[18ss376]

Originally Posted by wnta1ss

False. The stock LT1 hpfp will typically run out of capacity (drop pressure) somewhere in the mid~upper 500s with a supercharger when using pump gasoline. I am talking about a truly stock LT1 hpfp supplying the fuel, meaning no cam lobe change, and no supplemental fuel added such as methanol injection.

What do you base this on? I have not been able to find data that supports this.

[KingLT1]

Originally Posted by 18ss376

What do you base this on? I have not been able to find data that supports this.

Here is one post from a guy that has done extensive testing on this platform.

https://www.camaro6.com/forums/showp...72&postcount=2

[18ss376]

The guy at Wildhammer Motorsports says he has done 750hp with a stock LT1 hpfp, everything else was upgraded to LT4 parts or better. That is why he sells the LT4 kit with injectors & in-tank pump. Again, he said "everyone thinks you need a LT4 hpfp but you do not". That is what I was going to use with my Whipple until I returned it. I can't trust anyone anymore...lol

[KingLT1]

Originally Posted by 18ss376

The guy at Wildhammer Motorsports says he has done 750hp with a stock LT1 hpfp, everything else was upgraded to LT4 parts or better. That is why he sells the LT4 kit with injectors & in-tank pump. Again, he said "everyone thinks you need a LT4 hpfp but you do not". That is what I was going to use with my Whipple until I returned it. I can't trust anyone anymore...lol

Fwiw I am at the limits of a LPE DI pump (which flows 40% more then a LT1 DI pump) @ 8psi on E80. I couldn't even run E on a stock LT1 DI pump. So it's pretty clear the guy at Wildhammer is wrong.

[6spdhyperblue]

750hp on 93 and 750hp on E are very different things to the fuel system, no? You’re saying e80 but wild hammer could be saying e10

[KingLT1]

Originally Posted by Nicul15

750hp on 93 and 750hp on E are very different things to the fuel system, no? You’re saying e80 but wild hammer could be saying e10

You are missing the point...I couldn't run E anything with the LT1 pump with boost. You are not going to make 750hp on the stock LT1 fuel system, with a stock cam, on any type of fuel. You are also not going to get to 750hp on 93 with the LT1, the octane wall is around 700 with it's compression ratio.

[6spdhyperblue]

Just threw it out there. Doesn’t make sense why someone would make a statement like that

[wnta1ss]

Originally Posted by 18ss376

What do you base this on? I have not been able to find data that supports this.

I have seen multiple reports of the LT1 fuel system having issues on a supercharged car in the mid-upper 500s. I have personally seen the hpfp having trouble with a supercharger making 500-something. There could be weak pumps/strong pumps out there, as well as differences in the dynos reporting the numbers, to explain some difference in the 'limit'. But the idea that so many of us have seen issues at 600hp or less, but someone tells you 750hp is doable, well, that seems like pure fantasy to me.

[18ss376]

Originally Posted by wnta1ss

I have seen multiple reports of the LT1 fuel system having issues on a supercharged car in the mid-upper 500s. I have personally seen the hpfp having trouble with a supercharger making 500-something. There could be weak pumps/strong pumps out there, as well as differences in the dynos reporting the numbers, to explain some difference in the 'limit'. But the idea that so many of us have seen issues at 600hp or less, but someone tells you 750hp is doable, well, that seems like pure fantasy to me.

Everything on the internet is fantasy, I'm at the point I don't believe anything anyone says. I'm out.

[Juiced1]

I would not recommend trying to run 750rwhp on a LT1 high side pump. On a boosted car we have had fuel pressure drops around 650rwhp. Can you tune and drive a car when the fuel pressure is dropping off? Sure, if you have enough injector you can make it work but you are playing with fire. Hell, we can even help tune for a pressure drop but I wouldn't recommend it when you have options to fix it. An LT4 pump is a nice easy upgrade and we have made up to 750rwhp on them. The LPE high side pump, paired with a cam is your best bet if you're looking to make power beyond that.

[BlueCamaro6]

I didn't change the lines and no problems for over 15k miles. There is a blue sealant on the threads which I purchased, put it on, let it dry, installed with no worries. I think it's more personal preference on replacing them.

[D K]

Can someone explain something to me....

the hpfp is a positive displacement pump.
If you simply add bigger injectors, it doesn't do anything - the amount pumped is the same.
So it would make no sense upgrading to LT4 injectors while keeping the LT1 hpfp - correct?
The only way to get more out of the LT1 hpfp is to get a bigger fuel lobe - correct?
What would that max power be on gas?
What would max power be on LT1 hpfp, fuel lobe and LT4 injectors?

Lastly, is the LT5 pump different from LT4 - or did they simply add PI?

David

[oldman]

the flow rate through an orifice (injector) changes with the square root of pressure delta. So the bigger pump supplies more pressure hence there is more flow based on the above. Yes liquid is compressible and / or the fuel lines are expandable enough that there is no concept of "positive displacement pump" at this PSI level. Ergo a bigger injector has a bigger hole so it will supply more fuel no matter what the delta is; albeit it will drop the rail pressure to levels that will NOT work for DI and or see above the flow rates drops via delta change. Meaning step one is always LT4 pump and injectors, step two is a bigger lobe and includes step one and this is say 700 HP on E60. After that the LPE pump give another 50 WHP on E60: estimate 750 WHP. Last step is just to do the bigger injector, either the 30% for $3000 or the dunno 52% LPE for $4500. I literally did each step. I was on the fence for a long time to do this or dual inject. To me just get the DI setup for your target level and be done with it. (don't forget the low side). The dual inject at this point is a LT5 with gm performance harness and brain..... (wish I had the cash). I'm sure my whp estimates are conservative and based on 32% cam lobe.

Nutshell DI gets expensive above 700 WHP and even more so if you add E60 or more. Hence people go to dual inject via meth. Added that meth can yield max rich power like 4:1 Air fuel, you can literally pour the stuff in and it will still make power way above stio. At that point your engine is a steam engine, based on liquid to gas expansion laws, just saying steamy.

https://www.hotrod.com/articles/wideband-oxygen-sensor/

Complete LPE setup including cam (they have a new 8.x lobe) (which I don't have yet) is good for right around what my D1X is good for 1000 engine HP on gas and hopefully E85. I don't know as this is way past my pay grade....


https://www.lingenfelter.com/product...l#.XFIH26ZYaUk

[D K]

Originally Posted by oldman

So the bigger pump supplies more pressure hence there is more flow based on the above.

I know this, so how does that relate to my question?