leffes87rx7

Hi Guys
I have a 87 RX7 Turbo ll With a newly built street ported S5 engine,
Himni FC V2 T04R (T67) Turbo Kit with HR V2 3” downpipe TiAl 44 mm Wastegate and GReddy boost controller. GReddy intercooler, Bosch 044 fuel pump, AEM regulator, 720 cc primary injectors, 1680 cc secondary, Snow Stage 2 W/M kit, Haltech E6K.
I run 104 – 109 octane and my dyno test gave 389.3 hk and 272.1 f/p torque at 14 psi boost.
My last run at Texas mile was 159.0 m/hr.
Now my question, My friends from Europe tells me that I will get better performance if I convert to E 85 fuel !!! but I have to calculate with 30 % more fuel and be aware of corrosion in fuel lines
Any expectance out there??

Evil Aviator

E85 is crap. Your current setup is overkill for 14psi boost anyway, so there is no reason to use lame fuel when there is no need for knock resistance. If you actually need that high of octane and W/M for knock resistance at 14psi, then the engine is not tuned correctly and you would be better off spending your money on professional tuning. However, if you are just using the race fuel for its higher energy content and W/M for additional performance, then that is fine.

wthdidusay82

iTrader: (15)

I'd look into alcohol injection as well, that will increase octane rating, as well as reduce intake temps, and suppresses knock/detonation etc.

Rob XX 7

iTrader: (8)

seems a waste to be running 109 octane fuel at only 14psi
You ever try turning up the boost when you were in the dyno? with 109 I think you can easily tune to 20psi safely.

as far as changing fuel- what do you project your power to be @20-25psi? Start from there and we can figure out how much you will have to upgrade your fuel system

btw- there is an "alternative fuel" section of the forum where you will get bet answers than this one

RotaryEvolution

iTrader: (30)

bigger turbo and more boost, i also agree that your current fuel is better than E85 and you aren't utilizing its potential.

the main problem is that T04R isn't going to outbreathe even pump gas let alone E85 with your water injection, with race gas and water injection you could be running well over 40psi worth of knock suppression.

wthdidusay82

iTrader: (15)

I didn't even realize he already had an AI kit, I thought you can run like 18 psi on pump gas anyways

Evil Aviator

W/M kit means Water/Methanol kit. Technically, the term is ADI (Anti-Detonant Injection), but I guess "W/M" works for internet slang.

There is no such thing as "AI" except on this forum. I'm not sure if somebody made up the term due to ignorance, or if it is a lame attempt to reinvent the wheel and give it a new name. Maybe both, lol.

leffes87rx7

Thanks for fast response, I am sorry that I misled you with all the data on my engine. My previous engines setup was a bridge ported S5 with S4 rotors making 455 WHP at 8000 rpm at 20 psi boost. That engine was built in 1997 and just wore out. I know that this setup is very conservative, but I am happy to run this at the road track for long livability, at least for now, if I get past to many times I know what to do.
After hearing about all the great performance of E 85, I was curious to know more, as one of the benefits was cooler running engine. That has been my biggest hurdle over the years despite numerous upgrades. (Texas has two seasons, hot and bloody hot)
So… how great is E85? any benefits at all??

Evil Aviator

Here is how great it is...

In the USA, the octane rating for E85 is not posted on the pump. Depending on the time of year and the local regulations, the mixture can vary from 70% to 84% ethanol blended with regular unleaded. The wonderful thing is that unless you take a test sample every time that you fuel up at the pump, you will never know exactly what you are putting into your tank. How great is that?!!!

Now, let's say that you do know the octane rating. Are you familiar with the (R+M)/2 method used in the USA? It is an average between the Research Octane Number (RON) anti-knock index based on cruise, and the Motor Octane Number (MON) anti-knock index based on an engine under heavy load. For sports cars, the MON matters most because the engine is under load when the car is accelerating rapidly, although the (R+M)/2 method is a nice way to portray the overall stability of the fuel. Here are some typical numbers for fuel:

Ethanol - RON 108-115, MON 90-92
Super Unleaded ("91 octane" pump gas) - RON 96, MON 85-86
Racing Unleaded - RON 104-106, MON 94-96

From the above stats, you can see that pure ethanol has a better MON than 91 super unleaded, but it is not as good as the racing fuel example. Ethanol has a very high RON, but unfortunately this doesn't matter much for a sports car, and when you factor it into the (R+M)/2 method it will give ethanol a deceivingly high rating. Therefore, if E85 were to have a pump sticker stating "95 octane" (R+M)/2, it would be more comparable to "93 octane" super unleaded under heavy load. Also, due to the larger difference between RON and MON (usually called the "octane differential"), ethanol is not as stable as the other fuels listed.

