I never said a Biki Board cannot handle 300+whp what I said is this guy sitting
behind his computer running his mouth with nothing to prove has got big balls.
I ask him his age… No Response
I ask him where he works… No Response
I ask him what he’s tuned… No Response
I ask him for proof of anything… What do I get? Take a Guess
I’m not one ever to bash someone if they have something to back it up with.
I’m from Missouri the Show me State.
I can search the internet all day but I’ve found best to learn from books
since I have no real access to someone who does tuning or a shop I can observe in.
I didn’t read the other posts in this thread im just gonna throw a quick reply.
Timing is when the spark ignites the mixture obviously, you want to acheive peak cylinder pressure so you change timing to acheive that, it is determined by peak torque at a certain rpm with all other variables held constant.
Air Fuel Ratio is the other major one. obvoiusly its how many parts air for one part fuel. lower the number = richer higher the number = leaner. Here is a typical graph that denotes power and egt’s for a certain air fuel mixture. the actual mixture isn’t in the graph as it is just a general guideline, but this shows you how EGT gauges are useless unless you have more information.
Now if you look at that graph you’ll see something rather interesting. peak efficiency is different than peak power. why is that? well you use a LOT more fuel to ge ta LITTLE more power. The cost in economy outweighs the advantage in power, so from the factory cars are tuned for this peak fuel ratio.
Because this mixture is lean and there is actually signifincantly MORE heat than peak power (most of the time) timing needs to be pulled back (retarded) slightly from peak torque. Other reasons oem’s pull back timing is because no one listens to fuel recomendations and if we had 350z’s blowing up left right and centre because poeple were putting in 87 do you think anyone would buy a 350z? Sure there are knock sensors but detecting knock and then fixing it after means damage has already been done. It is a last resort type of measure.
So what have we established so far?
From the factory cars are tuned to be more fuel efficient (leaner)
From the factory cars are tuned with a conservitive timing curve
There is one more point. Evertime you modify your engines volumetric efficincy as a complete system (read: complete system - that includes exhaust, intake, manifolds, ignition system etc), the way the engine runs will change. It will be flowing more (hopefully not less!) air then before, and because of this it will put the engine in a spot the manufacturer hadn’t tuned for.
Now don’t get me wrong, many many manufacturers tune beyond what their cars are capable of in their ECU’s, and it is usually driveable, however rarely is it ideal.
Another example: Say you took an SR running 7psi. Its flowing X amount of air, say 65% of the factory flow meter. Now that you have 11pounds of manifold pressure, your flow sensor is at 77% or so (((11+14.7)/(7+14.7))*0.65) What made nissan tune their flow sensors to be accurate at 77%? Well who knows, maybe one cold day some dude in japan will be ripping and for some reason his car will spike. Its easier if the motor just takes it rather than blowing up. But it is by no means designed to be efficient.
Ok so another summary
So what have we established so far?
From the factory cars are tuned to be more fuel efficient (leaner)
From the factory cars are tuned with a conservitive timing curve
Manufacturers tune their cars to operate outside of their predicted conditions, because it prevents problems in the future
The further you go from OEM conditions, the less accurate and less efficient the tuning becomes.
So at what point is it worth it to tune my car?
It obviously depends on the car. Newer Lexus’ throw codes as soon as the Air Flow is SLIGHTLY off what is expected. Changing the intake and exhaust alone on the GS caused it to throw codes because the car was flowing a lot more air than expected.
On an older OBD I system like ours, a car can make some decent jam without any tuning what so-ever, and often is it cool to just chill with the conservitive timing stock ecu. Remember, stock ECU’s are designed for peak driveability and reliability. They are not JUNK. Anyone who thinks they are better than nissan should jump off a cliff. They have hundreds of professional engineers working on this stuff.
Our needs are simply different. We are outside what nissan developed and we need to alter that a bit.
You just need to find the most cost effective way to do so. I’ll leave that up to you to research as that could go on forever with tons and tons of different products.
