FiTech tuning for trails and rock crawling.

[Hinmaton]

First off, I’m happy with my Go Efi 4 600hp on my roller cam 5.0L in my 74 EB trail rig. I’m running timing and using a 6A box to get multi spark and a G-Surge lift pump to get the fuel pressure.
NP435 D20 4.10 gears and 38’s

The FiTech is designed to work well out of the box on street vehicles, crisp throttle, very little engine breaking. It likes to get up and go, which is great when your driving around town.
But when you’re picking lines and negotiating tight trails, it can get a bit frightening when it just wants to go!
I spoke with Cody @ FiTech and we worked through some tuning and I now have engine breaking back. And the throttle is a bit less On/Off.
I still feel there is more I can do with the tuning, but it’s more of a deep dive into tuning than I’m comfortable with. I’m pretty new to tuning period, but I’m not afraid to get my hands dirty as long as I feel I have a decent idea of what I’m doing.
The issues I would like to solve are-
1: smoothing transitions. Often when crawling you spend time at idle under load, like descending steep terrain or coming off and obstacle, even climbing. I find the unit sees the load in decreasing/increasing rpm’s and no throttle position and it’s fighting to maintain the set idle rpm, which often results in increasing the rpm’s which can be disastrous if you are counting on the engine breaking to slow you down and keep moving slowly ahead. Or say when you can’t make it up a slippery slope and need to back down in gear and not use your brakes, and the unit thinks you need more gas.
I think this stuff is all in the accel pump settings, but there are a lot of them and I do not know where to start.

2: The throttle is still super snappy and it almost feels like 80% of the throttle response is in the first 20% of the pedal stroke. Which makes easing into higher rpm’s on tricky obstacles while bouncing around, really hard. It goes from idle to animal in a fraction of an inch. In a street car, this is awesome! On a really tight off camber trail this is terrifying.
I’m not super sure how to resolve this one, it may be in the dTPS Acc Gain setting, but when I asked Bryce, he suggested that I shouldn’t mess with this, as it would ruin drivability.
Which... maybe, is what I want?

I’m thinking that it would be great to develop two tunes, one for the trail and one for getting to the trail.

Has anyone here messed with this stuff?

Hinmaton



Sent from my iPhone using Tapatalk

 

[Broncobowsher]

The aggressive throttle is nature of the 4-barrel EFI. I am pretty sure that the back throttle bores open in sync with the fronts. On a typical carburetor application they open in a staged manor. That is the backs don't start opening until the primary are about half open. This allows low speed throttle control. There are some EFI throttle bodies that are progressive secondaries, I don't think FiTech is that advanced.

What can be done is make a progressive throttle linkage. If you look at the early GM LS engines that still had a throttle cable the drum on the throttle body clearly exhibits this. There is a long lever ratio at idle and as you get deeper into the throttle it quickens up. This keeps the overall throttle travel a reasonable amount, deadens the off idle response, and makes the deeper throttle feel strong. Try to copy that idea. I had to do that to get a controllable throttle with an old 4-barrel ProJection system years ago.

Now for the erratic idle, providing that isn't anything to do with throttle linkage binding and pulling open a little it will have to be with the IAC in the throttle body. That is all computer controlled. Probably dealing with some anti-stall programming. If you can't get the software to control it, I have some un-orthodox ideas that are probably last ditch.

I know you said the ignition isn't computer controlled. But if you could slow down the ignition advance just off idle that might help as well. As the RPM rises the ignition advances, which raises engine speed. You might be brining in the advance a little too early. Great for a performance feel. Don't have to change the overall advance, just delay when it comes on. Lighter weights, takes more rpm before they kick out. Heavier springs may work but I think that slows down the high RPM apply more then the low RPM where you need to control it more.

 

[Hinmaton]

Interesting idea on the linkage. I'll definitely look into it.
I am running timing control with the unit, and I have thought about retarding the timing 2 degrees during the idle to 1800 rpm range. I just need to try it and see.

 

[markw]

I think the throttle tip in is in the lambda settings. Still working on mine so it's learn as I go.

 

[KyleQ]

I didn't have to mess with mine much - are you sure you don't have a vacuum leak with that runaway RPM issue?

I'm running my throttle off the top of the unit - giving it the longest range of travel possible. I do like the idea of that progressive barrel for throttle input - although I'm so used to my setup right now it may be a hindrance.

 

[Dlish]

Subscribed.
Just got the FiTech installed and have maybe 150 miles on it. Going to Roundup this week and wheeling for 3-4 days. Looking forward to see how it does.
I swapped over to a throttle cable, and it felt a little stiffer vs the old linkage. Between that and the FItech learning, it may be interesting on the rocks.

