If you want to pull aprox 400 + hp out of an 13b-re engine, I have heard that you must change the studs that hold the engine together, too some bigger one´s .

Is this true ?

It's called dowel pinning... They add some steel dowels around the engine,



Some people say, at the top and bottom, because there is the most room to make the holes bigger and add dowels, other say you can better place them around the sprak plug area because when the sparks ingnite the mixutre, the pression on the housing is the biggest in the spark plug area.. Maybe also a little higher for bad tuned engines to make the housings more resistant to detonation, but then you'll probaly destroy the apexes..



Rub.

there's also a race stud kit, extreme rotaries (?) sells it, where each tension bolt has the function of dowels.

but according to the experts on this forum, you don't none of these things for your goals

I think you'll need different exhaust sleeves before you'll need different studs at 400+hp

Put TII ones in and smooth them.. maybe port yuor exhaust ports a bit down..

That's correct. The problem is high combustion pressure (such as from detonation) flexing the rotor housing outwards. If you look at the way the engine is put together, the important combustion area is exactly the part that the factory dowels do not support.



You can get by with conservative tuning and no dowelling, but many builders (myself included) believe that the "brick shithouse" approach is the best. You don't have to worry about it if it's done overkill.

amen 50 million dowls baby

You don't need to dowel pin at 400 hp.

Thanks for all the info. It have been moast heplfull.

So I dont need new dowels to get 400 hp out of the engine..

But what was the thing with the exhaust sleves.... ?

No dowels or sleves needed... Just myths started from the big name shops as a way for them to grab some more of your $.



A decent side port and good turbo will net you 400 with no problem....

You mean something pretty like this? I agree with Dragon 400hp has no need for it.

[quote name='Dragon' date='Jul 21 2005, 07:25 AM']No dowels or sleves needed... Just myths started from the big name shops as a way for them to grab some more of your $.



A decent side port and good turbo will net you 400 with no problem....


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Its not needed to obtain 400+rwhp, but it sure helps keep it together longer. I have noticed that most people can't keep their motors together longer than a few months, and when they do blow they have no idea at all as to why.



In pistons motors once you go beyond 10.5 s/c its common practice to change to studs, versus the stock bolts. Its been proven the heads will float around if you don't.



If you're making serious power or cracking the boost way up on an Rx-7, I view it the same way. Things are going to start moving around. Maybe this is one of the reasons so many people blown motors and have no idea why....



I'll have my stud kit finished soon, I plan on posting on how it goes.

I don't know what unit of measure an "s/c" is, but I have many customers that are making absurd amounts of power with high compression or forced induction, using stock head bolts.



The difference between the piston cylinder head problem and the rotary rotor housing problem, is the forces against the cylinder head try to push the head upwards off of the gasket surface, while the forces against the rotor housing try to slide the rotor housing sideways along the sealing surface plane.



The force on the piston engine is against the bolts, while the force in a rotary is against the dowels.



This isn't to say that there is no sideways force (trying to spread the side housing away from each other) in the rotary, but the surface area available to the pressure is much greater in the "break the dowel pins" direction.

So what are "smart upgrades" to get to the engine, to make it stronger ?

I Like hp, and think 400 hp would do the trick for me , but just to be safe, what are smart upgrades to an rotary engine, to make it last...... ( longer....https://www.nopistons.com/forums/pub...IR

[quote name='viking' date='Jul 24 2005, 06:09 AM']So what are "smart upgrades" to get to the engine, to make it stronger ?

I Like hp, and think 400 hp would do the trick for me , but just to be safe, what are smart upgrades to an rotary engine, to make it last...... ( longer....https://www.nopistons.com/forums/pub...IR


[/quote]



make sure you've got good oil pressure, the right oil and coolant temps. and tune it right

[quote name='Zero R' date='Jul 23 2005, 04:03 PM']You mean something pretty like this? I agree with Dragon 400hp has no need for it.


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Do you have any closer pictures of the cut outs near the ends of the studs?, do they have them at both ends?