602128" timestamp="1560095735"]One of our club members removed the restrictor that prevents the butterfly opening. It had zero effect on power. Modifying the air box however did make a difference.

FS

Have you got any pics of the modified airbox?

[drs]

the inlet manifold has the inside cleaned up with a machine turned finish, may have been opened up.  i have never had an original in my hands to see.

 

the TB end stop was modified to open a "bit" more.

 

not sure about the "pliers modified" PR, mine is not the same part as an original one!!

 

the air filter inlet was modified on the works version, this part is now available from M Sport.

 

janspeed manifold was on works version, earlier version s5/touring just had a silencer.

 

paul

Edited by drs, 02 July 2019 - 12:37 PM.

[Bobbins]

David, a suggestion I’ve had is to cut large holes around the filter box possibly using a step drill. My intention is to make a series of holes around the rear (non-visible) side then bond some mesh inside to prevent any large stuff getting into the air box ... I just need to find time to get started!

Stu.

[drs]

sorry stu

 

i thought is was best to get the coolest air into the air box possible, JC initial mpi conversion pics had ducting from the air box down to the grill. my assumption was they where trying to get the coolest air possible ie outside the engine, this developed into the big air scoop later.

 

I would have thought holes at the back of the air box, would give you the hottest air possible. At the top and back of the engine at the hottest point above the exhaust manifold.

 

paul

[Bobbins]

You're correct Paul, cool air is better than hot air because it's denser. My problem is a complete lack of space under the bonnet (JDM with a/c) to get any suitable inlet ducting and I'm trying to keep close to original albeit with a few carefully chosen improvements .. holes on the front of the box might be more appropriate than on the rear!

[Fastorq]

Hi Stu
Have you done the mods to your air box yet?
I’m interested in how well that would work compared to a K&N 57i round filter
Wonder if there are any dunk results out there ... (if you know what I mean . Wink)

[Bobbins]

Hi David, mods not done yet ... I'm enjoying the sunshine too much to take the Mini off the road!

 

I'm trying to keep the appearance of the engine bay pretty standard so have fitted a K&N filter inside the existing filter housing rather than using the 57i kit. Cutting a selection of discrete inlet holes in the o/e airbox will have a similar effect to fitting the 57i in that the 57i is not fussy where the air comes from, it's just going to collect air from above the engine, cold, warm or whatever. A better solution would obviously be to duct cooler air into the o/e airbox either through the existing nozzle or via additional holes, this is the bit I need to work on.

[brivinci]

I read an online somewhere about a mod for the airbox...assuming it was an MPi but all the mods were done to the inside. It had something to do with removing the columns that surround the 3 screws that secure it to the TB and smoothing things out. Maybe someone remembers seeing that well.

 

If you were too drill holes, I'd imagine you would be just letting in A LOT of really hot air. It will also had a lot of induction noise to the cabin. I seriously wish I had a rolling road at my shop to test all these things back to back. Would be so cool to see what really works and what works "in theory"

[rich_959]

I think it was something about removing part of the internals? Someone put some pictures of the inside of an 'S' airbox on the topic below

 

http://www.theminifo...48864-s-airbox/

[brivinci]

I was JUST looking at that thread after I posted mine. HA

[Alice Dooper]

I read on another forum, can’t remember where, that drilling holes in the stock air box can be negligible counterproductive for 2 reasons -
1. Airflow shock. The clean flow of air is interrupted and there I still pressure wave buffeting just like driving at speed with your window open.
2. Your taking in warm thin air from over the exhaust manifold. The best air is clean cold and dense air. Did see a Turbo Fiat Abarth one time that had water mist injection on the inlet manifold to cool the air charge instead of a charge intercooler. Couldn’t see it working on a non turbo but it would fairly steam clean the piston chambers!!
A K&N come filter like the one in earlier conversion kits sits in a hot air zone and seems to work fine though they have supplied fresh air ducting with some of the kits.

I’ve a square adapter from an S works Kit. Looks the part, dear knows if it makes a difference.
.