dowel or studing?
 

I'm in a process of rebuilding a 20B, my goal is to make around 800rwhp. Would you recommend a stud kit, dowel pin, or both? Also street port or half bridge?

I say stud kit, street port.

Studs no question about it. But it will be a pain due to the machining involved to use the studs. Since the only studs u get for the 20B is the 12.7mm kit. And the stock tension bolts are 10mm.

The 12.7mm studs are good for 1000rwhp+ so u should be in good shape there. And a streetport would suite u good.

JT

Guru stud kit (www.xtremerotaries.com) and street port. Jantore is right about the machining - you don't want to mess this up or every thing's toast. It's best to send the irons and housings to someone who has done it before on a 3 rotor.

Don't know about MO, but Gotham Racing in TX has experience in this. They take their parts to a machinist that has a template set up for the machining.

You don't need the stud kit. A large street port + race gas will do it on a standard well built engine. Dowell pinning is a thing of the past at this point and many reputable engine builders never believed in it in the first place. Stud kits have seemed to replace that train of thought.

A bridgeport will make that power easier or even better, port phased rotors. Avoid the half-bridge. Why do things half-asked.

Thanks

I respectfully disagree. For the average joe who isn't going to run race gas and wants a mean street car, studding is a must to prevent engine flex. This mod should be on the top of the list. Combine this with a nice street port and a center oil modification and you have the beginnings of a winning combination.

Studding is not a must to prevent engine flex.
You could use thicker oil pan flanges or go dry sump and run a thick plate on the bottom of the engine. Mazda did something similiar, though be it on both the top and bottom of the engine on their 4-rotor 787b.

Last time I checked, stud kits will not replace the power gained by using race-gas and larger ports? 800rwhp is in all likelihood a pipe dream without racegas and/or at least a bridgeport. People have been successfully running big power on 3 and 4 rotors without using stud kits for a long time.

^A studkit can't hurt. Though you do bring a good point about putting a plate on the bottom and going dry sump. I never even thought of that before!

Does anyone know who does the studding for Gotham??? Someone get the dirt!

Very interesting ideas. Certainly would help quite a bit with the flexing. For the average Joe though I still say the stud kit is the way to go.

As for the 800WHP, this might be a stretch on pump gas. Certainly, with a large street port, studding, and water injection, you can get in the 700+ HP range.

Gotham uses the machine shop that does the work for the RX7.com car.

It could hurt your wallet...

What about balancing your rotating assembly? Wouldn't that prevent flex better than a studding?

Balancing lowers the engine bearing wear and allows for the engine to have a higher rpm red line. Studding keeps the housing plates from twisting under really hi torgue levels (or when boost really hits). Think of it as a really tall sandwitch. The more layers you have, the more toothpicks you will need to keep everything together.

^To add to the above, balancing the rotating assembly is mainly a good idea for applications that will run extended periods over 8,500 or so RPMs. Studding is a better idea for torque and boost as t-von points out. Doing both though, IMO, is the ultimate way to go. A little more protection never hurts.

As for the money issue, studding, including the kit and the machining should set you back a little over $1,000 and dynamic balancing is in the $750 range for a 3 rotor. A very good investment though for the ultimate in engine building. I'd do both and, coincidently, have.

If anyone knows or have the experience it would be mr David Hayes. He knows what listening to the e-net gurus normally leads too.
There's no substitute for actual on hand experience. The rest is just repeating what they heard or read somewhere.
No matter what method used if it's not done correctly the results are not going to be good may it be 'dowelling', 'studding' etc.
I've seen more damaged motors as of late by people who jumped on the bandwagon of using studs all due to incorect machining. The funny part is that most of these people are the same ones that claim that extra dowelling don't work. :rlaugh: Some of these reputable engine builders only exist in the E-World. :lol:

just get some angle iron and build a jungle gym around the block....... that will keep that sucker from movin

Yes, I've learned the hard way - cost me a lot of money and time but hopefully I'm now on the right track. Crispeed is right, it starts with actual experience, or with a very well qualified mechanic. And in the rotary world, it's much more difficult finding the good ones. They exist, but are few and far between. In FL, it's crispeed and Carlos Lopez. In TX, Gotham Racing has my vote (and also my car:)).

I'm very pleased with this 20b section. I must say I haven't yet seen a strange thread posted by someone. I'm starting my research early as I'm looking toward building my 20b next summer/fall/winter. It's really high class in this section. Thanks for all the good posts so far :bigthumb:

+1

BTW crispeed, I'm looking at actually doing this exact thing to my engine. I don't know anybody close to me in FL that does this. Maybe Kilo? Did you wanna take on a project?

Mazdatrix does balancing as well. I wouldn't consider studding or dowelling until you actually blew a motor up because of the block flexing.

Why is that? Seems like if youre building a motor that will be high powered, why wait till it becomes a problem? doesn't make sense.

^+1 I still say it's very good insurance money. For $1,000 (cost of kit and machining) you eliminate the flex issue, period.

why?

that's just stupid saying that. oh just wait untill u blow here up then u can buy all the parts new and then use the studs. lol

if ur gonna go for that power it will cost u alot more money when the motor blows because of block flexing. it's just stupid to save 1000 usd when it will cost u a shit load more with the potential damage a block flexing on a 20b might do.

i have seen a 20b flex due to no reinforments and all i can say it's not cheap. thank god it was not my engine. it did cost him 4 times the price of getting it studded the first time around buying all the broken parts.

so to all of u recomending against the studding, build your own 20b without studs and see it flex at high hp. untill then stop saying something u have no fucking clue about.

Can you guess which one I was referring to regarding the dowelling and studding? I'm not trying to detract from the other of course.
David, ask him about it next time you talk to him. He has your rotating assembly doesn't he? He was able to answer some of my questions regarding engine flex that no one has clearly answered because they simply don't understand what is happening.

All I'm saying is that you don't need a stud kit to make the power. It's kind of like ceramic apex seals; you don't need them to make the power but if you want the best and perhaps a bit more room for error or bigger safety margin, then by all means, go for the goods.

What happened to this engine from flexing and what brokenn parts did he have to replace?
I have and it won't and so have many others over the years.
Perhaps you should listen to some of your own advice.

Sure, he's also on the forum so maybe he'll chime in with his advice. IMO, you don't need the studding to make the HP, just to protect against blowing up the engine. I've done a lot of research on this forum and others, also with the Australian and New Zealand guys, and with the Gotham Racing group, and this is the number one recommended mod to the 20B outside of the center oil modification and with balancing the rotating assembly right up there also.

But to each his/her own. Research the topic and make an informed decision. I think all the pros and cons are listed in this thread.

Makes sense if something works, don't mess with it.

I'm not arguing, just simply providing information that the stock block can handle alot of power.