Thread: no top end power

it may be the fuel pressure if anything. i had the issue of running lean on my top end,so i lost power, but all i have to do is bump up my fuel pressue to re-gain that lost power. at least for my car, which is a DE, but thats just my 0.02

Get tuned.

ok so i just double checked to make sure both solenoids are working they both are. i guess my next step is to get a tune and see how much of a difference that makes.
yow gio i have been trying to call you bro..... give me a call yow

Originally Posted by Chriscar
What's your thinking behind it running lean? The engine has larger injectors than the ecu is programmed for.

I would have to agree with Chris, the car is N/A and is running VE injectors (bigger than stock) on a ECU that thinks that is running DE injectors. How would it be that the car is running Lean on bigger injectors than what it is tuned for???

The only way that he could be running lean is if the car has other fuel related issues, clogged fuel filter, bad fuel pump, bad fuel relay. The car should be running Pig RICH period.

Could the ECU be going into some type of “limp” mode to (try) correct the Rich conditions????

Originally Posted by Teal97
+2 on running lean

Teal,

JWT tunes have been widely known to be on the conservative side (rich tunes), most people who run JWT ECU’s hook up some kind of AFC to lean the tune and gain a little, especially top end.

I have went from

SR20VE , DE maf/ DE inj, DE ECU (stock fuel pressure)
SR20VE , DE maf/ DE inj, DE ECU (raised fuel pressure)
SR20VE , DE maf/ VE inj, DE ECU- (stock fuel pressure)
SR20VE , DE maf/ VE inj, DE ECU- (lowered fuel pressure)

SR20VE , DE maf/ VE inj, G20 ECU- (stock fuel pressure)
SR20VE , DE maf/ VE inj, G20 ECU– (lowered fuel pressure)
SR20VE , DE maf/ VE inj, G20 ECu- (lowered fuel pressure) + increased timing

SR20VE , JWT ECU for DE maf, VE inj, Raised limiter to 8k (stock fuel pressure, 15* timing)
SR20VE , JWT ECU for DE maf, VE inj, Raised limiter to 8k (lowered fuel pressure, 17* timing)

Although I never had the car Dynoed, I did have a friend with a bolt on Cobalt SS Supercharged as my constant variable. ; )

Between two years of trial and error and many highway pulls, the best two set ups were the;

SR20VE , DE maf/ VE inj, G20 ECU- (lowered fuel pressure) + increased timing
SR20VE , JWT ECU for DE maf, VE inj, Raised limiter to 8k (lowered fuel pressure 17* timing)

I had no problem in fourth gear reaching 130 mph with room to go.

http://youtu.be/6c5MKyswRHE

Set up:
SR20VE , JWT ECU for DE maf, VE inj, Raised limiter to 8k (lowered fuel pressure 17* timing)



There was also a old Youtube video of a guy in a 200SX SR20VE running against a accord H22 swap,

The first vid the SE-R had stock fuel pressure was very even with the accord.

http://youtu.be/tJ2b6RrS6jk




The Second Vid the SE-R lowered the fuel pressure and the accord ate his dust.

http://youtu.be/Z7qdJiXRTRY

I’m not saying any one is wrong, its just my .02

did you have a wideband installed during any of those runs? never took it to the dyno?

sounds like speculation to me.

i have tried de tunes on both my cars, both of which ran LEAN 14.0-14.5 afr

Using a de maf and VE injectors? With everything else up to par and working correctly, a stock de ecu with de maf and ve injectors will run rich. It's just common knowledge that a motor tuned for smaller injectors will run rich if replaced with higher flowing injectors. It's a fact, not speculation.

That is of course if every other component is working correctly (ie. fuel pump not keeping up) which would cause it to run lean up top even with the larger injectors.

when in closed loop (feedback) the ecu uses info from the o2 sensor, maf and tps in attempt to keep things near stoich. it compensates some, for the larger injectors.
the values in the fuel tables are primarily for open loop operation, iirc. so when you tromp on it and go into open loop the afr's WILL go richer with the de ecu/ve injector combo than a de ecu/de injector combo, no doubt. "pig rich" is a point of view, however.
but, what has been dyno proven already is the fact that the ve likes to run richer than convention wisdom dictated for the de. there are lots of ppl running de ecu/ve injectors with NO ill affects.

im just going off what i seen/know an when a car goes stupid lean the power goes out the window.. he could be lean for a number of reasons his ecu setup may not have anything to do with it..

i'll be tuning dans car this weekend, i loaded his g20 tune from the ecu he's been using for a long time now an we'll go from there..

another note, i made best power with a afr of 13.0-13.1

alex. my jwt tune was very lean. i had to ADD fuel pressure to
my ve ecu/ve injector setup
maybe it was a lack of consistency on the part of JWT

I understand the difference between closed loop and open loop.. And I agree with you that the DE ecu will try to compensate for the larger injectors during closed loop, but it can only go so far. I know from my own personal experience that DE ecu and maf with VE inj will not cause a problem beyond crappy mpg's and shorter spark plug life.

Closed loop takes care of keeping the car as close to stoich as possible. Or at least it tries to.
What I'm referring to is WOT , the ecu goes into OPEN loop in which it only looks at a couple of sensors, (TPS, maf Voltage, engine temp) and IGNORES the 02 sensors... Why??? Because it goes to a predetermined set of values programmed into the ECU... In this case a DE ECU which thinks it has 259cc inj, when its really not.

When people "tune" their ECU's they are mostly changing the values (In the OPEN loop tables) to compensate for things like Bigger injectors, mafs, intakes , exhaust, boost, ect. .
If this weren't true then there would be no need for "Tunes" as we could just slap on bigger injectos and be fine..


Once again I'm not saying anyone is wrong, and it might as well be that some people experience "Lean" conditions running DE ECU's and maf, with VE injectors on a SR20VE.. For all I know the VE might just be one hell of a thirsty motor that needs bigger injectors from what nissan provided and is seeing lean conditions fairly easy without proper tuning..

I'd like to see some of the dyno graphs where these lean conditions are seen with SR20VE, DE ECU, DE maf, and VE injectors... Wether a G20 ECU or a regular DE ECU ...

Lynch, I don't have a wideband, and I have never dynoed my car.. I'm just simply giving my .02 on MY personal experience, and have provided some basic knowledge and vids to support my statements..