Getting Started

[k-huevo]

This forum section is my favorite topic. I have a few performance goals I’m working towards and would like to share them when I get to them.
I’m on a very slow rural dial-up, so posting pictures has to wait. Here’s a link to my gallery on the NAM site, it shows some things I did over the 4th. I didn’t take any pictures of the new head, but it was a beauty.
http://www.northamericanmotoring.com/gallery/showgallery.php?cat=500&ppuser=13976

[scuderia]

looks pretty impressive, did you worj on it yourself, or got some assistance? Give some feedback so we can take some from your experiences.

[k-huevo]

Yes, I did the disassembly and reassembly myself. Asking for general feedback is an open-ended question, for which I could write a book length response ;). The modifications were planned in concert with each other and work very well at increasing seat-of-the-pants mid-range torque. If there were something in particular you would like to know, feel free to ask.

[Will]

This forum section is my favorite topic. I have a few performance goals I’m working towards and would like to share them when I get to them.
I’m on a very slow rural dial-up, so posting pictures has to wait. Here’s a link to my gallery on the NAM site, it shows some things I did over the 4th. I didn’t take any pictures of the new head, but it was a beauty.
http://www.northamericanmotoring.com/gallery/showgallery.php?cat=500&ppuser=13976

K-huevo,

How does our site work for you on dial up? One of the things I tried to keep in mind is not making it too graphic entensive so that it would be dial up friendly. Hopefully I have accomplished that. Let me know how it is working out for you.(anybody else on dial up chime in too)

[Will]

K-huevo,

Did you get a new supercharger? I'm checking out your gallery trying to figure out what your doing.. Is it done yet? I cant wait to see it!!

[k-huevo]

Yes, that is an extensively reworked supercharger. It has been ported, interior case coated with an anti-friction material, lobes coated with a very durable and high heat resistant material, timed rotor, pressure relief ports covered with a liquid aluminum compound, numerous other tweaks and a 19% reduction pulley. The MINI has been up and running since the fourth.

There are more pictures in the gallery now with short descriptions under the larger versions.

[scuderia]

how about the rims? obviously they are lightweight, however do you prefer 16s over 17s? If yes, why? I have 17s w/runflats, I am trying to determine if I should go smaller rims and lighter (16s) with wider tires. What is your input?

[k-huevo]

There are many things to consider when making a wheel & tire choice. First, define your needs and the answer will fall into place. Since I don’t know your needs, aspirations and aesthetic sensibilities, I can’t say what’s right for you.

Here’s a short primer from my perspective. As long as the wheel is strong enough, lighter is always better. Reduced un-sprung weight allows the suspension to work without having to overcome an added burden. Wider tires change the contact patch and alter the amount of effort it takes to turn-in (read that as an increase). On the track, it is a compromise you accept to gain added traction. On the street, wider equals: more noise, less ride comfort, poorer gas mileage, slower and harder effort turning, depending on the tread design an increase in the likelihood of hydroplaning. But, wide tires look good. One of the strengths of the MINI is its handling prowess. It would be a shame to give that up just for looks. A smaller wheel allows for a taller tire (aspect ratio) and still keeps close to a stock-rolling radius. That combo would provide a fairly comfortable ride and close to accurate speedo readings at the expense of more sidewall deflection, but that’s not such a bad thing on the street.

Now I’ll go out on a limb and give some advise. Drive with the wheels and tires you have until the tires wear out. If you have the money to spend, buy lighter wheels with the same or close to stock offset. Put on tires that have good wet weather performance (Yokohama ES 100s do that well and stick in the dry too), keep close to a 205 width and an aspect ratio that isn’t taller than stock. All of this goes out the window if you use the car on the track or autocross regularly. For those conditions seek the advise of an experienced competitor.

[scuderia]

I think you are right, more I read about it and think about my old experience with the GTI I had, I will stick to 17s and get a lighter set of rims and good rubber. For autocross and track, I would definetely get another set that is suitable and more performance focused. Now I am running on runflats, and really hate them, any suggestions on tires for street that will behave on wet but won't sacrifice form performance? Am I asking to much? Obviously people go with Yokos or Kumhos, but I prefer to stick to Pirelli or Michelin, do you think it is worth spending extra? thanks for your inputs and hope to meet you soon:)

[k-huevo]

I can’t comment on performance versions of the other brands you mentioned without first hand experience. The ES 100s were the best, wet weather tire I have ever used. In the dry, they had a moderate road noise level and a very sure-footed stance at the moment of turn-in. Very planted during transitions and good feedback at traction limits. I was able to get almost 18,000 miles on them before I started to lose confidence in the wet. I’m going to experiment with a different tire choice in a few weeks and I’ll let you know how that turns out.

