I’ve had my specV for a while now and although it’s a fun car... it seems to be lacking one thing that I believe is limiting the performance. I’m speaking of the ignition timing. I believe that Nissan has been very conservative in the initial engine timing. As some of you know, the timing can make a night-and-day difference in performance. The problem with the 2.5L engine in this vehicle is that it has a DIS (distributor-less ignition system) type engine. This type of ignition system has its benefits... but allowing the owner to tweak the timing... is not one of them. I started pondering this problem and see only a few ways around it. Some of my thinking is as follows with the associated advantages and disadvantages in the implementation.
1.) Take advantage of advanced timing parameters in timing/fuel map by artificially simulating a lower engine temperature. This can be done rather easily but since the engine cooling fans are operated via a signal from the ECU... they wouldn’t come on at the proper engine temperature. Some other means of starting the fans at the proper time could be implemented???? Hmmm... Certainly don’t want to hardwire and have them running all the time!
2.) Reducing the operating temp of the engine by means of a different/no thermostat to again taking advantage of the timing/fuel map. This gets around the cooling fan problem but allows the engine to operate at a lower than optimum temperature. I have done some tests in his area and have found to get a significant timing advance you need to go down to an engine temp of about 100F. This could have a negative impact on emissions and engine oil sludge buildup and ????
3.) Physically move the CKP in relation to the crankshaft. This would be exactly like turning the distributor (on an engine that had a distributor) and would be the best overall solution in my opinion. The problem is one of implementation. This sensor has a fixed location at present and may not be easily adapted. Anybody make any hardware to accomplish this?
4.) Physically move the CKP signal plate in relation to the crankshaft. This might be really messy... involving disassembly of the engine and not lending itself to being adjustable from the outside.
5.) Change the ECU software. Well, that may be a tall order... lol I guess there are several companies doing just that... but I don’t believe there is any finished product available right now... or in the very near future. Correct me if I’m wrong.
Well, any way... I certainly may have missed some possibilities and would like to hear some of your ideas. Also, don’t hesitate to comment on anything that I have said here... should be an interesting discussion!
Well I don't know enough about cars to understand anything you said except changing the ECU and I thought JWT was going to be coming out with one fairly soon, like at the beginning of summer... I don't know for sure though
Well, the knock sensor will give you as much timing as your pistons will take. The better quality fuel you run the more timing it will allow. I dont know if Nissan has installed a "Clamping mode" in their OBD3 setup. I am sure the tables only allow so much adj.
I Dont know how much can be picked up be having a custom computer tuned? I suppose we will leave that to JWT and his dyno tuning.
As far as cooling the engine off it sounds like a great idea right. Cooler air coming in right, more power right, Well the actual efficiency of that is stink. Lots of wasted power. Honda in races runs their engines around 205 + degrees because thats actually where the more power is extracted. Power is in terms of heat Thermodynamics. Think of it this way Fuel energy going in is 100% but the internal combustion engine only uses 26% of the heat energy for mechanical work. You have to factor in the cooling system losses of 36% and Exhaust losses of 38%. Think of the engine as a heat reservior.
In essence by lowering the thermostat temp you just inturn run more fuel into the cylinders and thats that last thing you want. Excess fuel washes the oil off the cylinder walls and provides more ring wear and even further reducing the heat energy in the engine
To want more fuel you need more air comming in. Just by cooling the engine down you arent making anymore power. If you dont believe me just take it to the dyno and put the coolant temp sensor in a bucket of ice water to fool the computer thinking the engine is cold . It proved that there was not a show of more power , in fact, it didnt do anything.
I am sure to get many replies that cooling the engine down does infact make more power do to air molecules being closer together.
That doesnt have anything to do with the thermal efficiency of the internal combustion process though. Cool air comming in is great but a hotter combustion chamber is better as well.
Just my two cents!!
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Takes a great driver to make a car perform to its full potential
Originally posted by SilverBullitt03 Honda in races runs their engines around 205 + degrees because thats actually where the more power is extracted....
I think that you are losing track of the street setup vs. a full race setup. Also i think that the motor you may be refrencing is a turbo setup. In certain race aplications you do want heat, thus some race cars have tape over verious vents. As far as my understanding of this function, it is as you say used for optimal combustion. But in a street setup the ECU makes the mixture adjust to the airflow and the temp (weight/density) of that air. A cold air intake yeilds dyno proven power in virtulay all applications. Not to mention that all the race cars i have ever worked on (from clasic F-production SCCA british race cars, to the 302 mustangs) have all had some form of highflow cold/ram air intake systems. occationaly in circut racing we have taped over the radiator grill to help keep the temps where desired, but no matter what that has always been in conjunction with the CAI setup.
Certainly if a CAI reduced the temp in the motor drasticly you would loose HP and that would be reflected in the Dyno sheets.
So i am going to respectfully disagree with you on this one, although you have the right idea, i just don't see a CAI making enough of a change.
I never stated that the CAI would lower the cylinder temps. CAI does allow a cooler, more dense, charge lowering INTAKE. But according to the law of Thermodynamics , second law
Ideal efficiency=T (hot)- T (cold) devided by T hot
This has nothing to do with the air molecules in the intake but the combustion process. This law which I stated above has to do with Fuel and the efficiency process of energy expelled. If I could build an engine that had a hot reservior of 400k and the exhaust to be 0 devided by hot that would give me a 100 percent effecient engine and the power would be more than anybody could ever imagine. I am talking in terms of energy how much is wasted before it even gets to the road.
So dont worry Spec you didnt disagree but you did do what I had stated would be an argument above
"I am sure to get many replies that cooling the engine down does infact make more power do to air molecules being closer together.
