[JANNETTYRACING]

Originally Posted by DorkMissile

Sorry this took so long to come full circle, just remembered to post this data after saving some log files.

Did some pulls tonight (1433DA), nothing on the setup has changed. 3rd gear roll-in from 55mph, shift to 4th and back into full WOT.

Rail Pressure holds north of 2000psi for about 9s, then will nose to 1850 before the shift. Back up to 2800 and will taper slightly until redline in 4th with pressure above 2000. I wouldn't want it to get any lower in 3rd.

I feel that I am pretty much max capacity on E85 on LT4 fueling, but it would be hard for me to get the fuel rate up high enough in the lower gears to run out of pump, and it would be hard to do a pull long enough to nose the pressure over in a gear higher than 3rd. Redline in 4th is pretty much 145mph.

If you have an LT4 fuel system your high side fuel pressure should never drop below 2900 PSI or you are asking too much of it.

You also have to look at your injector opening time should not exceed 6 milliseconds.

You will see injector opening times jump up when high side pressure falls.

Low side pressure should maintain min 60 psi or 400 Kpa.

Ted.

[KingLT1]

Originally Posted by DorkMissile

Under full load on the longest of pulls, PW will max at 6.8ms, low side is above 50psi across the board (is a stock 1LE / ZL1 pump)

I always run the meth, but it is minimal usage. I use between a quart to two on a weekend of hard racing (roll and dig - 400 to 500 miles of driving)

You are out of fuel...actually you are past the point of being out of fuel. Ideally your injector MS should be under 6 and your rail pressure should hold around 2800psi. low side is struggling a little to.

I will say the combination of Meth and E85 are likely what is keeping it alive.

Did your tuner let it leave the shop like this?

I would mix the E85 down to E60 and see what things look like.

[Jaime1le]

I am also new to the forums and learning alot about boost on a lt1. Trying to get all the correct info I can before choosing between a blower but my question is how many people are having piston/ ring failure with a stock boost Maggie/procharger/whipple and a stock tune from the same companies

[KingLT1]

Originally Posted by Jaime1le

I am also new to the forums and learning alot about boost on a lt1. Trying to get all the correct info I can before choosing between a blower but my question is how many people are having piston/ ring failure with a stock boost Maggie/procharger/whipple and a stock tune from the same companies

The ones that do their research will likely not have issues. Try pushing the stock fuel system to the limits on 93 and you will run into trouble.

The key with the LT1 and boost is octane, proper fueling, and tuning. Make the combination efficient as possible. Fuel system upgrade and E60 would be wise. For exhaust, I would at minimum remove the factory cats. Rotofab intake and LT5 throttle body are must haves for a PD supercharger.

[JANNETTYRACING]

Originally Posted by Jaime1le

I am also new to the forums and learning alot about boost on a lt1. Trying to get all the correct info I can before choosing between a blower but my question is how many people are having piston/ ring failure with a stock boost Maggie/procharger/whipple and a stock tune from the same companies

Most if not all piston failures can be traced back to trying to make more power than the fuel system will supply.

We have Zero Issues making 560-580 RWHP with our recommended supporting mods and our tuning.

Regardless of what supercharger you choose.

Feel free to call me with any questions.

Ted.

[Umbriel]

My car is going to the tuner Tuesday for my Procharger tune and this thread has me nervous, lol. It has a 32% cam, complete LT4 fuel system, SMG auxiliary low side, SMG flex fuel sensor, 2 inch headers, AWE catback and F-1a Procharger with the largest pulley the make for now. I asked for 7 pounds of boost but they said it might make more with the larger head unit. Hopefully it stays together, lol.

[Joshinator99]

Originally Posted by Umbriel

My car is going to the tuner Tuesday for my Procharger tune and this thread has me nervous, lol. It has a 32% cam, complete LT4 fuel system, SMG auxiliary low side, SMG flex fuel sensor, 2 inch headers, AWE catback and F-1a Procharger with the largest pulley the make for now. I asked for 7 pounds of boost but they said it might make more with the larger head unit. Hopefully it stays together, lol.

32% cam will help your situation significantly! Your tuner will have to watch the fuel system carefully.

