[TitaniumTT]

Originally Posted by NoDOHC

If you polished the outside radius of each bend and equalized your cross-sectional area throughout the runner and matched that to the port. You should see significant improvements on my 216 WHp. I would expect your engine to make about 240 WHp as it sits, (given the previous assumptions based on piston engine knowledge) With the following additional assumptions:
Intake port timing has been changed to close a little later than stock.
Intake manifold has been port matched, but not blueprinted.
Non-polished rotors do not significantly impede flow past TDC cusp in the rotor housing.

If your manifold were Blueprinted (constant cross-sectional area through entire intake runner) I think you could look 260 WHp in the face.
If you didn't change stock port timing, I think you could get 285 WHp.

That's retarded amounts of HP.
Intake timing is slightly later on closing, intake mani port-matched but not blueprinted..... thought about going the extrude hone route but decided to save that expense for two reasons,
1-see if there actually is a difference worth the $600 or more cost
2-didn't want to spend the coin of I didn't need to in order to hit my goal

Originally Posted by NoDOHC

Believe it or not, (it seems impossible to convince turbo guys of this) 0.91L will not hurt your engine NA. 1.1L will not hurt your engine NA. You will not burn a hole in a rotor (your rotors are oil-cooled) and detonation is not a problem when you are naturally aspirated. Ignition timing is not a problem either, run whatever give peak power (34 BTDC may be better for you with 9.0:1 CR and un-polished rotors). If it makes you feel better, run 0.86L (this will give almost identical power to 0.91, these are the edges of the peak power range).

You don't have to convince me, I know for a fact that it won't. It just amazes me the difference any amount of boost makes to these engines. .85-.9 seems to be where the most power can be made though, regardless of turbo or not. There's just an extra safety margin when you tune it to .8. For example, I was looking through the datalogs from this past weekends auto-x, L were around .9 the whole time, when on the highway they were below .8....... tires were constantly breaking loose. 3rd gear pulls will read leaner than 4th gear pulls on the dyno too because everything is slowed down.

Originally Posted by NoDOHC

Why RE and not REW? I think that the RE has bigger intake ports (could be good, if runners will match) and earlier exhaust port opening (not necessarily good for EGT). What other advantages does it have?

RE has bigger runners, less of a complex UIM, and the LIM is MUCH more balanced. The only way I would do an REW would be with the GZ LIM. To fit an RE in an REW all you have to do is get the rear iron drilled and tapped to accept the stock motor mounts. You actually might not even need to do that. You could probably fabricate something off the subframe to use the RE's stock mounts and adapt some FB or FC mounts.

I like to open the exhaust up for an earlier opening but not change the closing at all. That's what I did with this RE engine and it seems to work pretty well. EGT's are just fine with this.

Originally Posted by NoDOHC

Bone Stock 200,000+ miles coils that came on the car.

Nice, I'm wondering how weak the LS1 coils are compared to the LS2 truck coils. Cleaning my fuel up from .75 to .8 nets HUGE gains in power. Much more than you would expect. I'm wondering if there isn't a problem igniting the rich mix and that's were all the stumbling comes from.

Originally Posted by NoDOHC

The rotors are 9.5:1 because they have been polished to 2000 grit and lightened to < 4kg. (CR empirically determined with sealed ports).

Gotcha, interesting that you lost so much CR from such minimal work. Were they balanced as well?

Originally Posted by NoDOHC

I have a very limited budget for this car, most of my parts were either obtained out of the scrap hopper at work, given to me by friends or custom fabricated by your's truly. I try not to spend much money on this hobby.

me too

Originally Posted by NoDOHC

I don't intend for the P-port to be a crazy runner, I am not building it for such. It will have 9.4:1 normal rotors, minimal overlap (for a PP) and tame port sizing. My goal is not to rev it to 12,000 rpm and make power all the way, but rather to see if I can get it to be mild-mannered and street-drivable while still making 250 WHp. I see it as the poor man's PP.

The only way to make a P-Port swallow more air than a streetport is to make the intake port larger than the combined total of both intake ports on the street port and to make the exhaust backpressure absolutely minimal, while maximizing the intake pressure. High-overlap engines tend to be more finicky and make less average power than equivalently built lower-overlap engines. Building them is not really that easy. (For example, I have a combined cross-sectional area of intake ports/runners of 3.2 in2, this would be a very large P-port, slightly over 2-inch diameter). I am intending more like a 1.7-2.0 in2 port cross-section for the p-port. I want to try for max power on a later p-port, but this one will have stock internals and I will not rev it past 9,000 rpm (eliminating the need for big ports).

Piston engine guys need large overlap times to scavenge the chambers and to get air through their restrictive intake valves and runners. Rotaries don't have any of those problems with > 270 degrees of eccentric shaft rotation per intake stroke from a street port or 320 from a p-port (duration is not that much better on the P-Port)

The VE (empirical, based on fuel and AFR, probably reads 3-5% high due to injector energization delay) on my 4-port breaks 100% @ 4800 rpm, peaks at 108% @ 7700 rpm and drops to 102% @ 9,000 rpm. At tuned resonance, a P-port could achieve ~125% VE (due to overlap), but could not hold that for a broad torque curve. Peaky power bands do no good for performance, area under the Horsepower curve is your friend.

I really should be posting this in the general Rotary tech section, but most of it is already there.

Interesting math on the P-port vs street port. As for the VE's, that's a ton of math man!