GSLSE-YA

Does anyone know how much power can be gained from the Renesis rotating assembly? I am currently running 89-91 rotors with 9.7 compression. I am going to rebuild my motor after my season is over and am considering a lightened and balanced rx8 assembly.

Currently using a 4 port BP from a 3rd gen block. Currently making 217WHP on a Dynopak & Dynojet (SAE corrected).

rglbegl

VERY little power gains. 9.7/1 or 10/1 does not make a big difference at all.
But it would allow you to rev a little higher because of less weight. So since you did a bridge port, which only gets power WAY up top, you could benefit a bit more.
But on a stock motor, I bet you wouldn't even notice a difference


BTW - I always thought a BP 13b would be closer to 250 at the wheels???

GSLSE-YA

It's not a J bridge, but I estimate the motor makes around 260+hp, but my 10.5" slicks eat a lot of horsepower on the dyno rollers. It makes peak Hp at 8100 rpm and is rev limited to 9000. I usually shift at 8500.

Rotors have been clearanced and balanced. Also, I have carbon apex seals.

P-nut

What intake are you using

GSLSE-YA

It's a 3rd gen lower and upper manifold with the lower ports matched. 3rd gen throttle body then full custom piping to the filter in front of the radiator. MOTEC FI, engine built and tuned by tripoint. Engine feels strong allthough I've had many who feel it should make more WHP.

Tripoint has numbers for stock Mazdaspeed 3's and Rx8's and my 217whp beat both cars. The dynopak they use is said to be conservative.

GSLSE-YA

The car is fast and corners on rails. I hold two lap records in the NASA Time Trial - TTS class for Socal. It is a 2.5 mile course, which means my average speed around the track is around 101-102mph. I'm hitting around 131-132mph top speed. I also hold a record for TTS at Buttonwillow configuration #1 CCW. I'm looking for ways to improve my times for next year, but I can't tear it apart until the end of november when my season is over. Hopefully my engine makes it through nationals in Sept. at Mid-Ohio.

Willow Springs International Raceway
Class No. Name Vehicle Time Date
TTR 4 Bart Carter 05 Radical SR8 1:20.27 5/25/08
TTU 66 Russell Warr 04 Subaru STi 1:26.73 8/5/06
TTS 7 Scott Howard 85 Mazda RX7 1:28.21 7/13/08
TTA 212 Patrick Lindsey 01 Audi S4 1:29.48 2/11/06
TTB 81 Keith Parker 72 Corvette 1:33.12 9/11/05
TTC 777 Greg Greenbaum 04 Dodge Neon SRT4 1:33.99 9/11/05
TTD 777 Shawn Dolan 01 Pontiac Firebird 1:35.20 7/12/08
TTE 18 Dan Gardner 07 Scion Tc 1:37.47 8/12/07
TTF 321 Dan Gardner 91 Nissan NX2000 1:41.21 5/7/06

rglbegl

Well, in your case they may make the difference you need.

For a street car, especially an unported street car, they would make little or no difference. But with a well tuned race engine, they may make the few extra hp that would get you the win.

GSLSE-YA

Thanks, I'm not looking for huge gains anyway. My class is based on an adjusted power to wt. ratio. I'm fairly close to the limit in my class but allways looking to make it closer. I'm assuming the rotors would also have a small effect on torque which would also help coming out of corners.

I'd like to have a PP in the car, but it would put me into the next class. I would be competitive on a regional level but probably not nationally. If I mated a 13PP making close to 290whp to a sequential dog box I might have a chance. I just don't have an additional $20,000+ to spend.

P-nut

Do you have any videos of the car in action?

GSLSE-YA

Nothing in car yet. I have some video from earlier this year at Fontana. It was my first event with the wide body, but didn't have the front splitter or GT wing yet, only a deck lid spoiler. It's amateur footage and I never transfered it to the computer.

Tripoint just installed a chase cam for Nationals. I should have some good on board shots my mid sept.

GSLSE-YA

http://showard1223.googlepages.com/pictures

crispeed

First thing you need to do is loose the factory intake manifold. That **** does not even belong on a good streetport much less a bridgeport.
You're giving up a lot of power with that setup.
The key to making huge power with ported motors is through intake and exhaust tuning. Many believe making 350whp on a PP is based mainly on the port. I've made 250-350whp on the same motor with just changes to the intake and exhaust tuning.
RX-8 rotors most of the times result in less power if you have maximised 9.7 rotors. A lightened set of 9.7 rotors are way superior to renesis rotors from my experienced. I'm not even going to get into the sealing in-efficences with rx-8 rotors or how difficult is the setup to get proper sealing with them.
A good bridge port should be in the 240-270whp range. Seen it done many times. Some are alomst on par with most PP but the PP will always provide a wider and more reliable powerband than an all out BP.

classicauto

iTrader: (3)

Higher static compression won't always result in higher dynamic compression, and thats ultimately what makes power.

crispeed

GSLSE-YA

Are your HP figures with a SAE dynojet or dynopak? I've heard mustang dyno's read higher than normal.

