Thread: Desparately seeking 700 rpm
12-12-2009, 03:50 PM #1
Desparately seeking 700 rpm
OK guys, I got an issue here. I have an 07 rxt with the following mods (x-charger with upgraded washers, 42's, rude rrfpr x intercooler with riva mod, 15-20 4 blade, x waterbox with freeflow exhaust, riva intake grate, 2 degree pump wedge, riva 3 inch intake, 82mm nozzle).
Ran the ski and there was a little chop. 84 degree water temp (almost year round)
Best speed as 66.2 at 72-7300 rpm. Hookup appeared good but rpm planed out on topend)
I know I can change the nozzle to a bigger one. Also may need to check charger slip (I assumed ok because it was recently rebuilt by Jerry).
Also know that increased water temps means decreased performance.
Any other advice. Riva stage I ran 66.1 previously.
12-12-2009, 03:55 PM #2
- Join Date
- Aug 2009
- Discovery Bay, CA
4" intake, did ya have a boost gague or check for boost leaks?
12-12-2009, 04:04 PM #3
Have you checked your A/F? Are you sure you have 42s and not 50s?
12-12-2009, 04:06 PM #4
- Join Date
- Dec 2006
- Crest Hill, IL
1) what is your base pressure for the RRFPR?
2) GET RID of that 3" intake, its choking that X SC...
3) The 15/20, is that straight out of the box or is it used?
12-12-2009, 04:52 PM #5
12-12-2009, 05:48 PM #6
How big do you think the nozzle would have to be to get the rpm's up reasonably, say another 4-500 rpm's.
12-12-2009, 07:16 PM #7
- Join Date
- Aug 2007
- Reading PA
U positively have an issue somewhere, I ran basically that same setup and was good for 74.5mph in 95* air and 82* water, on a rxt, i would look at all ur IC lines and clamps, also get a boost gauge on it cause u will never know whats going on with out one, should see around 10.6 out of that charger at about 8000 rpm, u have the right prop thats for sure, stock nozzle is the way to go unless ur looking for more take off then go bigger, I would also get ur slip checked cause thats what was causing me to loose RPM's big time by the end of the summer i was down almost 500 to 600 RPM the slip was at like 6lbs.
12-12-2009, 07:37 PM #8
12-12-2009, 07:40 PM #9
Check for boost leaks and upgrade to a 4in as stated above
12-12-2009, 08:25 PM #10
You do look to rich, I would quess but that is at 7,200 and 8,100 so will vary.
I would do as speedskixp, stated and you need to start testing and rulling out issues.
You need to be sure what slip is on charger.
lower fuel, and see what afr and rpm, go up on nozzle size.
What prop did you run with your stage 1?
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