Hurricane 270 tune difference compared to 300 header tune?

[hpmaniac]

Share feedback and experiences when upgrading from the 270 pm tune to the 300 header pm tune.
Belt and clutching set up mountain and or trail.
I'm running the 270 tune now and still want more, called Dave and decided on 300 header tune. I'm running closed loop. I will also add a adjustable regulator for possible fueling adjustment if needed.
The 270 tune sound happy around 89-9k rpm.
Mine is a mtx so it has stock helix 35 39 and the Dalton black orange spring with stock silver orange silver spring in primary. Belt runs cool, might try a straight 44 and see if I have enough spring for that angle.

 

[fatchance]

Ummm, the tunes are night and day difference. Obviously the clutching is going to have to be much heavier to hold the belt. Probably the best bang for the buck goin with the header tunes. Upgrade the fuel pump, put an adjustable fuel pressure regulator in there with the proper exhaust and you'll have no regrets.

 

[hpmaniac]

Ummm, the tunes are night and day difference. Obviously the clutching is going to have to be much heavier to hold the belt. Probably the best bang for the buck goin with the header tunes. Upgrade the fuel pump, put an adjustable fuel pressure regulator in there with the proper exhaust and you'll have no regrets.

I have the adjustable regulator coming, in process now looking at fuel pumps.

 

[Turboflash]

155 lph is plenty big enough.

 

[hpmaniac]

I got to thinking about this, heck we were using a 255 pump in mustangs back in the day. I have maid well over 500hp on a v8 with a 255. Way overkill for sidewinder.

 

[Turboflash]

I got to thinking about this, heck we were using a 255 pump in mustangs back in the day. I have maid well over 500hp on a v8 with a 255. Way overkill for sidewinder.

Exactly. Why I commented 155 is plenty for even a 320hp 998 with stock injectors and stock turbo. Simple math.

 

[hpmaniac]

I will data log the 300hp tune with stock fuel pump, Closed loop so i can also watch correction factor. If the tune is good and clean the wideband should never correct more than 10-15% either way from commanded Lambda.

 

[fatchance]

I will data log the 300hp tune with stock fuel pump, Closed loop so i can also watch correction factor. If the tune is good and clean the wideband should never correct more than 10-15% either way from commanded Lambda.

I believe closed loop will only correct up to 125% so after that you're pushing your luck. I would not have knock protection flashing before i installed the larger pump but it would constantly be pulling timing. Remember these tunes are all a bit different and Dave's tunes want to run rich. Highly recommend the AFPR and monitor closely if you're doing any long high speed runs without putting the bigger pump in.

 

[fatchance]

Side note, i was running the Header tune this year and it would still be correcting fuel up to 110% @ 53 lbs key on with the bigger pump.

 

[sideshowBob]

I am at 50psi key on fuel pressure on my Hurricane Header tuned SW and it is correcting fuel up to 114% as well on the 300tune to have 11.8:1 AFR.

As a side note....I just did a full day back woods trail and lake ride and before the trip I adjusted my FP down to the stock 43 psi as I was going to be a relatively low rpm and speed all day on the 240 tune in the operation envelope where the closed loop isn't always active.
We did over over 100 miles and the sled used only 18 liters/4.8 us gallons....great mileage.

 

[Turboflash]

I will data log the 300hp tune with stock fuel pump, Closed loop so i can also watch correction factor. If the tune is good and clean the wideband should never correct more than 10-15% either way from commanded Lambda.

Walbro 155 lph will pump almost 2x what stock injectors can flow at 80% duty cycle at 43.5 psi fp. That means at wfo, 155 pump can pump almost twice what injectors (engine) needs.
One has to remember that if you use a fuel pump that's too big, you might outpump the capacity of return line (assumes most use either 1/4" or 5/16" hose). That means the fuel rail will have too much pressure in it (when it's not needed) because the return hose restricts it's ability to dump excess gas back to tank. Too big of a fuel pump is not a good thing. 155 lph is plenty for up to 350hp pump gas trail tunes. That covers most of us.
P.S. Even at negative low ambient temps. Again, a 155 lph can pump twice what stock injectors can flow at wfo at 80% duty cycle at 43.5 psi static base. No issue whatsoever. Guys who think they need a 340 are misinformed. In fact, if they use a pump that big, they will have problems.

 

[stgdz]

So adjustable fuel pressure regulators.

I have seen this mentioned but does this take the sled from a set it and forget it tune to something you have to adjust and watch from time to time?

 

[sideshowBob]

How many lph is the stock fuel pump?

 

[AAdavis]

I am at 50psi key on fuel pressure on my Hurricane Header tuned SW and it is correcting fuel up to 114% as well on the 300tune to have 11.8:1 AFR.

View attachment 178266


As a side note....I just did a full day back woods trail and lake ride and before the trip I adjusted my FP down to the stock 43 psi as I was going to be a relatively low rpm and speed all day on the 240 tune in the operation envelope where the closed loop isn't always active.
We did over over 100 miles and the sled used only 18 liters/4.8 us gallons....great mileage.

View attachment 178267

What is the total intake temp gain on that pull? What intercooler?

 

[AAdavis]

I am at 50psi key on fuel pressure on my Hurricane Header tuned SW and it is correcting fuel up to 114% as well on the 300tune to have 11.8:1 AFR.

View attachment 178266


As a side note....I just did a full day back woods trail and lake ride and before the trip I adjusted my FP down to the stock 43 psi as I was going to be a relatively low rpm and speed all day on the 240 tune in the operation envelope where the closed loop isn't always active.
We did over over 100 miles and the sled used only 18 liters/4.8 us gallons....great mileage.

View attachment 178267

I have no place that I ride where I could hold 100% throttle for 14 seconds!