Mike,
I have a question and hoping you can answer it.
We have installed a P-1SC Procharger on our 98 F-150 w/automatic and the 4.6 litre engine we have kept all stock settings in the computer (no chips) as recommended by ATI instruction manual and the only other modification is a Baumann shift kit set for supercharged applications. My problem is this when the vehicle reaches 100mph a top speed limiter comes into play and shuts down the truck till you return under 100 mph. I have been advised that the 5.4 litre trucks don't have this limiter in their computer. What needs to be done to eliminate the limiter and keep the stock engine tuning. We researched the Hypertech PP3 and found that it only allows us to raise the limiter to 128 mph. Customer wants limiter gone.
Thanks in advance for any info you can provide.
Jack

 

I beleive superchips microtuner can do the same thing. As for keeping engine stock with an ATI, thats not a necassity. As a matter of fact you can get a lot more out of your blown application with a well done chip. Also, the 5.4L cuts off as well, I think most vehicles now days have the cutoff.

 

Yes they do.........I have been told that the limiter on vehicles is there more for the stock recommended tires than anything else. It makes sense to me....with law suits and what not being so prevailant.

My buds Dodge has a limiter of 120....but his tires from factory are rated to handle this.

One other thing I will offer up is taht if the fuel pump and injectors are not upgraded....you may have trouble feeding the beast enough to get it much past 120 anyway....this is speculation based on what I have read here and there on these forums, not from personal experience.

I just thought of something else.....is it possible that the rev. limiter will get ya if the speed limiter doesn't? I guess it depends on the gearing and what not.
The more I think about it....having an ATI with no chip or power tuning seems like getting a hamburger with no french fries.


Rocks

 

Thanks for the reply guys! For some reason this customer loves top speed and is not interested in any 1/4 mi. times only top speed. This truck has stock gearing so I dont think the rev limiters gonna get him. He has already installed hi-perf tires. I guess my only option is to call Mike @ Performance Products and talk to him about the chip. I called Superchips directly on Friday and they scared me half to death with the cost of a chip. Thats why I was looking for an alternative for the top speed bypass. Thanks again for the replies. This group has a great forum going here
Jack

 

1320racer,

If the customer is most interested in top speed, definitely ask mike about your injectors....I believe the ATI comes with a booster pump doesn't it?
Anywho, I can tell you that with my mods. I got up to a top speed of 118 mph according to my auto tap. At that point I felt as though I could get more out of her but the darned thing seemed to want more go juice. I only have the stock fuel pump and injectors and I believe Mike is the one who had told me that they are only capable of x amount and then after that it is like hitting a wall...no more go faster.
I was going to upgrade the injectors and pump but instead I decided to go ahead and get a faster truck...LOL. Get my truck ready Ford...LOL.


Rocks

 

I believe that the stock 19 lbs. injectors can handle just over 300 HP in the 5.4L configuration. I am not sure what their capabilities are in the 4.6L configuration. The chip would probably be the easiest way to eliminate that top speed limited & get more HP & TQ out of the correct tuning for the supercharger. Of course he owner would have to run high octane fuel (above 91) and it will help firm up the shifts some more as well. Talk to Mike T., he won't mis-guide you at all. He knows what he is talking about and even though we can't talk prices on the board. You do get a discount for being a member here and besides I don't think that the prices are all that bad for what you get in return.

Have Fun & Keep on Truckin'
Dean

 

With my 5.4 im currently putting down 298 horse to the rear wheels (in a 4x4 with 33" tires). The stock fuel pump should be good to about 400flywheel horse or so. The boost-a-pump with the ATI is as much for preasure as it is volume. Due to the small #19 injectors, in order to get enough fuel the FMU restricts the fuel return line (via boost, more boost=more restriction = higher preasure). I saw my truck hit 135 on the dyno at 5200rpms so I know these trucks are capable of decent top speeds. I agree with Izzy that chip would be the best way to go and it will help take advantage of the ATI as well. Additionally you may want to relocate the air temp sensor form where ATI recommends (which is between bypass and blower) to before the bypass. It gives some additional power as well.

The stock 80mm MAF seems to reach peak voltage at approx 4800rpm and after that the 5.4 starts to go lean with a stock fuel system. There are a lot of us in the blower forum taking the ATI to the next level. Im simply waiting for a chip and in go the #42 injectors, 90mm MAF, in tank 255lph fuel pump (and out with the boost a pump and FMU)75 mm throttle body and a 12PSI lower pulley and I should be in the neighborhood of 400rwhp.

 

Hi Jack,

What you've run into is the top speed limiter, which you will find on almost every computer-controlled vehicle ever made by any automaker. Generally, the only exceptions are perfiormance vehicles, like the SVT Lightning, or SVT Cobra, Corvette, etc., which will have TS limiters of 155 mph or higher, and some performance vehicles have none at all, but that's pretty rare. Even most performance vehicles have some kind of TS limiter.

It is *not* true that the 5.4 F-150 does not have a top speed limiter, or that it's TS limiter is any higher, it's the same as the rest of the F-150's, usually 98 mph but can be as high as 108 mph.

These late-model F-150's typically have a 98 mph top speed limiter, though they can range from a few (usually V-6's) being as low as 95 mph to as high as 108 mph, but most 1997 & up F-150's have a TS limiter of 98 mph.

The bottom line is yes, we can proivide you with stock tuning and just have the TS limiter removed if that's what your customer wants, no problem, just give us a call. I would advise having us tune that vehicle *correctly*, as the A/F's will not be close to optimal on the factory program with the ATI FMU setup (or with any other blower & FMU setup, they all have room for significant improvement) but that's of course up to the vehicle owner.

Give us a call when you get a chance, and we can go over all the other details if you like as well, from tuning to mechanical configuration, limits of stock fuel pump, injectors, MAF, TB & everything else for these F-150's.

 

Hi Jack,

Just a quick note to say thanks for calling, I enjoyed speaking with you the other day.

Hi Zyg,

Thanks to you for calling as well, I enjoyed getting a chance to talk with you at some length, & we got your fax.

Hi IzzyEddy,

The 19# injectors are good for the exact same amount of horsepower on either the 4.6 or the 5.4 V8's in these vehicles. Or any other 8 cylinder engine that is naturally aspirated & has a fuel injector for each cylinder, for that matter.

The power level the same size injector can support at the same rail pressure and with the same number of cylinders (hence the same number of injectors) does not change with engine displacement. That only changes based on things like whether the engine is naturally aspirated or has forced induction (supercharged, turbocharged, etc.), and the number of cylinders an engine has, which dictates the number of fuel injectors it has in most modern engines.

Whether an engine is naturally aspirated or supercharged affects the BSFC (brake specific fuel consumption), a forced induction engine is going to need, on average, about 15%-20% more fuel to make the same amount of power as compared to a naturally aspirated engine making the same power level. The number of cylinders an engine has will also have an effect, of course 19# injectors cannot support as much power in a 4 or a 6 cylinder application as they can in an 8 cylinder application, simply because with more cylinders you have more injectors, 1 for each cylinder in the engines we're discussing here and most other modern fuel injected motors (Mopar V8s excepted).

Just FYI...................

 

I knew that Thanks for the information Mike. All I know is someone had to change out thier injectors for larger ones so they could get more HP & TQ. I wish I had that problem.

Have Fun & Keep on Truckin'
Dean