Do you really need a 'tune' or is it bs

General karthief

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I get a chuckle when I read 'I have a bla bla mustang with a belly button engine, a 70mm tb and maf with 24 lb injectors, twisted wedge this and equal lenth that and a (pick a cam). My buddies (that likely drive 'tuner' toyotas and hondas) tell me I need a 'tune'.
I have my uneducated thoughts on this: a well thought out/planned engine putting out say 350hp at the crank should not need a 'tune' to make it manageable on the street with the stock ecu, now this may be on the edge of what the eec1 computer is capable of managing. Like I said, an uneducated opinion. I ain't running 350 crank hp (yet lol).
I'm also not talking about the guy that has a stock block with canfield race heads, 90mm throttle body, 36lb injectors and a stock maf with a B cam, I don't need to discuss what kind of 'tune' he needs.
And I need to add that this is a street car.
I have read too many times where a tuner took money from someone that had a miss matched combination or say it runs great but surges or stalls, get a grip dude, you got stroked.
But when do you need a 'tune' ? And (I already know the answer to this) what does the 'tuner' need to know before he loads up the rollers?
Also what to look for when going to a 'tuner'.
I call them 'tuners' but in reality they are (or should be) a dyno operator.
Let the sparks fly :cool:
 
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MustangIIMatt

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It 100% depends on what you're doing with the car, how much you've done to the car, and how balanced your combination is.

For the record, I've driven a speed-density '86 Mustang LX with a crate motor that included aluminum heads, that had an Isky Cam, Explorer intake, and 24lb injectors on the stock tune. I've also seen thousands of forum posts on how that's impossible. Twister on Allfordmustangs built the thing to comply with California smog laws and still make power, and succeeded. He spent a lot of time doing a lot of math to figure out what the working combination was. I drove that car in Missouri and Illinois when he and I were at World Ford Challenge 6 back in 2003. He even paid to have it chassis dyno-ed while we were there, but I can't remember the numbers off the top of my head.
 
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91TwighlightGT

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I think a decent combination of quality parts on an N/A build probably gets by without a “tune” in most situations. Power adder cars benefit from it because they have a smaller margin for detonation and causing engine damage.

With that said, I think that any car can have some benefit from being tuned for maximum performance, but the cost/benefit can vary greatly from car to car.

I think it is a rare situation that someone selling their car that “just needs a tune” is actually being truthful ordoesn’t have deeper problems.
 
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a91what

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I don't operate a dyno... :shrug:

For a typical build with a good ECU that has no issues a good MAF and quality injectors are all that's needed.
If the cam get overly wild then raising the idle speed usually helps.
 
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90sickfox

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Back in the days...many of us didn't even know what "tuning" was. Wasn't that when you'd dent the FPR with a hammer ? ...or was it when you'd flip the throttle body around so the IAC was on top ?
 

Ryuk

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There are more things to tune on a modern engine than on ours. Ours are pretty plug and play.
 

HemiRick

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tuning an engine is to get the fuel and spark optimized for power....if you're not running an EFI that use a wide band O2 sensor, you could prob gain some power from a tune. Also an engine that is not running optimum fuel amounts wears faster/more.
 
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General karthief

wonder how much it would cost to ship you a pair
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tuning an engine is to get the fuel and spark optimized for power....if you're not running an EFI that use a wide band O2 sensor, you could prob gain some power from a tune.
OK, but at what point is a 'tune' beneficial?
Remember we are talking about a street car up to 350 hp.
 

96pushrod

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OK, but at what point is a 'tune' beneficial?
Remember we are talking about a street car up to 350 hp.
“It depends” is kind of a dumb answer, but that’s my answer lol.

If you put on h/c/I and the maf curve gets along with the injectors then there are plenty who make it work. Cam plays a pretty big role in how idle quality will work. It’s tough to account for all situations though, like when the ac cuts on while you’re turning the wheel from lock and the car wants to stall.
 

Noobz347

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OK, but at what point is a 'tune' beneficial?
Remember we are talking about a street car up to 350 hp.


This is the wrong question. At least, the qualification is the wrong question.

OK, but at what point is a 'tune' beneficial?
- When proper air-fuel mixture cannot be efficiently obtained across the useable RPM range by mechanical means.

