ProtoCab

Fast951, how much are we talking for the MAF conversion for the Motronic? Protomotive's MAP Pressure Sensing conversion costs just over USD$2k, which includes a base map for whatever turbosystem you're running (i.e: their Stage 1/2/3/4 etc). It's really just a plug'n'go type setup without any real dyno tuning effort required since all their base maps are mapped on an engine dyno, on a similarly setup motor. By that I mean, a motor with 3.3 P&C's, GT2-EVO CAMs, Carrera Injection etc... Of course there'll be slight variations between each motor, but their base maps are designed to get you up and running fast, withouthaving to spend an exorbitant amount of time and money on chassis dyno tuning another aftermarket system like Autonic/Haltech/Motec etc...

BruceM, your car must be an animal! 600 engine HP is just insanely quick! My aim is also around that figure. Whether I achieve that with a TT setup, or a bigger single, I'm still undecided as yet

Rock on fellas

fast951

The beauty of a MAF is that you always know how much air your engine is taking. You spec out the MAf to support the target HP, set your AFR and forget it. The MAF conversion is $1250, add the PiggyBack which gives you control over fuel, timing to be 100% on target for your car, and you are still less than $2000.

The MAF software no longer comes on a chip. We have a designed our own board where we can store up to 16 images (race gas, pump gas,...) You select the image via toggle switches on the board. In addition, each image comes with different maps externally selectable via a switch. If you take a look at the 951 products on our website, the same is available for the 911.

I will be posting some more info on this on our site in a few weeks...

Don't mean to hijack this thread, if someone like to continue this discussion, please start a new thread..

Thanks.

edpurplett

.. EFI chat always welcome... Bruce.. you conveyed what I always thought (and heard) about Geoffrey :-)... and btw, was talking with Todd.. he's running 5 bar on the 52 lb injectors which shuld give about 650-680 at 1.4 bar on a 3.3 with TT...

Fast 951.. my only question is limits of MAF on high HP.... maybe I'm press sense/throottle position biased... :-)... less 'stuff' more airflow...

... come out and drive her... I want my new ride please ;-)

Ed

....

fast951

MAF can support lots of HP.. Based on experience, the MAF works much better with the Motronic than a speed density system.. A brief example..

At 1bar boost a map sensor gives you the same voltage no matter if you have a 3LDZ turbo or a huge Garrett.. Same signal for a 3.3L or a 3.5L.. It's sensing boost which is the same with all of the above combinations.

On the other hand a MAF measures the air ingested by the engine. Larger engine will take more air at the "same boost". The MAF will capture it, while the MAP will not..

Not saying a MAP based system is bad, there are many good stand alone systems that use it. When using the Motronic the MAF works much better... Do you ever wonder why the 996TT, 993TT use a MAF.. a MAP sensor is much cheaper than a MAF sensor, so why use the MAF?

We have seen few MAP systems used on the 951, they had many issues. Most converted to a MAF system, with great results...

Not all Motronic MAF conversions are the same. Some use a signal massager to emultae the AFM signal, this is a cheap not well done conversion. When converting to a MAF system, the Motronic code must be changed to understand the transfer function of the particular MAF. (MAF sensors do look the same, but they can be calibrated differently). So not all MAF transfer functions are the same..

We will be completing a 3.4L 930 in a few weeks. The goal is to program the desired AFR on the chip... More than likely, we will have a 96-98% dead on target AFR without any tuning.

Jean

fast951
Why is it then that all the race 993GT2 EVOs had pressure sensing rather than MAFs? A MAF setup will work fine up to a certain limit, high HP TTs with large air requirements will be limited by the MAF and performance and efficiency will suffer.
I have driven both and can tell you that my Motronic N/A pressure sensing setup runs as smooth as my FVD 540 MAF setup, only it is a gazillion times faster.

fast951

Jean, is the 993GT2 EVO running the old Motronic? No.. We are talking about converting the older Motronic (3.2L era) to a MAF from a AFM.

There are MAF sensors out there that can support 1000+hp.. You can even use them on the pressure side og the turbo.. So there will be no restriction in front of the turbo... A properly sized MAF sensor with the correct curve and correct size (70, 80, 90mm...) will not cause a restriction.

On your car with the speed density, make any change to your engine that causes a change in air flow (such a s a different turbo, a more flowing head,..). You will have to remap your system to correct the AFR. On a well designed MAF system it will compensate for it..

edpurplett

... fast951.. I agree with Jean.. with a caveat... to take a stock MAF system and try to 2.5X the horsepower .. I don't think there's one out there....so there are a lot of tweaks you need to do versus 'plugging in' a MAP and configuring it...

and as much as I agree with your 'displacement analogy'.. and I will further it by saying that to do it 'right' you need to periodically evaluate your 'tune' to accomodate changing engine efficienceies with wear.. If you drove my or Jean's car versus the NUMEROUS maf cars.. you would understand... though recognizing MAF IS getting better.... but the base parameters (ala 996TT need to be a bit stouter..)

.. I don't think many folks will spend money on an engine and not have it tuned... so if you want to build a MAF that will 'plug and play' with more variables on more configs.. enjoy... but Protomotive was 15 years ahead of the market with MAP... and was pulling 700+ HP from 3.5's 12 years ago..

Now people shrug about 700-800 HP.. and Todd just built a 3.6 with 862 crank HP with just 1.32 bar...with stock pistons and cams... as has Stephen.... the world changed... but for us with 930s and 993's I think MAP is the way to go all MHO.. but I would love to see your GUI....

.. just try to remember you're stepping on our $40-50k peni*es.. uhh engines....

edpurplett

BTW, new pics on 911turbo... about 15... since there is a size limit here.. and all I have are mostly 300-400k images...

fast951

edpurplett, I agree with everything you said regarding the evaluation of the engine from time to time. This is where the MAF shines, it always measures the correct air flow, which is directly related to your engine's condition.. The MAP does not see the change in air flow (it just measures boost).
I also agree about an engine needs tuning.. No there will never be a one size fits all kit, and tuning is required.. A kit can get you close enough, then you can fine tune it with the PiggyBack. Which gives great flexibility...

Take a look at the Motonic Monitor which displays the data as seen by the DME.. This image is for a 951 DME, the 911 3.2L is similar..

http://www.vitesseracing.com/Catalog...momonitor.html

A link to the PiggyBack which we use...

http://www.vitesseracing.com/Catalog.../SMT6/smt6.HTM

One more thing.. We are not taking the stock MAF system, we are taking the AFM system, rewriting the code to understand the MAF signal (transfer function)..

edpurplett

John,

Your tools look very nice and well thought out... (I wear CTO hat at our company)... eventually I think the world will be mostly MAF...

..... Have one of your customers buy my car and then see if you can make it as fast with your kit :-)

Ed

fast951

Ed, Didn't mean to hijack your thread, and didn't want to take anything away from your car, not my intentions. Your car looks one of the nicest I have seen.. If I didn't have a 930 already, I'll be calling you myself..