2a+RoN

I can't elaborate much, but I've personally seen a dyno sheet of an n/a non-bridge, non-Pport consistently run 290whp. Just thought I'd throw that out there to mix things up a bit..

peejay

3-rotors don't count

I *have* "heard" of 260 crank HP from a mongo street port (not sure if it's a "cheater" or not) using 45 or 48mm DCOE type throttle bodies... and it was an ordinarily trustworthy rotaru guru from this forum, but he never posted dyno sheets.

Roen

iTrader: (2)

Is it 2-rotor?

2a+RoN

yes, it is a 2-rotor.

Roen

iTrader: (2)

290 whp? Wih no extra power adders, stricty NA? No aux injection, nitrous, etc.? And it makes 290 whp? I need to see a dyno graph at least.

peejay

I have a very, very hard time believing that from a side port engine, given that about 140-150ish is as much torque as you can expect to make. That would mean peak power/torque at over 10k. For that much PITA I'd just do a bridge and live with the part throttle issues as opposed to the high RPM/narrow powerband issues.

j9fd3s

iTrader: (3)

this ones painted blue though.... and its got MoTeC exhaust....

2a+RoN

I think you mean "motec systems exhaust"... and hell yeah that adds 100hp by itself.

rotarygod

iTrader: (1)

Speedsource Racing's Renesis race engines make 260-265 crank hp on 98 octane fuel. That's with stock ports and good tuning. You can't do much porting on the Renesis. Beleive me I've tried. David Haskell talked about it at length at Sevenstock IX and said no matter what they tried this power level was all they could get. That's actually pretty damn good for an n/a rotary that could pass emissions with a cat! You also can't bridgeport a Renesis. There is not enough material.

peejay

I thought "someone" has a bridge port RX-8.

265 crank HP turns into 265 wheel HP which is about 290 crank HP which turns into 290 wheel HP...

Pretty soon we have 400hp stock port 13Bs! Or 400hp stock port 12As with the original fuel pump...

rotarygod

iTrader: (1)

Numbers always get skewed like that.

They actually do right around 230 at the wheels. It's about a 30-35 hp loss through the RX-8 drivetrain at that power level.

The Renesis intake ports open so early that if you try to bridge them, there just won't be enough surface area left for any degree of strength. The exhaust side is a different story. It's not quite the same problem. The water jacket is very strange. If you tried to bridge a Renesis exhaust port, you'd hit water! It sounds odd but I've got a housing here to prove it. I've actually posted pics of it before on the 8 forum. What you can actually port on those engines is minimal. The exhaust ports can only get larger ever so slightly. All you can really do is radius the edges. The primary intake port can be made significantly larger. The secondaries can't be changed and the aux ports can only be opened slightly earlier. That's it aside from cleaning up the castings in the runners. That engine is nearly maxed out stock.

Roen

iTrader: (2)

Moving the exhaust back to the periphery?

Peripheral port the MSP?

j9fd3s

iTrader: (3)

thats pretty good, seems like getting more than 220hp NA to the ground is hard, have the feeling that rpms to do it, increases friction.

peejay

Check out the IPRA thread in the tech archive section on Ausrotary. Lots of interesting info there re: intake manifolds.

Of course those are bridge ports, but they are *small* bridge ports.

shm21284

What kind of dyno was used? What kind of torque correction factor was used? I'm calling BS until we see some numbers and pics. This just doesn't seem possible by what you're describing.

2a+RoN

it was a dyno jet. not sure what correction factor was used, but the dyno was calibrated. Only a couple weeks before we used the same dyno on another n/a car that put down ~230whp which had much more midrange than the car in question.

23Racer

I know a few of you know about my setup. The car made 195whp/ 145 ft lbs of torque on the Holley carb setup on a Mustang dyno and we have since converted to a Megasquirt with throttle bodies. After a bunch of tuning issues, which ultimately ended up being us having the timing inverted we worked out the bugs and the car runs very clean on the ITB setup we are using now.

The car has way more torque on the ITB's and I can blow the back tires off it, from a roll, in 1st and 2nd and going into 3rd it will spin the tires for a second. We have 225x50x15 RA1's on it with the stock 4:10 rear gear. The exhaust is a custom one with a ton of tricks and we need to optimize it for the ITB's. The motor is an S5 rotating assembly in an S5 TII with superlight flywheel and all the tricks. Big issue now is that even with TII injectors we are running out of fuel at about 6500 rpm, so no new dyno numbers yet, but the bottom end seat of the pack grunt is fantastic. A/F's over 6500 rpm swing super lean and the car starts bucking under load. Unloaded we can scream it to well over 9,000 rpm.

Here is a link of the car running and it idles at about 900 to 1000 rpm. The A/F ratio is in the mid 13's.

http://video.google.ca/videoplay?doc...69563795267888

This year we will be installing a Walbro fuel pump and if necessary larger injectors as it is crying out for more fuel. I don't know how much track time it will see this year as we have a new noise maker to play with and this car will be used only for an enduro or two and maybe a track day just to make sure it is working well.

I wish the chassis was a 1999 instead of a 1989, so that I could still race it in the CCTCC.

Oh well........

Roen

iTrader: (2)

And it's a 13B 2 x 654 cc 2-rotor motor? Is the motor even streetable at all? I wonder what kind of gas mileage this motor would get.

NOPR

.

shm21284

I flat out don't buy this, unless nitrous was involved.

peejay

Naturally aspirated, by definition, excludes nitrous.

I'd also like to see the dyno's correction factors and the test method. On an engine dyno, we were able to see +50 ft-lb and +20 hp just by altering the test method...

Roen

iTrader: (2)

I could make any power I wanted with the altitude adjustment.....

It's strange that while everyone else is rather consistent in their power levels, there's someone who's made 100 whp more without any power adders.

The original intent of this challenge was to locate a streetable NA engine with the highest useable power. Granted, a car that make 290 whp NA is respectable, but if it makes that power at 20k rpm, has horrible part throttle manners and gets obscenely low city gas mileage, I would tend to exclude it from this sort of challenge.

2a+RoN

I trust that the people running the dyno and tuning the car did not use correction factors to over-inflate the numbers. I am not sure of gas mileage on the car, but streetability would be a concern as its pretty doggy until the power comes on hard at 5k.. So I guess it doesn't quite fit into the original intent of the challenge.

Roen

iTrader: (2)

still, respectable to see such power, but are you sure it wasn't a wide open port like a bridge or something? Streetports still usually have decent power from 3-5k.

peejay

My mild P-port 12A, in untuned state, was far stronger than my stockport (yet sleeveless) 6-port 13B in the midrange. It literally barely made enough power to turn itself below 2k and then *wham*.

Intake closing is the prime factor in where the powerband lies. Later closing gives you more power higher up but hurts low-end.

Overlap determines the "height" of the powerband (how much torque it generates). More overlap means more port open time for a given intake closing. The downside is *drivability*.

My P-port had an intake closing time of 60atdc, about what a mild street port is.