I've got an 03' R53 with the JCW kit. It's making around 12-13 psi boost with the JCW pulley. Since this is an 03' JCW kit, it doesn't have the 380cc injectors, or JCW intake.

I'm thinking about going with a 17% sc pulley to up the boost a little more. I have a good intake on it now, but I'm still running the smaller injectors. Am I already pushing the limit for the smaller injectors since I've got the JCW head and exhaust? Is it safe to put a 17% pulley on with my correct setup, or should I get a set of 380cc injectors first?

If I go with the 380cc injectors and a 17% pulley, will I need to get the car tuned....or should it run good with that setup?

Any info would be great. Thanks!

 

you will be fine to run it without 380s. It is highly recommended that you get a Tune for it. It makes your AFRs very safe, and makes a big difference in power levels. You can run it without a tune but it isnt the safest option, and you arn't getting 100% of the power you should be.

Mods: 17% pulley, MSD ignition / 1 step colder plugs, alta intake, jcw catback. DT Bypass Valve.

Here is a chart of my 04 R53 before/after tune.

-B

 

How did you like working with BT? Their prices look better than RMW. Do they do remote tuning with a data logger type setup, or will I need to put my car on a chassis dyno and have them remote tune it that way?

Also...I've heard that if you run the 380cc injectors on a stock tune, they will run a little rich at WOT. Would that accomplish the same thing as a tune?

 

1) Bren is a great guy to deal with. I'm not sure he does remote tuning, you would have to call him and ask him.

2) 380s under stock tune will be rich and cause some breaking up in upper RPMs. but being rich is always safer than being lean!.

a Tune would be able to adjust your stock or 380 injector's flow rate to make for the perfect AFR ratios

-B

 

Well, I ordered a WMW 17% pulley for my 03' JCW R53. I'm not planning on changing the tune, I'm going to run what it's got....the 200hp JCW tune.

I do have one question though....am I better off running smaller injectors with the 17% pulley and 200hp jcw tune......or should I throw in some 380cc injectors, and use those with the 200hp jcw tune and 17% pulley? They should make it run a little richer up top, isn't that what I want?

Thanks again for all the info!

 

Yes, you're better off with the 380's, tune or not.
Injector duty cycles run on a % basis, at WOT above 5800 or so it will be asking for 100% of what ever is there, In order to match the air, since the 17% will be giving you more air, the ability to give it more fuel "if needed" is of course the safest option.

But I still think I'd limit my over 6300 rpm usage until it can be tuned or at least have the AFR checked.