Z3 engine

[Palle Man]

We are going to be upgrading to a Z3. Would like to know if anyone is running above 3500 feet in elevation with the raptor 400. Dealer is trying to upgrade us to the 440. According to what wake9 and a few others, the 400 fuel consumption is awesome. We run at 3500 to 4000 foot elevation. Dealer is telling me that it won't be enough power at our elevation. We surf 90% of the time.

[Z1Fan]

Hmmmm sometimes you can compensate for High altitude with a prop change, but I am of the opinion, there's never enough horsepower

[boardman74]

Now keep in mind the ONLY difference in the 400 and the 440 is the ECM. Thats it, change out the ECM and the 400 becomes the 440. I remember it being a big jump to the 440 and I thought it was crazy considering it was just a ECM change.

[Z1Fan]

Now keep in mind the ONLY difference in the 400 and the 440 is the ECM. Thats it, change out the ECM and the 400 becomes the 440. I remember it being a big jump to the 440 and I thought it was crazy considering it was just a ECM change.

Its all about timing and fuel adjustments, when I advance the timing on my 68 dodges ignition, I get a substantial power increase, but along with that comes the possibility of detonation etc.. But with computer control... That becomes a thing of the past, .....
But curiosity does the 400 run on just regular unleaded and does the 440 require premium?? Just asking...

[Palle Man]

Unfortunalty, I have discovered that running at higher elevation, we pretty much need to run premium all the time. 87 octane just doesn't cut it.

[Z1Fan]

Unfortunalty, I have discovered that running at higher elevation, we pretty much need to run premium all the time. 87 octane just doesn't cut it.

Interesting.....

[Palle Man]

It's probably the prop we are running I guess.

[Tomp]

To gain both speed and hole shot power it takes more HP, usually allot more to make a noticeable gain at both ends.
I would say the propeller is all you may need to play with, give up a few mph for allot more pull.

Like first gear compared to second gear in a car.
The standard propeller 15 dia 12 pitch should be fine?

[tonka8ty]

Octane does no good at higher elevations unless you have high compression. The lower the elevation the more octane you will need. So those of you running high octane at high elevation are throwing away money. It works bolth ways to much octane will loose horsepower if you do not have high compression. Higher octane fuel burns cooler

[dilpickle]

Octane does no good at higher elevations unless you have high compression. The lower the elevation the more octane you will need. So those of you running high octane at high elevation are throwing away money. It works bolth ways to much octane will loose horsepower if you do not have high compression. Higher octane fuel burns cooler

This would be true all other things being equal, on engines with a distributor (5.7 would be the only engine used in our boats recently that still has one of those). However, one of the other things we see at elevation is the actual octanes are reduced compared to our sea level brethren. Here (5,300 ft.), our fuel octanes are 85, 88, 91 for regular, mid grade & premium where they are 87, 89, 93 closer to sea level. More octane resists pre-combustion (detonation) & allows more timing to be used, this allows the engine to reach it's full potential. Running less than what is called for in any of these engines (89 in my 2014 Indmar, this is premium at my altitude) will allow detonation & the ECM will pull timing back as a result-this will not cause any great deal of long term damage, but will reduce the power available to you.

My 350 HP @ sea level is only 295 under ideal conditions here, I'd like to be able to use all of them. The other downside to using less than spec fuel is loss of efficiency due to less than ideal conditions. Take any newer vehicle that calls for 88 octane & fill with a sub-par fuel & you will see a measured drop in fuel economy-my history has been somewhere around 10%. If you are not paying @ least 10% less for that fuel, you are essentially paying more per mile to have less power.

I'm not sure what you'd consider high compression, the 5.7 GM is the lowest used in newer boats @ 9.4:1, the Raptor is 9.8:1

To the original poster, I think you'll be fine with the 400-it is essentially the replacement for the previous 6.0 GM engine. I demo'ed a Z3 with that engine & a 1235 prop with the equivalent ballast of the surf XL package in Denver, some 15-1800 feet further up the mountain & that setup had no problem at all. With the tractor pull prop Tige is spec'ing now, you should not have any issues either.

[Palle Man]

i work offshore and I am gone for three or four weeks at a time. That is the main reason we use premium with no ethanol. Don't like leaving it sit with low grade fuel. Thanks for the help though. I think we will roll the dice and go with the raptor 400.

[Z1Fan]

i work offshore and I am gone for three or four weeks at a time. That is the main reason we use premium with no ethanol. Don't like leaving it sit with low grade fuel. Thanks for the help though. I think we will roll the dice and go with the raptor 400.

Good call... Think you will happy!!!