PhillipM

The golds actually aren't too bad for an MX5, they have a specific internal set for them, but there's definately more to be gained if you can shift up to something a little better. Even if you want to keep what you have, you could revalve them to give you a little more compliance on the low speed damping at the rear to help you put the power down.
I'd also ditch the Torsen for a decent plate unit from Gripper or the like if you can too.
Torsens are better than nothing but if you start lifting an inside wheel then you've basically neutered it.

sideways-dan

we have a 4.1 fuji diff sitting there. may give it a go. there not as tough as the torson though. could possibly do with a different ratio. a 3.6 would make driving easier.

for now at least we have to give the gaz setup a go as we are a dealer for them. they are a very much tried and tested setup here in the uk with some good results. there is no doubt there are better options out there but these are extremely good value and can be custom made to any required spec.

Tampa1stRotor

iTrader: (1)

The fact that a 13b drops you into the lower displacement category could be very advantageous. An older 13b with a peripheral port ITB's and a cutom intake manifold could net you the power you want and drop you to the lower displacement category. Depending on your intake setup you could still have a good enough powerband. I would post this thread again on Rx7 club see what those guys are pushing N/A right now.

SaveTheRotary

My tuner down here in Hollywood, FL has a stock Rx-8 dropping 228.4HP to the wheels with a COBB Access port and free flow exhaust. Pineapple Racing is getting way more in semi-PP . E & J Autoworks gets even more with their Billet Alluminum rotors. I am the process in the process of Making a Renesis/13B hybrid with both PP and side intake combined to get the ultimate all-motor 2-Rotor HP.

If you want the best HP with low weight get billet flywheel and rotors with a semi-PP . That will give you the 250HP you need. Maybe more...

pdxhak

iTrader: (2)

Hmm seems I need to go see Rob and talk to him about this build. Last time I talked to him was about the two 3 rotor Renesis engines he had built.

SaveTheRotary

If you want to go 20B na then get the 20B aluminum plate set from RotaryEngine.com and the aluminum rotors, Apex + Side seals from EastCoastParts.com plus the billet aluminum flywheel and PP Housings, then you will have a super light na with way over 400HP at the wheels. Parts are though.

stinksause

iTrader: (5)

he is currently at 2.72L? Would stay in the same class, but that is for OP to decide

OP, if you do decide to go the 20b route ... definitely talk to either Gordon (the following thread's OP or KDR) ... they currently have a small side project going on to see how much power you can get from an NA 20b running on MSP high compression rotors. http://www.rx7club.com/showthread.php?t=940997 ... I think they are putting out about 350 - 400 whp ... I may be wrong tho

bse50

Kinda right, 350-400hp is what you can see from a NA 20b within a human budget. 500 is kinda unrealistic, speedsource's car put down around 420\430rwhp at 8300rpms.

SaveTheRotary

Speedsource was looking to get E & J Autoworks Billet Rotors to get 15% more HP To output 495whp, but they changed rules for next season, now allowing Turbos.

I you want to see real fast na and Turbo Rotaries, check GRS-Motorsports.com and will be shocked to see 2-Rotor all-Motor cars doing 9 sec. 1/4mi. Times, and Turbos on the 6sec.

If you can attend the Pan-Americar Nationals this coming weekend(7/15-7/17) at Atco Raceway in New Jersey you can see them in person and ask them how they do it.

bse50

Engines built for straight line performance perform like crap on a track usually.

olddragger

iTrader: (3)

and are rebuild very frequently.
but do they haul *** and sound good!!
OD

TeamRX8

iTrader: (25)

20B NA fully built with all the support systems will run you $35-40k when its said and done. Every thing is custom; fitment, intake, exhaust, engine management. In reality a turbo 2-rotor setup on high quality race fuel and a conservative fuel tune can be reliable and stronger. Even when you eventually lose an engine you will still be ahead of the game. After considerable research I still believe that a Renesis intake/13B rotors & exhaust housing hybrid with a turbo makes the most sense from a cost vs value perspective for the RX-8 chassis.


.

bse50

Absolutely right Team. The huge price difference in that kind of build comes from the fabrication. If you can fabricate and build what you need on your own then the savings will be huge.
Another problem is the study behind the design. Nowadays everybody tends to copy the previous designs and the study\reasoning behind them is often "lost in translation".

There's even one more concern in my opinion: When you approach a turbo build (for racing purposes) once you have the heat management set up straight if you don't find the desired power output you can still play with the turbo's operating pressure, size etc (at the expense of power delivery and longevity of course). If you don't get a NA build straight you're just SOL and have to go back to the drawing board completely.

Many shops and fabricators act like trained monkeys, copying and building without thinking too much and that's a real waste of resources.

Rotaries are heavily penalized here anyway. Turbo rotaries even more. Multiply by 1.6\1.8 for the engine itself and then by 1.5 or so for the turbo... Fia rules aren't that clear so most racing serieses adopt their own rules, some freer than others but you still get the point.

stinksause

iTrader: (5)

you retain side exhaust ports?

SaveTheRotary

Stop the old school piston mentality. In the old times engines can only be tuned one way since Carburetors could not dynamically adjust, same with ignition systems, you have to choose between Drag or road race. Even valve opening on piston engines. Now we have sophisticated Not just EFI but EMS that make the old obsolete. Even piston engines have thing like VTEC and Dual VANOS (BMW) to dynamically adjust. Same peripheral port in drag racing is used for Speedsource to win 24Hrs of Daytona. You just need to know how to tune the motor right.

