Are my 951 gtx expectations off?

[Triorieel]

I'm wondering if my expectations are out of whack.

I have 4 similar seadoos of mine and family members I am trying to figure out. I feel like I might be getting held back or maybe my expectations are off.

Seadoos:
Seadoo 1) 98gtx ltd.951. WOT speed 54mph (gps) at 6500rpm. Compression 142psi,142psi. Upgraded to st-cd 15/20 impeller.
Seadoo 2) 98gtx ltd.951. WOT speed 54mph (gps) at 6800rpm. Compression 142psi,144psi. Original Impeller
Seadoo 3) 99gtx ltd.951. WOT speed 54mph (gps) at 6500rpm. Compression 125psi,135psi. Original Impeller
Seadoo 4) 00 gtx millenium edition.951. WOT with choke assistance 64mph (lie-o-meter) at 6950rpm. Compression 120psi,120psi. Unknown impeller.


Seadoo 4 needs some work, still diagnosing. I only question if it should be able to properly run with 120psi. I understand it may need a rebuild soon.

Seadoo 1-3 is being put to shame by a seadoo that can't even really run off idle and has a much lower compression. Is this what I should be expecting, or do I have 3 seadoo's that need work somewhere?

I just did a rebuild of the pump on Seadoo 1 and was hoping for a WOT give/take rpm of 6800.

I'm looking for people with experiences with these engines in these hulls.

 

[SabrToothSqrl]

You may have some other differences. the 1998 had a single coil ignition and no TPS. The 99 had dual coil. I'm not sure the year TPS was added to the 951.
Also, the 98 had a 'bronze' pump, vs. the 99+ having the plastic pump (I think those were the years).

From what I've found, using the totally scientific method of my butt and the OEM guage:

The Concord 15/20, allows the engine to spin up faster than the OEM prop. This means you get to the higher HP RPM faster, and the 0-30 should improve. Interestingly I've also seen that it drops your WOT RPM by about 200-400 RPM over the stop prop, however top speed actually improves a hair (not much).

This is all anecdotal, and at your own risk. Usually people find the Concord cheaper than OEM, so it's a no brainer for cheaper and better go power.

The devil, is in the details... and no prop can (usually) boast faster acceleration AND top end... all props are a compromise between 0-60 and top end. boats, jet skis, etc.

You can't shift a boat. (at least not that we are going into here).

One prop will let your tow a skier with ease. One will give you a 80 MPH top end. Choose wisely.

as for your skis, I like to see a 915 hit 7k WOT in the water. It can be done with a 100% stock engine... but your skis are also pushing 20 years old... so you've lost 500 RPM. it's your choice if you want to dig into that, but you are missing that last 500 RPM that can make a big difference top end. I like to see the GTX touch 62, best conditions. (low fuel, downhill helps)... skinny rider. light chop.

The OEM prop also appears to have better hookup in rough water than the concord. It's all personal preference, but again you're missing 500 RPMs. Do you spend hours and hours fixing it, (and money)... or just ride the thing?

up2u.