08-09-2013, 07:58 AM #1
need some help with injector choice for et137+4
well somethings up with my setup, afrs are on point spinning 8100 rpms avg, but the ski is barely pulling past my cousins stock rxpx.... i dont know if its the injectors or what, but i guess ill try putting the stock 42s in and see where things go unless someone can shine some light on my issue of lack of power. my ski when i was running riva 50s and charger pulled harder and went faster with a 10.5 afr then it does now being at 11.8 11.9... ive noticed the ski runs better up top if i dont give it full throttle keeping my pinky underneath vs the lever pinned all the way was where it felt the best.....
before installing fuel pump and rrfpr i was walking my cousins rxpx with only riva 50s and the et137+4 with a 10.8 afr. ideas ?
Last edited by 98gsxl951; 08-14-2013 at 02:59 PM.
08-09-2013, 08:38 AM #2
This can't be answered effectively without knowing the ECU and max rpms desired. Tune?
08-09-2013, 08:46 AM #3
stock ecu, 8100, i went out last weekend with out the rrfpr just the 48 lb injectors installed, 80* day , and was seeing 8120, stopped riding as my wot afrs were at 12.5
08-09-2013, 09:07 AM #4
I suggest you install the RRFPR and leave it on, then you can tweak the pressure as the OAT changes. Use the 48's.
The ET 137 is a fantastic SC and at 8100 you are really holding it back. The Riva ECUs for those years at 8650 really perform well. I can not recommend a VTech tune for your Siemmens ECU.
08-09-2013, 09:21 AM #5
If you're sticking with a stock rev limiter you better make sure your prop is pitched right and under the limiter or you'll destroy your engine. Stay off the limiter
08-09-2013, 09:37 AM #6
yes slow91 re pitched prop, rrfpr is on and staying on. im just trying to figure out what direction to go with for injectors. originally, before i decided to do the rrfpr install my self chris ( slow91) was going to do it and tune my ski with the stock 42s. i have a set of 12 px 48lb injectors in right now, but am told bosch injectors have a better safer spray pattern, and will cause my ski to run richer at idle, etc.
next year i will do a valve train upgrade, and cmd. im more than happy with the skis performance as of now.
what should i start base pressure at? 45lbs with the 48s?
08-09-2013, 09:46 AM #7
Start with around 56 psi. Stock is 58. The RRFPR is NOT a set and forget deal, you have to tweak it daily as the Temp, humidity, pressure changes. Normally just 2-4 psi changes are needed.
08-09-2013, 09:51 AM #8
thanks a bunch, hopefully tomorrow will be smooth sailing. should i start with the boost reference line hooked up? or try with it off?
08-09-2013, 09:55 AM #9
off. The system is setup static and more than likely you'll have a better looking AFR curve without the line connected
08-09-2013, 10:11 AM #10
so then just throw in the little breather fitting into the rrfpr that came with the riva kit vs the barb or block the barb? thanks again
alright one last thing, i want to drill the manifold where the boss fittings are as stated in the riva instructions, can i use the fitting closest to the front on the manifold vs removing the ecu bracket? I just want to have this done in case my afrs are off and i would need to use the boost reference. i might actually just leave it for now and have a drill in the car in case i need to drill it on the fly but would be easier to do now while the seat cowl is off.
Last edited by 98gsxl951; 08-09-2013 at 10:51 AM.
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