My previous motor was a partial bridgeport made from a 6 port and we were only able to make 191 WHP. That had a second gen lower manfold, custom upper manifold going into a custom throttle body with (2) 50mm air horns & Motec FI. Both exhaust systems are Dual 2" into a single 3" before the rear axle.

Why does mazda and mazdatrix only claim 300-315 engine hp from their 13B PP?

crispeed

Probably because that's what it actually makes!
Mazda also claimed the Renesis was around 250hp and yet when everyone dynoed it it could barely do 170hp at the wheels. Thanks to the general public that overated power claim was reduced.
I've seen some of those 'claimed' textbook 300-350 flywheel HP motors only do 220-240HP at the wheels also. It's much easier to sell a product with a big power rating especially way back when that was the norm. Now everyone is acustom to horsepower at the wheels because dynos are readily available.

crispeed

Here's a little video demonstrating what a 13B PP motor is capable of!
http://videos.streetfire.net/video/T...otor_83250.htm

Do the math!
How much power does it take to run 130mph in the 1/4 at 2040lbs?
BTW. That motor was 25-30whp underpowered due to renesis rotors.

GSLSE-YA

Sweet video, how many runs before you have to rebuild. Where do you hit peak HP? Is it below 9500? How much Hp did you make at the wheels?

EpitrochoidalPower!

Thats the problem. Finding good information on what kind of setup to use seems to be very difficult. Im also running a bridgeport that i'm currently breaking in and im still unsure about where to start with my header and exhaust system. Crispeed, it seems you know a lot about high power N/A rotaries any chance we could pick your brain? Because its hard to tell whether the information I find on the web is from people who have actually done it or not. Especially with all these myths that BP's and PP's must have crazily high idle's and be impossible to drive at low rpm etc etc. Which I have seen for myself(in multiple large BP and PP setups) is most often not true at all which makes me wonder how much I can trust half the information.

EpitrochoidalPower!

Oh and I almost forgot. That is one very, very nice car you have there GSLSE-YA. Thats almost exactly how i'd like my car to end up

GSLSE-YA

Thank you, I will have some updated pics real soon. The car was just painted. I need to finish a few things and get new stickers on before nationals.

My car idles at 2000 - 2500rpm depending on warm or cold idle. I'm starting to wonder how much the exhaust port has to do with the idle. My last engine had a smaller intake port but with the same race exhaust port and the idle was almost the same.

EpitrochoidalPower!

Perhaps you are right. How large are your exhaust ports? Here are some pics of my exhaust ports and my bridgeports. With my efi i can get the car to idle below 1000 rpm but I keep it to 1000 at the moment to keep oil pressure adequate.







Could it perhaps have to do with your intake setup? I'm running twin 50mm throttle bodies on a weber IDA manifold.

I guess it doesnt actually matter though seeing as its in a race car . I'm planning on using mine on the street and track so I'm more interested in a nice idle.

GSLSE-YA

You know, I use to use a twin 50mm throttle body/air horns with my old motor. The new motor uses a 3rd gen lower and upper manifold port matched. Both setups I've had utilize MOTEC FI.

Motor was built and tuned by Tripoint. Ports look similar but it's hard for me to tell without looking at them side by side. My earlier motor still had an idle around 2000rpm. That first motor had smaller intake ports than my current allthough the duration was the same or longer since it was a 6port. The only thing that was the same in the two motors was my exhaust port. I wonder if my exhaust port overlaps quite a bit with the bottom of the intake port?

EpitrochoidalPower!

Yes perhaps you have a lot of overlap compared to mine. I was looking at your car again...I wish I could get a hold of a widebody kit down here in South Africa. I dont think importing one is an option with something that large.

GSLSE-YA

It might be difficult and expensive. Here is the website. ISC racing originally used the kit for SCCA EP. When I talked to the owner, he said they may discontinue the kit soon. Not enough demand for 1st gen kits anymore.

http://www.iscracing.net/Fiberglass.htm

The kit is fairly inexpensive but does require quite a bit of work to fit properly. Some of my body lines aren't perfect but OK for a race car. Part of my problem is the fiberglass hood is flimsy and could be slightly larger to fill in the body lines. Also, my race does not have headlights, the headlamp covers are dummies incorporated with the nose. I suppose you could cut the fiberglass and use the stockers.

Mazda mariah kits are more expensive but fitment is better if your using it for a street car. Mariah sells rear fenders that are real similar but the front fenders are different.