Jump to content
SAU Community

Recommended Posts

I'm sure many of you know about the Nelson racing engine cars from youtube. These guys setup their insane horsepower cars with a duel fuel system that allows them to cruise on low octane fuel, and then switch to race fuel when the power is needed.

With rising fuel prices in mind, I just had an idea that might be useful for those of us driving thirsty skylines.

You could leave the most of the fuel system standard in the car and just change to a billet twin entry rail and a set of 1000cc ID injectors.

(Have a look at my diagram)

Then install a 20lt fuel cell in the boot with external pumps and an under-car surge tank, with its own larger supply and return lines.

The plumbing at the rail would use seperate fuel delivery from two regulators.

Under boost a switch opens the race fuel solenoid valve (pressure switch), and the higher fuel pressure in the race fuel setup closes the back flow valve in the low octane fuel circuit so the engine is running on race fuel only. Low the low octane setup still runs, but returns all fuel to the main tank.

Off boost, the race fuel solenoid is turned off. Fuel supply then flows through the low octane fuel reg to the rail. High octane fuel still circulates through the high octane reg, but it all returns to the high octane fuel cell.

Considering how dam complex fuel systems are in most skylines these days, I don't see this as being any worse. Also, you could do away with the need to run really big injectors, multiple pumps and E85, and just go for a ULP race fuel like Martini 116 octane.

You would use less fuel by volume, and have higher octane fuel and only be using the race fuel when your on boost.

Any thoughts... ? Discuss...

post-26553-0-67816100-1336214446_thumb.jpg

  • Replies 44
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

I kind of skimmed this but I'm sure the ecu would have to be quiet complex with being able to swap maps etc

Unless content sensors can handle this?

Perhaps if your using MAF sensors... but really who does these days.

Any MAP sensor based setup could tune this.

how fool proof is it regarding snapping the throttle open to overtake etc?

for me it would come down to the few thousands bucks it would cost to setup would buy a shed load of E85 and/or PULP

how fool proof is it regarding snapping the throttle open to overtake etc?

for me it would come down to the few thousands bucks it would cost to setup would buy a shed load of E85 and/or PULP

The volume of the fuel rail would need to be consumed before making reasonable boost, but every turbo car has at least some lag initially. Once your into the boost zone, its not an issue.

Using ULP low octane and a ULP race fuel has a very similar calorific value, so that transition back to low octane when getting off boost wouldn't cause too much of a glitch.

Using ULP and switching to E85 is another story because it would go rich just as you got off the throttle for a moment when fuel mix switches back to ULP.

Pretty interesting stuff hey.

How does the sensors work with swapping the tune etc

Do you have 2 different tunes and it adjusts between them or is it one complete tune that works on both fuels

In theory a MAP tuned ECU would do it transparently with one map, so a D-jetro power fc would do. No crazy sensors or anything required. Using 2 fuels with similar calorific properties would make it easier to setup, and would make any transition a lot smoother and easier to tune for.

The issue is that you have to use LOTS of e85 to make power so the tank has to be larger. Using a full blown race fuel makes sense as you can use a smaller tank. Evening using 98 in the second tank is worth considering, or 98 with 10-15% methanol perhaps...

The only way I see it happening is with 2 totally seperate fuel systems and two sets of injectors.

Or

Don't drive so fast...

Do you have an explanation to backup that opinion? Where is the problem?

Everything is impossible until you put in some effort to making it work.

I have seen it done, but not switchig via MAP

just a switch and an output on the ECU, hit the switch, switches on the race fuel setup and off you go, flick it back again and back to PULP

not as fancy as your idea, but imo more fool proof (the car in question had the boost control setup to match the fuel map it was using

The plumbing at the rail would use seperate fuel delivery from two regulators.

Interesting idea.

Would it be easier to run two fuel rails, two sets of injectors (e.g. nismo plenum can be set-up for this). It would allow a more exact transition between the two fuels and the ecu could be tuned accordingly to totake into account the changing calorific value.

I think one fuel system and one tune would be most efficient. With lower grade fuel you are going to need bigger throttle openings and more gear changes. I have a quite noisy exhaust and no WOF at the moment so I tend to drive around off boost most of the time and can still easily keep up with the traffic and my fuel consumption is lower than it has been for ages! But whenever I want I have the power of the GT3540 on tap.

really, i just see an idea that while interesting in theory is self defeating in practice...

i mean he complains about having to carry extra e85, but is prepared to add extra fuel tanks to carry race fuel which Im pretty sure is illegal anyway..

as for complex fuel systems, well a surge tank and larger lines is hardly complex and is nowhere near as complex as this crazy get up is going to be..to make it work would most definately need twin rails and twin injecotrs, otherwise by the time your fuel rail floods with the race fuel you want its already at 7000rpm and knockin its head off..add to that the weight of the system your running...

i guess if you want a 1000hp street racer with good fuel economy there is some merit to be had here, otherwise it seems completely pointless

Anyways, if you think it is worthwhile go for your life but personally i think it is MUCH easier to carry a few jerry cans of e85 in the boot

