S-CAR MAF install in a hotrod 911 3.4L

[gliding_serpent]

Hi folks, some of you might now me from here, and here.

In short, I bought a bit of a fixer-upper 1984 911 3.2. As time has passed, my car is being molded into a bit of a dream car. Basically, take a childhood dream car, throw some money, blood, sweat, and tears at it... and make it your dream version of a dream car. What I have is a 2300lbs car with an engine and interior that sits somewhere between stock and full out race car. Call it a track car with class, or a road car with big teeth.

For those that know me, you know that I geek out on the technical aspects of engine design. I also kind of like custom, and innovative ideas. A few threads last year brought my attention to a Mass Air Flow (MAF) system by Sal Carceller (edit: this is him if you want more info- Pelican Parts Technical BBS - View Profile: scarceller ). I figured it was right up my alley.

So here it is


What we have here is a state of the art blade MAF sensor, six point modern injectors, a big fat cone intake, and a custom DME with customized performance chip for my engine that will be dyno tuned. (And detailed full color instructions with lots of pictures)

The cool thing here, is that Sal basically reversed engineered the code of the Bosch Motronic system, and reprogrammed it to communicate properly with modern injectors and the MAF signal. Everything is modeled in, including the minutiae of injector specs. It is literally all plug and play: Plug in your stock harness to the MAF and new DME. The only real work is the injectors, and I was able to do that, and it was my first time. (If I can do it, anyone can) You can opt to have him upgrade your DME, or get one of his units, and keep your original. I kept my original, and got one of his DME's.


The DME came with a custom 28 pin performance chip, modified to my specific engine specs, and my goals (91 octane, 6500 redline, etc). Once you get some data on the fly (he strongly suggests a wideband AFR gauge... and I don't leave home without it), and eventually dyno data, he can customize your chip further to refine it. Beyond power gains, and smoothness improvements, there are a lot of cool little features that I will not get into.

Another awesome feature? He uses 28 pin chips that can easily be reprogrammed. I bought this chip burner for maybe 25$ on ebay. If I need a code change, he can email it to me, and I can burn a new chip. He gave me a few extras, but I can copy over on chip many times. If I arrange it, I can be at a dyno, feed him data, and he can send me chip updates on the fly. It operates by USB.


As a quick educational session, why bother with a MAF? Well, a modern MAF has none of the shortcomings of the early ones, and they basically meter air mass, so they do the work of your Air fuel meter (AFM) barn door, air temperature sensor, and altitude sensor, all in one... and to a much higher precision. They also take into account for humidity. Basically what you have is more accurate air metering (and faster metering response rates).



No restriction here.


This is paired with a cone air filter to basically remove any chance of air restriction being an issue prior to the throttle body. An the best part, you have a nice bell shape curve connecting it to the maf. No circle peg trying to be stuffed into a square (AFM) hole. I just don't think you could reduce restriction anymore at this part of the intake.






To make the most of this high precision MAF, you want to increase the accuracy of your fuel output. Here we have modern six point (racing) fuel injectors. They are a direct swap for the original injectors (but they are more than that... read about the importance of proper injector modeling here). Also check out this video on the advancements in modern injector spray patterns (basically, better low and medium load fuel atomization). Sal has a few injector options he will provide for your build, based on your needs. Here are mine:


Up next is install...

[gliding_serpent]

A bit about my engine: I like to call this an engine designed to hit peak torque near stock rpm, that will be both reliable and driveable. This is not a "spinner". I want useable, reliable power. My focus is on torque and driveability, while still having enough power to pucker your bottom. No lumpy idle, and no reeving to the moon to get my power. Also, no fancy ($$$) custom head work (a secret to getting near stock engines producing incredible power).