Now let's look at the cooler running of ethanol. This is known as the latent heat of evaporation (or vaporization). The higher the number the better the cooling:

Ethanol - 364 BTU/lb
Unleaded Gasoline - 135 BTU/lb
Water - 970 BTU/lb
Methanol - 472 BTU/lb

As you can see from the above numbers, your water/meth kit is far superior to pure ethanol, and even more so when you factor in the gasoline content of E85.

Therefore, as I stated earlier, E85 is crap.

AnthonyNYC

iTrader: (3)

E85 is amazing stuff. I would recommend for everyone to run it. In the NE it does vary but we test the fuel (takes 3 min). If you visit the same station I have noticed they do not mix to E70 in the winter months. For that low boost you really don't need it but it really is amazing stuff.

I've been running E85 for about 5 years now. I've opened quite a few motors running E85 and the motors are spotless inside. There is no build up anywhere.

Howard Colemen and BDC have also been using ethanol in the past month or so. Brian loves the stuff now as well. Even though you're running such low boost, it will still help on the mile runs.

Good luck!!!

Anthony

BDC

The graph below was produced at 1 bar of boost... ONE BAR of boost on E85... done night before last on Friday on a 2nd gen engine. The same car, after tuning for two hours that night, ran a 10.81 at the track today on 1.5 bar of boost.

Continue to try convincing the rest of the world it's "crap" when those that've been running it with great success prove the opposite.

Sheesh, Internet car people sometimes...

B

RotaryEvolution

iTrader: (30)

it is crap when you factor in all the other downsides..

it collects water, it is difficult to ignite in cold weather, it seeps through any imperfections and makes your car always smell of ethanol, it strips the fuel system clean and pushes all the fine particles through the pump, filters, injector screens, injector pintles and can even foul the whole system if your fuel system is dirtier than it appears to the naked eye.

add in the lowered energy content and the necessity to upgrade the whole fuel system by 30%.

then add in losing that 30% fuel mileage and being locked to a certain type of fueling station with now a shorter refueling range.

then add in the aforementioned changing alcohol content of the fuel which can throw a tune into unsafe territory.

E85 has it's place, it also requires more care. if you can afford race gas, it works better. i don't do E85 conversions all that often because of all of the above.




throwing up dyno figures means nothing. i've pushed 450whp from a 35R undivided .96A/R turbo at 1 bar- on pump gas with water injection- on a rotary engine.

it's not a magical fuel, it does run cooler, it does have higher octane with nearly 1/3 better knock suppression than 91 octane pump and it does work but you have to determine if it suits your needs.


eventually i might trust flex fuel sensor EMS', as of now i still do not.

rotorholic

iTrader: (53)

I love actual results instead of a bunch of typing I'm a fan of e85 also and would recommend it.

Rob XX 7

iTrader: (8)

if you are doing an e85 conversion chances are your entire fuel system will be new anyhow, except the tank itself which are usually spotless inside. With the right cold start tune it starts in the cold no problem.

What is "seeps through any imperfections and makes your car smell of ethanol"? you saying if you have fuel leaks?

matter of fact compared to running pump gas and standard 2 stroke oil e85 is so much cleaner burning, exhaust fumes are greatly reduced. If you were to run it with no pre-mix at all its almost as clean as how a new car runs. Yes 30% more fuel, yes little less fuel ecomony- but compared to the price of race fuel the fuel economy argument goes right out the window

its not for everyone but just because you dont push it doesnt mean its bad

sleeper7

E85 for the win, period. This is from first hand experience. Not from information on the net. I'll never go back to race gas. NEVER had a issue with the fuel. NEVER...

