It is starting to get hot in here.

*shameless act of post whoring by 88IntegraLS*

 

Maybe you left the initial set connector shorted from when you were adjusting the tps or idle a/f mixture?

My guess is there is something stupid wrong, just give everythign a once over and you'll probably find a number of things messed up. I know I always do whenever I look over someones car helping them solve a problem. Sometimes all you need is a fresh set of eyes so maybe you can have a friend that knows about rx-7's come over and look under her skirt with you.

just a thought. and you should probably try getting it running well (producing decent power) on the stock ecu before you jump into programmable engine management land... you'd just be adding alot more variables, and it's probably something mechanically wrong or something like swapped ignition wires or a coil not firing... or timing not advancing (boost sensor connected right? orifice in the line?) lots of stuff to check.

 

Add 10% to my mustang dyno numbers (167rwhp), and that will give you what a dynojet would put down. If you do that it gives you 183.7rwhp. Now keep in mind i'm running the stock injectors. Not even a aftermakret fuel pressure reg. Also note, that I have my s-afc leaned out to -28% at 8,000rpms under wot. I don't want to give out my s-afc numbers as I paid big $$ to have my car dyno tuned, but you'll see that the factory fuel system is pretty safe for 190rwhp.

Soon, I'm gonna back up my dyno claims (hopefully) with a dynojet. I'll be shure to post them however they turn out. CJ

 

I stand by my original statement, and think that with those mods that he should be able to make over 180RWHP. A BP or PP is not required for ~200rwhp or less, you just need a nice large streetport and some fuel and timing tuning time on a dyno. Like I said, Von make 159 rwhp with a STOCK PORT S5 n/a.

 

Seriously, stop trying to give advice. Little to no backpressure helps boost hp! Having a free flow exhaust will never lower your hp, if it did, then why does everyone on this forum have exhaust mods? Free exhaust lowers low-end power, and since rotaries suck down there anyway, you might as well get as much flow as you can.
Oh yeah, the lower compression rotors are not gonna lower his hp by anything more than 10 hp, so get off it!




So anyway. Check your compression first, to make sure that isn't the problem, then start looking for something that wasn't plugged in or something that was plugged in wrong. Who knows? the ECU might be running in limp mode or something

 

ok-i just did a compression test.i jusy used a regular gauge with the check valve removed,engine warm,throttle open,i got pretty close to 100/100/100 psi front/back.that calculates to about 7 bar.seems a bit week for a 1 year old motor,but ok.what do you guys think?
i checked the timming again,its 4 degress advanced,wich is how i set it.so,using a induction style timming light,hooked up to L1 and andvancing the dial on the light 4 degrees,i'm right on my mark.
as far as limp mode-i have diagnostic led's hardwired into my dash,wich flashes codes whenever i get any.seems like it would throw some code if it was in limp mode.actually,i get the 3 light "all clear" whenever i start it up.this is really frustrating.cool in a way,i suppose,as i seem to have 30-50 hp to unlock somehow.i just need the magic key!grrr...
i guess i'll check stuff out again
thanks for all the input.
david

 

100 is probably a great number.

you need to know the RPM at which the test is done to be of any use beyond comparing between the chambers ona single rotor to check for blown seals.

What I do is pull both trailing plugs (so the engine can crank quickly without having to compress on the chamber not being tested) then crank it for 15 seconds, and count the spikes that occur during the 15 seconds.

Take your count, multiply by 4. you have your RPM. There is a chart in the shop manual you can use to compare your compression to the specs, you plot it based on RPM and PSI, there is a line drawn where the minimal spec is. If you had 100, and it probably cranked around 220RPM (old starters most of the time) that is a great compression #.

good luck on finding the problem(s).

 

Anouther way to test your car is either take it to a drag strip and see what mph it runs, or do a 40-70mph test. Then you could compare your car to other peoples cars. Perhaps the dyno had a bad pickup, or the car was torqued down to hard.

