This is all hypothetical at this point. (until next week ) If you were to use a 19% supercharger pulley with a 4% crank pulley is this completely beyond the limits of the factory supercharger? If not what other downsides is there to using such an extreme combination?

I have heard some concern about the idler arm hitting the crank pulley. Would this be even more of a concern with a 19%?

If everything worked perfectly I do think that you would have an extremely torquey monster. Only problem would be finding software.

 

hey there
are you going to test it?????????????? let me know! im alway hungry for more boost! of course i dont wanna hurt my engine!

the reason im not getting it and testing it myself is b/c had some drunk A-hole hit my car and damage my door and im fixing that first...

right now i got a light weight crank and the 19% and I LOVE IT

 

You will be spinning the SC very very fast. Also, you may convert the extra work more into heat than anything else, gaining little. You for sure will need extra intercooler capacity, and you may still find that it doesn't gain much. I think one of the Randy's was looking at IC output temps, and the 19% creates much more heat than the 15%.

With air pumps, there is a point of diminishing returns. I don't know if you're going to hit it, but you're getting out there! You may just trade some low end torque for a severly impacted high end (when all that SC spinning is heating the air!)

I'd so some serious research and talking to some experienced tuner before I were to go there!

Matt

 

Wow this place is filled with myths and unsupported information. At the Dragon I had a rather lengthy talk with a rather well respected tuner and he said that testing between the 19% and 15% only showed a 5 deg. temp. diff. in intake charge.

Does anyone know for a fact what the manufactures (the person who produced this supercharger should know a good bit more about there product then any tuner) limit is on our supercharger? I would just like to make sure I am not going to have a bearing fail or something go flying through my hood.

 

step up to the plate and try it...no one else has, and all else is speculation. worst case, you fry a supercharger bearing and have to put in another blower; they can be had for not too much cash due to the JCW mods.

 

Has the engine been shown to hold that much boost without a BHG or something similar?

 

Temps climb pretty rapidly when you get on boost with the 19%. With over 20% reduction, I think you'd see the supercharger's inefficiency plummet (both increased power consumption and temp increase). But, as John said, go for it ... let us know how it works out. :smile:

 

Oh yes and much more. I believe there was a twincharged car running at 26psi on all stock internals. Larger pulley on the supercharger though.

Well I'm going for it. What should I look for as far as the supercharger becoming inefficent? What type of instrumentation do you suggest Randy?

 

I can tell you that there is more than a 5 deg F difference between intake air temperature with the 15 and 19% pulleys. At similar ambient temps, running time and rpm's, I found that IAT was at least 10 deg F greater with the 19% than with the 15% pulley. The comparisons were made in my car which is equipped with a GRSmotorsport intercooler. I have not set up probes pre and post intercooler, so my comments are based on IAT observations.

I would think that you'll need larger injectors along with a modification of your ECU. Another concern might be detonation and potential piston damage at higher rpm's. Any comments from jlm or Andy?

For gauges, I think you would want boost, water temp, and if you can do it, EGT and IAT. That may be overkill, but I believe in gauges

Good luck with your project and keep us posted....

 

wth this mod, one could argue that the boost will come on lower in the rpm band, poviding a wider torque curve. the engine and blower won't start to experience more severe conditions, compared to the 19% alone, until the engine rpm is 5% lower than your redline. so if you redline the 19% at 7,000, redline the 24% at 6,750.

that sort of curve shifting would be very useful for the drags, I would think, so try to get some before and after 1/4 mile times.

definitely monitor your A/F and if it were me, I would put in larger injectors and the Apexi to tune A/F.

 

Autodynamica in Mexico City recently installed a 25% pulley in a MCS. I immediately suffered the Freudian condition of Pulley Envy. Initial reports were that it ran like a champ, and I haven't heard anything since. They have been getting 19s from us so maybe they are dialing it back a notch. Maybe the Central Scrutinizer for MINI testing (y'know: Andy at Rosstech) can illuminate us about intake air temps for the various pulleys, and speculate what a 19+4 would give.

On a side note: ask Nuzzo what he thinks of aftermarket crank pulleys.

 

If you look at manifold pressure divided by ABSOLUTE temp (degrees Kelvin), that is proportional to molecular density. I've been looking at this with a Carchip E/X, but the 5 second sample time pretty much sucks. but this only tells you the efficiency of the intake side of the equation.

The A/F is a must, and exhaust temps too, if you really want to push it to the edge....

Matt

 

What _does_ he think??

 

Seeing as how I currently have a slight lack of funds I think I will hold off on larger injectors and the Apexi. I will however be purchasing and installing the crank pulley.

I will be running high test race fuel. Any suggestions on what type. I was thinking either sunoco gt100 unleaded or gt plus.

 

Won't race gas quickly cost you as much as the Apex-i and injectors? . It's like 3 dollars a gallon of a premium!

 

wudnt this have a detrimental effect on the cooling system (waterpump spinning toooo fast) with the charger running such a high speed ?

 

It's amazing how some of you like to see someone with no experience in tuning the MINI, put his car/engine in harms way .

To start with you will overdrive the supercharger exceeding it's upper rev limit.

The waterpump Will cavitate, possibly overheating the head leading to
detonation knocking etc.

Using a 4% crank pulley will have some deleterious effects on the accessories
like the alternator and a/c pump.

