N/A 13B performance ‘upgrades’
 

I know it seems a little obvious, but overheating is a big no-no for these engines. To start, check the compression and also check the chambers for antifreeze.

As far as performance upgrades are concerned, it really comes down to what you want to accomplish (within reason) and what you're willing to do to achieve it.

Higher numerical ratio diff gears, auto counterweight, aftermarket flywheel and clutch and scatter shield/blanket if you don't have them already. If it is mostly for track use long primary exhaust divided to the diff area, porting, water/water wetter mix instead of coolant (if your ambient temps don't go below freezing), better ignition, fine wire irridium plugs, aftermarket ecu, clearanced rotating assembly if you have to pull it down for water seals anyway, flex/ethanol fuel if possible.

are you premixing oil or is it running an omp? If it is stepper motor controlled omp i would stick with aftermarket ecus that already have rotary support features not sure what speeduino has to offer but i suspect mega/microsquirt stuff is more developed if you are budget constrained.

There isnt a ton of power to be had from NA rotaries, 200whp is a reasonable goal on a stock block, 250whp with aggressive porting. More is possible, but not typical without radical work.

As far as power upgrades other than porting:
Make sure everything factory is working properly, especially the 6th port actuators, and VDI as well if the car is an 89-91. If these aren't functioning the car will suffer tremendous top end power loss.
The first big power mod is a full exhaust. Pick up a quality one such as racing beat, rotary engines will burn the packing out of cheap mufflers quickly.
The next best power mod is a stand alone ecu, adaptronic makes a plug and play and is pretty popular right now.
After those there are a bunch of small mods that eventually add up.
A high flow panel filter for the stock airbox is your best bet on an intake to avoid it becoming a hot air intake.
pineapple racing and atkins racing both make aftermarket 6 port sleeve options
ignition upgrades such as wires and an ignition amplifier such as the MSD 6a are pretty popular, factory coils are very adequate.
removal of accessories such as AC, powersteering, air pump.
Modifying the throttlebody to remove the secondary throttle plates, warmup system etc

If the engine needs to be rebuilt porting can be a good power adder but keep in mind the more aggressive of porting the higher the power but the rpm band also shifts up, drive-ability goes down, and fuel economy goes down.For most people a streetport provides the best compromise of qualities.

Great advice! The rotary really responds to exhaust and intake upgrades. On my 3rd gen, I used a Dwyer differential pressure gauge to find restrictions in the intake, and like Templeton, found that a simple drop in filter worked great with my oem box, although in my case, I had to revise the path of air to and from that box. Like he said, it avoids creating a hot air intake.

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The large port will make the car less enjoyable to drive on a regular basis as it become alot more temperamental. On a N/A car I wouldn't think that the downsides associated with bridge drive-ability would be worth the minimal HP you would be gaining. Honestly, you could run a 100-125 hp wet shot of nitrous with minimal effort, complexity and costs. I'm sure alot of people will balk at that idea, but none from actual experience.

Skeese

You stated that the car is only going to be used only on the track, so there are no real downsides. The things that make them "not" streetports are non-issues for race cars - well, except maybe the noise levels.

If you are trying to cruise or come on and off low rpm coasting throttle in traffic a bridgeport will buck, doesn't matter at all if you are the kind of person who is using the car for spirited driving or can put of with a welded center/detroit etc.

It is really just people who are deluded about how they drive their car who want the brap noise and then are disappointed that all of the overlap and late port closing has lost them low rpm drive-ability.

I simply suggested it because you specifically said you were "looking into options for more power whilst avoiding any turbo nonsense" and didn't specify you were staying N/A, only that you wanted to avoid turbo. If its only a track car, then like slides and diabolical1 said, there shouldn't be any real negatives SO LONG AS whoever does the actual bridge porting on the irons knows what they are doing. With a stock port, the side seal rides well above the port opening, but with a bridge port they have to walk the bridge between the factory port and the additional eyebrow port added. A crappily done bridge port can repetitively suffer from side seal failure and add way more trouble than its worth. With a true N/A car where you want to go and beat on it hard and often, I don't think the extra 20 hp and few hundred rpms are worth the reliability loss and fact that you are going to have to replace custom parts if things break at the track instead of bolting on a spare factory part.

Skeese

Have you done anything to reinforce the diff mount? You will almost certainly destroy the front diff mount with clutch kicks etc without fitting a snubber or prefereably adding plate or something in there. There are probably a heap of threads in the 2nd gen section on improving it.

As per normal I agree with slides. For consistency and max track time I would place more emphasis on bulletproofing your driveline and upgrading suspension components in your situation and just stick with a stockish keg that is simple to fix if shits.

Skeese

This is vaguely the same idea as FD diff brace and i strongly suggest you do something similar.

http://www.ausrotary.com/viewtopic.php?f=4&t=251192