justin29cccat

58' Venom cat carbon fiber reinforced hull and tail.

Since mod g26pum are more expensive to repair and replace parts when one hits the fan.

**Performance Unlimited sells a new for 2010 Dominator Zenoah 29cc 6.7hp and 3 ftlbs torque
($595.00 g29pum with big bore 4 bolt cylinder, 36mm cylinder, stock crank for rpm and so on.)

**Quickdraw 25cc 7.5hp and 2.5 ftlbs torque $900 to $1200.00

**Quidraw 35cc 8hp$1,500


What do you guys think is a good choice for a reliable fun motor, i dont race as of yet.

FlogginHarvey

Hey there...looks like you are planning a fun cat! If you are thinking 35CC then another consideration might also be the J&G Racing Engines 35CC with mouts, pipe, etc $1,600. The build and machining quality on teh J&G is hard to beat and both companies have GREAT customer service and support I have experienced so far.

Both the QD and J&G are liner-based motors which i have read is a big plus for service-ability and long term ownership if something needs replaced down the road. With proper maintenance and setup (props) they last forever. I know a guy here that has 10 year old QD HR when they were still sold as kits only. They still scream...up-keep is EVERYTHING.

With the QD 25HT, the 35CC, 29cc Dominator, and the J&G 25Hemi and 35cc you have some GREAT choices. I have a Hemi in a Rico Mono right now waiting for the water to thaw and a 25 HT I am planning on putting in a PPB/ClassONE Skater Cat later this year when it comes to market...

I am not toally sure, but I think the J&G 35 might be a little lighter than the QD 35? The J&G is rated at 7.8hp at 16,500 where the new A5P QD 35 is rated at 8hp and 18,000 RPM. The 35's are a bit more RPM sensative and require a bit "taller" props and do not like to be over-rev'ed with teh peak power being more so torque vs higher-rev'ing all-out hp.

I wish I had some running expreience to report today but am VERY much looking forward to playing and tuning in motors later this spring.

There is a cat with twin J&G motors for sale that has yet to be finished and run on another forum...I wish I had the money right now. Please keep in mind that the QD and J&G motors are full out race motors and need a little extra daily care and maintenance after running each day (spraying Rustoff in the heads so the liners stay in good shape long term) and you will definitely want to use a good after run oil in the cylinders and case as well like you would on a high perf lined nitro motor for longevity.

Not much specific help but some good gernal info...I hope it helps. Keep us posted on the project!!!

How much power/speed can the Vern Hulls handle? I would think these motors will take it to its limits? The extra weight of the 35's might help keep it on the water in rough or windy conditions...?

Most of the maufacturers supply detailed spec info on height or if not available I bet the proprietors' would be happy to supply the specs so you may find what fits and will work prior to pulling the trigger and spending the money...just a thought.

EDIT: is this a Venom King of Shaves hull? You might reach the limits of the running surface with a full-up race motor? I might try a RCMK EVO for this one to start with. GREAT power for the money and an honest 5+hp out of the box. I think you will be surprised...I have been

mistycreekboats

My Feedback: (1)

I would try the RCMKevo - a QD might be a bit much for this hull, fairly light. there is a few Venoms on utube with a RCMK just do a search. A friend in UKhas one.

http://www.youtube.com/watch?v=QZrsG5pCW-sthis one is from a friend Wayne ANdrews - email him and ask him what he thinks of the boat with a RCMK in it

Have fun

apache 56

mate stay well clear of that performance unlimited crap......... we tryed one on a large cat and it was slower then a stock motor. that guy works the motors to the extreem . in other words over ports every thing. yer he reconds thay run good on a dyno but you put it itnto a large boat and its a nother story..the motor i got from him was a throw away job, dont wast your monney unless your putting it into a realy small hull then it may work......the motor he sent me had snapped key way when delived, carb was secondhand, the exaust port bolt holes were stripped out. once wa got it running it had no bottom end ,and was very hard to start....and keep tuned/running...
there are far better motors out there
one more thing ive never seen anny one on these forums say what a great motor thay are stay well clear of them.
for the price he wants for that you can get a rcmk and have lots left over...
or have a jg ,or qd and never look back....

gtopillado

RCMK Evo. I've got a QD HT in my cat and she's tough to drive at full speed (but fun). I've seen a boat like yours run at our lake and it performs well with a slightly mod Zen. RCMK is the best bang for your buck.

jaybird11

Not sure what the guy above got but I'm extremely happy with Performance Unlimited. RCMK engines are junk compared to a Zenoah. Performance has modified all my engines and I have never had a problem. Hard for them to test your motor in the water when you have the boat they have to use a dyno. Just a prop alone can make a ten mile an hour difference and you can 't run the same prop on a stock engine after a mod. My RIO 51 did 45 mph then took it to performance and had the top end done and carb now the boat does 58MPH. Performance stands behind there work and I am very pleased with them. Capt Jay. PS I have four boats modified by Performance Unlimited www.zenoahmodifiedengines.com
Check out the U Tube of my RIO 51 http://www.youtube.com/watch?v=TLZKe...eature=related

HendricX

I serious think you are mis-informed ;-)

ONLY part of a Zenoah that is better as an RCMK is the ignition. :-)

Scott Schneider

Have too agree with that !!
Nothing per-say wrong with Zenoahs at all ... Just the RCMK's are much tougher and better build quality across the board.

SS RC Boats

[quote]ORIGINAL: jaybird11

RCMK engines are junk compared to a Zenoah.