That doesnt have anything to do with the thermal efficiency of the internal combustion process though. Cool air comming in is great but a hotter combustion chamber is better as well. "
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Takes a great driver to make a car perform to its full potential
I made a technical boboo when I was typing a hotter chamber isnt what we look for because of anything over 2500 NOX goes through the roof. Cali folks know that creates SMOG... I do apologize for my typo. I meant to say the less energy wasted , heat soaked into other than mechanical motion, is what I was after
I truly do apologize for the mishap!
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Takes a great driver to make a car perform to its full potential
You guys are dealing with problems that the GM boys have been dealing with since the late 80's.
Let me tell you a few things:
Confusing the computer into believing that incoming air is cooler than it really is (IAT mod), increases throttle responce slightly, but is usless as a power enhancer. Likewise, a lower temp thermostat is of very limited usefulness as well.
As for trying to hack power out of the computer by messing with the timing, DIS systems normally have a LOT of leway in how much they can vary the timing, and if Nissan is at ALL like GM, you will find that there is less than 3hp to be found by messing with this. And on a modern sequential port fuel injected engine, there isn't much to be gained on the fuel side of things either.
I think you'll find out you are best off waiting for the JWT ECU, but don't be surprised if it's only good for 2-4whp (even B13's only got 4-5whp).........cars ARE getting more efficient from the factory you know.
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15.214@90.06mph out of a fridge....I don't get it?
Originally posted by BIGBULS As for trying to hack power out of the computer by messing with the timing, DIS systems normally have a LOT of leway in how much they can vary the timing,
Originally posted by BIGBULS You guys are dealing with problems that the GM boys have been dealing with since the late 80's.
Let me tell you a few things:
Confusing the computer into believing that incoming air is cooler than it really is (IAT mod), increases throttle responce slightly, but is usless as a power enhancer. Likewise, a lower temp thermostat is of very limited usefulness as well.
As for trying to hack power out of the computer by messing with the timing, DIS systems normally have a LOT of leway in how much they can vary the timing, and if Nissan is at ALL like GM, you will find that there is less than 3hp to be found by messing with this. And on a modern sequential port fuel injected engine, there isn't much to be gained on the fuel side of things either.
I think you'll find out you are best off waiting for the JWT ECU, but don't be surprised if it's only good for 2-4whp (even B13's only got 4-5whp).........cars ARE getting more efficient from the factory you know.
Exactly...
Just so you know people with there Timing Advanced with OUR cars are getting 3-5whp more then those of us with the same mods but no TA. I know it can be a number of things but it is prove in my eyes that it helps a little. But, it's not just whp it helps it is the power band. This is the important aspect of the TA.
JWT ecu will help but like it was said before NOT by much...
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14.7@94.01mph with Heavy ass 18's :D
I guess the bottom line for me is that I feel that a timing tweak on this engine will be very beneficial to low and mid range operation. I have no real desire to change the fuel mixture. It's interesting that nobody has modded the CKP sensor yet to accomplish this... Does anyone have a closeup photo of that engine area?
Thinking back, We used to put some teflon tape around the threads of the sensor to dull the peizoelectric capabilities of the sensor. The more you would thread it in the more sensitive it would become. What I mean is you start by only threading it in by just a few threads and depending on what grade gasoline you ran you could easily get more timing out of the OBD1 FRED.
As far as BlackoutSpecV's question, here it is
Yes, I have just a bit more than the average bear.
Two years of advanced automotive computer controls and diagnoses, along with every other area imaginable on the autos.
As you can tell I was the top of my class in college and right now I am in the process of finishing up a Bachelors in Management.
Right now I manage and maintain a fleet of vehicles and that paycheck goes to pay for my outrageous college expenses which does not leave anything for mods. LOL
I also do research and developement for Stallion Racing Team in my town. That keeps me on my toes to say the least!
Higher Ed is costly for sure, but I wasnt fortunate enough for my mommy and daddy to send me on a free ride.
Thats the briefest summary I could supply you with if you want more drop me an email.
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Takes a great driver to make a car perform to its full potential
Well then you should be able to tell us how we can get just a timing advance on his engine without any mixture changes...
Quote:
Originally posted by SilverBullitt03
Yes, I have just a bit more than the average bear.
Two years of advanced automotive computer controls and diagnoses, along with every other area imaginable on the autos.
As you can tell I was the top of my class in college and right now I am in the process of finishing up a Bachelors in Management.
Well to get more timing out of the computer first of all you need to specify base or total.
As far as everybody getting all timing happy with base setting, thats all fine and dandy if you want to just look at base.
Total timing is gonna make the most difference on a variable valve timed engine and when and where it advances and retards.
As far as setting base I haven't studied how Nissan has positioned their crank sensor. Fords you just buy an aftermarket adjustable one, very simple.
For right now if I want more timing I just throw some 93 octane in the tank and the computer can institute a more aggressive curve.
It is pretty much a no brainer with a knock sensor.
Old school ways of bumping the timing are out the window for performance. Last time I checked, we were no longer stretching the advancement springs inside the distributer LOL. Most of the computer systems today are already set for max timing, until a ping occurs, then retards it.
Jwt is working on a puter for our cars but I doubt he will let the cat out of the bag as far as how he changed the curves to what parameters for fuel and timing amongst other variables.
I think focusing on other areas other than timing would be a much better investment.
my .02
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Takes a great driver to make a car perform to its full potential
The feeling that I get from reading the Nissan manual differs from your theory. My take is that the engine has some base timing... and advance tables during engine dynamics that are added to the base. Although I think you're right that there are several advance tables... the ECU doesn't have the ability to bring the timing right up to the "pinging" edge of performance. Why else would others (such as Ford you mentioned) have crank position modifying hardware if the ECU can automatically take care of that???
For right now if I want more timing I just throw some 93 octane in the tank and the computer can institute a more aggressive curve.
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