Proper fuel for 17PSI on MCX 290 Kit.

[switchback1080]

Looking to find out what race fuel is best. The kit is on a apex and Im looking to turn the boost up to 17psi with a completly stock motor with proper head shim. Standard boost on pump gas for this kit is 14psi. Any advice would be great.

 

[NORTHERNAPEX]

i ran a 108 motor octane slpit 50/50 with premium on 17 pounds, i always ran full race between 17 and 20 pounds with no problems.(c12)

 

[switchback1080]

i ran a 108 motor octane slpit 50/50 with premium on 17 pounds, i always ran full race between 17 and 20 pounds with no problems.(c12)

And that was on a stock motor with only a head shim???

 

[NORTHERNAPEX]

stock motor with head shim only, also running at sea level. motor has not been apart since the original kit went in on 06.

 

[switchback1080]

stock motor with head shim only, also running at sea level. motor has not been apart since the original kit went in on 06.

Can you tell me exactly what c12 is?

 

[TBird]

Have you upgraded injectors?
Pretty near maxed out @ 17PSI!
Lean on fuel = doesent matter octane!
You don't have to worry much about the engines internals as long as you can avoid detonation, lean detonation, to high boost vs octane detonation, the internals are proven to withstand >350hp with no problem.

 

[switchback1080]

I have 4 stock injectors..... Also 4 injectors mounted in the intercooler. Fuel is controlled through the brain box and added when needed. I cant control that. I am assuming that there would be plenty of fuel... Please correct me if im wrong....

 

[TBird]

Then u need some info, the MCX injectors in plenum is ~40hp each x 4 = 160hp + 150hp = 310hp. Over that u need to upgrade the MCX injectors or add an EFI controller such as Dynojet or Rapidbike.

 

[NORTHERNAPEX]

i sent the box into PG yamaha, got re prgrammed for the high boost, good till 20 pounds. c 12 is vp fuel. i ve run like this all winter.

 

[TBird]

? Do you get bigger injectors in your kits ?
I know what i have in my kit anyway, and thats veryfied by Erik @ MCX.
The injectors might flow more then what they are supposed to, but the ones i have is Bosch brown = 40hp / each, then theres blue = 50hp / each and green = 65hp / each.
http://www.mcx.se/eshop/productsByCateg ... urbo+Parts

 

[NORTHERNAPEX]

if you want more than 350 hp you need to swap out the stock injectors in the plenum and switch to the bosch green ones. we have guys here running mcx 400 with the green injectors and running 25 lbs boost. the key is to have a very good map in the control box. Detonation does become an issue at this pressure.

 

[switchback1080]

Im not looking to go much more then 17-18psi for now... I just want to do it safely. I contacted High Altitude boost (Bought the kit from them) And they are looking into it and I will have a answer tmw for the injectors... Off the top of his head he said I should be fine fuel wise, his concern was when the mapping stopped on the mcx box. Which he thought was about 18PSI. Anything more and there is no mapping for it, unless you send your box out to be re-mapped.

Thats all the info I have right now.

 

[NORTHERNAPEX]

i sent mine to the canadian dist.(as im from canada) 100 bucks and good to go. Ive run it at 20 and i had no problems(other than getting a hold of the belt).

 

[switchback1080]

I dont think im going to run that high of boost. but ill def try 17-18.

 

[machzed]

Where can you get or find the bosch blue and green injectors? And do you know how many CC injectors they are?