[brewengineer]

I just did this mod over the weekend and it was well worth the ten bucks in hose. The car pulls so smooth I was shocked. Its sad that of all the mods I have done, this hose has been my favorite. It almost reminds me of my buddys Evo X in terms of smoothness and was well worth the time and money.

Did you use the same table adjustments? I am interested to here if zeroing it out works the same for everyone.

 

[kylehgb1]

I have made no adjustments yet. I have a retune on jan. 4 so I'm going to let my tuner handle it.

 

[SeeeeeYa]

Thinking about the questions concerning fitting the mod with and without zeroing the tables...

First, the assumption that since this is a fuel system mod it only affects fueling... is wrong. It is LOAD that's being compensated, and therefore afects not just fuel, but timing as well. Every table that uses Load and RPM as axes is affected.

Second, the question plagueing those without means (or guts) to zero-out the LC tables should NOT stop anyone from performing the fuel-line-mod. For one, various people have done the mod and reported a smoother engine. The reason takes some mental gymnastics to see, but here is a simple analogy;

Imagine you are on a playground assisting someone in a swing. You give a push and they swing. Time the push correctly, with the right force, and the swing does what you want.

Now imagine someone on the opposite side who is also assisting. Timing becomes equally critical for them, as well as operating on the same assumption of what the person in the swing expects. Now you have TWO input variables where timing is critical.

This isn't so bad a scenario... you can SEE your counterpart on the opposite side. But what if you couldn't...

Remove the reason for the opposing force and things change. The assisting/opposing then cannot be out of sync, and therefore possibly double errors. With BOTH the compensations AND a varying reason for compensation ALL input will be MAGNIFIED, not just right or wrong. Without the varying reason, the fuel-line-resonance, there is no magnification... and smoother operation. Obviously, zeroing-out the LC tables removes the rest of the unnecessary influence.

 

[LittleBlueGT]

Thinking about the questions concerning fitting the mod with and without zeroing the tables...

First, the assumption that since this is a fuel system mod it only affects fueling... is wrong. It is LOAD that's being compensated, and therefore afects not just fuel, but timing as well. Every table that uses Load and RPM as axes are affected.

Second, the question plagueing those without means (or guts) to zero-out the LC tables should NOT stop anyone from performing the fuel-line-mod. For one, various people have done the mod and reported a smoother engine. The reason takes some mental gymnastics to see, but here is a simple analogy;

Imagine you are on a playground assisting someone in a swing. You give a push and they swing. Time the push correctly, with the right force, and the swing does what you want.

Now imagine someone on the opposite side who is also assisting. Timing becomes equally critical for them, as well as operating on the same assumption of what the person in the swing expects. Now you have TWO input variables where timing is critical.

This isn't so bad a scenario... you can SEE your counterpart on the opposite side. But what if you couldn't...

Remove the reason for the opposing force and things change. The assisting/opposing then cannot be out of sync, and therefore possibly double errors. With BOTH the compensations AND a varying reason for compensation ALL input will be MAGNIFIED, not just right or wrong. Without the varying reason, the fuel-line-resonance, there is no magnification... and smoother operation. Obviously, zeroing-out the LC tables removes the rest of the unnecessary influence.

You are almost making my head spin.

To me it is simple, do the mechanical fix, then tweak timing and fueling a touch if required. For the most part the only thing the load will affect is timing, and that can be fairly easily accounted for.

 

[SeeeeeYa]

You are almost making my head spin.

To me it is simple, do the mechanical fix, then tweak timing and fueling a touch if required. For the most part the only thing the load will affect is timing, and that can be fairly easily accounted for.

I absolutely agree... my post was for those WITHOUT the ability/means to tweak their tune. Old Timers like you have the means.

In my own case there has been only a removal of bad timing inputs that caused Knock Sums to increment without obvious reason, and a far smoother engine to enjoy.

 

[kleinkid]

2010 STi--05-07 fpr kit is installed, Accessport. I don't want to re install the OE fpr. Any reason why I can't still install the 39" hose fix? Won't be changing any tables when this is done, for a while, at least.

 

[utahphunk]

Any reason why I can't still install the 39" hose fix?

Nope.

 

[STIdad]

This fix should be stickied.

 

[Mother]

I've done the fuel line mod and it seemed to help quite a bit by itself, but I do still have a stray stumble now and then.

I want to have the load compensation tables zeroed out, but my car was protuned by Doug at TopSpeed so the map is vendor-locked and they really don't seem to be interested in helping me out. It's pretty irritating that after spending around $4k with them on my motor, other various parts and my tune that they are brushing me under the carpet. I checked with Cobb to see if I could send them the map and have them make the adjustments but they said their vendor agreements prevent them from doing that.

Not sure what to do...

