overkill

I just had my car dyno'ed and I seem to have one or more problems. First off here are my mods:

M2 stage 3 ECU
M2 intake
M2 dp
M2 Med. I.C.
apexi' n1 dual exhaust

Stock engine, turbo's, injectors, and Cat.

Problem(s):

If you look at the dyno graph, at about 7k my horsepower and torque drop considerably. When you look at my air/fuel ratio at the bottom, you can see that I am running so rich, that the graph has fallen off the chart. At first I thought that I was simply running too rich up top and that at high RPM's I was not getting enough spark to get a good combustion. But at around 7.5 RPM's it seems like I start to regain my HP and Torque and then I hit redline.

I have heard in the past about how the M2 ECU's were excessively rich but if were my only problem, why would my HP/TQ rebound at the end? If that were the case wouldn't the graph dive down at the excessively rich point and just stay somewhere in that vicinity? I'm wondering if there might be another problem- somewhere along my ignition as well?? What do you guys think?

Does simply changing plugs and wires make much of a difference? What about bad ignitors- can they cause this kind of hp dip? Do you guys think an upgraded ignition such as the HKS Twin Power solve this, or simply mask the real problem?? I can use all the help I can get. I need all you tuning guru's to help me out. Thanks.

reza

dump the stock cat!

RX7Wishing

Gawd damnnnnn... rich as bill gates.


sorry i have no valuble imput for you

good luck with the troubleshooting.

rynberg

Yikes, that is a HUGE and sudden drop of power. I have no idea what could cause it to drop and then come radically back up like that.

cloud9

iTrader: (4)

you blew a seal, then it suddenly fixed itself........ thats weird

racerfoo

looks familiar....



my car seems to be a lot worse than yours as far as a/f ratio go's....but we have the same power loss at 7000....mine was so bad that i couldnt even stay in it till 8000 though, so i dont know if it would have pulled its way back up (doubtful). dunno what your problem is, i didnt even feel safe driving my car with it like that so i just got rid of the chip.

mail order chips are risky, i wont use one ever again.

osdesigns

The over rich mixture on top is probably causing the car to misfire and having poor combustion.
The graph goes below 10:1, it could mean 9:1 or worse. If the actual mixture is very close to 10+:1 you probably want to consider ignition upgrades.

When a engine VE is high (pressurized), the mixture in the combustion chamber is harder to ignite. The more pressure there is, the harder it is to produce the spark.

By the look of your dyno chart, you seem to have a stock engine or a porting that is not much more efficient than stock, thats why the VE drops pass 6500 rpm or so. When the VE is lower, the ignition requires less energy to spark that mixture, and there you got better combustion again.

That is why the horsepower curve will taper down after 6500rpm and probably why you getting the crazy dip in your powerband.

osdesigns

There seems to be a big misconception for people...
The higher the RPM, the more fuel the engine needs.
Thats not always how it goes. If the VE is lower the
engine does not need more fuel. Its a bit of amature
approach to adjusting (I won't call it Tuning) an engine
management system.

forcefed1

I agree. It looks to me like you are running rich, and then missing as a result which causes it to read even richer from the missing. As the VE of your engine falls off it is re able to ignite the mixture and your power comes back.

XSTransAm

well since your pretty much off the chart on the afr i would venture to say you are overly rich and not able to combust all the fuel.

got a boost chart?

KevinK2

I'm sure the M2 stage 3 program did not have the stock cat in mind, which has built in 2.25" restrictors at the ends. The resulting high backpressure greatly reduces the VE from here the chip thinks u should be, causing excessive fueling.

Your dyno plot is just like wael d's, where he had a fouling plug during mid dyno run.

Get new plugs, and a high flo cat (metallic if possible), or reso-mid pipe.

Still may need an apexi safc to lean out the mix, as others have done with rich chips.