I found that the haters are guys who have not really pushed E85 because of what they have read on the net. The octane rating

leffes87rx7

Thank you Evil Aviator & Rotary Evolution very much for excellent information, I suspected that there are some serious drawbacks using E85 and not glory all the way.
I have been renting cars in Europe running E85, and I shifted back and forth between premium gasoline and E85, the only difference was higher consumption on E85 not any better performance.
I will stay on racing fuel (price not an issue, not a daily runner) and ADI.
As soon as I have some more miles on my engine at the road track I will go back to Rotary Performance dyno and retune for higher boost, like 19-20 psi. My question now is how do we optimize my ADI for maximum performance? Snow Performance recommends 375 ml/min for 350 – 475 RWHP, but I don’t know if this # is for rotary engines, or pistons. Do you have any info?
Again, Thanks a lot for good info.

driftxsequence

iTrader: (8)

have you considered how many pumps are in your area?

I literally have one pump. the next closest pump is an hour away.

Another reason I have chosen not to run e85 is its more likely to absorb water in humid environments. our summer is routinely 70%+ humidity and the car would only be driven on weekends. I fear the fuel would sit too long causing issues. I'm not made of money and would rather not rust out $500 worth of injectors.

RotaryEvolution

iTrader: (30)

the haters have simply dealt with the other issues with the fuel and its tendency to clog up a system which would otherwise be fine on pump gas.

the other drawback can't be disputed, which is the low volume of filling stations and the fact that E85 isn't always the same mix from one pump to the next.

it does have superior knock suppression over pump gas however, but if you plan to switch you should probably look into a virtually new fuel system(mainly a new fuel tank or fuel cell).

sleeper7

Rob XX 7

iTrader: (8)

you will never notice it on a "regular" car

Here is how I noticed it-

I run 15lbs on a pump gas tune, about 360hp on the dyno if I recall. Drain the fuel and we retune for E85 ( I have the ablity to store 2 maps on board and can switch with the flip of a switch in the glove box )

we retuned the car and when my wastegate diaphram was leaking @19-20psi I was at 405( if Im remembering right )

so for me: bosch pump, stainless steel fuel filter, 2 new 2000cc injectors is well worth the price to run 20+ pounds of boost.

Only because of Hurricane Sandy have I not been back to the dyno after resolving my wastegate issue, my small turbo will no longer be efficient at high boost levels but looking at the graph we estimate 415-425hp

and RE- LOL@ the new fuel tank- come on man your reaching with that one unless the car been sitting around for the last 10 years the inside of the tank will be spotless prior to E85 being introduced



This is all nothing new, guys been running it now for what? 5-7 years?
People who use it, people who build and tune engines have all given it the thumbs up.
OBVIOUSLY if you have a single station selling it around its not for you, lets not talk stupid here

RENESISFD

iTrader: (13)

With how cheap (<$70) an ethanol content sensor is this statement is a moot point.

For people who have stations around the availability is a moot point as well. On long island there are pumps all over the place. This combined with the ethanol sensor makes for a win win. Thats why I will be running it in my car.

Using a decent ECU with a fuel pressure sensor that has engine protection can make the clogging point useless as well. If the system is clean when the ethanol is put in the tank you will not have problems anyway.

RotaryEvolution

iTrader: (30)

FFS are still rather new to standalone technology, i will hold off on relying on new technology because we know how well it always works.

sadly standalones are always roughly 20 years behind factory technology. 15+ years ago when i worked at the dealer wideband closed loop auto tuning and flex fuel trims were already nearly a decade old and were introduced when i first started wrenching in the early 90's.

RENESISFD

iTrader: (13)

FFS is already proven reliable there is really nothing to it. The most important component is the sensor and those are proven reliable. The standalones use an OEM sensor. The rest is just another correction table.

Rob XX 7

iTrader: (8)

FFS are not new tech
Manufactures have sold FFV vehicles for close to a decade now the FFS is not new tech. Guys tuning their cars have started to adapt them to other vehicles but the tech is not new

I bet GM cant keep the FFS in stock people have been putting them into everything

welfare

I think this statement pretty much sums it up. and I don't think the op is anywhere near the need to utilize ethanol