On road engine at GT car?
 

My dear friends i was thinking about install a Novarossi N21-7T in my Gt car.
My first question is that do you believe i will have problems with temperatures due to the smaller cooling head?
I know that there is also the N21 rally model of this engine with a proper head but the on road has 1500 RPM more than the rally model.
I hope any of you had already experience of something like that.

P.S. Do you believe that 7 port is too much for rally game. It would be better to go for a 5 port?

Go with the N21R7. It has plenty of power and the bigger head. 7 port engines are fine for GT cars if they are set up correctly.

Thanks for the answer buddy. What if i can find the on road engine almost at half price? Do you believe it worth the effort? Will i have problem with over heating?.
At the pictures you can see the fitting of my current engine (LRP 28) with Bysm lexan

You can always ask for an used offroad head. Engines comes and goes so there must be used parts available.

I would seriously consider the fuel you will be running as well. Perhaps Roelof will add some input but I would take a guess and recommend you run a lower oil content and run it rich to aid with cooling. If you run a high oil content and rich you will very likely damage your bearings quickly trying to compress a wet oily mix. Perhaps even 16% nitro too...

With your wheels spinning in rally and not much ventilation she will get hot.

Also the tuning will make all the difference, perhaps running a richer bottom end and run a smaller venturi to restrict the amount of air at lower rpms, which all then has to beg to question, why run a hi-performance Hi-RPM On Road engine?

I'd still go with a NovaRossi, the metalurgy, build and quality will give you reliability, it will be a better and longer lasting investment, providing the application of the engine is setup to the conditions you want to run in.


These are just considerations I would have, dont take any of it as gospel. I'd want more experienced engine ppl to give you the heads up than me.

So dear Blis if i understand right you believe that i will go hot with N21-7T.
I had the hope that two slices of aluminium couldn't give such a big difference
Of course i haven't mind to run the engine richer in order not to get hot.
I want a well performed engine and not intermediate solutions.
I run Byron Race Gen2 25% nitro 11% oil.
I read a lot also at igtforum and some the guys there run some on road engines on GT2.
They didn't mentioned something about temperatures. On the other hand no one told that they were cool.
My last question was what if i replaced the head with another one from rally or from of road engine, as Roelof said.
The 4 holes at the head are the same at some Nova motors. I mean the pattern-distances of the holes.

My point is that a rally car is like a nitro drifter, the engine is revving but there's no air passing across the heat sink. A can am on-road car has it's heat sink totally exposed all the time and it has a lot of air passing.

Im not an engine guru by any means of the imagination but this is simple common sense. And for any air cooled engine that is wheel spinning you will need to use the Methanol in the fuel to cool it down.

But please consider, that a good quality NovaRossi will be a lot more reliable! Regardless it's how you tune it for the conditions and if you wish to look in the Off-Road Engine thread there is a very strong discussion regarding fuels. No one fuel is perfect for all conditions and I believe this is a critieria you should factor into your decision process. Gearing will also play a major part in the strategy, once again completely dependent on the track.

Yes I've strayed from the original post of "which engine" but lets not discount the application of the engine which should have a strong bearing on the decision.

I´m not sure how the N/R-Basic engines are designed, but if there is a rough anodized surface on the cooling head where it meets the head button you could sand it smooth and flat to help-out with cooling.
Sometimes a little thermal compound for computers can get the job done also, but that´s sort of a last resort. :tire:

Then regarding if "two slices of aluminium" can make that much difference, I bet there is a difference in the diameter also... (and I get it to 1 slice of aluminium... :) )

Yes you are right. It is only one slice the difference and the rally head is bigger 5mm at diameter but i think it has bigger gaps

Onroad engines are well used in GT cars, even with onroad heads. I do not know about the setup but I can imagine that an onroad engine needs a lighter gearing.

I fought this last week while tuning for my last tanks of break in on my kangaroo. At 265* the engine ran like crap but at 300* it was a beast, sounded and felt like it was right. Thought it was my temp gun but every gun was about the same. So as a last resort I put an off road head on the engine and with no. No changes in tune the engine went from 310* to 220* and fat as a pig! Leaned it out almost a full turn and now it's a demon! So IMO the GT cars need the larger heads to be efficient. The flipside to this could also be the body you run, the locals that run the short alpha bodies and the same engine don't seem to have this issue. I am running the Audi LM body. But I still think you can't go wrong with the bigger head.

Ok So the worst scenario is to go for a replacement of the head.
Could you indicate me what heads could be compatible for this crankcase?
I was thinking something like king headz.
Somebody could write me down the distances at the 4 holes of the head?

Head
 

I run a p5 head on a 35+21 .

I looked on their site and they have replacement heads for RB (like S7) engines. RB is made by Novarossi and is a direct fit.

Can i ask something more in order not to open a new subject?
I was looking at kangaroo and kappo engines of Nova and i can't understand why they cost more than a N21-7T when the specs are lower?

N217T
N21R7
KAPPO21

They are similar but not the same. N21-7T & N21R7 use the same block and crank. The KAPPO21 has a better crank and block. N21R7 & KAPPO21 use the same piston/sleeve. The N21-7T uses a different piston/sleeve. Same bearings & rod in all three.

