More fuel?
Drifting
Joined: Aug 2019
Posts: 1,859
Likes: 1,264
From: Houston
If you want more fuel without getting a cam then go port injection. Nothing else will replace a better cam's ability to provide fuel. At least not a reasonable price.
Thread Starter
Burning Brakes
Joined: Oct 2001
Posts: 1,005
Likes: 102
From: Buffalo Grove IL
St. Jude Donor '11
Safety Car
Joined: Mar 2004
Posts: 4,048
Likes: 1,478
From: South Florida
I would say your choices are cam plus injectors or just go port injection from the start. I just tuned a cammed LT4 with stock injectors and it needed a decent amount of meth to take it past 800rwhp. The owner wanted to be able to run E60-E70 on the regular so that was also a factor in the amount of meth. I personally wouldn't rely on meth for my own car, but the owner knows the risk and chose that path.
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Michael S. Palmer
Safety Car
Joined: May 2000
Posts: 4,827
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From: Albuquerque NM
E-85 will make it worse. It will require more volume through the entire fuel system. If you need a BAP or aux pump and/or meth when using pump gasoline, you will need even more mods to run E-85.
It's a good fuel, high octane, you just need more of it.
It's a good fuel, high octane, you just need more of it.
Safety Car
Joined: Nov 2005
Posts: 4,386
Likes: 942
From: Huntsville Alabama
E85 is great for timing and boost. The problem is like 6speeder stated is it requires ALOT more of the fuel for it to work... which is already a issue with LT1/4/5 cars and direct injection. the pure volume needed to support say 850 rwhp on e85 is alot.
Last edited by mittens; Aug 7, 2023 at 12:05 PM.
Instructor
Joined: Oct 2002
Posts: 219
Likes: 68
From: MI
Port injection is the easy solution, with stock LT4 high side and stock cam full E85 is no problem.
You will need a solid low pressure side no matter which path you choose, but if you have good E available, it's a match made in heaven for the LT4 engines.
You will need a solid low pressure side no matter which path you choose, but if you have good E available, it's a match made in heaven for the LT4 engines.
Safety Car
Joined: Mar 2004
Posts: 4,048
Likes: 1,478
From: South Florida
Stock low side is the first limit regardless of cam or no cam.
With a cam, the next limit is the injectors as you will maintain high side volume but stock injectors will run out of spray window.
Without a cam, the injectors will still be the limit as you will run out of window first, but the high side will be right behind it. Say you have a stock cam, a low side solution, and upgrade your injectors. Your low side will stay at 80psi, but your high side pressure will tank if you try to push the injectors at all.
I've had great luck with cam + DSX low side + stock LT4 high side + XDI 30% injectors. Then adding dual nozzle Meth. I have a car on pump E85 (about E78) with this setup and it makes over 800rwhp.
With a cam, the next limit is the injectors as you will maintain high side volume but stock injectors will run out of spray window.
Without a cam, the injectors will still be the limit as you will run out of window first, but the high side will be right behind it. Say you have a stock cam, a low side solution, and upgrade your injectors. Your low side will stay at 80psi, but your high side pressure will tank if you try to push the injectors at all.
I've had great luck with cam + DSX low side + stock LT4 high side + XDI 30% injectors. Then adding dual nozzle Meth. I have a car on pump E85 (about E78) with this setup and it makes over 800rwhp.
Safety Car
Joined: Mar 2004
Posts: 4,048
Likes: 1,478
From: South Florida
Without meth or larger injectors, you might get to 650-675 wheel before you are out of injection window on E. If you run pump 93 you will probably be in the same power range because you will be limited on timing and not have the benefits of ethanol. Your best bet may be to run E50 and squeeze what you can out if it. If you add Meth you can get a bit past 700 wheel while running E70+.
Safety Car
Joined: Mar 2004
Posts: 4,048
Likes: 1,478
From: South Florida
If you run XDI 30% since they will handle 2900-3000 psi, which you can likely maintain with a fuel lobe(I would go 38% lobe, not 32%). You can probably get a little past 700 wheel, maybe close to 750 wheel. Just depends.
Safety Car
Joined: Mar 2004
Posts: 4,048
Likes: 1,478
From: South Florida
Not if you're trying to run high blends of ethanol. I have a client with a cammed ZL1 (38% lobe), low side and 30% injectors running E70. But we needed meth to get past 800rwhp. I imagine we could have stretched some on 93 but its just too hard to maintain power, keep spark in it and not heat up the blower trying to run 93 pump and no meth.
If you're not going to run Meth you need to run at least E50 to get these cars to make consistent power. E50 gives you 90% of the benefits of E so in reality targeting E55 with fuel mods will get you the most power for the money. Beyond E50 you gain more cooling efficiency in the combustion chamber which is beneficial when you spin the stock blower hard and don't use any meth.
Last edited by Internets_Ninja; Feb 7, 2023 at 08:03 AM.
Safety Car
Joined: Nov 2005
Posts: 4,386
Likes: 942
From: Huntsville Alabama
Bumping this.
Looking at a C7Z, Dynos 824hp / 735tq on E50 (Car is M7)
Car has CPR intake, Heat Exchanger, Expansion tank, Race Ported blower, 18% OD pulley (2.55" Griptec upper/stock ratio), Cam with 38% Fuel lobe, DSX Low side, DSX Flex Fuel Sensor, and 2" headers. Was told it can't go above E50 as it ran out of injectors. But that's seems higher than what we discussed back a few months ago? Thoughts?
Looking at a C7Z, Dynos 824hp / 735tq on E50 (Car is M7)
Car has CPR intake, Heat Exchanger, Expansion tank, Race Ported blower, 18% OD pulley (2.55" Griptec upper/stock ratio), Cam with 38% Fuel lobe, DSX Low side, DSX Flex Fuel Sensor, and 2" headers. Was told it can't go above E50 as it ran out of injectors. But that's seems higher than what we discussed back a few months ago? Thoughts?