If anyone smells a lot of clutch, its just me

 

[Hinmaton]

I didn't have to mess with mine much - are you sure you don't have a vacuum leak with that runaway RPM issue?

I'm running my throttle off the top of the unit - giving it the longest range of travel possible. I do like the idea of that progressive barrel for throttle input - although I'm so used to my setup right now it may be a hindrance.

KyleQ,
When you are slowing down and you put in the clutch, it doesn’t pick up the rpm’s at all? Or are you running an automagic? I think the unit is designed for them.


Sent from my iPhone using Tapatalk

 

[Hinmaton]

Subscribed.
Just got the FiTech installed and have maybe 150 miles on it. Going to Roundup this week and wheeling for 3-4 days. Looking forward to see how it does.
I swapped over to a throttle cable, and it felt a little stiffer vs the old linkage. Between that and the FItech learning, it may be interesting on the rocks.

If anyone smells a lot of clutch, its just me

If you find yourself in the same place as me, I can share a couple settings that will fix a lot of the issues.
What are you running as your base idle?


Sent from my iPhone using Tapatalk

 

[DirtDonk]

Are you running a PCV valve on that setup Hinmaton?
I see the cap with fitting in the back on the passenger side, and the oil-fill that likely has a hose fitting on the driver's side front, but wanted to make sure that a PCV was actually there and working.

And speaking of those valve covers... Where did you get them and what are they off of?

Paul

 

[73azbronco]

Do you have a single plane intake?

Off hand, the issues you describe in first post, snappy throttle but hard to control low rpm, suggest single vs dual flow intake issues. With TBI, you need just the opposite of conventional carb thinking, I think, a single plane is needed to make it work right. This based on numerous discussions with Holley folks with their sniper system, which I did not install as of yet.

The more throttle early in throttle position is an issue of throttle linkage and mechanics of how it cams into the throttle.

 

[Hinmaton]

Are you running a PCV valve on that setup Hinmaton?
I see the cap with fitting in the back on the passenger side, and the oil-fill that likely has a hose fitting on the driver's side front, but wanted to make sure that a PCV was actually there and working.

And speaking of those valve covers... Where did you get them and what are they off of?

Paul

I don’t have a PCV, I have a breather running out the back. My plan is to run the Moroso crankcase evacuation system, which is half installed. I have no idea what that oil by the filter is, I am not running any hoses back into the air intake ducting.
I’m not running any vacuum lines.
So it has to be coming out of the throttle body?

The covers are stamped with the Ford Oval and they were on the vehicle to start. I really like the tall oil fill which looks to be factory. And the dipstick matches the cap.
The engine came from Jasper, maybe it came with those?

Hinmaton

 

[Hinmaton]

Do you have a single plane intake?

Off hand, the issues you describe in first post, snappy throttle but hard to control low rpm, suggest single vs dual flow intake issues. With TBI, you need just the opposite of conventional carb thinking, I think, a single plane is needed to make it work right. This based on numerous discussions with Holley folks with their sniper system, which I did not install as of yet.

The more throttle early in throttle position is an issue of throttle linkage and mechanics of how it cams into the throttle.

I am running the Performer RPM Air Gap, which has a notched plenum divider, with a 1/2” open spacer.
I read about this issue a lot and it makes sense that you want your map sensor to see the pressure of the entire area under the throttle body. But due to it being located in one place (typically near the rear of the throttle body) a dual plane intake cuts off half of the ports it can see.
However, the FiTech unit claims to not be effected by this issue.
But I gave myself nearly an inch of open chamber for the sides to mix and normalize, just incase.

But I would be interested to try a single plane. I really like them, particularly a high rise. But I get scared off by the high rpm power curves they are designed for.

Hinmaton

 

[Eoth]

I'll be wheeling mine for the first time at the Roundup, but I see your concern. I'm resisting the urge to mess with mine to allow all its "self learning" to happen first. Rattling the issue around in my head, I think everything is operating as designed and all that is left is to "de-tune" the system to be less responsive (I don't think that is a great idea). SO..... Going backwards to the physical pedal sensitivity. Something that comes to mind is that the throttle cables on LT1/LS1 throttle bodies use an egg shaped pulley that the cable wraps around. It purpose is to give a progressive throttle opening.
Might be a direction to consider....

 

[Hinmaton]

Definitely considering this.
Haven’t found a good source for the pulley unless I go the Upullit route. Compound Bows have cam pulleys, but they are pretty crazy extravagant.
Also thinking about changing the ratio on the stock linkage.
Lengthen the connection point on the throttle body or shorten the connection on z arm thing?