Exploded views

http://www.novarossi.it/2012/images/...va/KAPPO21.pdf
http://www.novarossi.it/2012/images/...nova/N21R7.pdf
http://www.novarossi.it/2012/images/...ova/N21-7T.pdf

Hope that helps

It is a commercial thing... No racer would buy an engine saying "basic" or "stock" and no driver (on all levels) with a limited budget will buy high end engines.....
I do run the N21-5T but I do modify them. Out of the box it is already a good engine and after some modding they are as good as any other more expensive engine. The basic engines are made a bit slower through timings, a smaller hole in the crankshaft and missing optical things like a silicone insert.

Thank you my friend for the definitions. I saw the details of each engine but through the pictures i wasn't sure for the similarity of some parts.

Roelof i understand you exactly....... ;). I need my friend some pictures of your modding. Really if it possible i would be grateful.

About the differences i realised that there is somewhere fake specs on behalf on NOVA.
I mean it is not possible to add at a basic engine some exotic materials and technologie of NASA and still it produces the same HP and RPM.

Something else that i realised is that the expensive motors have installed carbs with single needle on the contrary with basic engines that have two needles.
Could someone explain me the the benefits pastic vs aluminum carb?

Hey bro I just bought a novarossi 35 plus 21 that's going in my gt I really need to get a bigger cooling head?

Hey buddy probably you will find it out earlier than me. In fact my engine is on its way.
But it believe the answers above were enough for me to understand that it would be better to work out with a bigger head.
I recommend to go on with the run in of the engine and then you will see how the performance and temperature are.

I just went through the same thing again yesterday with my XZR speed. It runs too hot with the stock head so I am swapping to a larger one today. It wasnt as hot as my nova but still too hot to tune properly.

Did you have the same problem running without body?
What was about the temperature?

290 body on 210 body off

Hmmm for this season it sounds high with body on. What body did you use? Enough holes on it? Which head did you used as a replacement at OS?
These temps was for Nova as it came from factory, for OS factory or OS with replaced head?

Do you have only an opening in the front window or also one in the rear? (which is needed).

And what plug are you using? The OS XZR wants to have a RP7 or even a RP8 plug (R7), if you are using offroad plugs like a nr 5 or lower then that can also be the cause of the heat.

And sometimes a different exhaust can make a difference in temperature.

legal holes on body, tried with the entire rear window out and it made no difference, enlarged front hole and it made no difference either. I have a Red Alpha head on the OS and A GO engine head on the NOVA. The Nova temps were way higher and that is expected because the head is smaller than the OS head

It actually ran cooler with the rear window solid than without it. I made the window removeable and tried it back to back both ways.

Running a RP7 plug but have an 8 ready for homestead.

All pipes were the same 2050, 2052 and even tried an RB off road pipe

Only thing that brought the temps down was simply a bigger head
I wouldnt think that any small thing would make up 100 degrees!! the NOVA went from 310 to 210 and the OS went from 290 to 230 ish but i wasnt pushing the car nearly as hard as i was the NOVA and the OS was on break in mode with no second gear shifting. I thin it just boils down to needing a bigger head. these engines are designed for Pan cars that have the engine head exposed and GT cars dont. Before i switched to the onroad engines, none of my Off road engines had this problem and with the bigger heads they run perfect. When i went to the bigger head on my NOVA i went immediately one full turn lean on the HSN and it was still a little fat!
http://i770.photobucket.com/albums/x...x/IMAG0184.jpg
http://i770.photobucket.com/albums/x...x/IMAG0183.jpg
http://i770.photobucket.com/albums/x...x/IMAG0172.jpg

Wow well what head will fit my novarossi 35 plus 21?
I don't want to ruin my perfectly new motor :-(

So far all of the bolt circles have been the same, I think the Nokia's are pretty close to the same just get the head off if an off road nova engine. As long as it sits flush with the CC you should be fine.

Any head from a non low head NOVA motor like a PLUS21-4C, P5XLT or P3XS...

What about Rb heads? Somewhere i read that they fit perfect at Nova engines

Just a FYI, I've ran the NOVA 35 plus .21 engine for the past 2 years in my GT cars and never had the engines above 270 degrees. Usually my 35 plus .21 engines run between 240 to 265 degrees. All my engines have original heads on them and never had to switch to different heads. During the summer I run colder plugs and during the winter I run hotter plugs. I use 25% VP Powermaster fuel.

Andy Liu "Flyin' Hawaiian"

Maybe its just the audi body!! Either way there is no harm done with using a larger head, with a cooler head you can run less fuel!

RB is made by Nova (not the Killer series) so they are a perfect fit.

I'll pick up a cheap head an test it out for myself an see what temps I'm running at better safe then sorry! Plus I live in Las Vegas I will be racing in 110 degree weather so I'm guessing a bigger head is the way to go. I can cook bacon on the pavement here in the summer and that's not a joke.

The killer rb concept motors were made in Taiwan or something by a different company so I doubt they would fit. I believe...

Well if you notice that all of the Engine MFG that are making GT spec engines all incorporate a larger head so it just makes sense plus it cant hurt the situation only help. There are no GT/Rally spec engines with small heads that i know of.

Hey Andy
How would you rate that motor in the GT I haven't ran mine yet but I'm praying its gonna be a monster at the track an kill on the straight away.
I'm running it with a buku clutch and nova Rossi efra 9886 pipe. Let me know what you think.

Clutch
 

I would think about running a centax type of clutch.

Why Centax clutch I thought buku was one of the best clutches.