[95 imp]

After reading King's post I realized one other thing I forgot to mention...

Altitude.

Where you live (and where your driving to) will have an effect on fuel requirements. Drive from Denver to LA and you'll need more octane due to air density.

The point I think we are both making is that the further you push the motor from stock the more you have to pay attention to the details.

You have to think, monitor, and adjust to keep the motor in one piece as you add power on boost more so than on NA cars.

[Eldi Z]

Originally Posted by Joshinator99

If you’re worried about longevity on the stock LT1 shortblock, you can keep boost reasonable, say 7-9 psi. Upgrade the fuel system to run at least some E (E30-E50 is a big help) to help pull heat from the chamber like King described. If you only have 93 to work with you’ll want to keep boost about 7 psi with the 11.5:1 compression. The stock LT1 shortblock simply will not tolerate very high boost on 93 octane only for long.

In essence, this is my plan, since I only wish to fuel up with 93 pump.

If I really wanted to, I could add some "E" to the mix from external sources:

Meaning, depend on a supplier (store) of thinners to the paint industry, which is local to me and from whom I used to get mainly Toluene to add ~ 30% to a prior boosted (turbo) engine I had in a different car.
From him, I can get everything from Xylene, Toluene, Meth -to- Eth
Thing is, I do not feel like having to store canisters of this stuff in my garage and be dependent on it.
But lets' say I would go this route and overcome inconvenience, just in order to keep my engine safer-cooler pistons - which Ethanol spec. should I get and what % should I pour into the tank together with the 93 pump, to be effective enough, on say ~8.5 PSI of peak boost on an TVS 1.7L (Stock LT 4 blower, where I am reducing boost from the stock spec ~ 10.5 PSI to ~ 8-8.5 PSI by means of a smaller SC crank ring = instead of the stock 8" down to 7.2", complete LT4 fuel system from LPFP=>HPFP+hard fuel lines=>Injectors)?

[Eldi Z]

Originally Posted by KingLT1

I have had my Whipple installed since Jan of 2019. I started with 8psi(currently @ 10psi), upgraded fuel system, running on E. I have logged over 10k miles on the Whipple setup...the car has just under 16k miles total. Not a ton of miles but this is a Weekend car that has probably seen well over 100 0-60, 1/8th mi, and 1/4mi pulls with the Whipple and probably double that since I bought. When I get it out the Accelerator pedal goes to the floor at least once or twice. So I run it hard but I also take care of it. I always check fluids, filter, keep the oil changed...

Here are some key things that I consider important if you want to boost a SBE LT1.

- Colder Spark plug. Imo run a 7 heat range...you will get more cold start misfires and they are easier to foul but this imo is a must.

-Proper crankcase ventilation. Catch can with a Metco valve cover breather or Mighty mouse system. You don't want to pressurize the crank case

-LT4 fuel system minimum. I posted this in another thread:

"One thing to keep in mind. A LT1 with about 7psi makes similar power to a stock LT4 which makes 9-10 psi. The higher compression of the LT1 allows it to make similar power at less boost. The LT4 comes from the factory with a better fuel system. Ideally you will need to run the LT1 a touch richer for cooling on pump 93 due to the increased compression which further increases fuel demand. So that means a 7psi setup really needs the LT4 fuel system hence why I always suggest it as a minimum."

-Correct AFR and Conservative timing. .82 Lambda and 10-13degrees of timing depending on quality of pump gas.

I see canned tunes targeting stock AFR and trying to run 15+ degrees of timing. Then they don't even trigger PE mode until at the top of the gear. This will blow a engine up fast. The only logical reason they do this is for some reason it squeaks by at the altitude where they tested the tune and to stretch out the stock fuel system.

One variable that is very seldom brought up is weather change and how it effects performance and fueling....especially on a boosted car. Most cars seem to be dyno'd in 70+ degree weather and often times hotter. In those conditions you might have enough fuel system. If you live in areas of the country that have 4 true seasons like I do, then you have to consider the coolest temps you plan on running your car and make sure to log data at those temps. A boosted car is going to make a lot more power at 50 degrees vs 80+ degrees and that requires more fuel. A lot of that is due to making more boost and PD / Centri setups control boost with Pulleys. We don't have electronic boost controllers to bleed boost off if it goes above a target.

