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Attn: Bill.. (fuel injection)

X 91_XR7
ahh i hate hijacking another thread not related to this so... :)

"For me, my disappointment is really more a matter of trying to run close to the edge A/F wise. The duals seem to have enough tolerance buildup in the linkage, TB difference, perhaps manifold porting, etc. etc. that I can't get razor sharp (e.g. 14.7:1) and have it run decent at all. If I am down around 11.5-12:1, the car is a beast, but those numbers are more like Turbo numbers, than NA cars. I just can't lean it out without it starting to run poorly in the mid-range. I was hoping to be able to get to the point I could strap a CAT on and pass SMOG. My car is SMOG exempt, but I wanted to clean things up if I could, without sacrificing performance. No way Jose, at least with Duals. "

Hmm and i take it your running the wideband o2 now right?? Well to get near perfect 14.7 is not a easy thing to do, even with a closed loop system.. Well if you got all throats tied together with hoses (IE balance pipe), the varibles between openings should have droped.. the linkage one can get dialed in to be nearly perfectly opening up side-to-side.. luckly on Webbers it's easier (i choose while running) since you can `listen' to the engine.. Also you got one the schycro thingys right?? :S
Also had you played with Sparkplug gap, Fuel pressure, check vaccum levels, i noticed you said you had more vaccum with the FI setup as oppose to the Webs?

The single TB setup (with one of the duals right??) may work.. also the setup looks not too bad either :) But wouldn't the runners be just as long or shorter but `laying down' instead?? :S

Also the EDIS module inside will work.. :) in around '96 ford went with the EDIS controls inside the ECU for that reason thou..
the coil packs should be okay.. heck mine are mounted to the front of the engine :) (4.6L v8) so yah, they should be okay there :)


Sorry i just hate to see an idea how i want to do a FI type 1 engien going blah :) Mind you i do not want to run MS, i want to use a Ford ECU (OBD1) and a Maf Sensor and a turbos induction system yes ugly but, can't see how else to mount the MAF sensor :S Also shoudl work, if i can find another 2.3L Turbo :)


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X 91_XR7
ahh i hate hijacking another thread not related to this so... :)

"For me, my disappointment is really more a matter of trying to run close to the edge A/F wise. The duals seem to have enough tolerance buildup in the linkage, TB difference, perhaps manifold porting, etc. etc. that I can't get razor sharp (e.g. 14.7:1) and have it run decent at all. If I am down around 11.5-12:1, the car is a beast, but those numbers are more like Turbo numbers, than NA cars. I just can't lean it out without it starting to run poorly in the mid-range. I was hoping to be able to get to the point I could strap a CAT on and pass SMOG. My car is SMOG exempt, but I wanted to clean things up if I could, without sacrificing performance. No way Jose, at least with Duals. "

Hmm and i take it your running the wideband o2 now right?? Well to get near perfect 14.7 is not a easy thing to do, even with a closed loop system.. Well if you got all throats tied together with hoses (IE balance pipe), the varibles between openings should have droped.. the linkage one can get dialed in to be nearly perfectly opening up side-to-side.. luckly on Webbers it's easier (i choose while running) since you can `listen' to the engine.. Also you got one the schycro thingys right?? :S
Also had you played with Sparkplug gap, Fuel pressure, check vaccum levels, i noticed you said you had more vaccum with the FI setup as oppose to the Webs?

The single TB setup (with one of the duals right??) may work.. also the setup looks not too bad either :) But wouldn't the runners be just as long or shorter but `laying down' instead?? :S

Also the EDIS module inside will work.. :) in around '96 ford went with the EDIS controls inside the ECU for that reason thou..
the coil packs should be okay.. heck mine are mounted to the front of the engine :) (4.6L v8) so yah, they should be okay there :)


Sorry i just hate to see an idea how i want to do a FI type 1 engien going blah :) Mind you i do not want to run MS, i want to use a Ford ECU (OBD1) and a Maf Sensor and a turbos induction system yes ugly but, can't see how else to mount the MAF sensor :S Also shoudl work, if i can find another 2.3L Turbo :)


FM Former Member
Kevin,

On the Dual TB's, it really is not just a matter of getting balanced at idle (as you point out, that's easy) or even getting them to come off Idle at the same time (again easy). It is really a matter of having them perfectly balanced throughout the stroke where it gets dicey. In my case, my TB's have different sized and shaped arms on the throttle linkage which is enhancing my woes. I am going to play with a couple of new actuator arms tomorrow and see if I can't get a little closer.

