[Ggradtech]

I've read a few posts where guys run turbos on Fox Mustangs and the stock ECM with no tune? How is it possible that they do this without running the car overly lean and melt Pistons? I've read they use "timing" and "fuel pressure" without dyno tuning or a chip. I just want to understand how it's possible . Thanks!!!

 

[5.0thunder]

Idk how they'd do it honestly and I can't imagine it will survive for long or run optimally. they may be able to use a mechanical dizzy with a BTM to pull timing or maybe set the TFI dizzy at full timing with spout out and use BTM with it. the stock ECU wont pull timing and I don't think it can read positive pressure to know when to pull it.

the fuel pressure regulator will increase fuel pressure 1:1 with boost when the regulator itself is referencing a boost source, so yes pressure will increase and injector flow will increase but that doesn't actually account for the change in combustion characteristics with added pressure and heat. Fueling isn't a perfectly linear increase so I don't think the stock map wouldn't suffice for all of the load region above 100kpa.

only thing i can imagine is that maybe they get these cars running a decent AFR at WOT only by throwing a big injector on it and playing with fuel pressure.

 

[snipe656]

We used to do it all the time but there existed a time when a chassis dyno was unheard of let alone any real form of tuning aids. The real key to it was getting a MAF that truly was calibrated for the combination and quite often you would order a MAF for that and it was not actually calibrated as it should. It all depends on power levels of course but we had a number of cars well into the 10s going that approach. We did not lock out the timing, we did not use BTMs, and we did not use FMUs. I will admit we initially tried BTMs and FMUs but those just never work out well on turbo cars, nothing like with a supercharged car. Friend of mine up near Chicago still has his old twin turbo 93 LX that has a stock shortblock and HCI. He is running my old 50 lb injectors and some Pro-M meter if I remember correctly. That car drivers perfectly on the street, hard to tell it even is modified, yet runs deep in the 10s.

Most people do it now days I think via locking the timing though. Really given what it costs to get a custom tune via a chip I do not understand why bother, I would just do a custom tune.

 

[5.0thunder]

for blow through carb we just lock the timing at 34-36 or whatev and pull timing per lb of boost with a btm or other ignition control. it works fine that way if your starter can crank the engine over at full advance. idk how your stuff lived advancing that much on anything over 4psi at full load. I've read that you can get away with stock advancing on low boost like 4-5psi but up near 10psi, you need to have the timing pulled back a bit. about 1deg per psi or so (depending on combination) just to avoid detonation. I use the Megasquirt standalone setup so i have full control but before I bought it, I had read about people doing this also and wondered about it too.

 

[snipe656]

The problem we always ran into with pulling timing out per lb of boost via a BTM on a turbo car is how the boost curve is and with more street-ability issues, just got loading up problems more times than not. Now for WOT we could make it work well. We quickly ditched BTMs because of that.

Heck I ran 18 lbs of boost on one of my old combos using stone stock ECU. I tuned the thing via reading plugs and an EGT gauge. That was my daily driver too, drove great for a year or two before I took it all apart to go to a bigger combo. I did have a BTM on that setup so i could turn things down/up depending on if I had access to race gas to mix into my tank.

 

[5.0thunder]

The problem we always ran into with pulling timing out per lb of boost via a BTM on a turbo car is how the boost curve is and with more street-ability issues, just got loading up problems more times than not. Now for WOT we could make it work well. We quickly ditched BTMs because of that.

Heck I ran 18 lbs of boost on one of my old combos using stone stock ECU. I tuned the thing via reading plugs and an EGT gauge. That was my daily driver too, drove great for a year or two before I took it all apart to go to a bigger combo. I did have a BTM on that setup so i could turn things down/up depending on if I had access to race gas to mix into my tank.

What did you adjust to tune it? base timing and fuel pressure? I can't imagine much else is controllable on the stock setup.

 

[snipe656]

Going off an old memory but if i remember correctly the FP was set to stock and base timing set to 18. But I might be mixing those numbers up with a combo when I used an FMU and if so that was on a Vortech combo. I honestly do not recall on any combos running FP too much above or below stock. It usually all boiled down to adjustments to timing, spark plug gaps, and spark plug selection. The times FMUs were used, then bleed off valves on those along with disc selection inside the FMU. I am sure we were never making near the power levels we should have been making. I am also fairly confident most of the time the cam selections hurt power more than helped. That was a different time for sure.