So as you can see there is a lot more to boosting one of these cars in order to do it correctly. It's not bolt-on 150hp in 6-8hrs, flash tune, and go live happily ever after like some of these companies claim.

Imho, the average enthusiast would be much better off buying a ZL1 or just sticking with a Bolt-on's for the SS.

King, you nailed it again! Spot on

So each point you listed here is "Check" on my to-do list and it seems that all of these allowed your motor to live damage free until now, despite driving it hard.

Things I do not plan to do and you have/ are doing:

1.) Drive hard.
No plans doing this. I have a tendency to baby my cars (bad habit not enjoying the cars enough...)
Mainly street / daily "spirited" but no WOTs and floor the right foot only from time-to-time / short bursts of ~10-12 seconds when the road is empty late in the evenings.
2.) Not exceed 8-8.5 PSI boost
3.) Weather: Temps seldom go below 50 in the coldest winter and most of the year between 60 (when it is "cold") and 95-98 when it is warm in summer. Average 75-85. Summer humidity ~ 65-70% average
4.) Geographic- Altitude ~ 50Ft above sea-level. .basically right at sea level

BtW: ZL1 is not an option for a couple of odd reasons, related to costs$$, I will not get into here...

[Eldi Z]

Originally Posted by 95 imp

So what in your opinion would be "proper fueling" on a boosted LT1 engine?

Higher octane fuel. What octane? Depends....

Weather, CR, boost PSI (really volume), intercooler efficiency, cylinder temps, amount of carbon in the chamber. It will vary from motor to motor.

I have always watched my logs and adjusted octane based on the knock sensors.

If they are pulling timing, raise the octane until they stop.

The engine can only handle knock for so long before things physically break and the PCM can only pull so much timing to try to stop it.

It's amazing these motors can run on 91/93 as it is. A L-88 or L-79, for example, would need 100+ octane NA to survive.[/QUOTE]

Yep. Higher octane is possible, but a bit challenging, since I would have to resort to adding "Octane boosters" to my tank- I could do it with Toluene or Xylene. Or I could resort to the method of "E" ...

I prefer to set the timing as low as necessary (remaining on 93 pump...) in order to avoid detonation, than having the PCM pull timing "for me".

Interesting that even in NA form, you say that these engines are delicate...Do these motors break so easy, even when they are driven stock? I thought that experience of most LT1 owners (Incl. C7 Vettes from 2014), that as long as they maintain the engine and change oils, filters, plugs, Etc. they can run for many miles (some over 80K++)

[Eldi Z]

Originally Posted by cjperformance

Not that you need my 2-cents , but I can vouch for everything you said. I am really hoping that in my ignorance I haven't done any serious damage. That said.... not that I WANT to spend money on replacing the shortblock, I have the money to do it if I blow up something.... but yeah... it's not straightforward. My other thread... I'm trying to put together a comprehensive blog-style list of all the boneheaded stupid things I've been doing and how to correct them.

I am following your long PC P1 Kit thread and for your learning on how to work with your HP Tuners suite
If your engine did not blow yet, then now with the corrected maps you should be OK I guess.
What is still unclear to me is, why these "kit" suppliers: PC, Maggie, Whipple, Vortex, Etc. cannot get their canned tunes to be better (even dare I say acceptable). Can't they align with a good tuner, who would perfect a nice safe and reasonably performing tune to go with their kits?
All I read from most users on the board here, who started off with "Canned" is how bad they are (especially PC).

[Eldi Z]

Interesting reading about the issue of knock and types of fuels / varying combustion loads:
https://www.sciencedirect.com/scienc...10218016303650

[Kerry]

Higher compression will make more power with boost up to a point. Then with 93 u have to dump so much timing that lower compression will win the day. Where is that cross over point different for different setups. High octane will stretch that out for sure. I ran 17 on top with 93 at 6.5 procharger 1000 ft but Like King said the procharger tune will not even go into pe hardly. In fact they left that stock on mine. 14.7 at 6400 with 6.5 psi. I was not happy to say the least. I was a fan boy for procharger but live and learn.