When I mention single TB, I am not talking using a single Dual Throat TB on a manifold like CB offers. I am talking about a proper 50mm (for my 2110) single TB, plenum and individual runner setup like every factory EFI setup in the last 10 years has put together (I guess they are all doing it for a reason).

I will say this, the level of control you have in dialing EFI A:F ratios around, versus jetting a set of webers is probably the difference in doing heart surgery with a scalpel versus a hand axe.

I just want to get a much finer level of control, the single TB, tuned induction, along with spark, will make it all come together.

Your EFI vision is right on. MAF is the way to go, again, there is a reason the big boys use it.
X 91_XR7
Yah, Get arms and such that are mirror images of each other is a key thing too.. also remember location of the arm on the hex shaft can have an effect on the rate the throttle plates open too.. you'll be suprised even on webber carbs, at like 2500-3000rpms how off the two sides can be, even if you have them dead on at idle and even just off idle.. (intial opening)

i think i now understand the setup your thinking of.. I'm totally in the carbed mood, and CB catalog burned into my mind state:( but i never truely noticed, is it still seperate runners to the Plenum or is it like a carbed setup, basic dual till the `heater outlet' then single to the `plenum' ??

Also forgot something.. also runner length plays a HUGE effect in FI.. Shorter the run higher up the RPMS need to be.. the reverse for longer.. hence why you may have to run it so rich to get your car to perform decently in the lower range?

MAF is a good thing.. since it messures the exact amount of air entering the engine.. where as a MAP can't do that.. and with out Figures programed into teh ECU to tell it at zero vaccum (sp) theres X-CFM entering an engine... and then the varibles inbetween full vac to 0 vac.. mind you you have to do the same with the MAF too.. but usually the MAF has set values for what flow is going through it.. So it's easier to punch that into the ECU..

enough rambling for now..
FM Former Member
Kevin,

CB offers a couple of single TB setups. One uses a single dual throat TB, essentially their old dune buggy single carb setup, that they just slapped a 40 mm TB on top of instead of an IDF and cast some injector bosses out in the end castings. It even includes the old heat riser! Someone really should tell them that heating the air coming into that manifold is not ideal (there is no gas in the air yet!)

The other items they offer are end castings with the Injector bosses out on the end near the ports but the runners merge into a single pipe. That leaves you with lashing that together with some large bore tubing, plenum and TB of you own choosing. The problem with this setup is it does not allow for indivdual runner to each port, the only way to go in EFI.

I am talking to a guy that lives down in Texas (I met via the internet, what a surprise, eh?) that is designing a Single TB, Plenum, individual runner setup for his large displacement Type 1. He has it all layed out in Autocad, including a really neat design for steering airflow inside the plenum. If this comes to fruition, that will be the way I go for the induction bits. It won't be MAF, but it sure will fix the sloppy air delivery I see with the duals.

One thing as an aside, I think people running larger displacement Type I's might see better performance with a little larger vents than 36mm that comes stock in the 44 IDF. I was not expecting much top end increase when I installed my EFI. I get a substantial boost in both thorttle response and WOT power with these 45mm TB's. I think maybe either the new IDF 48's, or perhaps larger vents in the 44's might yield more punch to the average 2110 and above user for small bucks.
X 91_XR7
So this guy is basiclly doing a typ 3? kinda FI system?? but in a type 1 way ? :S Hmm that should be a pretty interesting thing.. But diverter vanes and such?? i take it he's planing on sending the tubs horizontally into the plenum?? as oppose to have them Curve up into it? (i take it also that the TB will be vertical) for a straight shot.