Remember we are talking about a street car up to 350 hp.
- It depends on how you want to make that 350 HP. So, you can't pick a relatively small number to cast shade on the initial question. :p
 
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Habu135

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The tuner needs to know what size (pound) injectors you're running and will want to know if your spark plugs are fresh. A good tuner will ensure your fuel pressure is set at approximately 38 pounds and will then review the data (air flow ratio) using their wide band sensor.

There are really two benefits to a dyno tune. First is the car will run and idle better as a result and two you'll have a tangible results (measurement) of what your car makes in hp and torque. I've had my car tuned and have enjoyed the increased hp and torque and driveability.
 
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General karthief

wonder how much it would cost to ship you a pair
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I knew I was kinda vague or maybe just not wording the question clearly but still getting good responses.
Let's see who else chimes in.
 

Monkeybutt2000

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I see that term thrown around ALL the time,drives me crazy. IMO,you have to have a pretty serious N/A setup to really need a tune job. Shoot,back "in the day" we'd just adjust fuel pressure,timing and throttle screw. Heck,my 87 coupe ran a 95 Cobra engine w/24# injectors on speed density. Little fiddling and it idled like a stocker and ran 12.80's.
 

Noobz347

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I see that term thrown around ALL the time,drives me crazy. IMO,you have to have a pretty serious N/A setup to really need a tune job. Shoot,back "in the day" we'd just adjust fuel pressure,timing and throttle screw. Heck,my 87 coupe ran a 95 Cobra engine w/24# injectors on speed density. Little fiddling and it idled like a stocker and ran 12.80's.


You really just need a lumpy cam, some big heads, and fairly high compression through fuel injection. That is, if you intend for it to have any street manners. If it's a track car... Meh... Not so much. You're really only worried about WOT anyway.
 

2000xp8

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I think everyone here knows how i feel.
You can make damn near anything run on the stock fox computer IF you pick the parts correctly.
The whole idea of tuning a car to run the wrong injectors is idiotic. Injectors can be bought and sold at the same price, same goes for the meter.
With a friend owning a mustang shop for 25 years (about half with a dyno, when they went mainstream), i've seen it all.
Seen the stock computer run a r302 solid to 477rwhp with just the ford racing extender.
Seen pro charger and T trim cars make well into the 600's (650rwhp is the best i've seen, but i've heard 750rwhp is possible) all no tuning.
Mind you, all built by someone that had all the means to tune it. But wasn't into wasting people's money or his time on something uneccessary.

Best was all the home built, home tuned cars i've seen that simply had the chip pulled made more power and ran better.

What kills me most is the guys with gt40 iron junk that tune their cars. Why, seriously, why? There is nothing to gain. You can't afford better heads, yet you can afford a dyno tune or a standalone? Things like this happen because of internet misinformation.

If your car doesn't idle you F'ed up somewhere, it happens, we all mess things up, but a tune is NOT the repair.

Running non calibrated mass air sensors it another senseless move, especially on basic cars.

The argument could be made to run a tune to do away with the FMU, but the reality is that what the FMU does mechanically you are just doing with tuning. I forget his name, but a south jersey guy (that was well respected around here), did a write up on the comparison. Above my paygrade to explain properly and sensibly, but if i find the post, i'll add it.

I'd also like to add that the computer learning is over rated. No setup i've ever had learned a thing. They started and idled right from the get go. From basic to wild cams.

For me, these cars are black and white, you either did it all right or you messed up. Not a whole lot inbetween.

If the stock computer has failing caps, which i acknowledge can happen, it's sure as hell easier (and cheaper, caps are like 50cent or less each) to desolder and resolder half a dozen caps than it is to replace the system with a standalone.
If someone has the cap list of values, send it to me, i'll see if my guy would make a kit (i have a collection of arcade and pinball machines that need them all the time). Bet it would be less than $10.
edit: Slight off topic, but caps should be replaced BEFORE they are a problem.
 
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Noobz347

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...but the reality is that what the FMU does mechanically you are just doing with tuning.

This is incorrect. Some of your other assumptions are also incorrect but it would be like splitting hairs to bring the cumulative difference to the top.

An FMU closes off the return side of the fuel system to ramp the fuel pressure system up and out of the pressure operating range of the fuel injectors. Yes, we ALL KNOW THAT THE INJECTORS DO IT TIME AND AGAIN but that's irrelevant. They were not designed that way.

In order to "cheat" we stuff a high pressure, high volume pump behind them, close off the exit port, and run injectors to as much as 100psi in order to get the fuel [volume] necessary to support our HP level.