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

    • So, that is it! It is a pretty expensive process with the ATF costing 50-100 per 5 litres, and a mechanic will probably charge plenty because they don't want to do it. Still, considering how dirty my fluid was at 120,000klm I think it would be worth doing more like every 80,000 to keep the trans happy, they are very expensive to replace. The job is not that hard if you have the specialist tools so you can save a bit of money and do it yourself!
    • OK, onto filling. So I don't really have any pics, but will describe the process as best I can. The USDM workshop manual also covers it from TM-285 onwards. First, make sure the drain plug (17mm) is snug. Not too tight yet because it is coming off again. Note it does have a copper washer that you could replace or anneal (heat up with a blow torch) to seal nicely. Remove the fill plug, which has an inhex (I think it was 6mm but didn't check). Then, screw in the fill fitting, making sure it has a suitable o-ring (mine came without but I think it is meant to be supplied). It is important that you only screw it in hand tight. I didn't get a good pic of it, but the fill plug leads to a tube about 70mm long inside the transmission. This sets the factory level for fluid in the trans (above the join line for the pan!) and will take about 3l to fill. You then need to connect your fluid pump to the fitting via a hose, and pump in whatever amount of fluid you removed (maybe 3 litres, in my case 7 litres). If you put in more than 3l, it will spill out when you remove the fitting, so do quickly and with a drain pan underneath. Once you have pumped in the required amount of clean ATF, you start the engine and run it for 3 minutes to let the fluid circulate. Don't run it longer and if possible check the fluid temp is under 40oC (Ecutek shows Auto Trans Fluid temp now, or you could use an infrared temp gun on the bottom of the pan). The manual stresses the bit about fluid temperature because it expands when hot an might result in an underfil. So from here, the factory manual says to do the "spill and fill" again, and I did. That is, put an oil pan under the drain plug and undo it with a 17mm spanner, then watch your expensive fluid fall back out again, you should get about 3 litres.  Then, put the drain plug back in, pump 3 litres back in through the fill plug with the fitting and pump, disconnect the fill fitting and replace the fill plug, start the car and run for another 3 minutes (making sure the temp is still under 40oC). The manual then asks for a 3rd "spill and fill" just like above. I also did that and so had put 13l in by now.  This time they want you to keep the engine running and run the transmission through R and D (I hope the wheels are still off the ground!) for a while, and allow the trans temp to get to 40oC, then engine off. Finally, back under the car and undo the fill plug to let the overfill drain out; it will stop running when fluid is at the top of the levelling tube. According to the factory, that is job done! Post that, I reconnected the fill fitting and pumped in an extra 0.5l. AMS says 1.5l overfill is safe, but I started with less to see how it goes, I will add another 1.0 litres later if I'm still not happy with the hot shifts.
    • OK, so regardless of whether you did Step 1 - Spill Step 2 - Trans pan removal Step 3 - TCM removal we are on to the clean and refill. First, have a good look at the oil pan. While you might see dirty oil and some carbony build up (I did), what you don't want to see is any metal particles on the magnets, or sparkles in the oil (thankfully not). Give it all a good clean, particularly the magnets, and put the new gasket on if you have one (or, just cross your fingers) Replacement of the Valve body (if you removed it) is the "reverse of assembly". Thread the electrical socket back up through the trans case, hold the valve body up and put in the bolts you removed, with the correct lengths in the correct locations Torque for the bolts in 8Nm only so I hope you have that torque wrench handy (it feels really loose). Plug the output speed sensor back in and clip the wiring into the 2 clips, replace the spring clip on the TCM socket and plug it back into the car loom. For the pan, the workshop manual states the following order: Again, the torque is 8Nm only.
    • One other thing to mention from my car before we reassemble and refill. Per that earlier diagram,   There should be 2x B length (40mm) and 6x C length (54mm). So I had incorrectly removed one extra bolt, which I assume was 40mm, but even so I have 4x B and 5x C.  Either, the factory made an assembly error (very unlikely), or someone had been in there before me. I vote for the latter because the TCM part number doesn't match my build date, I suspect the TCM was changed under warranty. This indeed led to much unbolting, rebolting, checking, measuring and swearing under the car.... In the end I left out 1x B bolt and put in a 54mm M6 bolt I already had to make sure it was all correct
    • A couple of notes about the TCM. Firstly, it is integrated into the valve body. If you need to replace the TCM for any reason you are following the procedure above The seppos say these fail all the time. I haven't seen or heard of one on here or locally, but that doesn't mean it can't happen. Finally, Ecutek are now offering tuning for the 7 speed TCM. It is basically like ECU tuning in that you have to buy a license for the computer, and then known parameters can be reset. This is all very new and at the moment they are focussing on more aggressive gear holding in sports or sports+ mode, 2 gear launches for drag racing etc. It doesn't seem to affect shift speed like you can on some transmissions. Importantly for me, by having controllable shift points you can now raise the shift point as well as the ECU rev limit, together allowing it to rev a little higher when that is useful. In manual mode, my car shifts up automatically regardless of what I do which is good (because I don't have to worry about it) but bad (because I can't choose to rev a little higher when convenient).  TCMs can only be tuned from late 2016 onwards, and mine is apparently not one of those although the car build date was August 2016 (presumably a batch of ADM cars were done together, so this will probably be the situation for most ADM cars). No idea about JDM cars, and I'm looking into importing a later model valve body I can swap in. This is the top of my TCM A couple of numbers but no part number. Amayama can't find my specific car but it does say the following for Asia-RHD (interestingly, all out of stock....): So it looks like programable TCM are probably post September 2018 for "Asia RHD". When I read my part number out from Ecutek it was 31705-75X6D which did not match Amayama for my build date (Aug-2016)
×
×
  • Create New...