ALSO i have only one MINOR issue with the `quad runner' setup thou.. Since as we know.. the Alt is alittle offset.. cuase one to force the center carb, or in this case, FI plenum and TB to the left/driver side of the car, that'll will also make the runners on the drivers side shorter then those on the passenger side, Giving two different effects.. You be suprised what like 1/2-1" shorter runner can do in changing the RPM band on a FI engine.. i take it he did try to do his best to keep the runners the same length right?? I really don't know if one can play with Runner volume (or Dia) to counter effect the length issue.. I bet the guy did come up with a awnser to that problem.. and i hope he does come to be.. any ETA on it?? :)

yes.. a 2110 with a larger carb (say 48MM) will give you more upper end punch, and such.. but some say you'll loose driveabilty with that.. and when you went to FI, one you started to allow better air flow (IE no venturies, ect as obstructions) and you added a better way of Fuel Atomization.. which will give you better throttle repsonse and even better upper end.. would large vents on a set of 44s work out? possibily you like experimenting don't yah?? :P

Now i like to know how the FI on the Watercooled engine is gonna be like :) all it has is a Map sensor, and no o2 sensor :S

FM Former Member
Yeah, he has the runner lengths all figured out. He has also figured the diameter and volume issues on the runners and Plenum to optimize HP while keeping as flat a torque curve as possible. We shall see.

I think it is going to be pretty hard to setup without the help of a WB O2 sensor. Have you guys thought about investing in an LM-1? You could use it to get the map right and then plug the O2 bung.

I have an LC-1 I could lend you for datalogging to a laptop. It really will make all the diff.
D DavesD
John at Aircooled.net recommends a richer mixture than 14.7:1, and states:

The ratio of air/fuel for stoic is 14.7:1. While this is chemically correct, it is NOT CORRECT for the otto engine. Gasoline is a MIXTURE of many components, of which have DIFFERENT octanes and chemical properties. The "octane rating" is the average of these components.

If your engine is carbureted, you'll achieve the best results if you aim for 13.5:1 for light throttle, and 12.5-13:1 for 1/2-Full Throttle.

Full text of the ad for Innovate Wideband Air/Fuel Ratio Gauge Kit can be found at http://aircooled.net/new-bin/viewproductdetail.php?keyword2=LGU0016&cartid=1211200566987034
FM Former Member
David, thanks for the tip.

From my experience so far with EFI, you really can't say these engines need this A/F ratio or that A/F ratio. It all depends on the engine, it's build, the induction hardware you are using, the ECU you are using, how you are controlling spark, what your objectives are for the use of the engine, etc., etc. If you are mixing things correctly, and you can choose when your spark arrives, there is no reason why you can't run anywhere rich, right on or lean of stoichiometric.

If max HP is your goal, then a little rich of peak seems to do the trick. On the other hand, if you want to pass smog, ROP will definitely not be helpful.
X 91_XR7
Well the FI on the Watercooled engine is a VW FI system for the engine.. so.. only thing is, it'll always be running in `open loop' so it'll won't be able to adjust the A/F ratio :( but we're told it's system that's been used one a fair amount of swaps, and workd great so..

what we have at work thou is a Halmeter setup.. which seems to work pretty well..
X 91_XR7
"that I can't get razor sharp (e.g. 14.7:1) and have it run decent at all. If I am down around 11.5-12:1, the car is a beast, but those numbers are more like Turbo numbers, than NA cars"

I forgot to ask something about that comment.. and now that i remember (still)
When were you getting these kinda #'s? under acceleration or crusing??

FM Former Member
Kevin, anything higher than about 12.5:1 (even Idle) and it starts getting really nervous. The induction is just way too sloppy for numbers higher than that. To be fair to the Dual TB crowd, I may also have injectors that are not matched very well. The guys from which I bought my kit are a complete "F Troop", so that also may be part of the problem.

Hi Dale, the Corvette story was pretty funny. The way I figure it, she couldn't lose.
X 91_XR7
har-dee-har-har mister bates :P

Ahh this is one of the reason i want to do with a OE setup, that's adpative, and can adjust itself for odd-ball iregularities in the system/engine..