- S-CAR MAF intake/chip
- 66mm overbored throttle body (3mm larger, good for 10% more surface area)
- six hole fuel injectors
- Max Moritz (Mahle) 3.4L pistons designed for single plug, 91 octane operation at 9.8:1 compression ratio (mine is closer to 9.9:1)
- 964 cams
- ARP bolts and head studs
- SSI's (soon to be custom headers with heat and larger ID)
- Dansk sport 2 in 2 out (70mm tips). Soon to be custom unit
- KEP stage 1 aluminum pressure plate with Sachs steel clutch
- 91 octane
- 6500rpm redline

I have been told that SSI's limit power to 260hp... so I am gunning to beat that number. With my custom headers/muffler coming (hopefully) soon, I am aiming for 275+.

And remember, with 2300lbs and ~275 hp, we are in modern 911 power to weight territory.

[tmaull]

Love it. Great pictures. I believe Sal just finished building my kit - Couldn't be more excited. I'd also like to mention what a pleasure it has been working with Sal. For a relative newcomer to the scene, his advice and wisdom has been incredibly helpful.

[Rodsrsr]

I also have one of Sal's MAF's on my 3.2 and it literally transformed the car.

[trader220]

Has anyone run this set up on a stock 3.2?
What are the benefits like?

Thanks

[dyerkes]

One of the greatest benefits of Sal's unit is that it comes with Sal. He is eager to share his knowledge with those that want to learn. Also, he stresses the importance of thoroughly evaluating that the currrent fuel and intake components are in good working order before beginning your conversion, and provides all of the guidance required to self evaluate each of the components. I installed my complete solution late last year, and could not be happier with the results. I was one of Sal's first people that installed it by myself. While I am very familiar with doing all of my own maintenance, this kit can be done by a first timer so long as you have patience and follow the directions. My '87 is pretty much stock with only the following engine alterations: 66 mm enlarged throttle body, SSI's (pre-Dansk), and Dansk 2 in/2 out muffler. My goal was just to have smooth idle, great throttle response, max performance from stock engine with the capability to evolve when/if I choose to go down the slippery slope of internal performance upgrades. Sal's solution meets all of these goals, and while at first it might seem expensive, the fact that your 30+ year old DME (that likely has some issues that you are living with without knowing it is the source) gets totally inspected, fixed if necessary and upgraded to a 28 pin performance chip, as well as your 30+ year old AFM (which likely is near end of life) is removed from the equation and replaced with a modern MAF and cone air filter (gone are the days of having to squeeze your hands into the cramped quarters of the engine bay to replace your stock air filter) and finally the old school and likely dirty injectors are brought into the 21st century with a new set of Ford racing injectors. All of the components are engineered to work optimally as a package. You have the option to retain your old equipment should you (stupidly) want to return your car to stock, or Sal will inspect and correct any issues your DME might have, and either leave it stock 24 pin, or upgrade it to a 28 pin chip with an '89 configuration should you want it. You can also sell off your old components should you want to recoupe some money.

I am preparing to take my car to be dyno tested shortly, but I want to do a valve adjustment and leakdown test to ensure I have a good baseline understanding of my engine's health. My engine now has 101k miles, having had a top end at 96k. Oddly enough, aside from a periodic puff of smoke at startup, it doesn't leak nor burn oil - I don't have to add oil in between in between 4k mile oil changes. I will post my Dyno results when completed.

[Ferrino]

This system looks to provide a brilliant update for the stock Motronic intake setup, especially as AFMs and injectors become tired. I have communicated with Sal and he is a true enthusiast! My only criticism is the dependence on an antiquated ECU that very few people can manipulate/map. That said, the injectors and MAF could always be recycled if you wanted to move to an aftermarket ECU such as a Megasquirt in the future.

[Rodsrsr]

Originally Posted by trader220

Has anyone run this set up on a stock 3.2?
What are the benefits like?

Thanks

My 80's 3.2 now runs as smooth as my 2011 Cadillac CTS. No more hesitation, accelerates smoothly across the entire power band, no more running good one day and bad the next day. The car runs perfect every time. I am a huge believer in this setup and yes Sal is incredibly helpful, and seems to be the one of if not the best with the motronic system.

