StealBlueSHO said:
SM105K said:
ddlopes said:
First off your build is top notch. I think building the motor to support your power output is a very smart move. My car made 433hp and 513trq on the dyno. Later that day on my way home from the dyno I decide to goose the throttle going from 70 mph to 90ish. Shortly afterwards I heard a loud bang. Yup.... sent a rod threw the block. Now on the dyno it had zero knock. Meth tank was topped off just prior to being strapped on the dyno. At the time it blew up there was no knock. I say that because my aerospace gauges flash a red light when I get 1 degree of knock. When I got the car home I tested the meth system and it was working as it should. I’m not sure exactly what caused it but, I believe the stock rods aren’t made to support the amount of power we wanna put on them. I know there’s guys out there making big power with no issues but it may just not be there time yet. In my case I added approximately another 140hp and 240trq over a stock engine. That’s asking a lot of the stock rods that aren’t forged. Now lucky for me Ford replaced the motor and turbos. It wasn’t easy but I got them to do it. I’m saving up now to upgrade the internals. I got a quote of around $7500... to bullet proof it. I wish you the best with your build. You’ll definitely get 11’s very soon... awesome build!!!
Trying to not go off topic....but you hucking a rod sounds like a catastrophic LSPI event. More and more information is coming out that alcohol based fuels (including meth and pump) are shown to be suspect of these events. There are articles posted by Shodded about this on this site. This has lead me to step away from E30 and move to 100 octane Sunoco GT 260 for my fuel.
Interesting read... from my brief overview.. it appears that E30 is the best blend overall to prevent LSPI... once you approach E50 the risk of LSPI increases drastically.
https://ethanolrfa.org/wp-content/uploads/2017/09/Literature-Review-of-Ethanol-Use-for-High-Octane-Fuels.pdf
This article says the opposite. The higher the ethanol content LSPI events decrease. I have copied and pasted the summary and conclusion below. The way I know Ethanol works runs in line with the summary below. So much in fact, I am willing to spend double the amount of money for a gallon of fuel.
https://www.thefreelibrary.com/Influence+of+Ethanol+Blends+on+Low+Speed+Pre-Ignition+in...-a0528616644
SUMMARY & CONCLUSIONS
This study analyzes the influence of ethanol fuel blends on low speed pre-ignition events in a direct-injection turbo charged gasoline engine with a homogeneous ([lambda] = 1) common rail high pressure injection system, side mounted multi-hole injectors and dual variable valve timing. The investigated blends include E10, E20, E30 and E50 fuels. The following conclusions can be derived from this study:
Ethanol content seems to impact the LSPI number significantly in this side injected GTDI engine. LSPI occurrence increases in this study up to the maximum tested level of 50% ethanol. However, the gradient of increase decreases with higher ethanol content. The reason for this behavior is believed to be a trade-off between the increased in-cylinder cooling at high ethanol rates versus the decreased evaporation of ethanol blends. The low vapor pressure of ethanol, the increased charge cooling and the higher amount of injected fuel at constant lambda could lead to increased wall impingement in this side injected DI engine. The higher wall impingement may then lead to higher local fuel dilution, a decrease in oil viscosity and surface tension that subsquently leads to more frequent oil/fuel droplets blown or thrown into the combustion chamber. The increased laminar flame speed of ethanol blends as well as their reduced ignition energy requirement will lead in addition to higher LSPI numbers. The crank angle resolved FFID measurements confirm this theory to an extent that the measurements can be utilized to predict severe pre-ignition events based on gaseous THC emission spikes during gas exchange. More work is needed to fully understand this phenomenon though.
LSPI cycles with higher ethanol content fuels show strongly reduced engine knock. This behavior is caused by the high octane rating of the high ethanol level blends. The result leads to the conclusion that the knock behavior after pre-ignition is comparable to conventional spark knock and strongly impacted by fuel characteristics. The pressure characteristics from the higher ethanol content fuels also indicate that pre-ignition by itself, albeit unfavorable for engine efficiency, may not be mechanically critical if no subsequent knock occurs.
When combining these two results, E20 and E30 ethanol blends have to be considered critical fuels regarding LSPI in this study. These ethanol blends seem to increase the overall LSPI number while not mitigating mega knock to the necessary extent. This results in both high LSPI numbers and a high number of violent knock events.
