Stock cam w/ LPE Injectors and Pump - How much Ethanol?
 

I thought I would share for those wondering just how far you can push the LT4 with the factory stock cam on Ethanol before running out of fuel headroom. So began my quest to push as close to E-85 as safely as possible.

Here was my setup at testing:
Stock 1.7L LT4 blower and drive pulley
9.17" lower crank pulley (15% OD) (peak boost about 14 psi)
91 octane mix with E-85
Stock lowside pump
Stock highside pump and injectors

All log tests were done in 3rd gear, 1500 rpm to about 5,500 rpm rolling WOT digs.

As was predicted, my lowside fueling ran out first. I was pushing my way up and got to E-50 when the lowside tanked. Fuel pressure dropped below 50 psi and pulsewidth went to 9.3ms - yikes! So first order of business was to address the lowside. Tuner (Ted Jannetty) recommended a JMS FuelMax booster. I wired that in and repeated the test with E-50. This time the low side held strong with a steady pressure of about 73-74 psi. It did not waver. The highside though was just starting to dip at about 4,000 RPM and then recovered. Pulsewidth was still a bit high at 6.7ms at this dip.

At this point, without more fueling mods on the highside, this was about max I could go, and to get below 6ms I need to run E-45.

Not wanting to yet do a cam to address the high side, I thought I would swap the high-side pump and injectors for Lingenfelter's products. So new LPE pump and injectors went in. Once the tuning was refined, I began pushing up the Ethanol to see how far we could get.

I started at E-78. The highside dropped way low and the pulsewidth was at a steady 9.5ms between 3200 rpm and 4,000 rpm and then begins recovering just a bit. What is really interesting here is that the lowside fuel pressure never wavered. It stayed flat at 73-74 psi.

I began diluting my ethanol with 91 gasoline and got down to E-66. On E-66, my lowside was steady as commanded as expected and the highside was dipping at 4,000 rpm and then recovering. Very similar to E-50 before the pump/injector upgrades. Highest pulsewidth reached 6.0ms.

I run E-60 as a max which keeps my pulsewidths below 5.0ms.

My conclusion is that with the addition of the LPE pump and injectors, I can run E-60 safely. Before upgrades I could run E-45 safely. This is good for a 15% increase. Although, had I not had other upgrade plans for the car I would have never spent the money on the injectors (maybe the pump) as this is an expensive proposition to squeeze out an extra 15% ethanol.

I think the biggest surprise was that the JMS booster continued to hold up the lowside fueling demands. I thought for sure we would have seen a dip on the lowside running E-78. At least for my setup, I don't think I'll need to do anything further with the lowside fueling. At least not until the new weak link (high side fuel headroom) is remedied. I'm a big, big advocate for the JMS booster after going through this. It will move the fueling weak link elsewhere and keep it there for quite some time.

For those not wanting to break into the engine to cam it, this thread may be helpful. While I can't say for sure, it seems likely that at stock boost levels, I likely could run full E-85. Maybe I'll test that out.

Very good info, thanks for sharing!

One question regarding the low side: did you try upping the voltage in the fuel system control module first, or did you go right to the voltage booster?

Unfortunately there is no separate FSCM that can be read through HP Tuners on my car. I only have access to the ECU to control the fuel pump. Min and max Duty Cycle appears to be the only accessible variables to tune in relation to voltage. Regardless, no changes to voltage through the FSCM were made. Went directly to the voltage booster.

that's a lot of money for such a minimal gain. I feel like meth is a better option

Indeed it is expensive and lousy bang for the buck. Meth is a cheaper option for sure. But, I've never been inclined or had the confidence to go that route since there doesn't seem to be a good failsafe should the controller fail. A cam is also a cheaper option which I would entertain before meth.

I experienced the same thing you did when I ran E60 in my car, similar mods. My question is how many more HP's do ya think you get from E45 to E60? Excellent write up!

I don’t know how much more horsepower that extra 15% E yields. I’ve heard that around E50 most of the gains have already been realized. I was actually never interested in spending big dollars for small gains to get an extra 15%. Rather, what I really want is to not deal with the hassle of trying to mix gas and E85 at the pump, and hope I don’t exceed my limit. Yeah, I have a gauge to read Ethanol and I know that at about a little less than 1/2 a tank of E10 gasoline, I can top off with E-85 and be in a safe range. I just wanted to get to full E-85 and be safe simply as a matter of convenience. Fill it and forget it.

I hear ya when it comes to mixing and worrying! I ended up having Ted tune my car for the VP Fuels X85 so thats all I will be running! $45 for 5 gallons! :doh: I really only run it when I am going to the drag strip which is maybe 4-5 times a year. I spoke with Ted about the high side pump and injectors and the price tag on it made my decision. :thumbdown:

For me, it isn’t a wasted investment. I know I have more future mods which will include camming it. So in the long run, these will be good investments that I can leverage more fully down the road.

Yep! Your good to 1000WHP with a cam and that pump and injectors! :biggrin:

This is a great write up and gives another option to increasing fuel pressures and maybe food for thought in spending big money for minimal gains. For those of us that are not trying to hit 1000hp, we may not consider the bigger fuel pump and injectors. But, to get up into the 700+ range that voltage booster seems like a gem.

Agreed! This is a great write up! :thumb: I am not exactly sure where my car is on HP but with E38 in it it ran a 10.33 @ 135MPH with a 1.42 60 ft. I would say its damn close to 700WHP!

Wow, those are good times! I have the same bolt ons minus the e85 and ran a 11.3 at 129mph with a 1.86 in the 60’ on stock tires. About to
Order some R888R tires to help with the traction part. I’m looking into porting the SC and 103 TB. I’m now thinking a little E can help a bit too.

Ted tuned my car and I maxed out at E40. I spoke with him about the pump but I chose to wait for winter and do a cam. I was hoping for the same thing to be able to just fill up with no mixing