You are the first person i have heard say that about an RCMK and i dont even own one! Have been told by many owners that they are actually built tougher than Zenoah,just have a minor issue with the pullstarts in which some owners are putting Zen pullstarts on them!

HendricX

Due to the tighter clearances of the RCMK-starter ... if used a thinner enginemount as the original RCMK has ,

this will cause the pullstarter to 'stuck' (and destroyed when keep pulling).

Simple spacer-rings will prevent all this.

On a Zenoah it's the other way around ,

using a 8mm thick mount(MTC / MTL) , will prevent propper engaging.

So you need to mill the starter INTO the mount.

Tahoe1970

Theres no RCMK nor Zenoah that makes 3lbs of torque Period. QD's newest Pioneer doesn't even touch 3lbs of torque.

SS RC Boats

Guess that means a lot of false claims from Zen engine builders that rate their big bores @ 3ft.lbs. of torque. I can't say if they really produce that much torque since I don't have a dyno to test it on but my big bores do have WAY more torque than my QDht motor,which is the same power rating as the Pioneer motors just a more useable powerband. My father does have a Pioneer 26 and I'm waiting for my Pioneer 29!

brodjack

Depends who mods the 29's,my top end UNlimited Performance kit had no bottom end either,and was real picky on props.
A pal did another 29 head mod and pulls almost any prop at all good rpms,even on big boats..

Performance Unlimited

Bibby-
It depends on your setup on how an engine will perform in any type of hull. Pipe length, cg, carb setting, strut angle and prop not to mention the type of hull. Just installing a top end kit and a carb on a used case can cause issues since the bearings and seals being worn. There is a lot more than just bolt on and go. It sounds like your pipe tuning length was too short, since the 28.5cc kit / engine has plenty of torque for a 57" boat to go over 50mph...you are the first complaint out of 300-400 customers about the 28.5cc kit. You should of contacted us so we can get your issue resolved rather than complain on here a year later. You sent me numerous emails a month later about what should this and that should be if you put in a 2mm stroker crank with the 28.5cc modified kit and I told you that the timings will change and when that happens so does the power curve of the engine. We work with many, many customers that want to try different modifications and customer service is paramount, We are only an email or phone call away for any questions or concerns.

[link=http://www.zenoahmodifiedengines.com]Performance Unlimited[/link]

brodjack

didnt realise i was complaining[X(],this is a public forum and as such just stating a fact on another guys thread what your topend kit did.
I am fully aware that setup is the key to speed and performance.
Seems strange that a friend modded topend put about 10mph and much more low end grunt as your topend kit on the same bottom end.

Like it or lump it,that is a fact

Performance Unlimited

You are correct about a public form and you can make a statement either positive, neutral or negative. with that being said my point was you never contacted us that you had an issue with the kit your only contact to us was below:

From:
Brod (broderxxxxxxxxxsky.com)
Sent:
Wed 11/03/10 7:10 AM
To:
Performance Unlimited ([email protected])


Thanks for the quick reply,suspected the timing would be all wrong with a 2mm stroker crank,i have a stuffed crank i will use with the (Your) supplied base gasker on the 29 head.

I will report performance(if any) changes over the present stock crank..

It is fitted to an Expresscraft 60" MTI cat..

regards.

Brod..

On Wed, Nov 3, 2010 at 1:10 AM, Performance Unlimited <[email protected]> wrote:

Brod-

All the timings will change!
The head needs to have the combustion chamber raised for the piston clearence at .020". As well as the cases need to be machined to accept the 2mm Crank.
Just installing the crank there isn't enough room at the top and the piston will hit the head.
Exhaust timing with that modified 28.5cc cylinder will be high over 188* and the piston skirt will come above the bottom of the exhaust port quite a bit.
Intake timing will be high as well..over 165*

Your better off putting a 1mm stroker crank and using 2 standard cylinder gaskets or get the top end kit for 30.5cc, which is not listed on the website.
30.5cc Top end Kit less crank $395.00 with crank $445. + Shipping (Continental US $8.95 International $43.85)

Les Smith
Performance Unlimited Products
RC Racing Engines
When Performance Matters
www.PerformanceUnlimitedProducts.com

So with your intended application made the timings too high and that is why it had low torque, so you did something that caused the low torque issue and it isn't a problem with the kit since the timings are for a stock stroke and you were informed and aware of the change you did and you never got back with us... Like it or Lump it that is the real fact!

brodjack

Like i said i wasnt complaining then or now.
I was toying about fitting a 2mm stroker crank to your topend kit,and asked if it would work,which you stated no,as in the above post.The idea was to maybe give the 28.5 topend kit a bit more torque,for such a big boat as the MTI cat,which after your advise i didnt go down that route..
Instead i sold the kit to a mate.Another good engineering pal then purchased a stock 28.5 head and piston and milled out the porting/piston etc to his specs..this combination DID give me better power and performance than your kit,FACT,same boat,same crankcase/crank,same pipe,same carb.

Again not complaining or argueing,i dont online,just stating some simple facts.
Maybe other guys have better results with your topend kits,i am sure they do,its just mine wasnt as good as the other one i tried......i wasnt then or now that bothered as i have bought lots of other much more expensive hobby parts and some have been great and some not so great.Thats why i didnt complain to you..i can afford to just start again
Why did i post on here? like we agreed its a public forum for help and advise,either good or not so good...[8D]... i like to hear all of it and i'm pretty sure most other guys do....