[95 imp]

Originally Posted by Eldi Z

Interesting that even in NA form, you say that these engines are delicate...Do these motors break so easy, even when they are driven stock? I thought that experience of most LT1 owners (Incl. C7 Vettes from 2014), that as long as they maintain the engine and change oils, filters, plugs, Etc. they can run for many miles (some over 80K++)

Nope, never said that. I did say that it is amazing that we have come so far (engineering wise) that you can reliably run 91 octane in a 11.5/1 CR motor.

I also said that the farther you go from stock the more attention you have to pay to the motor to keep it in one piece.

And, I did say that if you don't fuel the motor right you will physically break it.

The first one attests to how good the motor/engineering is.
The last 2 statements are factual for any ICE.

[NickeyMatt1LE]

The other variable not mentioned is pulsewidth. I've seen it many times from other tuners pushing the stock high pressure system way too far. Anything over 5.5ms of pulsewidth is too much and is injecting fuel too late into the compression stroke. This does not allow enough time for the fuel and air charge to fully homogenize. You end up with an uneven mix of air and fuel, an erratic burn and detonation. You'll see it on a dyno plot too. Power will drop off early and the dyno plot will be wavy all while the air/fuel looks good. As King mentioned too, most of these cars get tuned in 70+ degree shops. The fuel system gets pushed to the edge on a warm day. Then the car gets run through the gears a couple times on a 55 degree night, the blower is making another pound of boost, pulsewidth goes over 6ms and the timing table is not populated out to compensate for the additional airmass. Boom. You're much better off with less boost and more timing. If you're pulling timing down into the low teens just to try and run 9-10 psi on pump gas with a blower only LT1, it's too much cylinder pressure for the octane. Add octane or lower boost.

I've got plenty of customers with 7 psi and just headers on 93 octane making 600-620 whp living summer after summer. Cammed, 32% fuel lobe, lt4 high side, aux low side, 6-7 psi, e85, 700-720whp, will also live no problem.

[Eldi Z]

Originally Posted by 95 imp

Nope, never said that. I did say that it is amazing that we have come so far (engineering wise) that you can reliably run 91 octane in a 11.5/1 CR motor.

I also said that the farther you go from stock the more attention you have to pay to the motor to keep it in one piece.

And, I did say that if you don't fuel the motor right you will physically break it.

The first one attests to how good the motor/engineering is.
The last 2 statements are factual for any ICE.

Thanks for clarifying Understood and correct

[Eldi Z]

Originally Posted by NickeyMatt1LE

The other variable not mentioned is pulsewidth. I've seen it many times from other tuners pushing the stock high pressure system way too far. Anything over 5.5ms of pulsewidth is too much and is injecting fuel too late into the compression stroke. This does not allow enough time for the fuel and air charge to fully homogenize. You end up with an uneven mix of air and fuel, an erratic burn and detonation. You'll see it on a dyno plot too. Power will drop off early and the dyno plot will be wavy all while the air/fuel looks good. As King mentioned too, most of these cars get tuned in 70+ degree shops. The fuel system gets pushed to the edge on a warm day. Then the car gets run through the gears a couple times on a 55 degree night, the blower is making another pound of boost, pulsewidth goes over 6ms and the timing table is not populated out to compensate for the additional airmass. Boom. You're much better off with less boost and more timing. If you're pulling timing down into the low teens just to try and run 9-10 psi on pump gas with a blower only LT1, it's too much cylinder pressure for the octane. Add octane or lower boost.

I've got plenty of customers with 7 psi and just headers on 93 octane making 600-620 whp living summer after summer. Cammed, 32% fuel lobe, lt4 high side, aux low side, 6-7 psi, e85, 700-720whp, will also live no problem.

=======================

Provides a good overall real-life picture of what is happening

Calculations in terms of boost reduction on the stock LT4 1.7L blower result in - when lowering the crank-pulley SC ring to 7.2" ~ 19,000 RPM @ top 6,600 engine RPM (6600x7.2 / 2.5 = 19,000, where 7.2" is the new crank pulley and 2.5 remains the stock blower /upper pulley) to produce ~ 7.5-8 PSI peak boost.
Do you view such boost figures as still acceptable (for LT1 daily reliability / engine longevity) on 93 pump octane on LT4 fueling (Low-to-High side parts), while keeping timing and PW in the right places? Average ambient temp ~ 65 - 95 most of the time?