All on an 8 mhz computer that isn't really doing jack. It's controlling the idle and it's reverting to a preset table of values at WOT while completely ignoring input from [all] sensors with the exception of TPS and MAF.

Any monkey can tune for WOT.


Where faster processors and better tuner and [tuning] come most into play, is about maximizing power across the entire power band, having good street manners, a turn-key start, and not having to any magic throttle/clutch/rpm work through the parking lots. It also means that no matter where you are in the powerband that commanded AFR is not only being targeted but that adjustments are being made and stored to help ensure AFR is dialed in at all RPM and load conditions.

I have done both. I pushed my stock motor by mechanical means through:

Heads
e-cam
intake
SuperCharger

Manners on the street were night and day when I finally got around to ditching the FMU and tiny injectors and going to 42lb injectors and a simple chip tune on an A9L.

Among other things, Now I'm delivering fuel at stock pressures without some crazy ass 90 psi spray pattern :poo:ting fuel all over the inside of the motor versus 38ish and all of the fuel volume I'll ever need.

The term, "Calibrated Mass Air Meter" is a term invented by folks that are attempting to tune fuel injected vehicle by mechanical means. It means that they are using a stock computer in some combination of fuel pressure, FMU, and injector size in order to [hopefully] get into the correct AFR territory for given engine combination.

"Calibrated Mass Air Meter" means exactly dik to a tuner. If that meter is 1. Reliable and 2. repeatable then the "calibration" means nothing. A tuner will pull the mass air transfer curve from that meter and use it with [any] fuel injector or [any] engine combination regardless of what it was 'calibrated' for. :rolleyes:
 

General karthief

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Are we getting away from the main question?
I think so, I am talking about a near 350hp- h/c/i car, no blower, no turbo, no nitrous. I understand there is a limit to what the computer can do.
The reason I asked this is because of a discussion with someone that had a mustang tuned after a h/c/i installed by a 'mechanic friend' that told him he needed it 'tuned' after the install. Nothing out of the ordinary.
It bucked at low rpms and fell on it's face at wot. After the tune (I don't know who 'tuned' it) he mentioned it ran better, but still bucked 'a little' at low rpms but wot was great. He spent $450 on the tune.
Btw, I did check his tps and it was set @1.24 with the idle @ 900pms and wot was 0, he chose not to do anything about it.
Oh, and I out run him consistently with my 'closer' to stock stuff.
I feel he wasted his money and I think I can make it run better with a new tps, a screw driver and pull the chip out.
 

Noobz347

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There was a day when digital tuning option were few and far between. It was alien technology and nobody in the after-market supported it. There was a clear and real need for workarounds.

Many of those workarounds got pretty good. The thing is: They are all based on the premise of a pre-existing tune. The one that the fuel injected car came with. Mechanica workarounds for these alien devices is no longer necessary. Now, you can modify the initial thing in order to operate properly to mechanical changes that it was never designed to anticipate.

The same thing happens when there's a Block Change on an F-15. They add another couple thousand pounds of thrust along with thrust vectoring then update the software to deal with all of those changes. They certainly have the option o making mechanical interfaces to deal with the old computer and software but to the Airforce, it just made more sense to modify the computer to accept the upgraded hardware.

It doesn't mean that there is no place for mechanical mods. At what point does it become more efficient to just modify the software? Back in the day, that point was high. There were no options. Today, we have options and when those options make the matter simpler and more efficient, then that's when tuning becomes necessary.
 

Noobz347

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Are we getting away from the main question?
I think so, I am talking about a near 350hp- h/c/i car, no blower, no turbo, no nitrous. I understand there is a limit to what the computer can do.
The reason I asked this is because of a discussion with someone that had a mustang tuned after a h/c/i installed by a 'mechanic friend' that told him he needed it 'tuned' after the install. Nothing out of the ordinary.
It bucked at low rpms and fell on it's face at wot. After the tune (I don't know who 'tuned' it) he mentioned it ran better, but still bucked 'a little' at low rpms but wot was great. He spent $450 on the tune.
Btw, I did check his tps and it was set @1.24 with the idle @ 900pms and wot was 0, he chose not to do anything about it.
Oh, and I out run him consistently with my 'closer' to stock stuff.
I feel he wasted his money and I think I can make it run better with a new tps, a screw driver and pull the chip out.


This sounds to me like whoever tuned it, was a hack, and did it wrong.

The other thought that occurs to me is that there's is something physically wrong with the combo that no amount of tuning will fix.