Okay so I've read all day trying to get some solid answers but everything appears to be opinion of the builder. I recently destroyed my motor and Ive found a new 13b which is getting street ported, race corner seals, side seals, and apex seals. My T67 had shaft play and the compression housing was gouged so next up is a 6266.

I've been advised that to make more than 500 whp dowels are necessary or else the reliability of the motor is not very high. Now I'm reading about studs as an alternative to doweling and unsure of what to do. The main point is I'm wondering at what hp range are you looking to get the shaking and twisting at requiring the reinforcement?

I'd like to reinforce this motor as much as possible while I'm going through the build to prevent a rebuild in the near future, but I don't have the money to throw into unneeded upgrades. Anyone have solid research for the hp ranges and effectiveness of the dowels/studs at those ranges?

 

At that power level I'd do the Turblown studs. Machining for extra dowels or larger studs just weakens the iron in my opinion.

 

I too am interested in this. I've heard doweling makes the engine last longer with higher boost levels but I don't know for sure.

 

What Ihor said. Cutting away material to make the engine stronger seems a bit counter-intuitive to me. Increase the available clamping force of the studs to increase the friction between the engine surfaces to keep the engine from twisting.

If you really want to you can also throw in an oil pan brace to or excessive oil pan to further aid in structural rigidity.

 

Also, if you're looking to make over 500whp on a regular basis than you need to accept that reliability is gunna go out the window. Studding the engine isn't going to magically negate all the additional stresses you're putting on the engine to make that power.

Pushing into that realm, temporarily, is one thing. Trying to keep it there is another. Getting there, and staying there, WHILE attaching the label of "reliable" is not for the faint of heart or shallow of pocket... lol

 

I understand that "reliability" is going to decrease as I make more power. The second we start to change out stock parts I think we all accept that fact. I just want to get it as strong as possible to prevent having to pull the motor again.

What do those turblown studs run price wise? I'm going through a reliable shop but just to get an idea of what to expect does anyone have a good idea?

 

Not a builder but I would like to point out that adding extra dowels to an engine has been done for many years and if it made the engine weaker it would have been common knowledge by now. I doubt drag racers would miss the fact that dowelling the motors had been causing premature failures. They would know and so would we by now.

 

Elliots studs run right around $400.

The thing about adding dowels.. in the earlier gen engines they did have relatively specific power thresholds that you would need/want to dowel/pin the engine to go beyond. They pretty much solved that problem with the 13B-REW.

Also, keep in mind that those serious drag cars tend to get broken down and rebuilt at the end of each season. How many miles are driven in a season of drag racing? 10 miles? Maybe 20, max? It's very hard to try measuring longevity/reliability in a street car when you're using a drag racing car as your basis for comparison.

I once had an engine doweled by a shop I considered to be reliable. That motor was only running like 400whp (down from 480whp on a previous build), it popped at 1,500 miles. Dowels didn't save the motor from the builder/tuners excuses on why the corner of my apex seal broke during a relaxed Sunday cruise.

 

So by the sound of it nobody can really show for that dowelling in that power range is going to save or improve the life of this motor. Contrary, has studding prevented or caused anyone issues? I'm looking to hear both sides, good and bad.

This may be going a bit off topic, but aside from these new seals and springs are there any other upgrades for 500hp range that are a no brainier upgrade everyone tends to follow? Again these guys have been building drift rotary engines since the 80s they're very good at what they do but I want to keep the options open. Dowelling was recommended for anything over 500hp but at this point I'm turned in the direction of studding or neither.

 

Which shop are you referring to? I also live in GA and the more rotary shops to choose from the better.

Thanks,

Alex

 

I live right by the Fl/Ga line and I'm going through Elite Force Motorsports in JAX Fl. The motor is being rebuilt by a Lowe Performance in Sarasota FL which Elite set me up with. The guys at Elite are awesome, not sure where in GA you're at but they have a mustang dyno and run events quite regularly.

 

Oh, I'm just north of Atlanta. I now take my car to DBW Motorsports in Cumming, GA.

 

Doweling was an older practice before studs were available. Some builders still swear by it. I prefer studs.

 

Are they necessary or supportive under 500hp though? What amount of power would you recommend them to be used at or would you put them in regardless for additional strength?

 

The way I look at it, anything that will provide more uniform and consistent clamping force is going to be good no matter what power level you're running. I believe the factory engine bolts are known to stretch at times. If they do that then you lose that even clamping force. If you lose the clamping force then your surface friction between the irons/housings diminishes. If that surface friction goes then your engine can torque, which is what you're trying to avoid.

Long story short... studs help your engine because they allow for more precise/uniform surface friction between the layers of your engine. Additional dowels don't help with that. That improved surface friction will benefit even low power levels.

I'm no engineer (I'm a research analyst by trait), but that's how it was explained to me by a buddy who is a mechanical engineer.

You can also help by reinforcing the oil pan with an oil pan brace (mine was made by Garfinkle, I think Banzai also makes one).

 

I appreciate all of the input, it looks like I'm going to go after the studs. I will continue to post pics of my build as it comes along, feel free to keep up with it!

Thanks for the help guys!

 

Questions also needs to be asked:
Dowels
Stock sized Studs
Oversized Studs
and stud material.

I've heard of stock sized studs binding or just feeling off, when assembled, maybe due to the additional torque, or material difference? any feedback/thoughts?
I've seen Elliot's studs that go straight through to the front cover?/iron? vs. ones that go to the stock front iron threads. Any thoughts?

Ihor, do you prefer studs, because of the ease of application/installation? and at what torque for the studs?

 

I was looking at the turblown studs which only offer one model, if you will. Correct me if I'm wrong but the oversized studs were replaced with studs that are only hardly 1mm larger and fit the same holes as the tension bolts without extra machining. I thought it was pretty straight forward on what studs to go with since options seemed limited.

As far as oil pan brace a lot of people swear by the banzai brace and it looks very easy to install and effective. For 120 dollars if it does its job as everyone says it seems well worth it.

 

The Turblown studs are stock sized. They are made from stronger material than stock and you are able to get more accurate torque than with a bolt. An oil pan brace both strengthens the motor and prevents the oil pan from flexing and leaking.