More Speed

[b_matt_10]

Just wondering what I could do to improve the top speed on my 03 gtx sc I have a 12/20 solas coming but haven’t gotten to put it on yet, but didn’t know if there was anything else I could do to improve the top speed. Intake grate?

 

[200mph]

It might help if you state your goal. There’s a big difference between 1-2mph vs 10-15 mph.

More boost, cam change, engine rebuild focusing on reducing ring drag, piston skirt friction, windage losses, etc.

 

[b_matt_10]

i had it to 61 with a bad prop so hopefully with the new one it will do 65 then hoping to get it to 70 just don’t know what is needed to get there

 

[b_matt_10]

Is that somewhat possible with keeping the motor stock

 

[ski-d00]

You'd be a lot of money ahead if you just sold it and got a 215 ski like a 2005 rxt. To get to 68 will take new pump, impeller, driveshaft, intercooler, flywheel, supercharger rebuild for 215, fuel injectors, reflash ECU, and probably a few more things I'm forgetting.

 

[b_matt_10]

Probably going to end up selling it so I’m not more in the hole

 

[KG1974]

Probably going to end up selling it so I’m not more in the hole

I can tell you what I've done to my 2007 RXT to achieve 78 m.p.h........and this is just so far the mods: just remember, speed costs money so if you wanna make your ski go fast, or at least close to 80+ m.p.h which is my goal then this is what I've done to mine.

I installed the 4 inch marine intake filter and kanaflex kit from Greenhulk. The filter is right above the battery on the right side. Removed stock head and installed a brand new aluminum 2021 RXTX head assembly. That newer head bolts right on the stock block with no issues. I am using the stock rockers and rocker shaft. The oil hole lines up perfectly. I installed the Supertech double valve springs and titanium retainer kit from Greenhulk. Those allow me to run at 9200 r.p.m. with a target at 8600-8800 rpm. This is about as fast as the stock rotating assembly can handle. I installed the oil breather catch can, I am running the stock exhaust pipe routing, but with resonator removed, and a free-flow aluminum J-pipe to factory exhaust exit. The exhaust is just about all aluminum except for the very last 90 degree bend out the exit. I installed a large size water filter/strainer to strain the pump forced water to intercooler. I installed the Fizzle F-1000 external intercooler, with the stock restrictive intercooler removed from the intake. I installed the intake girdle on the intake to handle more boost. I am running the X-charger form the stock 2008 RXT 255. It's rated at 10 p.s.i. boost. Coupled with that I am running the flow matched green 42 Lb. injectors. I am running stock fuel pump. The stock fuel pump is more than enough pressure to push fuel thru the 42 Lb. injectors to feed the X charger's boost. I am running the Ruthless Racing camshaft, which provides more power from mid-range to top end. I am running the Riva race sponsons set all the way up on the top setting. I have OPAS delete with block off's for a smoother hull in the back. I removed the reverse bucket for less drag. I am running the Lucky 13 pump cone with gold spacer only. The ski seems to like that cone length, in regards to the venturi nozzle exit diameter. I filled in the ride plate bolt holes with black RTV sealant, but with the bolt heads covered with a piece of electrical tape before sealant application. I am running all new coolant sensor, and exhaust temp sensor. I am running a new Crankshaft Position sensor. I took the PTO housing off and replaced the double ring starter gear. I replaced the trigger wheel that functions with the CPS. I replaced the drive shaft with an OEM shinny new drive shaft. New carbon seal and stationary ring assembly. I am running the SOLAS concord 13/19R impeller with stainless wear ring. Pump unit is factory stock. I polished the underside of my hull with turtle wax. Lastly, I programmed the ECU with a stage three equivalent tune with the Maptuner that I had custom written by Jesus Garcia from Riva. With all these mods, and many of them are directly changing out hard engine parts, this is the real way to gain arm wrenching acceleration and top end. Yes they sell all the performance bolt on kits, but all these parts are limited in performance and will only push your ski within the limitations of the factory programmed RPM limiter. The real secret is adjusting the RPM limiter which takes a maptuner, or Buds, etc. So, doing some research, I will be sawpping out my limited impeller and installing the SOLAS concord 15/22R impeller, because with my engine mods, it has the power to spin the taller pitched prop. I should see well into the 80+ m.p.h range. So, man I can rightfully tell you, that with all of these upgrades and hard mods, this ski is extremely quick and "launches" out of the hole with the bow "jumping" out of the water, and i have to literally hold on for dear life. Then I wastes no time getting on plane up to 70+ m.p.h. I can be cruising at 50 m.p.h. and punch the throttle and it simply rockets to 70+ m.p.h. in no time. It will easily outrun a stock or mildly modified new 300 ski.....I already showed that on the river with these guys I passed on the river, lol. It is so rewarding to be the quickest ski and your ski is 16 years old, lol. It's just costs an arm and a leg, but VERY rewarding.