TracyRX7

Actually here is the list of recommended mods for M2 Stage 3:

M2 Reprogrammed ECU
M2 Cold Air Intake System
3" Stainless Cat-back Exhaust
M2 3" T-304 Stainless Downpipe
M2 Med. or Large Intercooler Package
Aluminum Intake Elbow

They actually recommend that you don't run their ECU with a midpipe (you probably could with boost control) and I'm not sure about highflo cat upgrades.

KevinK2

You're right, stock cat for stg 3.

http://www.m2performance.com/pengpak.htm

and per this dyno sheet, I guess both stag 2 and 3 are supposed to fall apart at 6800 rpm, just like overkill's!

overkill

So are you saying that my problem is really the ignition rather than my air/fuel ratio?

overkill

I thought the same thing as you in the beginning myself, but if it were just a case of overly-rich, how was my ignition able to rebound in hp at the end? wouldn't it have just continued to bog down?

BTW, They did not provide me with a boost chart, but I should be boasting at around 12-13 psi.

jpandes

Sedley,

Here's the stuff that I recommend to try and trouble shoot your car.

Change/check you plugs
Grounding Straps
HKS Twin Power Ignition Amp
Manual Boost controller set to 13psi. (just incase)
HF CAT

Since you live so close to me, we can install my spare HF Cat and my HKS Twin Power on your car one afternoon. We should be able to readily notice if the High RPM clears up.

John

dis1

Id say it is both. You are probably having problems with ignition possibly because of the ratios. Running rich will foul the plugs.

overkill

But in your theory it would be a problematic ignition BECAUSE of the mixture right? So you are saying fix the a/f ratio and my ignition issues will clear up?

Sonny

overkill: I plan on going to either ATP or DSR in the next couple of weeks. I'll have my stock ECU and an M2 Stage 3. I have a boost controller so I can limit boost to 10 psi on the stock ECU.

My mods are almost identical to yours. If you wanna come with me and bring your ECU, we can play around with stuff and see if it is in the ECU or not.

It looks to me like the M2 ECU is dumping huge amounts of fuel and/or pulling timing back in the 7k region. This seems to be the case even with M2's "test mule" as shown on their site.

Shoot me a PM if you're interested in coming. Maybe we can both figure something out without having to resort to spending money on parts that won't change anything.

Sonny

overkill

That sounds good. What day were you thinking of? Also I paid $50 that dyno at the dyno. Is taht the going rate or was that less due to the fact that it was a group event?
DO you have similar problems?

TracyRX7

Somebody correct me if I'm wrong but running rich will only foul the plugs if the fuel isn't completely burned right? So with proper spark/ignition setup you could run rich and not have the need to swap plugs every 5k miles?

Sonny

Well in this case, something (running rich or something else) is causing a massive power dip. Even if you change your plugs often, you're not really fixing that problem.

overkill: I would probably go on a weekday. I've never been to ATP before. They just told me $65 for a baseline. You can rent the dyno for 1hr at DSR for $125 (with the wideband). I'd almost rather do that since I've always done my stuff over there. This will be my FD's first time on a dyno.

Sonny

DCrosby

From the chart two things look strange, one why are not all the runs solid, why are the lines broken up !? Are some of the sensors not securely mounted !?

The fact that AFR goes off the charts (Rich) and power is lost, points to that beeing the culprit. So taking gas out, and adding better sparc should solve your issue, I guess on the plus side, you don't seem to be hitting the ceiling with your injector setup

jimlab

What you're seeing is typical of high end (6000+ rpm) misfiring. Whether caused by fouled plugs or an ignition that isn't strong enough to light off the mixture, power drops and the A/F ratio goes to hell because of all the unburned fuel exiting the engine.

Remember that the sensor they're using to measure your A/F ratio has no idea of how much gas is going into the engine... only how much is coming out of it. Fix your ignition problem first, then worry about whether or not you're still overly rich on the mixture.

overkill

Good point Jimlab, Thanks. I'm thinking of getting the HKS TP for now.