Unleaded Premium w/ Alcohol Injection vs. Pump E85

[DoubleD]

I am planning my next season out and I have been doing lots of research. I am at a crossroads and I cant decide with way to go. The car is a 92 IROC R/T with plenty of mods. I am running a Holset HE341 and it makes good power at 18 PSI (FWD stage 4 tune, +40's, 255 HP Pump). I have the fuel for a little more right now, but I want to make more next year. My goal is 425 WHP. So Premium will not get me to my goal and I have been looking elsewhere. I know many guys are running Devils Own Meth Injection with a progressive controller, but I live in Minnesota where E85 is easy to find. I have been busy doing calculations and here is what I need for each set up:

E85 Set up:
950 cc Low Impedence Injectors (MIN)
Aeromotive Stealth 340 pump or
Hot wire current 255 HP Walbro, lower base pressure to 43 PSI
Fully Tune car using Shel Game Flashable Chip and Cord.
(I have experience tuning boosted motors on E85)

Methanol Injection:
Devils Own Progressive Methanol Injection Kit
Fluid Bottle

I know the Meth is a simpler install, but there is not as much tune-ability there. With E85 I can adjust the timing and really used the added value of the detonation resistance and the added cooling effect.

Not sure which route to go and I am looking for some input on peoples personal experiences.

[c2xejk]

The big concern I would have with a e85 and the stock controller is that there is variation in the amount of ethanol in e85... So you may go lean or rich from tank fill-up to tank fill-up... If you were running a megasquirt, you could add in an alcohol sensor...

For consistency, I would recommend alcohol injection...

[MILKCARTON]

I run e85 in everything here in Colorado, I also run meth injection with E85 on my shadow, mainly because I only have +40's in it for now. Buy a cheap E85 tester, but from what I have seen over the years it doesn't vary 1 or 2 % at the most, 30 psi on E85 with my setup has been trouble free...

[tkelly27]

E85. It'll cost more, but there's nothing like it unless you have race fuel at the pumps.

[turbovanman²]

E85 and don't look back.

[iTurbo]

I know the Meth is a simpler install, but there is not as much tune-ability there. With E85 I can adjust the timing and really used the added value of the detonation resistance and the added cooling effect.

Not sure which route to go and I am looking for some input on peoples personal experiences.

First of all, I will say I have no personal experience with this so I'm probably not much help. But I am wondering what you mean by being able to adjust the timing? Either method will net you added detonation resistance and a cooling effect...but it seems to me, unless you get a calibration tuned for the E85, you might actually have more flexibility with the meth injection and a progressive controller.

There isn't much you can do to affect the ignition timing on a TIII aside from a custom calibration. I suppose if you could fabricate a custom crank sensor mount and trigger wheel to run off the front of the motor (instead of the flywheel) you could retard/advance the base timing though.

Let us know how it goes though. I had my old Spirit R/T all set up to run E85 before I sold it. I couldn't find E85 anywhere here in Wyoming within 100 miles that sold it. Go figure, the same time frame I sold it, a local Kum'n'Go remodeled and started offering E85...

I had my Spirit R/T set up with 3/8" stainless steel supply/return lines, anodized FWDP fuel rail, an Aeromotive regulator, 6AN anodized fittings, a Walbro 255 ltr/hr pump with the sending unit modified for 3/8" in/out, and braided stainless hose to replace the rubber. I was at the point of researching injectors when I decided to sell the car instead since it seemed like E85 would never come to town.

Would have loved to finally try it though because I was having detonation issues even at lower boost levels. I did try low-lead 100 octane AV gas from the local airport once and the car loved it...no more retarded timing and the car pulled like a freight train compared to the 91 octane. Verified with OTC 4000E scanner.

[wallace]

I like the E85. I would go a little bigger on the injector size at least 120's. I've used the Summit 120's with e85 and they worked just fine.

[DoubleD]

Ok so my long term plan is still to go E85 but I have a couple of questions using premium fuel (91/93)

Not dependent on fuel injector sizing, what is the max boost you have been able to run on a Turbo Dodge engine on just premium alone. I have a great knock sensor, I just want to know how much boost you have been able to get before it detonates.

I have a lead on some Mitsubishi Evo 8 injectors which flow 650-680cc at 43.5 psi. I want to know if I can use these or are my +40's already close to the detonation limit of premium fuel.

I will be running Shelgame's turbonator TIII so I can scale the injectors and such.

I will write my own tune for what ever larger injectors I install.

[Ondonti]

E85 + methanol injection. Methanol really depends on how much you are injecting. I sprayed more 100% methanol cc wise then gasoline when running pump gas on a low compression motor.

