38 Fever setup
 

I have a '99 38 Fever with 700 blower motors. Last year I ran the boat with stock Bravos at 90 mph turning 29 pitch Mirage 3-blades. At the end of last season, I broke a Bravo so I am swapping -2 Imco's. Has anyone tried shorty's on an older twin step hull like this? What happened? I am planning on running a Bravo 4 blade or maybe seeing if Throttle-up recommends a five-blade. Any advice is appreciated.

I just installed -2 Imco shorties on my single step 2001 35'. Just in the break in period now on the new drives. I'm using a Bravo 1 now and it planes easily. I won't know on top speed for several weeks and I have it labbed.

Hi Rebel Heart,
I am very interested to hear the results on the new Imco's shorties. I have the same boat and have thought about the same mod. What gear ratio's and prop pitchs are you using, and what did you have before? I have Bravo drives with 1.5 gears and was told that Imco shorties would give more speed.
TIA
David

Is a '97 35 a single step or a twin. does it have a notched transom

I run a set of 26p Hydro Quad 4s on my 99 38 Fev. 500 hps. Boat runs north of 80. You definately need 4 blades. I think there is a guy on here running shorties and 5 blades though with super results.


RAF

I would love to here from the guy running shorties and five blades. setup is still a mystery at this point. this weekend i'm trying a pair of 30 bravos. i'll be thrilled if i can get on plane.

That would be me. Here's the thread you want to check out.


http://www.offshoreonly.com/forums/s...ghlight=picked

So far the best prop for my boat has been a Hydromotive PX-5blade.

But if you are running bravo's instead of XR's then you could easily start busting drives with 5 blades and that much hp.

ohh, and be sure to watch your water pressure when you test it - mine was off the charts when I went to the -2 imco's - so much that I blew a hose off and had to install pressure relief valves to get it down.

this is a 99 with naturally aspirated 750's, 2" shorty lowers on 1:50 XR's. boat used to run around 103 104 with tricked out 14 1/8 x 32 4 bld mercury props. it ran a solid 100 with worked 5 bld maximus wheels. much better cruise and planeing time with the max's, just sacrificed top end a lil.
the engines turned around 5800 6000

Bo knows Fountains :)

how much water pressure can i safely run? the 38 that monstaa posted looks like a lightning. are the bottoms on a fever any different from a lightning?

2001 was the last year for the Fever - up to that point the lightnings and fevers shared the same bottom.

As for water pressure I was running around 25 psi at wot with the sportmaster drives. When I switched to the imco's it was reading off the guage which went up to 40 psi. One my second run it blew a hose off so I put it up for the year and had strainers and pressure relief vales installed that winter.

you should be rite around 20 psi at w.o.t . this will save your intake and head gaskets. if you run higher pressure under normal conditions when you spike the pressure, like during rentry, you WILL rupture , blow, or pop something off.
as margin said stainers with pop vavles, and air bleeds in the strainers are a must when reaching trhose high numbers.

I run 1" shorties on my 99 38 Fever... no issues. You could go with 2" shorties and add back a spacer if needed. I see 98 MPH without ever having touched the props... the acceleration is like a drag boat with 750 COBRA's. Ratio 1.35 Props 26 P Hydro 4 blades.

most people do not check there x dimension before swaping lowers, which helps to determine which length would be proper for that application.

some boats came with higher x's, therefore some have experienced major p.s.i increase when going to shorty's due to the fact that the pickup on the imco's is right at the begining of the bulet on the bottom and is about the size of your lil pinky. this causes the water to just ram in. throw into that the increase in speed from said swap and you gots big pressure.

moral of the story watch the gauge.

i wish i would have bought 1.35 drives instead of 1.5s. i could have just used my stock props!

are my imco uppers and lowers much stronger than xrs?

not really the are the same gears essentially. i have been enformed the the imcos have more strength . but i know they both buy from the same manufacturer . imco is supposed to be freezing their gears which helps the integrity of the gear itself. but i can not say for sure.

my experience with both units have been good and have similiar failures. although imcos due blow easier when you spin your engine over 6000 rpm for extended periodsd of time which decintegrates the bearings for the prop shaft and the grendade. i have seen this atleast a half dozen times.

ran the boat with the -2 shorties and 30 bravos. at 3500rpm 52mph, 4000rpm 56mph, 4500rpm 62mph, 5300rpm 86mph(rev limiters). i hate the mid range slip but the top end hookup and acceleration is amazing.
the boat handles sloppy water way better than the stock bravos. i think because i need way less trim.
i'm thinking of trying 32 bravos and 1" spacers or 5 blades. input is appreciated

the pic above is of -2 shorties and max 5 blds. handles slop and ruff like a formula one car.

i d try the 32 with the shorties.

and if you can find em 5 bld 30 max's

if i ran 86mph at 5300rpm with 30's how should i do with 32's

-300 rpm give or take and add 1-2 maybe three on the mph.

usually for every inch in pitch you add or loose 150 -200 rpm depending on prop, # of blades , diameter, finish , etc,,,,

i'm going to try 32's this weakend. at 86mph my water was 21 psi. is that to much? instead of relief valves i'd like to modify my lowers. i would like to see a picture of a inlet that has been welded or grooved or whatever works for people.

I have a 1995 38 fever with twin 600's running 30 pitch bravo 1 props on imco drives we run about 87 at 5400 on gps

Mine was over 35 psi so I had to do something to get it down. 21 psi doesn't sound bad at all.

i will post pics of the machining process that i have found to work well. basically i welded the original channel closed then machined 2 new inlet's about 1/2 inch in front of the skegs on either side.

is that a twin or single step hull

here sthose pics

Great read, I enjoyed this thread.