Now that we know we need to tune a car and why we’ll look at different ways to tune and different measures you can take to make sure your motor doenst blow (lots of stuff my EMS has that i just didnt have the time to setup! -DOH!)
Fuel – The ideal air fuel ratio changes depending on if you are naturally aspirated or positive pressure driven (supercharger turbocharger, even ram air). When you have high positive pressure you have heat. There’s no two ways around that. Even cooling it with an intercooler there will still be immense heat as it flows through the head and is compressed even further by the piston. Say you are running 14.7psi of boost and a compression ratio of 10:1. You are theoretically creating the same heat you would be if you had a compression ratio of 20:1. Now you see why engines need to run rich when they are boosted! But don’t worry, extra fuel hardly takes power away. Rather it takes away fuel efficiency. Here is a quick general guideline for fuel ratios on a turbo car:
Obviously this charge depends entirely on compression ratio, the specific engine etc, however the guideline tends to be pretty close for most cars. Most anywhere you go the target is 11.8:1 for high boost levels. Lots of DSM guys run even richer however, like 11.2 or 10.8 (start to see large power losses from over fueling) to prevent detonation from running crazy high boost levels. This makes the most power but at a huge cost. It’s not very wise, hence why lost of DSMs don’t last long – they are pushed too hard. If they are kept within reason they are VERY VERY good motors! Likely better than SR’s.
Timing – like I said before, you tune your timing for ideal torque at a specific load and rpm. Torque will level off over a couple degrees of timing, you want the most retarded timing possible for peak torque. Now there is some argument as to whether or not it is possible to hit detonation at this point – I believe that you CAN detonate before you hit peak torque if you aren’t running enough fuel and you have too much boost/compression, however Scott (RSEnthalpy), feels with appropriate fuel you will not detonate with mbt (minimum best timing). Either way – timing go for peak torque more on this later.
So we have fuel and timing, which to tune first? Well we want to setup a very very conservative timing map first. Cool. Now we want to setup a very very rich fuel map, and run the car through and add timing until we see peak torque across the board. Then we pull fuel to our desired level. This is where my argument comes in. If you start detonating by pulling fuel you can either add fuel back to where you were safe (most power) or you can pull timing and reduce fuel (more efficiency – generally). Remember that ridiculous amounts of fuel to prevent timing means you’re pushing something a little too hard. Bad news! Either reduce boost, reduce timing, reduce compression, or find a way to cool the charge better. This will give you the peak power with a very driveable smooth car. It should last a long time so long as you aren’t pushing it too hard (too much boost, detonation etc)
Recap:
From the factory cars are tuned to be more fuel efficient (leaner)
From the factory cars are tuned with a conservitive timing curve
Manufacturers tune their cars to operate outside of their predicted conditions, because it prevents problems in the future
The further you go from OEM conditions, the less accurate and less efficient the tuning becomes. This is where aftermarket tuning is a good idea.
Fuel is richer with a turbo car than an N/A car due to heat
Tune timing conservative, then fuel rich as a baseline.
Tune timing to minimum best timing (MBT)
Remove fuel to desired level – if detonation is detected either add fuel or remove timing etc.
Funky features that are worth $$:
O2 Sensor Feedback:
This feature allows a wideband O2 sensor to work at all times to watch Air Fuel ratios and adjust accordingly. Works like a narrowband O2 sensor in a stock car except for all driving conditions, idle, cruising, full throttle. Everything.
Pros: Will keep your car from blowing up, keep your AFR in check
Cons: Very hard to tune, sensor failure can result in blown motor if you allow it to lean you out too much
Verdict: I would tune my car perfectly first so it is almost spot on every time, and then add a 5% rich / 2% lean allowance into the O2 feedback just so it could make minor changes. If I knew how to tune O2 sensor feedback better I would likely open up the ranges and trust it more
Knock Sensor Retard + Enrich:
This uses an aftermarket or factory O2 sensor to add fuel and pull timing when it detects knock. Factory uses this as do many aftermarket systems.
