Ok so I've been out of it for a bit but remember upgrading to JCW injectors on my first MINI. I believe I did it when I upgraded to a 17% but I cannot fully remember...

I have ordered a 17% for my JCW and was wondering if I need to do injectors at the same time. Also, I plan on having a RMW cam and header + tune by the end of the summer and RMW head beginning of next year. What size will I need for the cam/header combo? What size with head?

Thanks.

 

Someones always gotta try to show me up. haha. Jk. I am excited to see your car when you are done. Here is a secret about my R56 though, I am looking at ordering Wiseco pistons soon =)

I wish I could help on the injectors though, I know some of the guys on MINIUtah might also know even though that forum gets about 10posts a week if that. haha.

What power are you aiming for in the end?

 

Haha! Love it.

I would LOVE to get over 245whp. Is that possible? Maybe not. But I'm going to try. I've got the header and will be ordering the cam in a couple of weeks. I say couple but I get amped and it will probably be like one.

AND my GRS intercooler.

 

To me, JCWs would be a minimum for the 17% pulley. Adding the cam and header, and anticipating more flow, you might as well go for 440s or 550s. If you get the 550s, the nice thing is you will already be prepared should you decide to upgrade the head or SC down the road. Just keep in mind you have to immediately do a tune with anything other than the JCWs.

 

with such a list of future mods....go big...
you will need the fuel for that kind of hp...a tune will be needed, but with that list of parts, it should be a great ride!
for best performace, try to find a set with the same spray pattern as oem....I think rmw had ones that both sprayed the same, and had good scalibility for a good idle...some older desgin 550's would idle poorly, and had a less than ideal spray pattern (resulting in some fuel getting sprayed on the wrong areas, then dripping...not ideal).

 

Man I was hoping to not have to tune after the injectors and pulley. So I'll need to if I've got the 550cc's huh?

 

http://www.rceng.com/technical.aspx

do math.

you wont need 550cc injectors until your at around 290hp crank.

 

I think I've read where you can get away with no injectors for the 17% pully as long as you're not running it up to redline every shift. Someone, please correct me if I'm wrong...

 

This is technically true for even the 15% pulley. I should have JCWs, but I have not bought any yet. I too am looking at doing some more in-depth engine mods in the next year or so, so I'm already leaning toward 440s or 550s myself.

 

I'm just confused now.

I just got off the phone with my tech and he said I will not need injectors with a 17% and I won't be too lean. I called Way Motor Works and he said the exact thing. I called RMW and he said I'd need injectors. Everyone has different answers!

 

Well, considering the extensive work RMW does with a lot of the cars they work on, they may be working on the assumption that the pulley won't be the last engine mods you make, so they may be recommending the larger injectors with the future in mind.

And with 550 cc injectors, you'll definitely need a tune. The reason is that the ECU is programmed to work with the stock 340 cc injectors and knows that to deliver "X" amount of fuel, it needs to open the injectors for "Y" milliseconds. But using that same mapping with 550 cc injectors means that the injectors will be delivering about 60% too much fuel.

The ECU can compensate a little bit via the "fuel trim" feature when it senses that you're running too rich, but the fuel trim can only shorten the injector cycle by about 20-25%, which isn't enough to keep you from running horribly rich.

 

Here's my story on injectors. I had a new head/cam 17% Meth installed and ran stock injectors for 1 year and it was running rich. I got a RMW Tune and 450's. Still runs rich. I really don't see that much improvement from my stock injectors performance wise. There's a lot of misinformation flying around just to get a sale.

 

There may have been something else wrong with your particular car. With all the mods you made to increase airflow (overdrive pulley, head and cam), I can't imagine why you were running rich with the stock injectors.

 

Remember....optimum and "should be fine" are different....below 4500 rpm or so (just a guess) I bet all is ok....above a chance....but with a 17% prolonged high rpm running is counter productive....you begin to get cavation around the water pump, and you begin to make so much heat, you will likely make less power....that is why a 17% is a great daily driver, but a jcw or 15% reduction is better for higher rpm drivers and tracked cars...
I ran a 17%, no injectors for a bit...ran pretty good....then added jcw 380's..no tune...ran better at higher rpm's....then got a tune...
at the tune with the jcw 380's maxed (with just a CAI and 17% pulley), I could have gotten a bit more hp IF I HAD BIGGER INJECTORS....fuel and the A/F (NOT RUNNING TOO LEAN) was my limiting factor....
remembe, the jcw injectors are pretty well maxed out in a jcw...so about 210 hp....you want anything beyond the basic bolt-on's like a jcw and the VERY minor port, then you will greatly benifit from more fuel and a tune.....
My goal was to get a relilable, fun to drive daily driver.....so imo the correct a/f ratio was imperative....forced induction cars run lean tend to have a short life.....I did not want to have $$$ issues a year from now....and wonder....what if I had.....so bit the bullet, added more fuel, and tuned.
My car has been relilable, fun to drive, and gets good mpg too!!

 

I hate the fact that a 17% runs too hot on the track. I wish temps wouldn't be so out of control. I'm going to swap on a 17% as my car is 98% daily driver. Maybe 3 times a year at most I get on the track and it typically is for solo events where its one fast lap at a time. I'd hate to run 15% for the MAYBE 3 times a year I'm on track and then I don't get the added umph on the streets daily. But whatever.

The plan for now is to swap the 17% with shock injectors. I will run that for about a month - month and a half when I'll upgrade to 450cc injectors, RMW cam, RMW header, and RMW tune. I'll run that until December when I get my year end bonus and I'll slap on the RMW head and get the tune then too. At the time the head goes on I'll decide if I want to then swap to a 15% or stick with 17%.

 

One option to deal with the heat a bit (with the cam and maybe a header you will have an easier flowing motor air wise) is to still get the 17%, but find a GP intercooler....the extra 2 rows and effecient desgin will negate most of the heat issue. Just be sure to get the right ic diverter....with $$ most can issue can be dealt with on some level.

 

Just a reminder to all
randy webb over at webb motorsports did some early reserch on the "best pulley" size....while one is not best for all situations, he did find some intersting stuff....the write up should still be posted I think.
PS a 17 can be tracked....
just very a spare belt and a use a tennsioner stop......then it seems a spike in oil temps (from reduced water flow block and or oil cooler) is a sign of waterpump cavitation.....but a castiron block can hold lots of heat, so a lap is likely ok....just let the car idle a bit when done driveing....most do anyway.....you may see the temps go ip a bit in the first few minutes of idling from this stored heat.
for 2 or 3 times a year....you could also use unleaded race fuel....higher octane will help you deal with the heat sefely...preventiong detonation/ping...any for the $$ get you a bit of hp.

 

Is Randy Webb's write up on the forum or else where on the internet?

 

RMW ran 17% pulleys on their race cars all day long when they used the eaton blower. no problem. the 2% difference as far as heat and running the blower above optimum range isnt that large... really.

injectors are important, pulley size is less important, getting proper fuel mixture in a boosted engine will save you tons down the line. do some math, ignore all the opinions, thats what they are. I will say however after I did my calcs for my setup, I called Jan at RMW and he nailed the size on the head for what I was running.

 

+1 to this. Get the DDMWorks GP IC diverter, too.