Also a slightly rich idle isn't a bad thing, along with acceleration.. cruising is when a engine can start to lean out.. so.. mind you 12.5 is kinda on a nasty side..

even one of my cars, at idle has a rich eye watering exhuast :) no cats, and STOCK it had 3 cats :| the car is stock too SEFI, MAF, ect.

FM Former Member
Kevin, well tonight I had a major breakthrough. I just could not accept the fact that I could not get the mid-range tuned with my setup. It required me to run way too rich. The car would run fine at Idle and great at WOT, but mid-range at best was weak. If I tried to lean it out, it would just fall over.

I finally decided to look again at my linkage. When I took my throttle actuator arms off the TB's and compared them, lo and behold, they were not the same radius from shaft center to pivot point. They were not enough different to notice it on the car, but when off the Tb's and layed on top of each other, one was about an 1/8" longer radius than the other.

Thus, I could get them synched at the Idle stop and at WOT (with 45mm TB's I did not have a realtive disparity at WOT because at the extreme, the intake port became the equalizer). In the 3000-4000 range in steady state (e.g. high RPMs, relatively high vacuum, no accel enrichment) then engine would not run well unless I was dumping a bunch of extra fuel into the mix. The reason it would not work is one side (the side w/o the TPS) was running critically lean in this zone (that side throttle actuator arm was slightly shorter in its radius of motion, than the other side, hence its motion ratio was greater).

I fabbed up some temporary arms and wow, what a difference. The car is absolutely fabulous. It idles very clean and smooth, it runs right through the mid-range like butter and at WOT, it really hops! It is much faster than with my IDF's, something I was not expecting.

Brooks is going to be a very happy camper.
X 91_XR7
Congrats on getting it working how it should be :)

were the arms off of the webbers or something that came with the TB's??? the last webbers i set up seemed to open/close at the same rate (at 2500rpms they pulled the same side-to-side.. )

So now it's time to have a set of arms made up or gonna keep the ones you've fabbed up?? and then start a tuning :)

Still gonna go the way of the single TB now? or hold off 'till you have had enough fun with this setup??


and glad to hear you got it running much better now.. it's amazing how it's usually the LITTLE things that can do big problems.. :)


FM Former Member
Kevin, the throttle arms were custom pieces that came with the Billet TB's. They were fine looking pieces, Stainless, what a joke, the finest material, but they didn't take time to measure things carefully. In addition to one side being longer than the other, the offsets were wrong and they were both too long, making it very difficult to get to full throttle.

I am now trying some stubby arms from my Weber kit (you know the ones that are always extra in an IDF kit). The key slot on them is larger than on my TB's (I guess the shaft on the TB's is smaller than on the IDFs) and are kind of sloppy, but they seem to stay put when I tighten them down.

I was getting a little drunk with power and this evening when I got home, I jumped into the Roadster and went to the gas station. I averaged 15 MPG in the last 100 miles of testing (mostly WOT), I need to cool it and start driving normal. I also need to tone things down now and start leaning things out. I mean the whole point of this exercise is better economy and lower emissions, funny how power can pervert your intentions.

Anyway, I am going full speed ahead on the single TB, Plenum design. I have a friend down in Texas that has a design alerady done and will start fabbing it after the first of the year. I get prototype number 2 of his handiwork. Single TB is the only way to go, the duals look good, but they are so 1950.

Anyway, it is nice to have a car that runs right all the way through the power band. After I get things leaned out, I am hoping for an average 30MPG with this setup. No way I will pass SMOG with these Duals.
X 91_XR7
Oh yes.. power can change how one drives :) I liek my '96 since it screams cruiser so i take it easier.. but when i fire up my '91 and the engine comes to life with a rumble that rattles some windows.. gas milage is the LAST thing on my mind :)

Also 15MPG isn't bad.. better then my '91 :P but yah you should be able to get it in the mid high 20's for shure.. 30's might be possible on the freeway :)

and what's wrong with the '50's look?? kinda goes with the rest of the car :P

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