Hinmaton


Sent from my iPhone using Tapatalk

 

[KyleQ]

KyleQ,
When you are slowing down and you put in the clutch, it doesn’t pick up the rpm’s at all? Or are you running an automagic? I think the unit is designed for them.

I'm running an automagic will full manual control but I don't notice RPM jumping when going in and out of gear. There are adjustments that can be made to combat all sorts of driving conditions you speak of - this is one area where the Ford EFI rules.


I'm running an RPM air gap with the breather tube from my EFI valve covers plumbed into the back of the intake, but I think I'm going to ditch that and just filter the air coming out of the cover - I don't need that oily air going down the intake. Haven't thought of a carb spacer but it might help. I should nab some video of my startup and driving experience to compare against. Off roading will help the self tune a lot being that you will be under load and on lots of different throttle conditions vs cruising around and accelerating on low resistance surfaces.

 

[Hinmaton]

I may be wrong, but even with the manual shift body, the converter still allows stall speeds to slip, meaning that the converter evens out the input from the engine into smooth forward momentum. A couple hundred rpm may not register as very much. You have to bring the rpm up to a certain range in order to even overcome the fluid coupling. Which is why I think FiTech was designed for auto trans, it’s trying to keep that constant engagement to the tires through the transmission.
In a manual, in low gear a couple hundred rpm are everything. The difference between making it and not making it.
I two foot drive on trails (I own an auto trans trail rig as well) and it helps tremendously, but I haven’t quite mastered two foot three pedal driving. The clutch pedal gets in the way and is so close to the brake pedal.

Next time your out on trail in low, crawl along at an idle, engage your brake enough to slow your forward progress (note your rpm) then let off the pedal. Does the rpm stay the same or rise?

Hinmaton


Sent from my iPhone using Tapatalk

 

[Eoth]

Definitely considering this.
Haven’t found a good source for the pulley unless I go the Upullit route. Compound Bows have cam pulleys, but they are pretty crazy extravagant.
Also thinking about changing the ratio on the stock linkage.
Lengthen the connection point on the throttle body or shorten the connection on z arm thing?

Hinmaton


Sent from my iPhone using Tapatalk

I quick search in the interweb pulls up a number of options under (throttle pulleys). Here is something interesting:

https://www.efihardware.com/products/c93/Pulleys

 

[Hinmaton]

Nicely found.


Sent from my iPhone using Tapatalk

 

[73azbronco]

I am running the Performer RPM Air Gap, which has a notched plenum divider, with a 1/2” open spacer.
I read about this issue a lot and it makes sense that you want your map sensor to see the pressure of the entire area under the throttle body. But due to it being located in one place (typically near the rear of the throttle body) a dual plane intake cuts off half of the ports it can see.
However, the FiTech unit claims to not be effected by this issue.
But I gave myself nearly an inch of open chamber for the sides to mix and normalize, just incase.

But I would be interested to try a single plane. I really like them, particularly a high rise. But I get scared off by the high rpm power curves they are designed for.

Hinmaton

Single plane Hi power design based on use of a carb.

Remember that dual plane intakes solve the problem of atomizing and drawing/providing fuel at low airflow/rpm low velocity. And, because of the second plane, high airflow high rpm. All cross reference to torker II now.

TBI is already atomizing the fuel to a greater degree. And the fuel is coming out all four holes at the same rate which is NOT how a carb introduces fuel to the airstream in a dual plane.

Holley techs said theirs was designed only for single plane intakes, but also said it should work in dual plane but thats not what I keep hearing with cases like yours. Note you will not find any documentation from holley saying this.

There was someone else here who went single plane, i think Weiand, and all his low rpm issues resolved, forget who.

Dual plane intake with a TBI is basically shooting fuel through two different length paths to the cylinder and hoping it figures it out, even if you have the notched crossover.

A carb "figures it out" because fuel is only being introduced based on airflow/vacuum in the path being opened by the butterflys.

A TBI is injecting based on a MAP or RPM profile which may or may not work with dual plane runners. My research says nobody has yet solved the dual plane MAP reading issue, no one.

I would avoid an airgap intake even with TBI, you really do want the fuel to stay atomized, not cooled.

I would try to find the smallest single plane and go that route. Weiand X-CELerator Intake which claims rpm to 1500, and Edelbrock torker. My bad, the weiands being made today are not for 302 based motors.

 

[Hinmaton]

Single plane Hi power design based on use of a carb.

I would try to find the smallest single plane and go that route. Weiand X-CELerator Intake which claims rpm to 1500, and Edelbrock torker. My bad, the weiands being made today are not for 302 based motors.

well... shit.

I was thinking it was a good idea to try and keep the throttle body cool...

anyone want a nice dual plane intake?