Yes, a complete super light aluminum 20B will end up costnig about that finished. If you're not concerned on making it so light and save cash I have a good running 20B twin turbo complete assembly with harness and coils ready for $4,000 down in Orlando, FL and can set you up with a fairly inexpensive build.

It is also true that your best bet for reliable low cost high power is the 2-Rotor 13B where you can get 300whp on an PP aspirated engine for just a few bucks and built spared ones on a few hrs. And beat them up fearlessly. That's how the drag racers from Puerto Rico can do 6 sec. @202MPH with just 2 rotors since they're not afraid to take the engine to the extreme.
The Renesis inkake is made for na and will not help on a turbo, besides you cannot use the 13B rotors in the Renesis plates as the side seals will shave off and eventually break, since they now need to sit further outward. However you can use the Renesis Rotors in 13B by machining the apex seal groove to fit 13B apex seals. Guys in PR are doing it to get 9sec. 1/4mi. times.

If you want to Super light on 13B then put Billet rotors from EastcoastParts.com and aluminum plates from RotaryEngine.com or Racing Beat, machine rotor housings for PP and you can get around 300whp na. Even more on race gas.

Certainly can get around 250whp with the stock Rx-8, Billet Rotors, ALS seals set, COBB AccessPort and a good tuner.

If you want to build a Hybrid like Mazdatrix did on their Rx-8 Turbo but ib na form, you can use Billet Rotors with GSL-SE 13B Rotor Housings, custom exhaust, madatrix custom motor mounts, COBB AccesPort and a good tuner to see how much more you can get in na form. Your biggest mission will be to make an exhaust that can flow more HP. I'm currently that, making a Hybrid version myself but with a custom peripheral 8th-port and side port experiment, but will need to develop a custom manifold wit additional actuators, standalone EMS and have a lot of issues to sort out.

bse50

Show me one of these 6 seconds cars running around a track for 60 minutes and maybe i'll believe you.

TeamRX8

iTrader: (25)

last time I spoke to EastCoast (and that was a long time ago) they did not plan to offer the Renesis side seal configuration or placement anytime soon

anybody can slap parts together cheaply, but a built engine from someone with a proven professional road race record with custom slide throttle intake and all the hard earned experience and know how behind if will easily run what I quoted for just having it supplied, assembled, and tested to high standards. That's the ballpark I was quoted and it was not using aluminum plates.

stop the RX7Club coulda-woulda-shoulda smack talk mentality, lol ...

olddragger

iTrader: (3)

i have to respectfully disagree. engines are built for their purpose. a drag engine should not last on a road course and a road course engine should not win at the strip.
power output curves should be different, rpm redline should be different, max temps should be different etc etc etc.
just as the suspension is set for its specific purpose--so is the engine.
Some good options you are mentioning though and thanks for that!

SaveTheRotary

Now the 6 sec. rotaries are pulling 1,200whp. Show me a road race category that allows this and we'll drop a motor in your road race car... if your chassis can whitstand it.

I am talking about a race engine, just talk about the 6 sec. drag race about they can take them over the limits and tune them for more hp.

The race engine is one thing and the car is another. In a rotary, you can use the same engine, load a different program in the EMS ECU and that's it.

The car is a different story. A drag car chassis, suspension, differentia, wheels, tires, brakes and Transmission are completely different setup than a Road Race. In top of that are the Rules. Drag rules are just safety and time slip. You can run any boost, any turbo size, any tires, they place you in by your time bracket.

I been on races with Pettit Racing in both Road Race and Drag Race. I been with Loquito Killer on the Dragstrip as well. I is the car what you have to set up to do better times, the engine is half of the game.

Here is a 6 second 13B
http://www.youtube.com/watch?v=EUvg5WtdzV8

Here is the same car setup, but with all-motor 13B with Renesis Rotors. Was at 9.60 in video but now at 9.34

http://www.youtube.com/watch?v=vQn7ejYcffM

Here is a 6 second Rx-8
http://www.youtube.com/watch?v=nwlkuK5-KSw&NR=1

As you can see, they are all 13B motors since is the cheapest way you can get high horsepower and reliability.

bse50

1200hp won't last more than 30 seconds or 5 "races" probably.
It's easy to make top end hp, a lot less to build an engine with an "usable" powerband. We're talking about a NA race engine here so spare us the chassis comments. You picked up the wrong thread to discuss drag racing engines so just admit it.

It's not just a matter of map, it's a completely different build. Ask yourself why most track cars, even in open classes, have WAY less than 600hp. Are the builders stupid?

Now if we started discussing a NA 13b with 280ish rwhp this thread could become interesting once again.

stinksause

iTrader: (5)

i need to learn spanish it seems

PhillipM

Right here.
Are you also going to pay for my expenses when it blows up on the first run?

How about when it turns out to be absolutely crap on all the transitionals without serious work?

SaveTheRotary

I talked to Edgar last week. He says the Billet Rotors have the apex seals sitting a bit outer so can be used in Renesis as well as they do have the extra oil ring.

Edgar came with new unbreakeable ALS side seals so check them out, or you can go to the Pan-American Nationals on Atcoraceway NJ this weekend (7/15/2011 - 7/17/2011) ant talk to him in person.

About prices for setups we can't argue with their prices, but you can save a lot of money on a good motor build if you do it over with the guys in Florida. PM me if you want their phone numbers.

You can save even more if you build the engine in PR.

SaveTheRotary

bse50

Please stop spamming and pushing Eastcoast parts and gsr-motorsports, nobody is interested.