 

[5.0thunder]

Oh, okay. Seems like it'd take quite a bit of trial and error, and possibly a few spare engines. Lol it's always interesting learning about how people did stuff before all our modern tech was available. Some of the best are the engine building tricks employed in "stock" engine drag classes.

 

[snipe656]

Yeah. I remember when Murillo clued me in on getting an EGT gauge to help figure things out. No one I knew ever heard of such a thing. I also distinctly remember being on the street behind Murillo's then Texas Jam shop and he/I doing quick test runs in my car to try and dial things in. Do WOT through 2-3 gears, look at peak EGT and pull plugs ... repeat process until feel you got it all figured out. Now days just build the car following a recipe countless others have followed then load up on a dyno and get it tuned, so much easier but almost takes a little fun out of it for me ... almost.

 

[dmills4229]

I wondered the same thing as OP when I bought my car. It had a Hyfire ignition, 42lb injectors, and C & L meter. Hyfire was set to retard the ignition based off boost read from a MAP sensor. Only ran 6lbs boost, but it worked decent. Drivability was OK. Simple setup.

 

[MJs89GT]

I ran my car untuned at 16psi with a pro m maf and 39lb injectors with an fmu. i used to lock the timing at 15 degrees.

A friend still has his car untuned with the same setup on a 351 and has seen as much as 19psi before it ran out of fuel.

My car ran good for about two years before i upgraded. Buddy's car is still going strong, has been for about 4 1/2 years now.

 

[87Saleen209]

I had great success with an untouched A9L, blow-thru 76mm C&L MAF cal'd for 42's, 45psi base fuel pressure, pulled the SPOUT out with a stock TFI distributor with locked 20* timing, 110 octane fuel, and 22 psi boost on a 67mm turbo and Dart block 347 (Performer RPM heads none the less). I used a TH400 trans. I made tons of 1/4 mile passes and eventually ended up at 9.81 @ 139 mph. There have been many that have done it with great success. If I built another car like that, I wouldn't change a thing. The car was ultra reliable, never had a problem with the engine.

 

[Radrick50]

Yep...I'm right there with some of you guys...back in the late 90s and early 2000s, I ran a stock block 306 with a 66mm and tuned with a Crane HI-6TRC to pull timing, 42 lb injectors with a big fuel system...car ran 9.90s for 5 years before it cracked the block and lost oil pressure.

I'm currently running a stock EEc-IV with my girlfriend's car...351W with a Novi 2000 and 42s...car runs mid 10s and drives like stock.

 

[sen2two]

Reading through this... making think about doing the same. I normally go standalone. But damn, rarely does a full standalone drive as good as stock and always needs retuning.

Anyone here doing this currently?

Did you just buy any calibrated MAF for your size injectors? Or did you have to order one directly and let them know it was going to be used for turbo?

 

[Radrick50]

Reading through this... making think about doing the same. I normally go standalone. But damn, rarely does a full standalone drive as good as stock and always needs retuning.

Anyone here doing this currently?

Did you just buy any calibrated MAF for your size injectors? Or did you have to order one directly and let them know it was going to be used for turbo?

On my turbo car, I ran a Pro-M 3" Tube blow-through meter calibrated for the 42s...worked great! On my girlfriend's 351W with the blower I run a simple C&L 80mm MAF with the 42 lb injector cal tube.

 

[snipe656]

A few things that really turned me off my first fox body was going to a stand alone, going to a big fuel system, and ridiculous monkey gym cage. Something to be said about the driveability of a well sorted out car using the stock ECU. Now when I had my black car with a Vorturd on it, I did have a custom tune done using the stock ECU and in hindsight I really should kept that car, at least kept it for a few years longer.

 

[5.0thunder]

If I had known all this when first building my turbo car, I would have gave the stock computer a chance and just locked the timing at 24 or so. i'm sure it wouldn't have been optimal timing curve at all but it would have got me going nonetheless

 

[sen2two]

I have a plug and play AEM right now. But I'm thinking of swapping to this extremely basic set up. After doing some searches on Google. Seems there are plenty of people with good results. I really havn't found anyone complaining it didn't work...

For low boost stock-ish motor, this might be the way to go for a street car.

 

[5.0thunder]

I have a plug and play AEM right now. But I'm thinking of swapping to this extremely basic set up. After doing some searches on Google. Seems there are plenty of people with good results. I really havn't found anyone complaining it didn't work...

For low boost stock-ish motor, this might be the way to go for a street car.

It won't be optimal, but it might work okay. if you can't control fueling and timing on a per load or per rpm basis, you'll never get it dead on but it'd be interesting to see how well it does.