[DoubleD]

On the other side of the coin with E85.
I can make my power goals with 1000cc injectors, and my current fuel set up. I just need to lower the base pressure on the car. Is there a reason our base pressure is so high at 55 psi? I know DSM's and most other cars are at 43.5 PSI. Why is our base pressure that much higher?

[Ondonti]

On the other side of the coin with E85.
I can make my power goals with 1000cc injectors, and my current fuel set up. I just need to lower the base pressure on the car. Is there a reason our base pressure is so high at 55 psi? I know DSM's and most other cars are at 43.5 PSI. Why is our base pressure that much higher?

Think about how old turbo mopars are and how much mopar wanted to spend on new fancy injector technology.

[crusty shadow]

E85, no question about it. 120 pound injectors will be too much for 425 hp, you'll be drowning the engine in fuel it will work but you will have some difficulty getting the car to idle properly with that large of an injector. 120 pund injectors will support up to 510 whp on E85 at 85% duty cycle. 100 pound injectors will support 425 whp on E85 at 85% duty cycle. I would not use either of the fuel pumps you listed. you want the new walbro 400 lph E85 pump. enough fuel flow for over 600 hp on E85 and the pump is designed specifically to run E85, so no fuel compatibility issues to worry about. you don't need to run stainless fuel lines, just new fuel lines to accommodate fuel flow required.

[DoubleD]

I'm looking to run the fuel pressure at 43.5. I see no reason to run it at 55 with different injectors with a different design that run on other cars all the time at 43.5 base pressure. Also when running the pressure lower, the fuel pump I have will not have to work as hard to supply fuel to the rail, this will keep the overall pressure lower and the fuel supply level higher. My calculations put 1000cc injectors at lost to 100% IDC at 425 Whp. and 1200cc Injectors at 85% IDC. I have looked at the new 400 E85 walbro pump and that will be on my list down the road when I need more than the 255 HP. My "hot wired" 255 should supply enough fuel for these 1000cc injectors. I cant find proof to back up all my calculations and theory, so I am just going to have to put this all together and try it.

More and more reading is telling me there are numerous cars setup using 1000cc Injectors with 255 pump on E85 making 500 WHP. I will not go over 425, I do not want to see my rods exit the block.

[zin]

As this isn't a "production" type situation, it probably won't matter, but one of the reasons for the higher fuel pressure was the added heat from the turbo and the increased possibility of vapor lock that it brings.

Vapor lock might never be a problem, but if you run the lower pressure and have problems, I'd keep it on my short list of things to check first, assuming the M.O. fits...

Mike

[wallace]

E85, no question about it. 120 pound injectors will be too much for 425 hp, you'll be drowning the engine in fuel it will work but you will have some difficulty getting the car to idle properly with that large of an injector. 120 pund injectors will support up to 510 whp on E85 at 85% duty cycle. 100 pound injectors will support 425 whp on E85 at 85% duty cycle. I would not use either of the fuel pumps you listed. you want the new walbro 400 lph E85 pump. enough fuel flow for over 600 hp on E85 and the pump is designed specifically to run E85, so no fuel compatibility issues to worry about. you don't need to run stainless fuel lines, just new fuel lines to accommodate fuel flow required.

I'm running my 2.5 on e85 with 160's using batch fire injection. Idle is decent I can get it down to about 900 rpm. With sequential injection and 120's should idle ok I would think. If it will idle ok there is no downside to running the bigger injectors you have more headroom. You can also lower the pressure to get a smaller injector but the hot start may suffer.

[Ondonti]

I will make it clearer, 55 psi gives mopar fuel room without increasing their fuel injector costs to design something new. Back then injectors were not so easy to upgrade, even for an automaker.

[DoubleD]

Made sense to me already, I am not too worried about vapor lock. Ill be running the car at 43.5 PSI to make sure my fuel pump pressure stays low enough that I have the volume to flow the larger injectors.
Thanks guys.

[wallace]

Made sense to me already, I am not too worried about vapor lock. Ill be running the car at 43.5 PSI to make sure my fuel pump pressure stays low enough that I have the volume to flow the larger injectors.
Thanks guys.

Yeah I was talking about running lower than the 43.

[DoubleD]

How low were you thinking? I am confident I can get 1000cc injectors to behave and idle smoothly. I do not want to go any larger than that. I can make my goals with those 1000cc injectors and my 255hp pump.

[wallace]

Not sure you can search and find a calculation that will tell you how far to turn the pressure up or down to increase/decrease the size of an injector. I ran +40's for a long time on a stock tune and lowered fuel pressure. the only time I noticed a problem was hot restarts it would idle low and cut off if you didn't give it gas. If you believe the 1000 cc injectors will get you there I would just run them. Good luck.