-2 Lowers
 

Anyone running -2" shorties on a 28 Cyclone? Looking for feedback.

curious too, i'm sure i'll be blowing up my drives soon and need to replace them.

Just upgraded to XR gears and in the process found out they were 1.36 when I bought the boat. It explained many of questions I had regarding RPM, etc. We are converting to 1.5 with the swap so I know that will dramatically change things but was wondering the ideal drive height.

I have -2 Sportmaster lowers on my 28 Saber now. I've been running them for years. I tested with a set of -2 imho lowers and they were a couple (2) mph faster.
Standard lowers were way low on my boat, that is why I opted for -2 shorties.
Any other questions?

So it's been a while since any discussion on this. I have completed engine builds and converted the drives to XR hears with Drive Guardians. Like FunHome I feel my drives sit way low, I have to trim to between 6 and 7 for top end and they sit way deep, Not that I'm looking to, but the boat could not kick a rooster trimmed up if I tried they are that deep..
I'm thinking this is a winter projects just checking to see if anyone else has experimented.
Thanks in advance.
I'm currently spinning a 32 Bravo 4 blades with a 1.5 if I don't go shortie the props need a massage to pick RPM to where the builder wants them.

i actually talked to doug about this a month ago. he didnt think going to shorties would make much difference.

on a different note, swapped my 27 pitch 3 blade mirage props for 29 pitch ones. boat wouldnt hit 90 (93-94 before) and the whole boat shuddered when turning corners. were they overloaded? my motors turn 5600 rpm with the 27's but would barely break 5000 with the 29's.

I would listen to Funhome. Think he has the fastest twin 28 currently.

I have always thought the drives were really deep on the 28s.

ballistic and mine both run 90's with stock drive height. i think funhomes is in the upper 80's.

I'm running low 90's now with a best of 93 GPS 91 and 92 depending on the day.. They do seem deep and was thinking shorties over the winter.

As deep as they are I'm not sure if I will pich up anything. I guess thats why I'm asking don't want to spend useless money.

I'm running 85-87mph with my 450hp Small Blocks and -2 Sportmasters lowers that I have had the skeg cut down to more like a imco lower.
My Prop Shafts are still 3in below the bottom of the boat, I would like to raise them even more, like an inch or two...
That would take -3in Shorties or raise the motor and drives up this winter, then I could use spacers to bring it back down if need be.
I've run these speeds (83-87) for 15 years at the Shootout, and I've made it a goal of mine to get my boat to run 90mph at the Shootout.
Right now I'm running 30p labbed 4 blades, 1.65 gears, 5950rpm, 87mph, with a 15% slip.
Prop Slip Hering Propellers
I'd like you guys to post your set up so we can compare.

My Lowers
 

https://cimg8.ibsrv.net/gimg/www.off...efb2fe385d.jpg
3in Below bottom of boat.
https://cimg9.ibsrv.net/gimg/www.off...b5bdb878a9.jpg
Sportmaster -2in lower with Skeg shortened a little.

wouldn't you measure from the bottom of the running surface, looks like about 1.5 inches

i think i posted this before but i talked to doug and he didnt think it would help much.

I have to measure the depth compared to to the hull. I am running Bravo drives with XR Gears 1.5 spinning stock 32 bravo 4 blades at a best of 93 usually 91. Prop slip is also near 15%

I noticed a improvement from going to a Shortie from the Standard Length Lower. I also saw an improvement when we cut about 2in off the length of the skeg.

The tape is up against the bottom of the boat. (The lighting was bad so it doesn't look like it is.)

Are you measuring from the bottom of the Transom assembly?

No, I am measuring how far the front of the torpedo of the lower unit (which also would be the center of the prop shaft) is below the running surface of the boat, directly in front of each the outdrive.

Picked up a nice used pair of Imco SC drives with -2 Lowers. I guess we are going to find out!

Going back to this subject
 

I have upped my HP this year to about 720 per side. I'm running -1" at this point. Will probably get in the water in a week or so. Does anyone have anything else to add. I'm contemplating going back to standars length as I don't think -2" was of much benefit. I may play with props at -1" that I have now just to see. All calculations say should be just about the century mark.

That seems strange that you didn't see an improvement with the Shorties. My Drives must have been deeper to begin with than yours...
That is huge power! You should see well over 100!! Good Luck!
(BTW, I tested a month or so ago with a set of 5 blade Maximus' and it jumped on plane and ran flat with the same speed! I'm use to having to trim it up quite a bit to get a peak mph, the 5 blades were amazing with the control they gave. The driver I had with me said it felt much more in control the entire time.) So I'm looking for a set...

I get my 36s back tomorrow from BBLADES, the goal is to test again for baseline and see where we are. I'm expecting more RPM and speed but still high slip. We are them going back to standard length and testing again. We should be where I want or may send back for a final quick tweak from BBLADES.
The next week should be very telling. I have considered 5 blades but it planes amazingly now, basically no bow rise at all. I can only trim to about 6 now with mechanical indicators and it slows down over. I'm hoping to get a little more trim with depth and lose slip. I worry about 5 blades being hard on a drive.

got my -2 imcos less than one hundred hours ago and one has already **** the bed. 650 hp, only been on elk and torch lakes, no big air shots on lake michigan etc. royal purple gear oil , easy planning, less than 1 hour i'm guessing between 80 and 94 mph. having mr. gadgets redo it. if you are switching back to std. lowers and want to sell the imco's let me know.

I still am running the IMCOs but added 2" spacers to take it back to standard depth. It definitely runs best there. I am spinning 36s tweaked by BBlades. Mathematically should run faster but after talking to Brett and Doug we have determined that Hydrodynamics is beating HP. Has so far run a best of 97. That is about 20% slip. We are at 12% slip at 75 mph. So it's losing to the Hydrodynamic side.Maybe try running the Drive Guardians, they are definitely drive saviors for me. I'm making 720 HP per side. I'm on short lakes so I will take the quick that it has and I know 97 is nothing to sneeze at, just won't break the Century mark!

maybe i'm just not sensitive or dont pay close enough attention but i didnt notice much of a difference with the imcos, good or bad. handling and turning feels the same . maybe a mile or two at best. spin getting on plane, no big problem. look cool!

all this stuff gets confusing and expensive really quick.

there is a 28 called "ballistic" that runs some big power, curious what his set up is?

when you say runs best at std depth are you talking top speed, planning, mid range?

After way too many changes and stepping it back one at a time yes, all of the above. It overall drives best at standard depth. The only good part about my lesson was that the -2 drives were used and all I had to spend additional money on was putting them back -1 first and then to standard. Like I say spinning 36s at 5400 and 1.5 drives.

Not trying to be an a$$, just a heads up. RP may be your problem for premature failure. There's a couple threads on how fast new gears pit when using RP.

i hope not! that means i got another one on the stb. side to worry about.

mr gadgets didnt think the rp would cause the problem. guess i'll know in a few week when i take it apart.

I would not say the IMCOs made much difference in drive ability, I will say they are a stronger drive or at least built better. Same XR gears but cooling etc is different. Mine were used and had -2 lowers. Back to standard is what my boat needed. Talking to Doug and Brett I just don't think there is much more speed in this hull. I've heard 800 more HP only running 4 mph more. I'm not doing that.

Are you doing anything for a windbreaker or just roughing it out with 100mph wind in your face? I am going to start on having a custom windbreaker built so am curious if you are using anything and, if not, might could have an extra one built if you or anyone else wants one. Was going to have built one similar to ones used on newer cigarettes and other, basically a clear 4-5 inch lip over the full width of the fairing.

Toughing it our so far. Would definitely be interested.