I've read that the stock maps have too much ignition advance. I have a fairly new PFC with the 5.x software, and no commander. Until I can get it properly tuned by someone who knows rotary engines, Is it safe to drive it spiritedly with the following mods:

M2 intake
Greddy SMIC
Downpipe
Hi-flow cat
RB duals catback

Also have:
Supra TT fuel pump
New fuel filter
Fresh plugs and new Taylor wires

Thanks!
Doc

 

no...not at all....do not boost it at all if you want it done right...get it tuned...you need to log all your afr's.

the end.


j

 

Wow. So what was Apexi thinking when they developed those fuel and ignition maps? Pretty aggravating considering the price. It's certainly a nice unit but the fact that it's not safe out of the box with basic bolt-on mods leaves me perplexed.

 

its safe if you keep boost under 10psi.

btw: who the hell cares how many mods you got, mods dont pop engines, over boosting adn running lean does!

 

RoadsterD, get your butt down here and join us for our Steve Kan tuning session. It's only a 6 hr. drive and will be well worth your money and time. Drop me an email if you think you might be interested.

 

I'm on call. I'll be there if I can get someone to cover me that weekend.

 

Well, the whole point of buying a programmable ECU is to have it tuned. If you wanted it tuned out of the box, you should have gotten a Pettit/M2 or other reprogrammed chip. Apexi gives you what you need to start the car and get it somewhere to tune it.

 

Of course, I undertand that. I'm not talking about tuned out-of-the-box. I'm talking about SAFE maps to prevent detonation before you get somewhere to tune it. Is that too much to expect? This is assuming what artguy said is true...no boost is safe with bolt-on mods until properly tuned?

 

Your original question:

"Is it safe to drive it spiritedly with the following mods"

Artguy's answer was correct to your original question; it's not safe to drive "spiritedly" without being properly tuned. It is safe to drive conservatively to get it tuned.

That's not to say people don't drive on the base maps, however, a lot of people have toasted their engines as well.....

 

OK, thanks for the info. This forum is great.

 

I was running way lean before I got my car tuned. Steve Kahn didn't even want to do a full pull. He stopped at 5800 rpm. I made 289hp with that run. He couldn't believe I had been driving around with it the way it was. If you get a chance to get your car tuned by Steve, do it. Quit your job it's not that important

 

I'm almost embarrased to post this, but I'll do so for the greater good. Hard evidence is so much more useful than "I heard" stories.

Below is a series of dyno pulls I did about two years ago. The A/F readings were taken with a tailpipe probe and are waaaay dangerously lean. I'm pretty sure the higher hp runs were at about 12.5 psi. I actually pulled fuel on the last two runs via PIM because I had no idea what I was doing and the V8 guys at the shop told me I was running rich (black smoke out of the tailpipe). You could see why Steve Kan would quit at 5800 rpm: in my case, I was at 12.5 - 13.0. If you're familiar with how a properly tuned plot shoud look, you should be below 12 by about 4000 rpm and in the 11s at the end. Strangely enough, I drove around for a year running like that with no apparent lean-running related problems.

At the time, I was running intake, downpipe, midpipe, cat back, front-mount ic, stock fuel system, stock motor and turbos, and the base maps that ship with the pfc.

Scott

 

Using datalogit software, I'm able to compare various maps that I have seen to a dyno tuned map.

The 2.01B version has much much less fuel across the rev range from 2500-8000rpm. It has 8 cells with negative splits.

The original SR map for the PFC has less fuel across the board until high rpm and high boost and then they have an increased in fuel with leading ignition retarded on these ranges.

The map 5.08 from a well known mail order retailer has the same fuel map as the 2.01B version BUT the leading ignition and trailing maps have been extensively modified. For example, they're more advanced on certain areas but retarded under high load and boost for both leading and trailing.

Map 5.08 is again leaner than the dyno tuned maps but has only two cells with negative splits.


The only reason my engine never blew was probably b/c it had low compression.

Get it dyno tuned or at least a map from a car with similar condition (compression and modifications).

 

doesnt adding mods allow you to run lean? i always thought the 2 mod rule (on a stock ecu) was to keep you from running lean. so if you keep the boost low the a/f will stay in a stable range?

 

The 3-Mod rule had to do with the stock ECU. Also, the tests saying the 3-Mod rule was full of crap was also done for the stock ECU:

http://www.newwave.net/~flanham/wlan.../3modrule.html

While increasing airflow but staying at the same boost level does increase performace as well as change your A/F ratio, the stock ECU is rich enough to sustain bolt-on mods at 10 PSI (proved by the above link). The main problem is controlling your boost to keep it at 10 PSI.

However, the problem here is that the base map of the PowerFC is leaner then the stock ECU (I'm only going on other's hearsay on this part as I don't use a PFC). In this case, even 10 PSI can be more dangerous than the stock ECU. The PFC base map is not really intended to be used, it's just there to allow the car to start and drive so it can be tuned.

A programmable ECU is ONLY a good mod if you have it tuned, on your car, for your car's mods.

 

In that case, would it be better to leave the stock ecu in until I get it tuned? Man, that wasn't a simple question, was it?

Here's the deal:
I plan to install the mods one weekend, then the following weekend drive 3-4 hours to the tuner. Should I wait until I get there to install the PFC and just stay below 10psi until then?

 

Ok, so I'm about to install a reman with some mods, should I run the stock ecu or PFC during break-in? mods:
3" DP, 2.5" MP, intake, lw flywheel, aftermarket secondary fuel rail w/1600cc secondaries, and PFC. I've got an HKS EVC IV to ocntrol boost and might be getting an aftermarket primary rail w/720cc, and if ek9220ps hasn't sold his HKS Ti Exhaust that might be on too.

 

wonder why apexi would set the pfc leaner than the stock ecu, knowing that people buy it because they have mods on their car? anyway, thanks for clearing that up.

 

Because the leaner you run, the more power you make. The old saying is "the car never felt stronger than right before the engine blew".

You can't run the stock ECU with 720 primaries and 1600cc secondaries...

You need the PFC installed to get it tuned. If it's going to be a while before you get it tuned, just pull the boost pills (or keep your gas foot from hitting the floor too much).

Just keep the boost under control and you'll be fine until you can get properly tuned.

 

Duh, wasn't thinking on that one, that's what I thought, especially since I won't be gettin on it during break-in anyway, thanks.

 

the other cars maps is no guarantee...i had xs do my guess maps (they called it tune by mail or some ****) and nearly blew it remember....well my third set of guess maps came from KDR and they were off another m2 turbo machine....guess what...it actually ran worse than my tuning by the seat of my pants....and tons worse than the guesstimate maps from xs. how can i say it...it ran til i hit about 3k then it jerked and jolted all over the place with my knock sensor going insane.

be careful


dont drive your car without tuning. be patient. tow it if you can.


if you must drive it on guess maps...the do not get into boost at all. you will get knock....and you could easily blow an apex seal right thru your *** pipes.

be careful and good luck.


j