Sign in to follow this  
Followers 0

912 hp increase

20 posts in this topic

Posted

I have the chance to increase my horsepower from 80hp to 100hp with 100hp pistons. What are the pros and cons to this, will the extra hp beat up the gear box and crank? I am running the older 912, early 90's I believe.

Share this post


Link to post
Share on other sites

Posted

You may need to upgrade your starter. I my be wrong but check the cam timing as an 80 and a 100 may have different timing. Also an 80 is around 81 hp where a 100 is 97 hp without the air box which won't fit a 4. The gains may be negligible ? I looked in depth at the same issue when my early 80 hp became due for replacement, I can't comment on high DA ,but under 3000ft a 4 is a rocket with an 80!. A zipper kit was on the cards once the warranty had run but looking at how well the 80 goes I am going to leave well enough alone! At the recent national STOL comps I was out performing most of the 180 hp Cubs on takeoff!

Share this post


Link to post
Share on other sites

Posted

I guess the extra horsepower would allow me to have bigger tires and not sacrifice my airspeed?

Share this post


Link to post
Share on other sites

Posted

I guess the extra horsepower would allow me to have bigger tires and not sacrifice my airspeed?

Not hard to talk your self into it huh?

Share this post


Link to post
Share on other sites

Posted

I believe Larry recently commented that he had over 400 hrs on the 105 HP zipper kit in the Mangy Fox, and is very happy with it.  I've thought about sending them an engine as well, but haven't done it yet.... Tempting though.  JImChuk

Share this post


Link to post
Share on other sites

Posted

I would not put ULS (OEM 100 hp) jugs and pistons on an old UL.  The higher compression will tear that engine apart.  You'd be better off with the low compression kit that I used on my engine.  Much less stress on the (weaker) cases and bottom end of the engine.

2 people like this

Share this post


Link to post
Share on other sites

Posted

Thanks Larry, that's not what I wanted to hear but that's was I wanted know:)

Share this post


Link to post
Share on other sites

Posted (edited)

Hey firefox, I went fron a 94' 80Hp ul to a 107Hp uls spec...

I chose to replace the 80hp cylinders and pistons with 100 Hp rotax pistons cylinders (uls spec) . In order to accomodate the higher stress on the crankcase I had the original case machined to have the through bolts mod installed to prevent case fretting. Also to use your 80Hp heads  you need to machine them to fit the 100Hp rotax cylinders. I also have a high performance camshaft from edgeperformance/norway.

Here the coordinates of our canadian dealer...http://badasspowersports.com/badass-shop/performance-camshafts/

here the edgeperformance website  https://www.edgeperformance.no

Last and not least, you have to change your ignition rotor /pick ups to the different 100Hp spec..+ you need the stronger starter motor..

 

Edited by flywise
1 person likes this

Share this post


Link to post
Share on other sites

Posted

Even with the Zipper Kit and others there have been failures with the older engines.  Hal of Zipper fame will not buy the older UL engines for up grade pre 2006 if I recall.  I would give Ronnie Smith at Mississippi Light Aircraft a call they also sell a low compression upgrade kit he or his son will give you the actual serial number cutoff for the older engines.  Maybe if you go the route that flywise suggests above it would be okay but why not pickup a good used ULS and go fly.  All that said I do have my used Zipper kit that I will sell that I had on my early 90's UL for $2500 USD. It has about 200 hrs on it but I would have to look back at the logs for the actual number of hrs if anyone is interested. I lost confidence in the upgrade after a friends engine failed within fifty hour of installation ( Larry's old plane and engine that we upgraded after my friend bought it)

There is my nickel worth.  I  bought a new ULS after I lost confidence in the upgrading the old engines.  If I had a later model UL I would still be flying the Zipper.

