j_bryan

iTrader: (1)

There has been some debate in the past about whether the ECU program at wide open throttle (WOT) is fixed (static) or not (varies).

I recently received my JWT ECU and I also have a G-force ECU and am planning an ECU dyno comparison on my 4th gen (w/ MEVI).

I would like input on the whether the programming is fixed as this will affect how I stucture the dyno comparison.

For example, if wide open throttle (WOT) programming within the ECU is fixed then theoretically I could do 3 dyno pulls with the JWT, then swap the JWT with the G-force ECU and do 3 more pulls.

If that assumption is flawed, the dyno comparison would need to be structure differntly.

Mishmosh

iTrader: (3)

Sounds like a plan! Gotta give kudos to you for actually getting this done as it has been on just about everyone's mind. WOT should be open loop so your testing methods are quite sound. Just give the car some cooling time in between ECU changes or the second car may have the disadvantage of added heat.

Taken2DaMax

iTrader: (5)

I would really love to see this. This would actually set things straight for people that are indecisive about which ecu is more powerful and a better buy.

Mishmosh

iTrader: (3)

Also, do you have a stock ECU? Would make a nice baseline.

Nealoc187

iTrader: (23)

There's no question that ECUs run preprogrammed fuel and timing curves at WOT. They run in open loop at WOT and the definition of open loop is that no outside inputs are taken into account. Some people still maintain that the ECU "adjusts" in some way but I don't buy it. I have run 2 stock ECUs back to back, one which was plugged into my car for hundreds of miles and was "adjusted" to my car and one which was plugged into my car for about 2 minutes, the dynos were with 1ft lb and 1hp of eachother.

But there is a way to put this discussion to rest, AND to compare the JWT and G-Force at the same time.

Run with whatever ECU you have in your car and that is "adjusted" to your car for a few hundred miles or whatever, then swap the other ecu in, and see what the results are, and THEN go back to the original ECU and see if you get different results after having unplugged it from the power. This will tell you A) whether or not the ECU's adjust at WOT and increase power over time, and B) which ECU, if either, gives more gains.

Sounds like a good comparison to me.

I30tMikeD

iTrader: (8)

What neal posted is the best way to do it. Kill two birds with one stone.

DAVE Sz

iTrader: (2)

Are you going to do the dynos on the same day? I suggest you do them a week or 2 between. Drive with the g-force for 2 weeks and do a dyno, then drive with the JWT for 2 weeks and dyno it then. Then again I'm not sure if you need to since they are different ECUs and aren't getting used to mods.

Nevermind, it's the same **** that Neal said. Free fuggin' bump.

MrGone

iTrader: (30)

could just drive with the stock ecu around, dyno, then dyno the other 2 ECU's assuming they have been reset.

bahhhh

Blu

iTrader: (63)

thats what I was thinking you genius

j_bryan

iTrader: (1)

At the moment I only have 2 ECUs: JWT and G-force. I don't have a stock ECU to include in this comparison. My stock ECU was upgraded by JWT.

I was planning to try to dyno both on the same day.

I like Neal's suggestion to answer both questions in one dyno session.

So here's the plan. I have the JWT in the car now.

3 dyno pulls:
1. Do one pull with the JWT.
2. Disconnect battery, swap in the Gforce, , reconnect battery. Do one pull with G-force.
3. Disconnect battery, swap in the JWT, reconnect battery. Do one pull with JWT.

In terms of a having a baseline, I have data from my previous dyno which yielded 181 peak HP w/ Intake, Y and G-force ECU. I have not done any other mods since the last dyno. I did, however, replace the igition coils (from Hanshin to Mitsubishi), spark plugs (from plat to copper NGKs) and clutch (from ACT to OEM).

I30tMikeD

iTrader: (8)

What is with disconnecting the battery??

j_bryan

iTrader: (1)

JWT recommends disconnecting the battery before replacing the ECU. I typically disconnect the neg. battery cable.

krismax

iTrader: (15)

Thats what is says to do on the JWT installation sheet.

Dave B

If that was the case then how could we be making more power with our modifications then? All our performance mods help increase air in/out of the engine therefore the ECU must have to adjust. At WOT the MAF sensor does have to adjust to the additional air, but the emissions/EGR/O2 sensor, etc shut down. On my laptop OBDII software, there are clear differences in initial reading (WOT and part throttle) by simply swapping intakes or resetting the ECU.

You've got dyno proof and I've got data proof. Who knows who's right


Dave

Nealoc187

iTrader: (23)

Right, it will still take into account the amount of air flowing into the engine, and accordingly adjusts how much fuel is added. However, I still maintain that those values are all preset in a single "Air Fuel Ratio Map" that never changes. Here's a very simple example (extremely oversimplified).

Lets say your car is unmodded and ingests 10liters of air per minute at a WOT at 6000RPM. Your MAF recognizes this and according to the values which are PRESET and never change (in my opinion) sends a signal to your ECU telling it that 10liters of air is flowing in the engine. The ECU responds with squirting in 1 liter of fuel. So it's ratio is 10:1. I feel that the ECU is just plotting a datapoint, it says "hey according to this graph (the air fuel map) it says here that I need to add 1 liter of fuel for every 10 liters of air." It doesn't change that ratio if your ECU has been plugged into your car for 2 years or 2 minutes. The maps are preset, and no matter what, it always adheres to them (thats my opinion).

Then lets say you mod your car and it is all of a sudden ingests 20 liters of air perminute at 6000rpm. The ECU would use the same fuel map, and the same ratio, and accordingly squirt in 2L of fuel. 20:2 ratio = 10:1 ratio. That is the only adjustment the ECU does, it finds out how much air is coming in and accordingly gives the proper air fuel ratio. But I maintain that it doesn't matter how LONG your ECU has been plugged in, your ECU will always use that single, pre programmed air fuel ratio map at WOT, and will never stray from that map, no matter if its been plugged in for 2 years or 2 minutes. For X value of air, it adds Y value of fuel. For 2X air, it adds 2Y fuel. Same map, just different multipliers.

Nealoc187

iTrader: (23)

Also I forgot to ask my question, you say your OBDII sofware indicates differences when you reset the ECU even at WOT. what parameters are showing differences?

Washington DC Maxima

I'm still not sure why you're doing all of this but I have Stock GXE ecu at home if you need it..

j_bryan

iTrader: (1)

Thanks Eben. But isn't your 96 auto?

Washington DC Maxima

My bad...............

Nealoc187

iTrader: (23)

An auto ecu will work just fine in a 5spd, i use an auto ecu in my 5spd.

j_bryan

iTrader: (1)

Does comparing an auto ECU to a 5spd ECU on a dyno seem reasonable? Seems like it might be comparing apples to oranges.

THis would also mean 6 pulls instead of 3 which = more $$. I'm feeling kinda cheap at the moment. Of course donations are welcome!

I30tMikeD

iTrader: (8)

The auto ECU won't make a difference as far as power.

Nealoc187

iTrader: (23)

The only difference in the auto ecu is that the auto ECU will blip the throttle when you shift from neutral into a gear. the parts of it that control how your car runs are identical.

j_bryan

iTrader: (1)

I finally did the comparison. I'll post the results soon and a link to this thread.

http://forums.maxima.org/showthread....39#post3117839

Ceasars Chariot

iTrader: (16)

excellent !