If you don’t already have a tire in mind, Alex at the tire rack can give you better advice than I for those other brands of tires you feel more comfortable with. And yes, buy the best tire you can afford.

[scuderia]

I will send an e-mail to Alex when ready. Thanx

[k-huevo]

I have Avon M 500s on the car now. These tires are very, very quiet. Without all the road noise, the exhaust and everything under the hood sounds louder.

[Jeffy]

Do the ports match to the intake and the header? Mine is an MC sans supercharger, and I am going for normally aspirated power. I suspect that the exhaust side does not match the header, because I saw pics showing a port that is not round, though the header tubes are. What kind of valve pocket work do you recomend, considering that I have no supercharger, and will rely on high revs like 600 supersport racebikes. -Jeffy.

[k-huevo]

On the exhaust side the primaries are round but the header flange is D shaped. This is a good thing because you want some miss-match to act as an anti-reversion step. The roof and mainly the floor of the header flange are the critical areas for an extra step. The entire perimeter of the header flange port should be at least 1/16th larger than the exhaust port exit on the head. What I’ve seen with the stock and aftermarket headers is a tendency for some primaries to welded off center causing a shoulder to be placed in the flow path. On the stock header, the primaries are recessed into the flange thereby providing some support on the primary neck. The edges in the way can be smoothed over without too much fear of compromising the weld. On the aftermarket headers you have to keep returning them until you get one that’s right or give-up.

On the intake side a port match means the injector ports match exactly between the head and the intake manifold and the IM port is about 1/16th smaller than the intake port on the head. Once again this is to act as an anti-reversion step. What I’ve seen from the IM’s and heads is a tendency for core shift for the castings. Remove your injectors and take a look to see if you have a miss-match that you can see and that will be a tell tale sign but, not definitive. The IM gasket will need to be matched as well.

That core shift tendency can affect the ports dramatically with the shape of the floor having a drop-off instead of a gentile radius. I can’t give you a recommendation for the port shape. My advice would be to do the basics remove casting flash, marks, and the manufacturer’s valve cutter indexer in the CC, I saw a big blob off slag in one of my injector ports, smooth the sides of the valve divider, un-shroud the valves just a little and smooth the floor radius a very little bit. The water jackets are very close so you don’t have much margin for error. I had a FZ 600 for 12 years and rebuilt it twice, of course it was air-cooled, you can’t compare the ports, you’ll see that when you get there. For pictures of the header flange look in my gallery, for pictures of a modified head by the Master of in-line fours look here - http://www.theoldone.com/components/cylinderheads/MINI_COOPER/mini_cooper_cylinder_head_modifi.htm

Sorry, I’ve run out of time.

[Jeffy]

What do you think of the stock header for the MC? The outside tubes turn inward- is this a restriction compared to the inside tubes, which are relatively straight. -Jeffy.

[k-huevo]

It still makes power so I don't think the shape of the primaries, the crimped merge collector, or the pre-cat are a drawback. I have confidence in my header and it's the same model as yours. I'll have a report on my dyno measurements at another time but, the bottom line is my car has improved its output by almost 50% while retaining the stock intake, header, etc.

[leonsrocketcar]

It still makes power so I don't think the shape of the primaries, the crimped merge collector, or the pre-cat are a drawback. I have confidence in my header and it's the same model as yours. I'll have a report on my dyno measurements at another time but, the bottom line is my car has improved its output by almost 50% while retaining the stock intake, header, etc.

Reminds me of Hubie's 434whp twincharge. Alot of stock internals as well.

[k-huevo]

I dynoed the car last week to see what kind of measurable gains have been achieved since the last group of performance modifications. The best run results were 182 hp and 153 ft-lbs of torque. That’s 60 hp and 42 ft-lbs of torque above my stock base line numbers. The air/fuel ratio looked ok (post cat wide band sensor) but timing was being pulled back by the DME. Both the before and after pulls were done on the same very stingy Mustang dyno. All of the gains can’t be attributed to the performance enhancements; my car was a dog to begin with and I made some improvements by overcoming a few shortcomings at the stock level.

The conditions that day were brutally hot. The shop fan was moving slow and the good fan was broken. My intake air temperatures and coolant temps were stratospheric. The IAT’s at the start were higher than the previously highest street peaks. Despite the hostile operating parameters these were good numbers considering I still have the stock air box and camshaft.

