fast951

The sale takes place 9/17 through 9/22. I updated the first post.

I might be adding a few more items to go on sale, so stay tuned!

daigo

Like a very special custom turbo?

tommye

Hi !

If I understand correctly, the stock AFM is getting maxed out at somewhere around 4-5000 rpm (full load). From there on, the system relies on full-load lookup tables and is not using the AFM input at all.

Are you saying that your MAF system is using the MAF-SIGNAL all the way up to 700 hp (as opposed to only being able to flow this amount of air) for controlling injection/timing ?
So, no more fixed full-load maps ?
And, what happens beyond 700 hp ?

Cheers,
Tommy

stv951

John,
you state that you can alter the maps and rev limiter "on the fly" between two settings. How is this done ?

also, what would be the performance gains of a MAF kit alone (as well as 72 inj) when used with stock turbo ?

fast951

Tommy, The stock AFM or inproperly sized/calibrated MAF will give you a 5V signal at lower air flow. The RPM where it maxes out, depends on the boost and turbo you are running. The AFM flows generates a 5V (actually a bit less) at a flow of approx 800-1000kg/hr. So once you hit the max flow, it will generate the max signal. To figure out when a MAF or AFM maxes out you must know the max flow in kg/hr that they support, then figure out when your engine will flow the max Kg/hr and that's where you max out the sensor.

Our software uses the MAF signal all of the time, be it for 200hp or 700+hp. The same MAF is used on 300hp engine or 500+hp engine. You run 12psi boost or 20psi boost, we know how much air is being consumed and the AFR will be accurate.

The MAF we supply is calibrated to support in "excess" of 700 hp. I doubt any 951 will max it out! However if you have a 951 making over 800-1000hp or more, not a problem we can set you up with a MAF unit to meet your requirements.

fast951

We use a external switch to select between the maps & rev limits. We designed the software for this.

Gains with a stock turbo & MAF have been discussed plenty, a search will get you lots of info. To sum it up, the MAF opens up the intake, you get quicker spoolup (translates to a wider area under the curve), and the engine is more responsive. Peak numbers will not increase much as the K26 is the limiting factor. So you gain a larger area under the curve, more response.

Geneqco

Very nice write up and approach John - well explained!

fast951

Thank you, we are very pleased with the results.

fast951

UPDATE - 9/17/07
I already shipped the first batch. I will have the next batch going out soon.

We are down to the last 3 Stealth Kit. I will post updates as needed.

Thanks.

76 911s

What else is going on special? PiggyBack maybe.....?

grosminet

I John,

Your note is: Note: We noticed the stock injectors hitting 100% duty cycle with the MAF. You should upgrade the injectors when upgrading to the MAF.

So, with a 87 turbo, stock turbo, catbypass and 3 inch exhaust, which injector i need ? 55#?

If i install a bigger turbo in the futur, is the maf need to be adjust ( chip change ) or it's ok for any turbo.

Thank you !

fast951

With the stock turbo, if you are running around 16-17psi boost, we noticed the injectors reaching 100% duty cycle. Any injector operating at 100% duty cycle is not safe for an extended period of time.

The MAF can be used with larger turbos.

Naplesguy06

John, will this stealth maf work with a powerhaus k27/8 turbo?, do I need the j boot or homp hose as AA calls it. Will the stock airbox work with my larger turbo or should I go to the k/n standard maf setup? Can you burn the chipset to work with the agenda that I have already which is a k27/8 turbo,your maf,chipset and a nice broadfoot 3 inch exaust with cat elimination, and of course the larger siemens injectors(low impediance) and maybe a perfect power smt-6 piggy.
Thanks,
Naplesguy

fast951

The Stealth MAF works with the turbo you have. Things to keep in mind that the opening on the factory air box is smaller than 3", so in theory it will not flow as well as the std. J-pipe. Are you going to tell a difference, I don't know I never tested this combination to see the effect on spoolup etc. Also the factory J-boot must be modified to fit the K27 2.75" inlet. The std. J-pipe to run the MAF in std configuration can be added at any time!

The software can support larger injectors, I just need to know up front what we are using. The 3" exhaust is terrible, send it to me to junk it. K/D, exhaust is not a problem so is the PiggyBack.

Please email me directly if you have any questions regarding your own setup.

tommye

John,
How about using 3.8 Bar FPR, standard injectors and K26/8 ?

Tommy