[Quicksilver]

One of my main issues with changing to "upgraded" parts is that they are generally only tested in conjunction with large configuration changes. I'm not saying that you can't show that there is an improvement (or that it is bad). I'm saying you are never sure exactly what made an improvement.

If those injectors are an exact flow match for the stock injectors I would like to see a before and after dyno sheet and more then that, I would like to see a before and after smog test. I would think that you should see gains from improved atomization but I'd like to see hard data. (The video is impressive!)

Any chance this kind of test has been done?

[tmaull]

My plan was to dyno, before and after. Unfortunately, one of the stock injectors failed. So there won't be a "before" run.

[gliding_serpent]

Originally Posted by Quicksilver

One of my main issues with changing to "upgraded" parts is that they are generally only tested in conjunction with large configuration changes. I'm not saying that you can't show that there is an improvement (or that it is bad). I'm saying you are never sure exactly what made an improvement.

If those injectors are an exact flow match for the stock injectors I would like to see a before and after dyno sheet and more then that, I would like to see a before and after smog test. I would think that you should see gains from improved atomization but I'd like to see hard data. (The video is impressive!)

Any chance this kind of test has been done?

Oh it can be. I have my original afm, and i can run the stock system, sals injectors only, or the maf system. I could swap it all and compare the results. It would be very useful, and i for sure plan to compare stock airbox with his injectors to his Maf. That is an easy swap. Time, money, and reduced disire to spend my money on the Dyno (but mostly lack of time) is a deterrant.

Still, i have another chip for the stock system that i paid for and never got dyno tuned. I will eventually get that done as a spare. Maybe this summer.

more on how this system feels/works later. This thread lags reality.

[gliding_serpent]

So here we are before. Things ran well, but it was quite rich since i got the car (note i rune an AEM wide band air fuel gauge). I maxed out benefits from the afm mixture screw, and using the dme fqs switch. Fuel pressures were on the high end of normal spec. My engine bay is a mechanic's dream with backdated heat and no ac.


Here we are post install. The dme plugs in, the maf plugs in... And that was easy as pie. The injectors were a first for me. The passanger side was a breeze. I got overconfident on the drivers side and kind of glazed over Sal's detailed instructions... And got in a little trouble with access and seating one injector, and Maybe caused my swear jar to fill a little faster than usual. I solved the problem pretty quick however.






I guess Sal can swap the injectors in 20-30 min. As a newbie, i would be much faster next time. I suppose if you have a blower, you need to remove that, which adds a bit of time. For most of us (that have intalled injectors once), I think one hour would do it to install the entire system, assuming no bumps in the road.

I would like to go on the record for having the most accessable 1984 engine bay on the planet

[scarceller]

Few comments:

- The MAF will never pass smog simply because it will fail visual with that cone filter. If someone smog it it would pass with flying colors and fully supports stock O2 sensor feedback.
- I can run those purple 24lb injectors or 30lb bosch units that are more expensive to source. I can model just about any injector into the system from 24lb to 36lb possibly more but I tried to source injectors that are modern multi hole units at decent price. All are brand new OEM units.
- Folks often ask me what part of the system is worth what gain in HP. In the end I don't answer questions like this because they have little value, the system is a system of parts it's designed to use modern day better injectors to meter fuel and a modern day MAF to meter air. Why would I ever do one without the other? With that said I do also offer injectors with a chip and you retain the stock AFM, customers want the engine bay to remain stock or emissions but that offering is still not like the MAF system as it does not upgrade the air model but even that inj+chip offering has significant value, see this thread:
84-89 911 Exhaust, proven results!

Someone already pointed out that injectors are 30 years old and so is the AFM, often they are out of spec or about to fail at some point in the future. My systems simply address these components along with performance.

