kliftin

I think its perfect. Can anyone argue with this. I dont have a picture of what your set up is looking. In my head I mean. How long is the bike cable. Whats supporting the rod and shaft.

rx7_turbo2

I see this mod as a hack job, a half assed attempt at gaining power. It's no offense to anyone who chooses to do it, it's just not the way I want to go. I want the mods done on my car to be done properly. I rank this mod right up there with the morons who wanted to bolt a leaf blower on the intake of thier n/a.

Ryde _Or_Die

Anyone?

Mazda2ndgen

dude, i really like your idea! i think its a great idea. adn i dont see any porblmes with it at all. Iam going to try it as soon as i get my car put back together (motor comes out on saturday!). you *may* still need the afc depending on how lean you acutaly run. im not sure how much adjustment you can get from teh afm its self. but its defianly something to try first!! i think thats the best idea yet to running with no afm. good thinkin dude

Gearhead

iTrader: (1)

Guys, you are trying to turn a volume system into a speed density system. I don't think it will work. The problem with the afc hooked to a linkage is that when you hit the pedal the computer will think the engine is drawing in as much air (right off idle) as the car would draw at 7000rpm at WOT. It can be done, but it takes different hardware (computer or replacement afm). Hell, you guys might as well try to cook toast with your PC. Besides, I don't think that the car really ran a 15.2 on the front rotor. I would imagine it finally let go near the end of the run. The AFM is restrictive, but not that restrictive. I'm not flaming anyone. I'm just trying to save you all some time and engines.
Don.

Mazda2ndgen

actualy, as soon as the thorttle plates open all the way the flapper door swings all the way open. I varified this. I started the car, looked down the afm, and opend up the throtttle, and no matter the throttle posistion, as soon as you go wot the flapper door goes all the way open. so i think the linkage would work.

I cant tell you for sure when the motor blew. In 1st gear it felt fine and had more power than normal. when i shifted to 2nd the car hesited, and had no power, and my friends who were watching said the color of the smoke htat came out of the exahsut changed when i shifted to 2nd. i assumne i lost the rear rotor after 1st gear.

i am not sure just how much power is to be had either, but my car has just about every imaginable mod done to an na that you can do except for porting the motor (will be done soon) and the car still only ran a 14.8. with na cars you have to be imaginable and try new things to gain more power, b/c there just isnt a lot to offer with just boltons.

B430

how about this idea, you have a Y shaped intake, on one side of the Y is the AFM, the other a straight pipe (with a filter on the end) the bottom of the Y connects to the intake. this was 50% of the air goes through the AFM and 50% through the straight pipe, this means the AFM will be seeing 1/2 the air as before, which can be corrected with an S-AFC. it will also only have 50% of the restriction that was there before. you would have to play with the diameter of the unmetered pipe though because more air would tend to go through it if both sides where equal size because there is less restriction there. this could work even better if you had larger injectors because instead of leaning out the S-AFC you could make the unmetered pipe larger, reducing the intake restriction even further. just an idea.

tweaked

iTrader: (4)

No offense but that is the least thought out idea I have ever heard or read.
the air would just com in through the filter side and not the AFM sid at all.
try this, unplug one of those hoses on the intake pipe. Your car will die. you need to compensate for the extra air.
the air is going to follow the path of least resistance.
Now, if you could take two AFMs and make them work as one as far as the puter is concerned that would reduce som of the resistance. but you would have to make the signal that the computer sees the same as before.

FPrep2ndGenRX7

If you have to buy the S-AFC to correct the mixture what is the point in messing with everything else. Its my understanding the the Haltech doesn't need the Air Flow Meter(AFM). You guys are trying to get rid of that restriction. There is a unit available from www.sdsefi.com that will get rid of the factory AFM meter. It is a stand alone unit that doesn't need a laptop to make changes. You will need to add a 81-85 distributor to your car and two regular coils since this unit does not control any ignition functions but the system is proven to make more HP than the factory setup on a stock port engine. It can be used on the factory intake with the factory fuel injectors and fuel rails. Do the throotle body mod, port match your intake and get some ricer intake tube/filter to put on your car and be done with it atleast this is the route I'm going.

How much does the S-AFC and all the required extra pieces cost? The SDS unit and everything you need to put it on you car would cost less than $1000. Now $1000 is a good sum of money but no where near the Haltech stuff and you end up with something that is very reliable and programable.

Ryde _Or_Die

I have seen the S-AFC for $350-$450. If you are paying anywhere more than that you might as well go haltech and have complete control.

Gearhead

iTrader: (1)

I doubt that there is enough airflow right off idle even at WOT to open the AFM all the way. Have you measured it with a scope or your eyes? There is a big difference in almost all the way open and all the way open. It is not a linear progression. Let me know if you get thit thing to work. I'd be surprised. Again, I'm trying to help. I know quite a bit about how the FI system on these cars works, and I don't know of a way to fool a volume system into thinking it's a speed density system... which is what you guys are trying to do.
Don.

B430

that's why you don't make each side equal in size, you make it like this:

only using an S-AFC to correct you might be able to make it a little bigger.

FPrep2ndGenRX7

That is a better price than the SDS unit. I'm not familiar with everything it is capable of. Can you run it as a stand alone controller or do you have to use it in conjunction with the factory computer? The SDS eliminates all the factory pieces and has its own sensors to be used along with a new wiring harness.

B430

the S-AFC just overrides the signal from the stock sensor tricking the ECU, you still need to have the ECU and stock sensors though.

FPrep2ndGenRX7

The SDS unit definetly cost more but in my mind its a better deal. You get a new wiring harness(important on older 2nd gen cars) and eliminate the restriction(AFM) that this thread originally started talking about.

Thanks for the information B430 and Ryde_Or_Die.

Jahoo88

I just came across this thread. I have an idea too.

Say you do that same thing as in the last pic, a afm bypass to allow more air thru but have a valve in it and open it via solenoid only at WOT. The car already runs fairly rich at WOT so it shouldnt matter but you might get a few horses.

What do you guys think?

Angel Guard Racing Team

If you lean out at high rpms you will hear your engine knocking that means it went too lean and there is an 85 to 90% chance to warp or break the REAR apex seals.

Can anybody tell me why 95% break on the rear when they go lean?

rx7vadim

CAN SOME1 TELL ME MASUREMENTS OF AFM PASSAGE ? and 3 throtle body passages?
so that i can calculate sq"area) that way i can give you % of afm restriction.

toplessFC3Sman

iTrader: (1)

good job bumping an insanely old thread....
but for the record none of these will work, not even the afm-hooked-to-the-throttle one. if you mash the gas pedal at low RPMs in gear... say about 2500 rpm in 5th gear, the engine wont be sucking as much air as it would need at 7500 rpm. actually, it will be sucking roughly a third of the air. however, if the "afm" that's now a glorified TPS was stuck in this position, it would tell the computer that the engine needed enough fuel for maximum air flow, whereas it would only actually need 1/3 of that. To get around the AFM, you would need a combo of pressure and temp sensors at a known cross-section piece of the intake (that's also been flow tested and documented, to get a map from which to match intake pressure and intake temperature values to an air mass flow rate), and then use atmospheric P and T sensors for corrections. Either this or use a hot-wire anamometer (i think thats the spelling) that keeps a constant T in the varying airflow, and by measuring the current and current change required to maintain that temp, it can calculate the mass of air flow around the wire. However, removing the afm and not replicating it's function somehow is just idiotic. The AFM signal is used to figure out an estimate of how much fuel is needed at any one time (which is then corrected for with the O2 signal in certain modes), and the TPS is for trying to get the transient response correct based on driver input.