How To Wreck A Brand New Atomic Motor

[bugster70]

Thanks Bugster and please take some advice from me, do not trust a Walbro at these sort of power levels! As I said, I have proven that they are not up to the job with the factory fuel lines on the car.

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No worries mate, glad you took my post in the manner in which it was intended. Yeah, I've got a Walbro too, but (unlike you and unfortunately for me) I don't think I'll ever have to worry about it running out of puff!

Your car must be an absolute bloody weapon to drive.

[FR33DY]

I can confirm the walbros do run out of puff. I installed one in the ute and we did 6 consecutive runs and the fuel pump got hot and threw all the afr s out from 12.5 to 13.5. just to be sure we brought the car back the next day ran it fresh and it was perfect 12.5 This car made 321 @ the wheels. I wouldnt rely on just a walbro!

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quick question was is the safe limit on the factory pump at sustained load ? When should you upgrade the pump so not to get fuel stravation ?

[Kimberley Scott]

Sorry to hear that mate, guess at the power you are running there are going to be plenty of lessons to learn. Hope it is best case scenario.

As for all the bullsh*t in this thread, if I had just looked down the barrel of blowing my second motor I would be pissed as well, and a touch on edge.

Scotty

[GT290]

have u upgraded the brakes yet shane?? lol!!

[GOLDIE]

Sorry to hear shane mate I would also be checking for intake leaks as it appears to be only one plug maybe it is sucking some air to that cyl.

I have seen this car on dyno there is no worries with afr's.

Ian

[Romulus]

Bad luck F6 Rapid. I knew there was a reason why I have wound my power back to 330rwkw whilst still running a Walbro pump, as my fuel pressure was dropping off at high vehicle speed.

I must admit I'm surprised you are only running a Walbro intank pump when FSIX is upgrading his fuel system with 'only' 340rwkw.

Unfortunately you've learnt the hard way - I'll be surprised to hear anyone else running your kind of power with only a upgraded intank pump.

[Eugene]

I can confirm the walbros do run out of puff. I installed one in the ute and we did 6 consecutive runs and the fuel pump got hot and threw all the afr s out from 12.5 to 13.5. just to be sure we brought the car back the next day ran it fresh and it was perfect 12.5 This car made 321 @ the wheels. I wouldnt rely on just a walbro!

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quick question was is the safe limit on the factory pump at sustained load ? When should you upgrade the pump so not to get fuel stravation ?

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Going from your sig, I would say you are there NOW, the factory fuel pump has in inbuilt (factroy non adjustable) relief valve, this will release at anywhere from 400-550kpa fuel presure, stock cars wont ever see that presure because of the rising rate (boost controled) fuel reg on the rail, BUT, increase the boost, and the fuel regs relief presure goes up too, the factory pump may let go at any time. you need to lift your foot (no boost and hence lower fuel reg setting ) to alow the fuel pump relief to "reseat" and away you go, if you dont recognise the syptoms of no fuel, a lean condition will happen, and we now all know the results.

I found mine let go after 1.5 gear changes at WOT, it didnt matter if it was 1-2nd or 2-3, when held flat for more than a few seconds, the feul pressure just dropped and the car died/pinged etc, it is MUCH MUCH better with the Walbro, and can do like I said 90% of my driving no worries, but I wont be going to the drags again or going over 230kph without doing a surge (2liter) and big Bosh fuel pump, for a while I was blaming the tune, low fuel level etc, but it is the pump, end of story.

so for a quick question, a long answer, which I hope helps.

[FR33DY]

I can confirm the walbros do run out of puff. I installed one in the ute and we did 6 consecutive runs and the fuel pump got hot and threw all the afr s out from 12.5 to 13.5. just to be sure we brought the car back the next day ran it fresh and it was perfect 12.5 This car made 321 @ the wheels. I wouldnt rely on just a walbro!

←

quick question was is the safe limit on the factory pump at sustained load ? When should you upgrade the pump so not to get fuel stravation ?

←

Going from your sig, I would say you are there NOW, the factory fuel pump has in inbuilt (factroy non adjustable) relief valve, this will release at anywhere from 400-550kpa fuel presure, stock cars wont ever see that presure because of the rising rate (boost controled) fuel reg on the rail, BUT, increase the boost, and the fuel regs relief presure goes up too, the factory pump may let go at any time. you need to lift your foot (no boost and hence lower fuel reg setting ) to alow the fuel pump relief to "reseat" and away you go, if you dont recognise the syptoms of no fuel, a lean condition will happen, and we now all know the results.

I found mine let go after 1.5 gear changes at WOT, it didnt matter if it was 1-2nd or 2-3, when held flat for more than a few seconds, the feul pressure just dropped and the car died/pinged etc, it is MUCH MUCH better with the Walbro, and can do like I said 90% of my driving no worries, but I wont be going to the drags again or going over 230kph without doing a surge (2liter) and big Bosh fuel pump, for a while I was blaming the tune, low fuel level etc, but it is the pump, end of story.

so for a quick question, a long answer, which I hope helps.

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Thanks for information

[F6BF]

fingers crossed its only a melted plug nothing more

[F6 RAPID]

Ah well, at least I hope we have learnt something here from my mistake and I really should have known better - I will own up to it.

I will keep you informed as to what we find. First thing is checking the motor out on Thursday morning with a leak-down test. All good there, endoscope on Friday or Saturday and then check the turbo, all good there, take it easy until we fix the fuelling issues - and attend the LS1 dyno day this Saturday.