BIGGER is BETTER!!! A FAQ on the Bosch 550cc injectors for R53

I am curious which tracks a MINI would run extended high rpms all day long? Most road tracks in the US you would not be able to do that with the average MINI? Are you referring to 1/4 Drag Racing? But than that would only be for about 12 -17 seconds?

I personally seldom take my MINI above 6500rpm. Actually I built the Mods around a 7k red red max. On one of my few times on a dyno it was shown the the best utilization of power was to shift around 60,65,65,65,68,68.... and anything above was simply making noise?
The data displayed here is really indisputable and simply a form of which to make an improved and inform decision on future appropriate parts?

 

Virginia International Raceway, Road Atlanta and CMS to name a few. You really should consider actually going to the track sometime.

 

......^

 

Well thats my car that he is showing! And actually when I'm at PIR (Phoenix International Raceway) I start to bump the rev limiter in 5th on the front straight going into turn one. After turn one and going into turn two I'm somewhere around 6000 (I'm too scared to look) and still in 5th. After a quick heel and toe and heavy braking, I'm in 3rd and around 5000 and climbing quick. Thru turn three and into four I am all most back onto the rev limiter and depending on traffic will go into 4th which will put me around 5500 again or not, which will keep me around the 6800-7000 range. Under heavy braking into five and thru the carousel it's 3rd gear starting around 5000 and going to 7000 at the exit into turn seven. Then it's into 4th for the ride thru eight and almost back into the rev limiter on the approach into turn nine. Under HEAVY braking into turn nine it's down to 2nd gear for the 180* turn out onto the oval for NASCAR turn three and four banging the upshifts at around 7000 until it all starts over at turn one . I'm like you I don't like to abuse the car but as you can see it is almost always well above 5000 and some times on the rev limit. This lasts for the 20 min. that I'm on the track and at every session that I'm on the track. In short I'm not much of a driver and I think that most good (fast) drivers will keep the rev's higher and for a longer period of time.

I totaly agree to make an imformed decision you need the facts, just as Mike has posted them. Thats why they are the best!

 

Turn 7 to Turn 10 at Road Atlanta is for all intensive purposes a straight run. MINI can hit 130 easily.

Turn 5 (Keyhole) to Turn 7 at Mid-Ohio is a downhill pretty straight run, Turn 6 is small kink that is taken flat out.

Turn 10 to Turn 1 at Summit Point main track is long flat out downhill run.

Road America has to long high speed sections that tax the upper end too. Turn 14 to turn 1 then turn 3 to turn 5

You also need to think of the gearing on some of the short straights too. At Motorsports Ranch near Dallas you exit a high speed sweeper to a short straight that leads to the slowest section of the track. In the MINI it's not worth the time to shift up to forth to have to drop two gears down so one tends to bounce off the limited even when set to 8k on that little straight.

You can lecture me all day on the short shifting, easing up on the pedal and coasting up to some of these corners when a shift is questionable but when chasing down that PCar that is slower in the corners than you all semblance of lifting is wiped from your mind.

 

Do you know how Duty Cycle is determined here?

It appears to be a calculated value.

Fuel Injector Duty Cycle Calculator

So, I guess you meant the ECU would determine a larger pulse width is necessary which would cause an increased duty cycle. Just trying to think it through.

It would be nice if the graph showed A/F to validate the injector being over worked. The car wouldn't suffer if target A/F was being achieved.

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Nathan - Its fifth at MSR. I don't know what forth is. And I do the same. Run it to the limiter in fourth if necessary before braking for rattlesnake.

 

There's an app for that! Fuel Injector Calculator

Fuel Injector Calculator is an easy to learn, simple to use app to assist you in picking the right fuel injectors for your setup. Using a proven formula, this app can provide you with valuable insight into the injectors you require.

Simply enter your desired horsepower, number of injectors, BSFC, injector duty cycle, and fuel pressure. The lbs/hr and cc/min needed will appear at the bottom! Also included in this app, is an e-mail function so you can share the results with other people!

 

To deep for me, all I know is that I need BIGGER injectors!!!!

 

Nathan I'm sure as you know there is more than just the section from 7 to 10 that you are hanging in the high RPMS, there are at least 3 other places on RA that sustained high RPMs are necessary for good lap times in a Mini. Sustained high RPMs don't just happen in top gear on a long straight away. I could go on about the places on the other two tracks but I see no need as anyone with just a handful of track days knows what we're talking about....

 

Lets bring it back on topic please. Bigger is better.

 

Cool.. I'll just add then that I have run all 3 of those tracks on 380 injectors with a 15% pulley and tune with the redline set at 7200 without one single problem.

 

Well goody for you BUT bigger is better!

 

LOL ! Thank god it's the MINI ECU with all the failsafe algorithms. Do that on a stand alone with those 380s and see what happens. LOL! Huge learning curves in the MINI community.... seriously....

 

No one answered the question of how bad a thing is it to run the injectors close to max out..

Appearantly alot of people are...

but atleasat we did learn that yes, at a Road Course you will spend alot of time at or around max RPM...
I already knew that of course but appearantly some didn't..

 

Ummmm I do believe that 99% of the Mins running on the track and or are being modded for the street, run an OEM ECU..... So I run injectors for that application and my power range.

 

You also might be relying on the knock sensor to bring things into alignment and for the motor not self destruct. So there might be a decent amount of power left on the table, especially in the upper end of the spectrum on the smaller injectors.

Also, the MINI motors have proven themselves very stout in taking abuse, and surviving where many motors would have failed.


Just food for thought.

 

.....or they might just be perfectly sized for that power range. After all Mini/BMW spec'd the JCW 380 injectors for the JCW kit and that power range; a very similar power range of a R53 with the OEM S head and a 15% pulley/JCW CAI and a good catback exhaust.

 

My posted response seems pretty clear if you read the words used! Re-reading it the operative word here is "extended" with regards to my lose subjective query.
"I am curious which tracks a MINI would run extended high rpms all day long? Most road tracks in the US you would not be able to do that with the average MINI?"

I would say one aspect that running larger injectors would have actually run a sustained high rpm run would give considerable margin of safety to the engine for fuel demand?

As one person commented on a track between a couple of turns a Mini can easily reach 130mph. But how long in seconds or minutes did it take reaching that velocity and how long at what rpm range. In this example the rpm would be not sustained but increasing over X-time value? This is not "extended" rpm but acquired speed and rpm over a short time. Now you see my point in the response causing such controversy?

Bottom line is choosing a larger inject for a Modified MINI or MINI used for racing seems

sensible.

http://www.roadatlanta.com/trackmap.lasso

 

Ahh...there is no way to deal with this and leave everyone happy so it's for me to be a jerk. I can do it well when needed.

Lynn, take the MINI off the jackstands and do a road course please. As you get more comfortable making turns you will see that one tends to live in the upper reaches of the rev band when on track. So yes, there is sustained running at high rpm's.

The question I think that is on the table is how have all these MINI's that have been tracked that are using 380's a pulley, cai and exhaust not running lean when on track. Are the drivers being light on the gas and not getting the most out of it or is the ecu able to compensate and and provide more than 100% duty cycle from the injectors for a short period of time.