Had a conversation about an ideal fuel management system for TB ( Is there one?)

B

BARRACUDA1968

Well-Known Member
Joined
May 4, 2011
I'm relatively new to the TB world but have a decent grasp on fuel management. I use a Thundermax on my Harley and it seems similar to the Fast system or SD2 for the TB.

The Tmax auto tunes like the SD2 and the Fast within limits of the base map installed in the ECM using a WB. I can drive and let the computer do it's job them analyze the adjustments then save them and make that my new map and continue until the computer gets the tune correct. I can basically control anything I want with a laptop.

So I'm having this conversation with a buddy of mine who is a machinist/engine builder and my question or statement was why isn't there a way to protect my motor in the event I go lean /loose oil pressure or over boost? If there is I'm not aware of it.

I run 93/alky and worry constantly about hurting the motor because of detonation/too much boost etc.

It seems we rely on a few things to do there job or we break parts. I know this is part of the deal with high performance anything but if there is something available I would like to know what it is?

If I'm making a pass and for some reason I lose my fuel pump or alky people say I can't lift fast enough to save the motor. Ok fine. Is that all there is to it or is there something out there that will buy me some time or shut me down?

I'm making this thread for myself and other people who have the same questions/concerns I do.

I have read a few threads about the Fast system and SD2 but after about 2 pages the thread heads off on some direction I don't want to go.

So here it is, what is the best fuel management system/ fail safe system we can run in our cars? With pump gas and alky. I'm not going E85 because we don't have many stations around here. I need both systems to work or I'm in trouble so I want a safety net if there is one.

Thanks Brett
 
There is no system that will save the engine.the stock computer works great.keep it simple and leave a cushion in your tune and the car can run real good and live.
 
One way to to this easily is to set up the power adder to use two different a/f ratios, and a alky low pressure switch to turn off the power adder mode off, if the alky pressure drops ...
 
A fuel pressure gauge that you can monitor will be your best chance as you can see fuel delivery but every logging sensor is after combustion.
 
Nothing is foolproof, but the XFI has quite a few nice features. Running closed loop at WOT with a WBO2 monitoring A/F is probably the most important safeguard. It has the ability to monitor your fuel pressure and automatically compensate if the pressure isn't keeping up. It also has the ability to monitor your oil pressure and cut your engine if the pressure drops below a preset pressure. If your alky fails, the WBO2 can throw fuel at it, to try and keep it from leaning out. If it detonates, the knock sensor can pull timing.
 
Mr.Spool said:
A fuel pressure gauge that you can monitor will be your best chance as you can see fuel delivery but every logging sensor is after combustion.
Click to expand...

This requires you to watch the gauge. The XFI monitors the pressure and compensates automatically. You tell it what your base fuel pressure is, and it is expecting the pressure to rise 1:1 with boost. If it doesn't rise proportionally, the computer will compensate quicker then you can lift your foot
 
He doesn't have to purely rely on it. He can still watch the gauge (or in this case perhaps, he could watch the touch screen display) just like with the stock computer. The difference is, if the pressure drops, the computer reacts BEFORE the WBO2 sees a lean condition and BEFORE the operator can react to try and save the engine. This is s logging sensor that is (as you put it) "before" combustion IMO: Watching the road has priority over watching gauges.
 
HighPSI said:
if the pressure drops, the computer reacts BEFORE the WBO2 sees a lean condition
Click to expand...
the fuel rail gauge is still reading after combustion as is the pressure transducer for the meth kit since the meth sprays of boost,therfore all computer reactions faster or not are after combustion.fuel pump fails at wot things get messy that's the nature of the beast.
 
Thanks for the replies.

I was thinking about installing a fuel pressure gauge just because. I have taped one to the windshield for a test run but not real handy.

I plan to run a safe tune next year. My goal is a high 10 which shouldn't be a problem with my set up. I built a low 10 second car to run high 10's and just have some fun. It's mainly a street car but I do like to go to the track a few times a year.

I know the chip I'm running can do the job and I'm capable of tuning the car. I have made many passes down the drag strip over the years in my 68 Barracuda. It's a 416 small block 4 speed car and will run a mid 10 at 130+ mph. You have to drive that car down the track. Racing the Grand National doesn't compare in any regard. However I do not want to monitor gauges in a 10 second car even if it's a point and hang on ride like a GN. I just want to enjoy the ride and have a back up plan for 10 seconds in case something goes wrong.

