[laynlo15]

Thats true King, I don't know how much E you'll be able to run. Maybe if you keep the boost pretty low but as you raise the boost you'll probably run out of low side even with an Lt4 fuel system. King would know for sure since you are doing a similar build. Thats the same cam I ran and it makes great hp for sure. Good luck on your build. I agree with the Arp head bolts, GMs are one time use and there isn't much difference in buying GM and Arp price wish, it will save you money in the future if you want to change something else. Do it right or don't do it.

[KingLT1]

I did a few pulls this weekend in 48-50 degree weather. Boost was hitting a peak of 12.5psi at the top of the gear and 10psi through the mid range. Due to this I had to drop back to E50 to keep my injectors just inside an acceptable range. Maf was showing 86lb/min and 1.49g airmass. So its making some decent power but one thing I have learned is you need to really keep a eye on your fueling when the temperature starts to drop. Above 70 degrees I can run E65, between 55-65 degrees E60, and when temps drop below 50 E50. Low side holds strong, high side tapering down to 25-2600psi, injectors 6.0ms. If I get a set of FIC +30 and lower rail pressure to 2400psi, I bet I could move back to E75 even in the cool weather.

[asthmamax11]

Port injection would remedy all of this ?

[Joshinator99]

Originally Posted by asthmamax11

Port injection would remedy all of this ?

Sort of. You would still have to address the low side if you really want to rock and roll.

[KingLT1]

Originally Posted by asthmamax11

Port injection would remedy all of this ?

Larger injectors or PI would be the remedy in my case because I am not going to push any more boost then where I am at and my low side if fine. PI would be about the same cost as FIC injectors comparing toohighpsi PI setup. Could put the larger pulley back on too.

12.5psi @ 18 degrees of timing should be over 700whp. Either way I am pretty content at this power which is a decent amount for a SLB LT1 with DI only for fueling. Just deciding if I want to add injectors or just mix E50. Nothing really wrong with E50. It's only 2 degrees less timing then E85 and still 101-102 octane.

The main point was that up here in North you can see a swing of 2-3psi in boost with PD superchargers on the same pulley from mid summer to late fall. Southern states might not be as drastic. I barely hit 10psi at peak when it's 85 degrees out. That is why they call cool weather "blower weather". Lol

[toohighpsi]

Here's a quick rundown of what we've learned so far with running PI and E85.

For the LT1 we have an all stock 2018 Camaro SS:
1. With the addition of the TVS2650 and 110mm pulley, pump gas, and custom tune it made 576 SAE / 600 STP RWHP and ran 10.92 @ 127 MPH with 7.5psi (150kpa) boost.
2. Next we added port injection and E85. Unfortunately the low side was pretty much at it's limit with in-tank pump so we weren't really able to add any power over where we were at on pump.
3. Added a second in-tank pump which allowed us to maintain 50psi low side pressure and reduced pulley to 90mm. On E85 out of the pump (77%) the car made 728 SAE / 760 STP RWHP on 12.2psi (183kpa) and ran 10.33@ 135 mph on 20" drag radials.

Planning to go back to the track in Dec, against my better judgement we'll drop the pulley size by 5mm and add another degree of timing which should drop this otherwise stock car into the single digits. hopefully all the spinney stuff will stay where it's supposed to.

The LT4 is a completely different story, I don't know where the end is for this one yet. Currently running 19.5psi boost and 26 degrees of timing, thought we'd hit knock by now, but no sign of it so going to smaller pulley (~23psi) as soon as it gets here. Once we feel we're close to the limit we'll get back to the dyno with this one.

[KingLT1]

Originally Posted by toohighpsi

Here's a quick rundown of what we've learned so far with running PI and E85.

For the LT1 we have an all stock 2018 Camaro SS:
1. With the addition of the TVS2650 and 110mm pulley, pump gas, and custom tune it made 576 SAE / 600 STP RWHP and ran 10.92 @ 127 MPH with 7.5psi (150kpa) boost.
2. Next we added port injection and E85. Unfortunately the low side was pretty much at it's limit with in-tank pump so we weren't really able to add any power over where we were at on pump.
3. Added a second in-tank pump which allowed us to maintain 50psi low side pressure and reduced pulley to 90mm. On E85 out of the pump (77%) the car made 728 SAE / 760 STP RWHP on 12.2psi (183kpa) and ran 10.33@ 135 mph on 20" drag radials.

Planning to go back to the track in Dec, against my better judgement we'll drop the pulley size by 5mm and add another degree of timing which should drop this otherwise stock car into the single digits. hopefully all the spinney stuff will stay where it's supposed to.

The LT4 is a completely different story, I don't know where the end is for this one yet. Currently running 19.5psi boost and 26 degrees of timing, thought we'd hit knock by now, but no sign of it so going to smaller pulley (~23psi) as soon as it gets here. Once we feel we're close to the limit we'll get back to the dyno with this one.

In regards to the LT1. How much timing were you running @ 12.2psi?

Man that is a crazy amount of timing on your LT4 car I would of never imagined it could take that much with that amount of boost.

[toohighpsi]

Originally Posted by KingLT1

In regards to the LT1. How much timing were you running @ 12.2psi?

Man that is a crazy amount of timing on your LT4 car I would of never imagined it could take that much with that amount of boost.

Running a peak of ~22.5 degrees on the LT1 just before the shift, you can see in the plot how much timing we need to pull at launch to keep the 20" radials hooked. Just going to a 15" rear wheel and dialing in the launch would get this car in the 9s.

Have a bit more work to do with torque at high speed as you can see the throttle started to close before we hit the end of the track. You can also notice the continually decreasing A/F ratio as catalyst protection rolls in across the pass to keep the stock cats alive. Fortunately running a lot of timing keeps those exhaust temps down so we don't have to overfuel too much.

Fun stuff!

[KingLT1]

Great info and Thanks for sharing.