The increased compressor cavitation leads to soo much heat, that it lowers the efficiency to the point of no beneficial return.


Egging this guy on, to see him fail is absolutly absurd........ Don't do it.

What should be asked is, what do you like to see horse power wise and
if the answer is 200whp, we all know basically what needs to be done.
Give him the advice and feel good about helping out.

Peter
Team M7

562-608-8123

 

Thank you Peter.

Spillman,
We know that you mentioned "hypothetically"...
However, we all luv our MINIs so to be safe most of us try to stay at about the level of a 19% reduction pulley and even that is too far for some.

If 19% reduction pulley and 4% crank pulley were a viable option you'd see more discussion of it. Talk to Alta about using the crank pulley in combination with a reduction pulley and what limits there are.

 

it's all about the redline; the water pump reaches cavitation paranoia levels based only on the rpm of the blower. Raising the redline to 7200 (Evochip) and using a 15% pulley will spin the blower faster at 7200 redline than the 25% pulley and 6800 redline. same argument applies to overdrivng the accessories by 4% and extra blower heat.

 

#1... Where is your information coming from that this will exceed the superchargers rev limit? Have you talked to the person who designed this supercharger or have you tested this your self? Or is this just something you have just made an assumption about?

#2... When has someone seen cavitation happen? I have seen claims about cavitation with anything larger then the 15% pulley. From my experience with continous red line (between 6500-7250) testing I have only seen coolant temps have a 10 degree delta from crusing speeds. And when the coolant reached this level it stayed there and did not rise.

#3... Even if the waterpump did start to cavitate and temps were to rise and cause detonation on pump gas I am fairly confident that my 116 octane race gas will be more then sufficient.

#4... Sure the supercharger has a point where it does nothing but make heat. However if I was to do as JLM said, and simply lower the red line, I would not reach this point (if it is in fact the limit at 7250). However I'm not sure if this would yield a higher peak HP.

 

uhm...common sense ought to point to some of the assumptions as being viable, in the least. Which, puts your engine at risk. But go ahead, it's your car.

You're throwing questions back at M7 like they're the devil...Just add the 19% pulley, install a 6% overdrive crank pulley - forget the 4% - and reflash your ECU to rev 1,500 rpm higher. You'll make more power...

#2/#3 - cavitation has nothing to do with heat, it has everything to do with velocity. A fluid can only travel so many ft/sec in a given environment. What makes you think 116 octane anything is going stop cavitation and excessive heat? Uhm, where I come from, higher octane produces more heat - more energy content = bigger explosion = more heat. You wrote that because of a lack of funds you're opting not to install larger injectors...I'm baffled by your logic here???

And with all due respect to jlm, what's the point behind shifting sooner??????
To avoid excessive IC, SC and coolant heat, cavitation and detonation? How about approaching your tuning with a little more common sense...oh this was hypothetical, sorry...listen to everyone who tells you to go for it and argue with the one who says be careful

Thankfully I can turn the dial.

 

I apologize if my common sense doesn't reach your standards.

I agree cavitation it self doesn't cause heat. However the lack of circulation of water through the entire coolant system does cause things to heat up. In the event that the pump starts to cavitate and does not pump the water as it is supposed this causes the above.

I would also like to apologize to the people I may have flamed (a serious apology here). I understand your concern for a fellow MINI owner and the possibility of what could happen.

What I do not apologize for is questioning what seems to be the excepted practices here and on other message boards. It seems that certain theories are accepted as facts if they go long enough without someone proving them wrong. And then when someone does come along and ask about something new they are called idiots and have their common sense questioned.

 

They're certainly not angels.
The point was a lower rev limit will allow the SC to spin faster at lower rpms for more boost. The higher rpm rev limit will overspin the SC.

MORE BOOST=MORE TORQUE!

 

Why do you say that? I mean, come on man. What exactly has M7 done that is so bad? Did they hurt anyone? No. Did they malign anyone? No, they didn't. Did they initiate anything? No.

The thing I am beginning to get quite tired of is disrespect. If you don't like a product, civility begs you just keep it to yourself. You and I and everyone else have every right to an unfiltered opinion. But, we don't have the right to be hurtful. If your opinions are strong, if you just know there is something amiss, then please understand that other people with a sane and perfectly competent mind will come to that same conclusion. They won't need your help. If they don't, well, that's fine. It's all their prerogative.

Please keep this on topic. Please put everything in perspective. Please.

 

No flame here Meb, and I apologize if this is simplistic ... but a gallon of 87 octane and a gallon of 100 octane have the same energy content. There is no more potential energy in 100 octane fuel. There actually might be less due to the additives necessary to raise the octane rating of gasoline. Higher octane fuel doesn't blow-up bigger than lower octane fuel. It may burn hotter once ignited though- I'm not sure?

Octane rating is a measurement of flashpoint... i.e. the temp at which a substance turns to vapor and is ready for burn once a heat source is applied (like a spark plug). (gasoline or any fuel will not burn in its liquid state.)

Raise the flashpoint of your fuel, you can raise the boost or compression ratio of your motor and be less prone to detonation.

High octane fuel serves only one purpose - prevent detonation/ping/knock. It removes the potential for detonation, so you can tune and build more power without hurting something.
ciao!