The FAST system seems like it has the advantage in most areas. The SD2 looks decent too. I've done a lot of reading about both but I get a headache every time I do some research on the board.

I look at phoneguy's threads and the trouble he had. One was because of a faulty boost controller and I wonder if there is something out there that may have saved him in that situation? Hell I lifted my heads and never had any KR nor did I hear detonation.

I know I'm not the only guy who worry's about this stuff so if I can get something in the car that gives me the best chance at dodging a bullet I'm interested. Otherwise owning one of these cars can be a little stressful.:D:D:D:confused:
 
Did you ever determine if the head studs were bottoming on the threads and not clamping down?
 
BARRACUDA1968 said:
Thanks for the replies.

I was thinking about installing a fuel pressure gauge just because. I have taped one to the windshield for a test run but not real handy.

I plan to run a safe tune next year. My goal is a high 10 which shouldn't be a problem with my set up. I built a low 10 second car to run high 10's and just have some fun. It's mainly a street car but I do like to go to the track a few times a year.

I know the chip I'm running can do the job and I'm capable of tuning the car. I have made many passes down the drag strip over the years in my 68 Barracuda. It's a 416 small block 4 speed car and will run a mid 10 at 130+ mph. You have to drive that car down the track. Racing the Grand National doesn't compare in any regard. However I do not want to monitor gauges in a 10 second car even if it's a point and hang on ride like a GN. I just want to enjoy the ride and have a back up plan for 10 seconds in case something goes wrong.

The FAST system seems like it has the advantage in most areas. The SD2 looks decent too. I've done a lot of reading about both but I get a headache every time I do some research on the board.

I look at phoneguy's threads and the trouble he had. One was because of a faulty boost controller and I wonder if there is something out there that may have saved him in that situation? Hell I lifted my heads and never had any KR nor did I hear detonation.

I know I'm not the only guy who worry's about this stuff so if I can get something in the car that gives me the best chance at dodging a bullet I'm interested. Otherwise owning one of these cars can be a little stressful.:D:D:D:confused:
Click to expand...

I have installed Autometer Elite series gauges for fuel pressure, oil pressure, boost and water temp. These gauges have logging output and hi/lo warn outputs that are configurable by the user. These will be connected to the FAST analog inputs for logging and I will contact Cal to get his input on what to trigger with the outputs from each gauge. I have his Boost Leash controller that has an input that can drop the boost almost instantly by opening a solenoid, this could easily save an engine from catastrophic failure. I have some work to do over the winter to get this connected as well as some other electronic controls. I will also be installing a pressure transducer for the ALKY pump.
I should be able to open the solenoid on the Boost Leash on an overboost issue, low fuel pressure condition , low ALKY pump pressure.
Low oil pressure could cut ignition. Overtemp could cut fuel...

Bryan
 
I have often wondered about the J&S Safeguard It would give some protection. There are a few old threads about it.
 
Pronto said:
Did you ever determine if the head studs were bottoming on the threads and not clamping down?
Click to expand...

I was using heads bolts so I assume everything was clamped down properly and no the bolts were not bottoming out.
 
Last edited:
Phoneguy said:
I have installed Autometer Elite series gauges for fuel pressure, oil pressure, boost and water temp. These gauges have logging output and hi/lo warn outputs that are configurable by the user. These will be connected to the FAST analog inputs for logging and I will contact Cal to get his input on what to trigger with the outputs from each gauge. I have his Boost Leash controller that has an input that can drop the boost almost instantly by opening a solenoid, this could easily save an engine from catastrophic failure. I have some work to do over the winter to get this connected as well as some other electronic controls. I will also be installing a pressure transducer for the ALKY pump.
I should be able to open the solenoid on the Boost Leash on an overboost issue, low fuel pressure condition , low ALKY pump pressure.
Low oil pressure could cut ignition. Overtemp could cut fuel...

Bryan
Click to expand...

I would like to know more about the boost leash. I will do a search on the internet. Sounds like you are taking the same measures I want to take. I'm one cherry picker shop party away from what you went through. I do not want to host that party.
 
BARRACUDA1968 said:
However I do not want to monitor gauges in a 10 second car even if it's a point and hang on ride like a GN. I just want to enjoy the ride and have a back up plan for 10 seconds in case something goes wrong.
Click to expand...
these cars require monitoring at that level,trust me not paying attention will lead to broken parts regardless of the computer being used.
 
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