[Umbriel]

Originally Posted by Joshinator99

32% cam will help your situation significantly! Your tuner will have to watch the fuel system carefully.

I'm just hoping I have enough fuel system for it, not sure what it is going to put down.

[DorkMissile]

Plan is to meet the tuner at the track tomorrow (Brainerd International) and we will dial back the fuel on top a little bit and rely on the Meth just a titch more. Should drop the PW down and raise the rail pressure up.

next step would be to tune at E50-60 (above numbers were E80 on the sensor) and we are doing drop in pistons and a cam over the winter.

[steelheadrob]

Originally Posted by DorkMissile

Plan is to meet the tuner at the track tomorrow (Brainerd International) and we will dial back the fuel on top a little bit and rely on the Meth just a titch more. Should drop the PW down and raise the rail pressure up.

next step would be to tune at E50-60 (above numbers were E80 on the sensor) and we are doing drop in pistons and a cam over the winter.

You wont have any problems running e55. I am running 11psi with e55 and meth, rail pressure holds over 2,800, PW stays under 4. Now that I got the jms installed and lowside squared away I am going to start adding E to see where the limit is at.

[95 imp]

Back to OP- reading up on this, it is NOT a ring gap issue as some suspect.


According to TRW (and parent co.), The piston failed because of one (or more) of these causes:


Low Octane

Excessively High Compression Ratio
(Superchargers increase dynamic CR)*

Ignition Timing Too Advanced

A/F Mixture Too Lean

IAT Too High


This type of failure isn't caused by rings. One, more, or all, could occur while tuning a newly modded engine. Especially if IAT creeps up over multiple runs, or the car has low octane gas.



And, IMO, 91/93 is low for a static 11.5/1. Who knows what the dynamic CR is because of boost levels.


Section 3.4.5 has the dirt

https://www.memoparts.com/img/cms/Do...n%20Failue.pdf

*This part isn't stated in the PDF, but is common knowledge

[JANNETTYRACING]

Originally Posted by 95 imp

Back to OP- reading up on this, it is NOT a ring gap issue as some suspect.


According to TRW (and parent co.), The piston failed because of one (or more) of these causes:


Low Octane

Excessively High Compression Ratio
(Superchargers increase dynamic CR)*

Ignition Timing Too Advanced

A/F Mixture Too Lean

IAT Too High


This type of failure isn't caused by rings. One, more, or all, could occur while tuning a newly modded engine. Especially if IAT creeps up over multiple runs, or the car has low octane gas.



And, IMO, 91/93 is low for a static 11.5/1. Who knows what the dynamic CR is because of boost levels.


Section 3.4.5 has the dirt

https://www.memoparts.com/img/cms/Do...n%20Failue.pdf

*This part isn't stated in the PDF, but is common knowledge

I have been saying this for quite some time, Way too many people trying to squeeze 600 RWHP on stock fuel system.

[DorkMissile]

To come full circle gentlemen - I worked with my tuner on Thursday at BIR and he leaned my tune as we were .78 lambda on the wideband and rail pressure is north of 2800 all the time now and under 4.5ms on the injectors.

LONG pulls on the car (we were running on the road coarse - the front strait is 4000ft long and you come out of turn 9 and onto the start of the drag strip at 80mph) and we are talking 5th gear in my 1LE at 5000+rpm.

If we are keeping it fed for that long it should be OK on the street, however I believe we are at the absolute end of the LT4 fuel system on a stock LT1 cam.

[95 imp]

S

Originally Posted by DorkMissile

To come full circle gentlemen - I worked with my tuner on Thursday at BIR and he leaned my tune as we were .78 lambda on the wideband and rail pressure is north of 2800 all the time now and under 4.5ms on the injectors.

LONG pulls on the car (we were running on the road coarse - the front strait is 4000ft long and you come out of turn 9 and onto the start of the drag strip at 80mph) and we are talking 5th gear in my 1LE at 5000+rpm.

If we are keeping it fed for that long it should be OK on the street, however I believe we are at the absolute end of the LT4 fuel system on a stock LT1 cam.

That's great news! So, are you running E? gas (octane)? and are you still squirting meth to hit the .78?