 

 

 

3 people like this

Share this post


Link to post
Share on other sites

Posted

Even with the Zipper Kit and others there have been failures with the older engines.  Hal of Zipper fame will not buy the older UL engines for up grade pre 2006 if I recall.  I would give Ronnie Smith at Mississippi Light Aircraft a call they also sell a low compression upgrade kit he or his son will give you the actual serial number cutoff for the older engines.  Maybe if you go the route that flywise suggests above it would be okay but why not pickup a good used ULS and go fly.  All that said I do have my used Zipper kit that I will sell that I had on my early 90's UL for $2500 USD. It has about 200 hrs on it but I would have to look back at the logs for the actual number of hrs if anyone is interested. I lost confidence in the upgrade after a friends engine failed within fifty hour of installation ( Larry's old plane and engine that we upgraded after my friend bought it)

There is my nickel worth.  I  bought a new ULS after I lost confidence in the upgrading the old engines.  If I had a later model UL I would still be flying the Zipper.

 

 

 

Hey Wypaul,

I do agree it would be much simpler / better to just buy a good used ULS....but for me after searching for 2 years I could not find a good ULS below 11'000USD and hence decided I'd try to get my old  / low Hrs 80Hp up to spec. The mods I mentionned earlier cost me a total of 5200 USD which I could afford. In the end, If you have the cash get a ULS, if your half poor like me, maybe try and mod your 912 UL :)

1 person likes this

Share this post


Link to post
Share on other sites

Posted

Or I could just go and fly the 80hp I have, it performs just awsome the way it is;)    

Thanks for the replays everyone, I will keep studying it though, I might come up with something that works. 

Does anyone have any experience with IVO's IFA props? Just curious if that would allow bigger tires and keep my airspeed?? 

Thanks guys

Share this post


Link to post
Share on other sites

Posted

Wypaul, is your Zipper kit the 1484 high torque kit? I might be interested 

Share this post


Link to post
Share on other sites

Posted

There is a never used 912 ULS 100 HP on barnstormers for $14000 right now.  I emailed for details and pictures but have not heard back yet.  JImChuk

Share this post


Link to post
Share on other sites

Posted

There is a never used 912 ULS 100 HP on barnstormers for $14000 right now.  I emailed for details and pictures but have not heard back yet.  JImChuk

that'd be a good buy for someone.

Share this post


Link to post
Share on other sites

Posted

Wypaul, is your Zipper kit the 1484 high torque kit? I might be interested 

Yes it is.

Share this post


Link to post
Share on other sites

Posted

I called Ronnie and he said if it's an early 90 model he said bumping it to over 90hp is gonna tear the engine apart

Share this post


Link to post
Share on other sites

Posted

There you go!

Share this post


Link to post
Share on other sites

Posted

:othats about what I payed for the whole bird:drool3:

Share this post


Link to post
Share on other sites

Posted


I have an IVO IFA on mine with a 912 ULS and the 114 Zipper kit.  I can cruise at 95 mph  with 30" Airstreaks and an extended wing with the undercamber HH ribs. With the same prop on the Subaru 100 hp that was in the same plane and same set up it would cruise at 85 mph.  You still need the added HP to increase your cruise speed and you can do the same thing with a ground adjustable prop; you just can't change it in flight, so it requires you to compromise or decide between if you want to get off short or cruise fast.

1 person likes this

Share this post


Link to post
Share on other sites

Posted

Like a GOOD friend on here told me, KISS, easy to get caught up on the goodies out there, i did the same on goodies in the begining, but heck man just give that yellow girl a GOOD tuneup, keep it running its best, keep it clean, best bang for ur buck is lighten it up, (i killed 31lbs off on my first KF from previous owner) , and reliable, and shove as much gas as u can thro her. Far as tires those r up to the pilot and what he thinks he can or cant do with them, but ill bet those desser smooth 8.50x6 tires work most places and the not eat up airspeed.  

But dont forget just my opinion, im still in training,:bugeyes: hahahahahahaaaaaaaa

Randy, if u have to choise, i say get off short, i can enjoy the longer trip a little longer in the air.  Hahahahaaaaaa 

1 person likes this

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0