Pros: likely save your motor, would have saved mine had mine been setup
Cons: None, just takes some time to setup and tune
Verdict: I’m an idiot for not setting it up on my EMS.
Map Sensor + Air Intake Temp Sensor:
Lots of aftermarket systems allow you to remove the factory flow sensor to use an absolute pressure sensor. It has advantages and downfalls from a flow sensor, however once it is tuned it is very reliable and consistent compared to a flow sensor.
Pros: way to go over a flow sensor in a professional field. Very accurate and does not affect the engine when there is a leak in piping or from bov.
Cons: harder to tune than a flow sensor, requires a tuned air intake temperature sensor to be used in parallel with it or it will be inaccurate. Tuning an IAT sensor is often tricky, small changes in volumetric efficiency require a retune as your manifold pressure tells the ecu how much flow the engine has, if the same pressure will flow more air you need to tell the ecu that!
Verdict: love it on mine, car runs awesome and has crazy throttle response compared to flow sensor, however I need to hookup my ait and I’m an idiot for not doing it.
Boost compensation:
This is a neat little feature I look forward to tuning in my EMS. When you’re running from 0kpa up to 300kpa there is a huge huge variation in fuel delivered, from less than 1% duty cycle on my 850cc injectors up to about 80% duty cycle, you need to be able to tune very very finely for idle, however when adjusting in such small pulse width increments it poses a problem – the ecu only has so many different inputs. My EMS has 255. That means if I’m tuning in 0.25 of a percent pulse width increments I can go from 0 to 63.75% - I can only use 63.75% of my 850cc injectors!! And I have shit resolution down low when I’m trying to tune for idle (either .75% - 1.00% or 1.25% - my idle is 1.00% so imagine that! Only 25% fueling changes! I’m surprised my car runs at ALL!)
Now with partial boost compensation you only need to tune from 0kpa up to 100kpa, and then you use 100kpa (atmospheric pressure) as a multiple for boost. 200kpa = 100kpa fuel + multiplier (say 120%) So it adds the fuel for 100kpa + 120% more of 100kpa fueling. This allows you to tune your car with VERY VERY fine resolution, now I can tune 3 times more precisely than I was able to before! Not only that, but the car will run much much better, as you tune your 100kpa value PERFECT, like do 10 passes with your wastegate open, and then you’ juts doing mathematical calculations to determine how much flow you’ll have. Double the pressure is pretty damn close to double the flow, and whatever is a restriction will be consistent, so you just raise boost slowly and tune for it! Full boost compensation means you tune for 100kpa and now you REMOVE fueling for more vaccum! You can have basically infinite resolution doing it this way.
Pros: more precise tuning, very accurate and consistent.
Cons: takes time to tune, no real other cons
Verdict: I’m working on it for my ems now!
Fuel Trims – different stand alone systems will have different trims, the more they have the more accurately you can tune the engine. Say you have a trim for EGT, you can adjust fuel based on your EGT temp (from what we’ve seen above maybe not such a good idea), there are trims for pretty much everything you could think of in the EMS, one of the reasons I like it so much.
Ignition Trims – pretty much the same as fuel trims, adjusting timing based on coolant temp is my favorite personally. Real retarded until she gets up to operating temp to keep assholes from beating my cold car too much!
Of course there are other toys in each different system, anti lag, different types of rev limiters, traction control, data logging etc. Choose what you are going to use, if you’re not going to use it don’t buy it! Unless its jantos’ and hes trying to sell it then buy it regardless.
Long enough post eh, I bet this is my longest ever. 5 ½ pages in word
I am self taught…but find most of my learning comes from hands-on experience when it comes to cars. Books and reading is definately essential, but they are no replacement for actually seeing it and touching it.
For example, on the PowerFC, one cool thing I like is called MAP trace. You can basically watch your 20x20 grid graphically and as you drive you can see the affect driver imput makes on load and which part of the map your car is actually in. Almost invaluable when trying to understand the relationship between the driver and the tune.
