wide band readings

[mongoose666]

hello. Anyone know what are good wideband numbers under boost, and what bad numbers?? I know with a piston car car, but not with a rotary.

[NoDOHC]

Rotary and piston are really the same here. They both use the same fuel and the same ignition source.

Unfortunately, the AFR you should run depends on how much boost you are running and what your dynamic compression ratio is. It also depends on your ignition timing.

If I tune a boosted car, I aim for 12.7:1 - 13.0:1. But I never like to go more than 7 psi on a 8-8.5:1 compression ratio car. If you have 8.5:1 + carbon build up + excessive boost (>10 psi) then you should run much richer (I have seen guys run as rich as 10:1AFR at 25 psi).

As I said before, if you run conservative timing, you can run a little leaner. If you run rich, you can get away with a little more advanced timing.

Please don't take offense, but if you have to ask this question, maybe you should get someone to help you tune your car and save the expense of a rebuild.

[Rotary Inspired]

I would run a rotary a bit richer than a piston motor due to the heat it creates. I like to taper from 12.5 to 11.5 A/R from 0 PSI to about 8, obviously around 1,2,3 its pretty close to 13 or so. From 8 to 15 PSI like to taper it closer to 11 A/r. From there I continue to get richer. Hope that helps. Good luck.

[mongoose666]

no offense taken, I joined here in hopes of some help. There are no shops here in upstate NY that will even look at this car, let alone answer a question, hahahha. They are all running ls1 powered rx7s. Well, heres the background on the car. bought it off ebay, mint condition convertible, jdm s4 swap. 3inch HKS exhaust all the way to duals. cone filter, factory fmic. Im running 100 octane to be safe, as when I stomp on it, it boosts 10-13 lbs. of boost. The timing is stock, no other mods. I just sent out yesterday the ecu to RTEK for the 1.5. being that there is no FCD on the car, Im trying to keep the boost at around 6 or 7 lbs. of boost till I get the ecu back. Its my understanding that the timing will be retarded after 9 lbs, plus it has a built in fcd. so for 170 bucks, I fugured I better be safe than sorry. So I get the RTEK back, plug it in, go for a ride. When I get on it, and the boost is at 10 or 12lbs and pulling well, I wanna see high 11s or mid 12s?????????

[mongoose666]

Also, to richen things up a bit without going to bigger injectors, would switching the MAF to the original NA MAF help? along with maybe restricting the cone filter some??

[mongoose666]

almost forgot, theyve got the copper boost line tapped into the backside of the intercooler. Am I still getting an accurate boost reading to go buy or is there less boost going into the engine? god that sounds like a very stupid question, hahahahahahaah.

[Rotary Inspired]

I wouldnt want to see anything near 12 a/f at 12 PSI on what you described. One cold night you wont be happy. I have no experience w/ the Rtek. My suggestion is a Haltech cuz that is what I use and like. Where did this car come from? I know of one in OKC that fits the description and it started in Dallas.

[mongoose666]

came out of virginia. sharp car, big dollar wheels and tires, exhaust. hmmmm, Really dont wanna spend that much on an ecu. How about an s-afc??? Im reading that you can really richen things up. something to do with the afm. I know its the 3 inch exhaust and filter makin it overboost and run lean. any other ideas??

[NoDOHC]

I like standalone ECUs much better than piggyback ECUs. The piggyback ECUs still have all the limitations of the factory ECU only they give adjustability. A standalone has far fewer limitations.

A Haltech E6X is not very expensive (like $800, I think) and they are easy to install and use.

I have used megasquirt before (never on a rotary) and it works quite well also (more setup and troubleshooting, but less expense).

Basically, you are trying to avoid pre-ignition (sometimes called detonation or spark-knock). If you can keep enough fuel to cool the charge and keep from igniting the charge too early, you should be ok.

I have almost no experience with a Top-mounted intercooler. The first thing I do with a stock 13BT is take that inefficient engine-killer off and get a Front-mounted intercooler (some use a vertical-mounted near the hood latch).

If you get good cool charge air (<35C) you are Ok running 13:1 AFR at 7 psi boost with 100 octane fuel (using 8.5:1). (This should get you in the 250-300 WHp range).

You could also run 15 psi, stock intercooler and 11:1 AFR with the timing retarded 10 degrees and get about 300WHp out of the same engine, while using a lot more fuel and causing much more wear and tear.

The question is, what mods are you willing to do?

If you are going to keep the stock Intercooler, you should stick with Rotary_Inspired's advice, he probably knows more about the stock intercooler than I do.

[mongoose666]

So has anyone ever dynoed a turbo II running 10lbs. of boost, 3 inch downpipe to 2 and half duals, and just a cone filter and a FCD???? horsepower numbers???