gwhammy

I just saw where someone said they slotted the afc housing, can someone describe what this intails and what the benefits are to this. Is it mostly top end or does it help throughout the power band. Will it help on the combo I have on my97? Thanks Gary

INJECTOR JACK

I thought it came slotted?

infidel

Sure they weren't talking about slotting the TPS on an auto in order to adjust it?

INJECTOR JACK

Not sure what he is asking. If you are talking about the afc housing yes you can slide it foward and you will get more fuel earlier and more smoke it does the same thing as adjusting the star wheel but you will get more fuel and smoke. I would not do this on a auto with the stock convertor.

halerazor

i think he means what if you make the slots longer than what they are stock so you could slide the housing even farther foward

INJECTOR JACK

Well you might as well take the thing off if your going to do that.

CTD NUT

The AFC is just another internal throttle stop...........if the AFC arm stop travels past the farthest point of your fuel cam plate (another throttle stop) there will be no benefit and no increased fuel.........the AFC is just for boost enrichment control and should be set up to get bypassed once the throttle gets to a pre determined position.......ultimate fueling adjustments are achieved with cam plate profile and it's position..........it was mentioned that moving the AFC housing is doing the same thing as tensioning the AFC spring with the star wheel.........this is not true.......the spring tension adjustment controls how soon and how fast boost enrichment begins where as moving the housing controls the limit of boost enrichment.........really, we don't want the AFC to place a limit on fueling, we use the plate for that........that is why you move the housing all the way forward, to make sure the AFC stop is out of the way from the fuel plate at full rack travel.........slotting the housing and moving it forward even more will have no effect as long as it's stop is fully out of the way from the plate, which it should be unless you have some custom ground plate that is way too far forward........

INJECTOR JACK

I stand corrected!

CTD NUT

Sorry for the info over load .......I don't mean to come off like a know-it-all ............because I certainly don't know it all .........I just like to throw my .02 in the pot ya'know

gwhammy

I just saw on someones profile where they slotted the afc housing and it got me wondering if the afc could hold the fuel rack from going all the way open. Is there anyway to tell without completely diabling it. You can tell by my profile I am after max fuel, course I've got enough now till I can add the extra turbo. Uh, ya think a 0 plate all the way forward maybe to much!What about those lazer cut DV's CTD NUT, will they give me extra fuel too! I can hide cars at low boost I just usually choose not to. Thanks Gary

Don M

Most TQ plates, once slid all the way forward have way too much rack travel already. You mainly gain smoke and heat....not much power. IMO, the stock location of the AFC is fine.

I used a maximum of 17MM rack back in the days of the 215 pump. I now use 8mm. I had to build up my TQ plate by welding and ground it back smooth some to limit rack travel less than stock

The further you move the TQ plate...the later the fuel continues to be injected.
This, after a point, has too much fuel being injected late and the EGT climbs.

Don~

gwhammy

When you say late, are you saying late in the timing cycle? I guess any fuel shot in after tdc. is doing nothing but building heat? Is there no hp gain from this extra fuel or just not enough to justify the extra heat? I just thought you wanted all the rack travel you could get. Thanks Gary

infidel

I've found the most useable power is obtained by sliding the plate back about .15 from full forward.

MikeR

Me too. I've had lots of tune time on the dyno and found both my trucks made the most power with the plates 3/4 forward. They actually lost hp when at full forward.

Don M

Yeah, depending on the pump type, the size of the injector and the timing you can certainly get too much fuel that comes in too late to do much good with alot of rack travel. You can make a pile of smoke and add some additional heat. That last bit of fuel that is injected late wont add much to the cylinder pressure so it wont add much to the overall power sceme. The piston has just traveled too far down the bore to add much. Of course we still have guys removing the plate altogether.

Don~