how much boost can a "unpinned" 13b engine hold? by pinned i mean the when you place additional screws to hold the engine.

 

Hm... I´ll bet that you can put 3000psi into the engine before it explodes and you need bigger skrews!
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WTF?

 

i mean to pinned the rotors or placing screws that prevents the rotor from "walking" at high rpms

 

Pinning a motor is NOT adding screws BUT instead addding extra dowels like Mazda did. If I am not mistaken, our motors only have 2 and adding additional ones helps the motor from "torqueing" the plates and housings while under to much force. If under alot of torque, housings can shift from the plates and cause damage.
From what I was told, 19 psi is maximum without "pinning" your motor. When I had my 1st Gen dyno tuned, my tuner said he tuned it for 400HP only because I didn't pinn the motor.

Hope this helps.

L8R

 

Im pretty sure there are several guys in the 600rwhp range without pinning or adding larger tension bolts. However, it isnt common, most people see to stop around the 5-550rwhp mark without doing modifications to prevent the engine from twisting. Once you get above the 550rwhp mark several other modifications really need to be considered. It isnt any special to build an engine that will make 500+ as people have done it on completely stock engines, however, you have to pay to play to go 600+rwhp.

 

J-rat is making 550 to the wheels with an unpinned motor at around 25psi on a 2nd gen (series 5 irons). I think torque was in the high 300's.

 

Go with a stud kit. I believe (and so do many others) that machining and adding pins weakens the setup by removing material. If anyone want's to argue look at what happens typically... Cracked irons! So keep the irons stock and buy a factory stud kit. If you really want to machine something got the oversized stud kit and you'll never have a problem.

 

I was talking to Chris at Rotary Performance about this the other day and from what I was told. RP's drag 7 is completely stock as far as studding and runs in the 9's making around 700+hp. He mentioned that the 2nd gens were weak in that area but the 3rd gens are significantly stronger.

Hope that helps.

 

You can also pin/cut a circlip groove to stop the stationary gear from moving out of the rotor at high boost/rpm, theres tonnes of tricks top builders use.

 

Yup, that's one of Racing Beat's secrets.

 

fwiw I'm running about 18psi through my BNRs on a stock motor..

 

Having a hard time picturing and understanding this. Anyone care to share the details?

 

I dont have any pictures, If you could picture a groove cut around the stationary gear circumference and a piston ring style clip slotted into that groove, then a corresponding groove machined on the inner face of the rotor where the stationary gear is pressed into, so when the stationary gear is pressed in, the piston ring style clip squashes, just like when you use piston ring compressors and pops out once it meets the corresponding groove in the rotor, so then the stationary gear is locked into position as the clip sits in both grooves and wont allow the gear to "walk" as they tend to do at high boost/RPM, mainly at higher than stock RPM.

I would think it would be a major mission, virtually impossible to remove the stationary gear once this modification id done!!

 

very interesting,more details please!

 

Were puting down 620 rwhp on stock motor. Go with studs over dowel/pinned.