Many of my customers have made major engine changes, the MAF system was initially built for 3.4 or 3.5L upgraded motors and some with twin plugs. Mods like that are way beyond the capacity of the stock AFM and injectors. For example a 3.5L motor will drive injector signals to over 90% duty cycle, not a good idea to have injectors constantly on at WOT and high RPMs! Plus you may actually run out of injection time and simply run lean, this can easily happen on a very cold day where the motor takes in significantly more air mass! I also have seen the AFM issue first hand in a 3.4L where at hi-RPM WOT with the AFM we saw near 2PSI intake vacuum, then installed my MAF and intake vacuum dropped to 0.8PSI that's free power being left on the table with the AFM on a high reving motor.

[Jonny H]

Really cool product Sal, love it!

[Ferrino]

With a target of 275 crank HP, won't those 24# injectors be limiting? When I put 275 BHP into an injector calculator (at the Carrera regulator pressure of 2.5 BAR), I'm seeing a recommended injector rating of 31.5#, to get a duty cycle of 0.80. I'm using this calculator.

I was even going to go with 30# injectors with my stock 3.2 - plenty of example of hitting 250 BHP for stock 3.2 with exhaust mods and tune.

[scarceller]

Originally Posted by Ferrino

With a target of 275 crank HP, won't those 24# injectors be limiting? When I put 275 BHP into an injector calculator (at the Carrera regulator pressure of 2.5 BAR), I'm seeing a recommended injector rating of 31.5#, to get a duty cycle of 0.80. I'm using this calculator.

I was even going to go with 30# injectors with my stock 3.2 - plenty of example of hitting 250 BHP for stock 3.2 with exhaust mods and tune.

The 24lb injectors may be limiting and if they are we move to the 30lb.
Be very careful with calculators, the 911 motor is extremely efficient with fuel, way different than a V8 muscle. The 3.2L actually runs at about 102-105% volume-metric efficiency at 5800RPMs! and the torque on this motor drops hard after 6000RPMs. At 6000RPMs you have 10ms per crank rev so you have up to 9ms to fire an injector in batch injection after 6K the pulse width just starts to drop proportional to the RPM.

I have used 24lb injectors in 3.4L twin plugged motors at 280 crank horse and they stay below 9ms IPW. I have however recently moved to 30lb injectors as well.

The 911 motor has a Brake specific fuel consumption of about 0.4 not much higher than that. What helps is that the motor likes lean WOT mixtures around 12.8 to 13.0 to achieve best torque. Re-run the injector size calcs with BSFC=0.4 see if that changes things.

[scarceller]

That MAF with the cone filter is good for metering about 20,000 g/min of air, the stock 3.2L at redline 6500RPMs ingests about 11,000g/min. The MAF I use has tons of headroom and very little pressure drop across it at 15,000g/min. Reducing the pressure drop is what's most important.

[Ferrino]

Originally Posted by scarceller

Re-run the injector size calcs with BSFC=0.4 see if that changes things.

25# recommended for 0.8 duty cycle at 275 BHP and 2.5 BAR fuel pressure.
23# recommended for 0.8 duty cycle at 250 BHP and 2.5 BAR fuel pressure.

[scarceller]

Originally Posted by Ferrino

25# recommended for 0.8 duty cycle at 275 BHP and 2.5 BAR fuel pressure.
23# recommended for 0.8 duty cycle at 250 BHP and 2.5 BAR fuel pressure.

What's missing in the calculator is understanding what RPM is assumed for the 80% duty cycle.

But I already am aware that a very hot 3.4 or 3.5L with good torque above 6000RPMs needs 30lb injectors and I already have this solution. I'll so have 34lb injectors also modeled.

[jpnovak]

This is such a great solution. Well engineered and implemented. Thank you Sal for the effort.

If only I Had a 3.2 to install one.

How hard would it be to modify your motronic-base MAF for other engine sizes?