Fuel supply question.

smokescreens

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I have a 18 gt with stage 2 whipple. So i have the 38lb injectors and dw400 fuel pump that came with the kit installed.

I just put longtubes on and am scheduling a dyno tune. My question is at what point on pump 91/93 octane will those injectors and fuel pump start getting pushed to close to the limit? I would like to have 15-20% headroom at least.

 

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if you go 3.625, you'll need a bap. engineermike was seeing some lift pressure drop in colder weather on that size pulley.

so stay above that on the pulley size and you should have some headroom.
 
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smokescreens

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I have the stock 3.875 pulley that came in the kit. And i dont drive it colder than 50°F Looks like just enough for now then.

So sounds like the pump is the first choke point?
 

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if you're staying with 91/93 then yes, the dw400 will be the choke point before the 38 lb injectors.

On a totally stock fuel system, the 19 lb injectors would likely see max idc before the lift pump failed to maintain pressure.
 
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smokescreens

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Thanks guys. I called my tuner just to make sure he is happy with what i have and he said as long as i dont try a smaller pulley or e85 im good to go. Have a dyno appointment set for 8am on the 18th. Not sure if i will get it but fingers crossed on 700whp. Im kind of expecting 660-690 though.
 


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That pump without a BAP can make the same as a stock pump with a bap. There have been failures of that pump in certain circumstances. Stock pump with bap can make over 700.

I'm not sure about the 38lb injectors. You will need to go bigger for E85 but in the case of petroleum you should be fine. Staying in the throttle for a long period of time is not recommended on a single unboosted DW400.
 

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Thanks guys. I called my tuner just to make sure he is happy with what i have and he said as long as i dont try a smaller pulley or e85 im good to go. Have a dyno appointment set for 8am on the 18th. Not sure if i will get it but fingers crossed on 700whp. Im kind of expecting 660-690 though.
keep in mind if you go e85 you’ll need to run a full fuel system and larger injectors.

for your setup now you should be gtg on pump gas
 

 
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