Jump to content
SAU Community

Recommended Posts

good news guys!

as halle informed me, e85 is now available at the pump for 109c @ fueltown southland!

i have contacted the store and spoken to the manager, and the fuel is supplied by powerplus. the fuel is also a 91/ethanol blend like united's

http://www.powerplusfuel.com.au/

after speaking to geoff, he informed me that getting the fuel from csr was impossible as the big fuel companies have signed contracts for the next 6 months preventing anyone else purchasing e85, however they are not using it themselves... and the contracts are probably going to get renewed.

the fuel, is selling at a rate of only 300l per week, so c'mon guys, lets go help 'em out!

i'll be filling up and testing later this week, and will post results when done.

yeah, we have it for 99c @ united, as they use csr...

but csr stuff cant be used due to contracts, so fueltown are getting it from powerplus, which are a smaller mob and cant match the price :P

but hell... its less than half the distance and at least 10 times more defect friendly

  • 2 weeks later...

As I'm in the final stages of the planning my engine build I have been doing a lot of research on what compression ratio is best for a dual 98 (street use) and E85 (track use). Just curious as to what are people running on dedicated E85 cars? And whether people have thought forward a little and decked the head and running a slightly thicker head gasket to get their desired CR, then all you have to do is get a thinner gasket when E85 becomes more available and you want to run it solely on E85?

I think a 9.5 compression ratio would be good for a dual setup. use 98 for street stuff then take e85 to the track.

I think that would be good (most other people are recommending me 8.7 at the highest), as it allows you take advantage of the extra torque throughout the rev range but will limit your max boost level due to knock setting in earlier. However I guess it all depends what you want to use the car for, and in my case it's circuit so response over max power is what I want.

A bit of light reading for those who want to get technical with CR's. Hopefully this will be insightful to others as it was for me. Original post is at http://www.modularfords.com/forums/showthread.php?t=51059

Is it better to increase the static CR or boost pressure. There are a couple reasons why supercharged or turbocharged engines run lower static compression ratios. A static CR in the range of 8-9 is very common. Here are a couple considerations.

Consideration #1

Heat from compression by a supercharger or turbo can be removed (for the most part) through use of an intercooler. Heat from compression within the cylinder cannot. Also, the cylinder pressure at the end of the compression stroke (prior to ignition) goes up exponentially with an increase in static compression ratio, versus a linear increase with boost pressure. Therefore, increasing the static CR is going to unavoidably push you closer to the knock limit for a given fuel. In other words, the octane requirement goes up more by increasing the static CR than it does by increasing boost.

For example, increasing the static CR from 8.5 to 9.5 increases the temperature within the cylinder at the end of the compression stroke (but before ignition) by ~63°F, (assuming IAT2 = 130°F and ideal adiabatic compression with γ = Cp/Cv = 1.4. I won’t bore anyone with equations. The situation doesn’t change much even if IAT2 were only, say, 100°F. In that case, the increase in temp at the end of the compression stroke goes up by ~60°F for the same increase in static CR). Also, the pressure at the end of the compression stroke (before ignition) goes up by ~97 psi from 574 psi to 671 psi, assuming atmospheric and boost pressures of 14.7 and 14 psi, respectively. On the other hand, increasing the boost pressure from 14 to 15 psi increases the outlet temp of the compressor by only ~11°F, assuming AE=60% and IAT1 = 90°F. And by further assuming an intercooler efficiency of 80%, the increase in IAT2 is only ~2°F. Hence, the increase in temp at the end of the compression stroke will hardly change at all. Also, the increase in cylinder pressure at the end of the compression stroke only goes up by ~18 psi (from 516 to 534 psi) with this increase in boost pressure.

So summarising the effects of increased temp and pressure at the end of the compression stroke for the two cases:

Increased CR from 8.5 to 9.5: ΔT = ~63°F and ΔP = ~97 psi

Increased boost from 14 to 15 psi: ΔT = ~2.4°F and ΔP = ~18 psi

A higher temp and pressure increase the likelihood of deadly preignition for a given octane fuel. And for those astute observers that know the physics I’ve applied, yes, although I’ve idealized things to keep it simple, (by not including effects such as heat loss thru the cylinder walls during the compression stroke or ignition and valve timing in the calculations), I’m sure they’ll also recognize that this doesn’t change the conclusion.

Consideration #2

Power is increased by two completely different mechanisms for the two approaches. Increasing the static compression ratio increases power via an increase in thermal-conversion efficiency. Increasing boost pressure increases power via an increase in mass-air flow rate. There’s less gain in thermal-conversion efficiency (and hence power) via an increased static CR compared to the power gain by increasing the mass-air flow rate via an increase in boost pressure. For example, increasing the static CR from 8.5 to 9.5 results in an increase in thermal-conversion efficiency (for an ideal Otto cycle) of about 3.2%. On the other hand, increasing the boost pressure from just 14 psi to 15 psi, increases the mass-air flow rate by about 3.5%. If boost pressure is increased by 2 psi, (from 14 to 16 psi), the increase in mass-air flow rate will now be more than twice that compared to the increase in thermal-conversion efficiency, (~7% vs ~3.2%), and ΔT and ΔP still won’t be as great as they are when increasing the static CR from 8.5 to 9.5. Therefore, not only can it be “safer” from the knock point of view, but a little more power is gained as well, (relatively speaking that is).