 

[NSFW]

Are you guys inserting the additional hose upstream of the fuel rails, or downstream? In other words, between the firewall and the rails, or between the rails and the fuel pressure regulator?

Thanks!

 

[wiretap_MD]

Its the supply hose to the rails coming from the damper. Replace hose and use a longer one (1 meter).


Sent from my iPhone using Tapatalk

 

[SeeeeeYa]

Are you guys inserting the additional hose upstream of the fuel rails, or downstream? In other words, between the firewall and the rails, or between the rails and the fuel pressure regulator?

Thanks!

There is more than one thread, here is one that has the links:

http://legacygt.com/forums/showthread.php/stutter-studder-hesitation-etc-198070.html

 

[tweeked]

i'm looking into doing this. so far havent read any bad news.
now, my question is, why 3ft? why not more/less, at what point does the flow become laminar enough to eliminate the stumble?

Bring on the fluid dynamics!

 

[utahphunk]

i'm looking into doing this. so far havent read any bad news.
now, my question is, why 3ft? why not more/less, at what point does the flow become laminar enough to eliminate the stumble?

Bring on the fluid dynamics!

Not more because people's results indicate you don't need more.

Not less because nobody has taken the time to iterate over chopping/re-testing increasingly shorter lengths until they find the minimum viable length.

I would think certain ranges of lengths would not coil well in the space available, as well. *shrug*

 

[kyle82]

i'm looking into doing this. so far havent read any bad news.
now, my question is, why 3ft? why not more/less, at what point does the flow become laminar enough to eliminate the stumble?

Bring on the fluid dynamics!

I did a little less than 3ft so I could get an even 3 coils. And it still eliminated the stumble. I think chopped off about 10cm

 

[brewengineer]

I am performing this mod today. I have a long long thread on the strange issues I have been having with my car. It can be seen here: http://www.iwsti.com/forums/cobb-street-tuner/251012-2011-sti-stage-1-knock.html
Anyways, I thought my #2 piston was a goner and have been running stock tune for almost 3 weeks. Just before I took the car to the dealership, it started running great again. It had all the pep and power I was used to. Now, I just flashed to stage 1 (91 octane LWG), and have no knock in high load situations. However, I still have some strange stumbling and knock under partial load at 2400-3000 rpm. I am starting to think that I am experiencing this fuel system issue, and it could have been magnified by a certain fuel or weather condition. I will datalog after I perform the mod and report back on my results. Fingers are crossed!

 

[endrswrd]

Oh brew, I thought I told you about this in your other thread????? Seriously though, do the mod, then reduce the two load compensation tables(MP) (located under MAF/engine load) to 20% of original. Totally different car. Be ready for a smoother less rumbly engine. I miss the boxer vibrations a bit, but now I understand it wasnt just that!!!!

 

[brewengineer]

Oh brew, I thought I told you about this in your other thread????? Seriously though, do the mod, then reduce the two load compensation tables(MP) (located under MAF/engine load) to 20% of original. Totally different car. Be ready for a smoother less rumbly engine. I miss the boxer vibrations a bit, but now I understand it wasnt just that!!!!

Yeah, but I was having some strange issues, and Cobb was suggesting a #2 piston crack. It ran like it was in limp mode for over two weeks after I flashed back to stock. Then it suddenly went back to normal. Very odd. Could be a issue related to fuel viscosity or density of a recent cut out of the colonial pipeline, or it could simply be something working through my engine. Something did increase knock for a period of time. I am hoping this mod fixes any remaining stumble and knock.

 

[endrswrd]

I was hesitant to do it at first. But after some logging I finally understand how the compensation tables are trying to mask the problem. Or at least I think I do. Luckily, its a very easy fix with noticable improvements even without changing the tune. But you should reduce the compensations tables in question to 20% of their original value for best effect.

 

[brewengineer]

I performed the mod last night after searching around for the stuff needed. NAPA did not have the quick disconnect fuel line piece, so I ended up heading to Oreilly. They sold this part under the name fuel injection line repair kit. Met a nice 06 STI owner there.
I first pulled the fp fuse and opened the gas cap, then ran the car until it died. This did not relieve all pressure. I got a nice spray of high pressure gasoline after removing the line. I think you should restart the car after it dies to try and pull more fuel. I used 3 ft as suggested, and that made 2 coils. I tucked the coils vertically and zipped in place on the existing fuel lines. It does feel very smooth, but I get some odd knock in places I never saw it before. There was 0 knock on a 3rd gear wot pull. However, just hitting the throttle at idle shows 4.8 flashing on fine knock learn. This also happens when i quickly downshift. I will continue to monitor this and see if I can log it. Not sure if anyone else has seen this phenomenon. I hope this mod doesn't cause a delay in instantaneous fuel flow, which makes it lean for a second.