Grenade 10: I appreciate everything that you are advising me on your advice is worth WAYYYY more than 2 cents to me.... I consider you as one of my Rc gurus.... So please don't take my questions and questioning the wrong way.... I am only trying to learn ALL THAT I CAN ..... before I joined this forum that was all that I had to learn and go by..... I have made a lot of costly mistakes in this hobby and to be honest I couldn't afford some of the mistakes that I have made.... I am new to the wonderful world of GT... I have stood in the background and idolize GT'S for year,always wondering if I could do this..... Well to sum it up i'm betting the farm on this one.... All my chips are in on this one..... I have to learn any & all that I can.... you might say some of the questions that I ask are dumb question,I ask you theses questions because I don't kno.... I'm just only trying to learn, and the best way to learn is to ask questions right ? this is our hobby that we love so much some more than others.... you have my full and undivided attention teach on sensei ....

To sum it all up I am looking for legal race engine that is of the good or greater quality,highly reliable & MUST BE FASTER THAN A HYPER .21 8 PORT MUST HAVE PART SUPPORT (I've had this in a MONSTER TRUCK)......

These engines are bein considered

Nova Rossi .21 Ison GT
Picco TORQUE. .21 EMX-GT
Nova Rossi Flash.21 Rally PT/A
Reds Racing .21 M7 T GT
Nova Rossi .21 Kappo Rally 7 port (Discontinued part support questionable)

My Force motor burnt up and I am on the hunt for a new motor for the season. Looking for a reliable motor and hoping not to spend a lot. What would be a good choice, was considering the ISON but now reading this thread Im wondering.

I wouldn't consider any 9 ports for GT anymore. They are simply too much top with not enough bottom and at a steep price. ROAR has this one right with the 5 port. The balance of top end with enough grunt to pull the 3500 gram GT out of the corner is perfect. Given your input on durability and quality its really a simple answer. Get over to Uriah at Murnan Modified Motors and pick yourself one of his powerplants. Many racers rely on his expertise and are putting down Murnan power all over the world. I love them and Grenade will second that. You can't go wrong.

That motor is a gem. One of those works good lasts long time powerplants. You may also want to consider the Novarossi P5. Cheap but monster power. Last year I ran a Murnan Modified Novarossi CLIO P5 GT and not once did I feel like anyone had an edge on power. Perfect for a GT!

Compared to the ISON, what is the main difference?

Some food for thought at the end of the day the 7 mm venturi insert is going to be the limiting factor on all of these engines... The power loss going from a 9 mm down to a 7 mm is huge, in the realm of 25% power loss or better.... Doesn't matter which engine they all seem to be limited at a relatively similar HP by the 7 mm venture insert..... I Just got done dyno testing the new Picco GT engine and on a 9 mm its an absolute beast, but on a 7 mm its power and RPM is greatly reduced... from 2.5 HP dropping down to 1.8 HP all from the insert change... I Also tested a few Novarossi 7 and 5 ports and they all behaved the same way, every engines power was reduced substantially by the 7 mm insert.. So IMO as long as a 7 mm rule is enforced all the engines are going to be severely choked back from their full power potential... 5 port, 7 port and 9 port will all suffer equally and all be limited to a very similar power level....enforcing port count rules is kind of meaningless if they are all running a 7 mm inserts.no engine will have any real power advantage over another....

Woooooooow !!! When did this start ? How long has this rule been in effect ?

Maximo, Thanks for doing the testing and reporting the info. I had said that using the restrictor would be an easy way to tech the class, but others felt that it would not make engines similar. Question, how did the HP of the Picco GT compare to your 9 port with both on the 7mm restrictor?

ROAR rules when they were written in 2013/2014.

engine rules wll end up defeating the whole purpose they were created for.... companies will just build dedicated engines developed to perform on the 7 mm venturi and charge just as much money as every other engine....

The Picco GT makes good power..right comparable with my modified Novarossi....

Great info Maximo

And yes on every engine I have tested it on the small 7 mm venturi had the same effect with all engines ending up making very close power to each other. Which shows me the 7 mm venturi is a major limiting factor ...5 port, 7 port and 9 port doesn''t matter nearly as much, in fact the highest powered engine I have tested is a 5 port anyways..... As long as everyone is running a 7 mm venturi on the same nitro % everyone is going to be in the same boat...running their engines well below its full potential.........

Is there any rules against higher nitro ? as that would be a way to make more power with the 7 mm venturi is to increase the nitro content to 40 or 50 %.......

Does anyone know why this rule is in effect for the GT8 class ?