A good friend of mine built his engine solely to run on E85 and his CR is 9.5:1 has run 2.1 bar with no knock at all.

9.0:1 would be the best for both IMO.

Mine is roughly 8.7:1 i think.

I just came across an ethanol content advisor and wondering if anyone has had any experience with them at all? Some guys in Sweden are using it to automatically switch maps from 98 to E85 based on the output of the analyser, so they don't have to run their tanks dry to switch over.

Link: http://www.zeitronix.com/Products/ECA/ECA.htm

I just came across an ethanol content advisor and wondering if anyone has had any experience with them at all? Some guys in Sweden are using it to automatically switch maps from 98 to E85 based on the output of the analyser, so they don't have to run their tanks dry to switch over.

Link: http://www.zeitronix.com/Products/ECA/ECA.htm

i have a s14 customer that whants to run the flex fuel sensor (not interested in the content advisor), just waiting on the parts atm (not cheap). we are just using the 0-5v inputs on the ecu to get it working. will be interesting.

the mob at southland gave me some details to the garage next door, some guy name tom :banana:, who will be doing flex fuel conversions... didn't get any specifics last time i filled up.

reckon the Nistune will handle a 'flex' option Trent?

Im running E85 full time, loving it

Km per $ comparison works out to be about the same with 98 PULP

Just hoping it would be more widely available in sydney

Iv heard that Holden are bringing out an E85 commo this year so this should force availability to increase i think

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • To follow up a question from earlier too since I had the front bar off again (fking!) This is what is between the bumper and the drivers side wheel And this is the navigator side, only one thing but its a biggy! So basically....no putting coolers in the wheel arches without a lot of moving other stuff. Assuming I move to properly race prepping this car I'll take that job on and see how the computers respond to removing a whole bunch of ADAS modules
    • So I prepped the car for another track day on Wednesday (will be interesting to see coolant temps post flushing out and the larger reservoir, with a forecast of 3-14 being 20o cooler than last time I took it out). Couple of things to mention; since I am just driving the car and not taking a support vehicle, I took the rear seats out and just loaded the back up Team Trackday style. Look at all that space! To cover off removing the rear seat....it is weird (note the hybrid is probably different because it wouldn't have folding rear seats) Basically, you remove the lower seat base, very similar to a r series but it is a clip that pulls forward to release the base rather than it being bolted down. Easy Then, you need to remove the side section of the rear seat on each side. There is a 14mm head nut at the bottom of the side piece, the it slides upwards off a hook at the top to release; you also need to unhook the seatbelt from the loop at the top. Then the centre piece is weird. You need to release/fold the seats forward with the tab in the boot on each side From there, there are 2,x12mm headed bolts holding the rear of each seat to the folding bracket, under the trim between the rear seat and the boot (4x christmas tree clips there, they suck). The seat is out but you can see where the bolts attach to the bracket
    • As discussed in the previous post, the bushes in the 110 needed replacing. I took this opportunity to replace the castor bushes, the front lower control arm, lower the car and get the alignment dialled in with new tyres. I took it down to Alignment Motorsports on the GC to get this work done and also get more out of the Shockworks as I felt like I wasn't getting the full use out of them.  To cut a very long story short, it ended up being the case the passenger side castor arm wouldn't accept the brand new bush as the sleeve had worn badly enough to the point you could push the new bush in by hand and completely through. Trying a pair of TRD bushes didn't fix the issue either (I had originally gone with Hardrace bushes). We needed to urgently source another castor arm, and thankfully this was sourced and the guys at the shop worked on my car until 7pm on a Saturday to get everything done. The car rides a lot nicer now with the suspension dialled in properly. Lowered the car a little as well to suit the lower profile front tyres, and just bring the car down generally. Eternally thankful for the guys down at the shop to get the car sorted, we both pulled big favours from our contacts to get it done on the Saturday.  Also plugged in the new Stedi foglights into the S15, and even from a quick test in the garage I'm keen to see how they look out on the road. I had some concerns about the length of the LED body and whether it'd fit in the foglight housing but it's fine.  I've got a small window coming up next month where I'll likely get a little paint work done on the 110 to remove the rear wing, add a boot wing and roof wing, get the side skirt fixed up and colour match the little panel on the tail lights so that I can install some badges that I've kept in storage. I'm also tempted to put in a new pair of headlights on the 110.  Until then, here's some more pictures from Easter this year. 
    • I would put a fuel pressure gauge between the filter and the fuel rail, see if it's maintaining good fuel pressure at idle going up to the point when it stalls. Do you see any strange behavior in commanded fuel leading up to the point when it stalls? You might have to start going through the service manual and doing a long list of sensor tests if it's not the fuel system for whatever reason.
×
×
  • Create New...