I don’t think many books could easily illustrate that as well as “real life”
forget all the BS with $3000 EMS’s, call scott, tell him what you got and he’ll tune your ECU for you.
he has an unbeatable reputation and has proven time and time again that his tunes can beat all the other mail order ecu’s out there.
there are so many variables, the ones sasha mentioned, but then you have human error. i’ve heard so many different things about so may different tuners in the GTA and heck, even sasha hasnt ever fully tuned his car on the EMS.
sasha said set the timing to minimum best timing, you may sacrifice some power but you will gain reliability. the same trade-off should apply when tuning your car on a budget.
it would be better to go with something that has a proven track record.
there are only so many mods that people do to the SR (change the MAFS size, change the injector CC, turbo, cams, etc.)
Scott has already successfully tuned for these and just plugs proven changes into your ECU.
you may not get the abosolute most power from your engine but you will get a tune that hundreds of other people are running successfully encluding all the the Enjuku cars and hundreds of 300 - 400rwhp SR’s on FA, zil, et al.
So what does Scott ask for when you want him to tune your ECU?
What details do you provide him?
Because the way it seems, I bet he already has prebuilt maps (from
years of making for various mods) and he just burns it depending on
your MAF, injector, motor, cams, (what else?)
And what about when you upgrade your injectors from 50# to 72#?
Yeah, that’s what Scott does. You tell him the mods, send him your ECU and 2 days later you get your ECU back, now reprogrammed to take advantage of the mods provided.
He typically charges $500USD for a tune.
The only problem is should you have a part failure or upgrade your part…you need to redo the process of sending to Scott.
Also, although this process works a great deal of the time I’ve read there are still a number of customers that need to resend him their ECUs because something is “off”. This is certainly not the norm though as Scott is a tuning stud for sure.
My car is tuned by me but based on the Enthalpy PowerFC base map. My car felt drastically different when I switched from the stock PowerFC map to Scott’s.
I actually bought this book a few months ago, unfortunately I haven’t gotten around to reading it. Its look jam packed with info though because the print is rather small. Should be a good read.
i’m just going to post a little blurb here about something posted on our forums in wpg;
anyway, i have no experience in real tuning, but i’ve gone to the dyno with friends in tuning their cars. in that time, i’ve learned some valuable things.
1: your tune will be as good as your knowledge
2: having the ability to adjust things on the fly is awesome, but unneccessary.
the debate of standalone vs eprom flash will always be there. and it’s true that OEM will always have the R&D behind it, making it the best management, but when you have a car that’s 15 years old and an 8 bit rom you begin to think it’s time to upgrade.
kits like the FJO is a full harness replacement with all the optional sensors as well. this type of system is better than AEM EMS because you’re replacing harnesses and wiring that could be heat damaged, corroded and brittle from age. this would also be my reason to buy standalone over using OEM.
anyway, i have no experience in real tuning, but i’ve gone to the dyno with friends in tuning their cars. in that time, i’ve learned some valuable things.
1: your tune will be as good as your knowledge
2: having the ability to adjust things on the fly is awesome, but unneccessary.
the debate of standalone vs eprom flash will always be there. and it’s true that OEM will always have the R&D behind it, making it the best management, but when you have a car that’s 15 years old and an 8 bit rom you begin to think it’s time to upgrade.
kits like the FJO is a full harness replacement with all the optional sensors as well. this type of system is better than AEM EMS because you’re replacing harnesses and wiring that could be heat damaged, corroded and brittle from age. this would also be my reason to buy standalone over using OEM.[/quote]
to add to your post, the ability to adjust things on the fly is sometimes terrible. I honestly had so many maps from different things i tried that I forgot what was what and eventually forgot which was my “safe” tune
the best way to do things when you’re fucking with this shit is anytime you make ANY change do a couple passes under the wideband and make sure you’re ok. God i wish i gave more respect to my motor, the poor girl
SDS is really popular and works like a charm with the SR’s thats what i’m running on mine and i haven’t had a problem. it’s pretty much a plug and play unit really easy to instal and it takes about an hour to get it tuned on the dyno
Its look jam packed with info though because the print is rather small. Should be a good read.