Last I had my FC on the dyno, the car was making 10 less rwftlbs less than the previous time on the dyno. We backed the straps that holding the car down off a little, and viola. There was the power that was missing. A dyno is not a perfect tool, and is subject to user inputs. CJ

 

rotary>piston:

dude you don't know what are you talking about when you say this:

quote: "Little to no backpressure helps boost hp! Having a free flow exhaust will never lower your hp, if it did, then why does everyone on this forum have exhaust mods?"

I suggest that you brush up on how combustion engine works!!! Dude, every engine needs beckpressure!!! On turbo you have turbine so thats restriction itself, so you cant go wrong with 100% free flowing exhaust. But NA is whole different story! I guearantee if you put 3 inch, 100% free flowing exhaust on NA, you'll lose lots of power. Dude if you dont know this, I suggest you shut up until you understand how combustion engine works!

 

Baloney, Petex. With respect to piston engines, you're right, but when it comes to the Wankel rotary engine, you're not. The rotary engine is 2-stroke engine with 4-stroke tendencies -- look at it that way. It has no valves that require a measurable amount of exhaust outlet pressure to work; they're simply ports.

If you think that perhaps I don't understand the workings of a combustion engine, then let's talk about things like turbine inlet pressure, CHT's, pre-ignition vs. post-ignitive detonation, effective compression ratio, charge dilution (what happens on a rotary when the amount of mass air being moved through the compression/ignition strokes is greater than the amount of exhaust able to freely flow out of the exhaust port), exhaust scavenging, port overlap, etc., etc., etc.

You can write this down and stamp it on the back of your hand:

Rotaries work best, and make their highest power, when their exhaust plumbing is able to handle the maximum amount of mass air the engine is able to injest and exhale out. Period.

B

 

BCD


What about my 5th and 6th ports? they work off of back pressure. This is why when most people put on race pipes they have to wire them open because there is no backpressure to open them anymore causing lose of top end. wiring them open then creates a lose of low-end. If you can explain how this is not true then go for it.

 

it is actually impossible to achieve no backpressure, because the exhaust ports are not big enough. The closest you could get is take off the manifold completely (but this would set the engine bay on fire). On a piston engine this would burn out a valve, because they require some backpressure for their lubrication system to work, but on a rotary, it is just a hole, so there is no danger of damage. Yes, less backpressure=less low end power, but more high end/peak power. Believe me, a car with just a header would be a lot faster than a car with full ehaust.
Why do you think dragsters run only headers? Because when you're racing (staying in the high rpm), less backpressure is much faster.

I don't understand what point you're trying to make 1987RX7guy.

 

what I meant was that there are valves(sleevs) that need backpressure to open. He said that rotaries do not have any valves(sleeves) that need back preasure to open but six port engines do. Maybe not four port.

 

yeah, but that was just a bad design on mazda's part. They corrected that for the s5 cars.
You should agree with me more than anyone 1987RX7guy, you have even less backpressure than me. Plus, I'm sure your car got much slower when you added those true duals.

 

WTF


you *** they still open since there is enough preassure to make them open. i think the s5 is bad design not s4 why the hell do i want a heavy *** air pump and acv/split air tube? ask the local hoda boys if my car is slow wait you might have to wait a while they are still in second gear from my race like three days ago. hahahahahahaha

 

Your dual exaust is not the problem. While you can go to big of an exaust, making the car "peaky", a dual 2" won't do that. Trust me- CJ

 

i guess i would have to divide the number by 3 first,right?or,how many chambers actually fire on 1 crank rotation[per rotor]?the esentric shaft thing still confuses me some times.


and,no,i'm definately not thinking the 2" dual's any problem.

 

just multiply by 4.

it can be hard to do with a stopwatch and counting the spikes with just one person (while crakning the engine in the car)... nice to have 2 or more people, have everyone count the spikes then average the count you get out of everyone

theres 1 combustion event every 180 degrees, so 2 per full rotation. Since you are only measuring one rotor, it will be 1 compression event every 360 degrees. So it's simply multiply by 4 to get the # in 60 seconds. This, of course, is just an approximation.