As a point of comparison I put the car on a DynoJet dyno yesterday. The session ran into multiple problematic issues and couldn’t be used for a true comparison of dyno differences. It did provide me with some first hand insight as to why some dyno numbers can be so flattering. One of the plots registered 643.49 ft-lbs of torque :eek2. I posted some of the plots in my gallery, you’ll see one plot showing almost equal hp and torque, not so outrageous but still not correct for this vehicle. A/F readings on this dyno were very rich (tail pipe sensor). The rpm sensors were quitting during the pulls and an optical sensor had to be used. For the MINI this means the air dam and splash shield have to be removed or in the case of an aero bumper, the whole thing has to be removed in order for a magnet to be placed on the vibration damper. The magnets wouldn’t stay attached above 6000 rpm or the optic device would move resulting in short pulls. The hp numbers were still climbing so I believe better results were possible.

Here is a link for some differences between an inertia dyno (DynoJet) and a load bearing dyno (Mustang). http://www.germanmotorcars.com/Dyno...20inertia_1.htm What ever type of dyno you chose, plan to use that same one for before and after testing to get realistic comparison benefits.

[Jeffy]

I just outran a current model Toyota Celica GT, while entering the freeway. My car is not supercharged and has a CVT automatic transmission. I'll have to admit that my car was slow enough to be dangerous in traffic when I first bought it. I would not have even tried a speed contest back then, but some easy (some kind of difficult) mods produced modest accelleration improvements effective enough to drive it more agressively. -Jeffy.

[leonsrocketcar]

kick arse Jeffy!

[weezer2282]

Impressive... :rolleyes: How about a Porsche next time? That cvt will slip like no other if you put too much power through it. I've driven a couple stock MINI cvt's and could feel it slipping under full throttle. Be carefull...that's a somewhat fragile transmission compared to a typical manual or auto.

[Jeffy]

And, after the computer adjusted (At first I had NO power after), which took a few days of driving, I have this feel like the transmission is shifting too soon at full throttle. In fact, it shifts at the same 6000rpm as before, but maybe if it reved up a bit more I'd get more power and accelleration. So I feel like this mod would help, but at higher revs. This engine's about revs, since it's so small. I didn't lose anything. My terminal velocity at my mark remains the same, and I pass cars just fine. -Jeffy.

[weezer2282]

And, after the computer adjusted (At first I had NO power after), which took a few days of driving, I have this feel like the transmission is shifting too soon at full throttle. In fact, it shifts at the same 6000rpm as before, but maybe if it reved up a bit more I'd get more power and accelleration. So I feel like this mod would help, but at higher revs. This engine's about revs, since it's so small. I didn't lose anything. My terminal velocity at my mark remains the same, and I pass cars just fine. -Jeffy.

That's your problem right there...the cvt can't rev past 6000rpm. Any higher revs than that will destroy it or shorten it's functioning life quite a bit.

[Jeffy]

Are you referring to the V-belt slipping, or the clutch packs? I'm thinking that a little slipping (if not for much duration) shouldn't be damaging. If I'm wrong about that, then I need to find a way to lessen slippage. Maybe clamping force, or lubrication needs to be addressed. Personally, I don't feel the slip- I know that the reaction time of this trans is too long, and wish I could cure that (software), but I just anticipate the delay, for example, when passing, I floor it, but wait for the downshift before moving out to pass. I have always preferred a 5 or 6 speed manual trans for a car like this, but I decided I still liked the car with this transmission anyway. -Jeffy.

[Jakedog]

I have Avon M 500s on the car now. These tires are very, very quiet. Without all the road noise, the exhaust and everything under the hood sounds louder.

Keith,

I, like many others, am in the market for new tires. When doing a comparison at TireRack, the Avon's look great. Do you still have them? How well have/did they hold up and perform?

Naturally, I would like as much response as possible. However, financially, I am looking at extended tread wear. I just don't want to buy tires once a year. I realize with a performance car one sacrifices such things, but I am still looking for the best of both worlds. I welcome comments from everyone and thank you all in advance.

[k-huevo]

The tires have 21,000 miles on them and probably have another 5,000 miles of good wet weather performance left. Tire rotation, air pressures, usage, and toe settings will affect tire wear, so mileage will vary. As a comparison, the ES100s which had great overall performance began to lose wet weather traction at the 18,000 mile mark and had become noisy long before that; the Avon M500s have only now become noisier (but still fairly comfy) and still stick good in both wet & dry, although never the confidence inspiring turn-in performance of the Yokahama ES100s. Anything above 20,000 miles for a summer performance tire is good.

Don’t forget to include consideration of the tire’s aspect ratio when making a choice for the replacement tire size. Rolling diameter will be affected if the tire is wider but the aspect ratio remains the same or has not been reduced accordingly. Here’s a tire size calculator to see how much the speedometer reading will be altered http://www.miata.net/garage/tirecalc.html . A taller tire will provide more comfort at the expense of slower acceleration, whereas a shorter sidewall (smaller rolling diameter) will accelerate faster and have less edge roll over (sidewall stiffness/construction will play a part also) during turning.