Power goals I set for myself:
Right about the typical ZL1 (6-Speed Stick) stock R-WHP ~ 545-560 tops.

So why would I shy away from changing the upper pulley to reduce boost?
I do not wish to crack open the stock OE unit's snout calibrated and locked in at the Eaton factory, to press in an upper ~2.75-2.80" (I.E. ZPE) pulley locally and get chances of losing the perfect factory fit & balancing afterwards.
And Yes, I know, many are doing it with apparent success, but I prefer to go the "lower" / crank pulley route (in any case, I must replace the crank pulley of the stock LT1, so while I am at it, might as well install a ATI balancer+ lower size SC pulley to dial in the reduced boost. And yes, I know it costs more $$, but the bonus is I get an ATI Dampener-Balancer with it

[cjperformance]

Originally Posted by Eldi Z

I am following your long PC P1 Kit thread and for your learning on how to work with your HP Tuners suite
If your engine did not blow yet, then now with the corrected maps you should be OK I guess.
What is still unclear to me is, why these "kit" suppliers: PC, Maggie, Whipple, Vortex, Etc. cannot get their canned tunes to be better (even dare I say acceptable). Can't they align with a good tuner, who would perfect a nice safe and reasonably performing tune to go with their kits?
All I read from most users on the board here, who started off with "Canned" is how bad they are (especially PC).

What others have speculated, and i have mostly verified, it's because the stock fuel system wont support a proper tune, at least on the LT1. One you get to proper PE and everything else, you are running out of fuel with the stock system. Not sure why they prefer to run a lean tune instead which is just as, if not more dangerous. Most people might not ever notice they are only making half the claimed gains, and running lean at wot with tons of KR. I didnt until i ran a crappy 1/4 mile time and was like WTF.

I imagine they dont want to scare off potential buyers by saying you need to upgrade fueling too. IMO, if they were completely transparent about everything it would be fine. Maybe offer a kit that maxes out at 5psi for a stock fueling system. Then maybe a kit that includes all the fuel upgrades. Its not that hard to do, prob esp on the PD blowers whers the manifold is off already.

[Eldi Z]

Originally Posted by cjperformance

What others have speculated, and i have mostly verified, it's because the stock fuel system wont support a proper tune, at least on the LT1. One you get to proper PE and everything else, you are running out of fuel with the stock system. Not sure why they prefer to run a lean tune instead which is just as, if not more dangerous. Most people might not ever notice they are only making half the claimed gains, and running lean at wot with tons of KR. I didnt until i ran a crappy 1/4 mile time and was like WTF.

I imagine they dont want to scare off potential buyers by saying you need to upgrade fueling too. IMO, if they were completely transparent about everything it would be fine. Maybe offer a kit that maxes out at 5psi for a stock fueling system. Then maybe a kit that includes all the fuel upgrades. Its not that hard to do, prob esp on the PD blowers whers the manifold is off already.

Exactly! They should provide at least the complete LT4 fueling parts (LPFP, HPFP, Hard-Pipes, Injectors for SS and same, less LPFP, for the SS-1LEs) together with their kits and adjust pricing accordingly.

In addition, work with a serious tuner (there are quite a few out there...) to work on the file, which would be tuned on a stock car + SC "kit" parts installed and make it good to a 90% optimum reference (not saying perfect, because "every motor is different" and you would need a dedicated fine-tuning performed on the SPECIFIC motor/setup, to make it absolutely spot-on).
What is the problem for ATI-PC, Magnusson and Whipple to make it like this??

[cjperformance]

For the $600 premium for their canned tune... or whatever it costs... it's not even worth it. For that price, some remote tuners will tune your file, have you do a couple logs, and retune a few times...

Heck, for $600 I'll sell someone MY tune lol. It's mostly my own handiwork at this point. With of course the amazing help of the folks on this board. I guess I'll have to split it with a few of the folks who have been helping me

Just kidding. Would never charge for what I've learned.