Octane Boosters and Fuels

Post by **lewd lude lover** » Thu May 31, 2012 11:13 am

nothing beats standing 5 yards away from the track at the pod as twin top fuels go down.

AWSOME

Duo · Post by **Duo** » Thu May 31, 2012 11:30 am

I'm just thinking more in the short term, with the boost controller off I just have stock boost and v-power/momentum99 in a 50/50 blend works really well, certainly close enough. This is more for if I feel a bit frisky I can dump something in the tank that will stop knock/det at higher boost with much hotter intake temps. I can't be running on it all the time as I would need the car mapped to make use of it and the cost of fuel in a 70 litre tank that only goes 300 miles on average, not so good

Same thing goes with the R-FIT, it has 3 options 2 channels for two different fuel maps and a pass setting that basically turns it off to run stock fuel, I'd get the second channel sorted to run higher octane on high boost and the other two for stock pump fuel, possibly have a stock fuel map for high boost though.

Would adding more of the stock fuel drop intake charge temps? Methanol injection for high boost/hot days? Intercooler spray bar and an FMIC?

I need more pennies

probably help if it was an actual Skyine too, Stagea's might run the same engine as the GTS-t or GT-T but not everything will fit in the bay in the same way/place. Well that and the fact that nobody knows what to do with the ECU, don't even think a Nistune would work, possibly a flashable ROM but nobody in the english speaking world has done any serious ECU work and a MINES ecu will cost £3k from Japan and again outside the country the ECU can't be tuned as it's all in Japanese. Standalone would work but too many $

On the up side I hope to have a kevlar timing belt with some other new goodies soon, possibly an N1 water pump and uprated oil pump of some kind. Depending on how skint I am at the time, new timing belt is a must for safety though. So many options

skinny · Post by **skinny** » Thu May 31, 2012 1:00 pm

ah, was gonna suggest just remapping for 98 RON but seems it's not that easy.

you could have methanol / ethanol injection as long as it doesn't confuse your ECU with lambda feedback.
dont greenergy do a race fuel that you can order?

judderod · Post by **judderod** » Thu May 31, 2012 1:28 pm

Duo wrote:Would adding more of the stock fuel drop intake charge temps? Methanol injection for high boost/hot days? Intercooler spray bar and an FMIC?

I'm no expert on FI but I know a thing or 2 about NA so with a pinch of salt - Adding more stock fuel will just make you run rich. Lower than about 12.5:1 and you'll start loosing power. Running on methanol cools the whole combustion chamber more as you need a lot more methanol to get lambda 1 (complete burn). Something like 5:1 AFR I think. Chucking in that much extra liquid cools things down, and cooler pistons means you're less likely to knock, which means you can push the ignition timing further advanced.

Water/methanol injection is another way to cool things down but I don't really know much about it.

It gets confusing with AFR and lambda for different fuels, but lambda 1 is a complete burn regardless of the fuel or the AFR. Wideband or stock narrowband sensors are all lambda sensors so regardless of the fuel as long as lambda is at 1 or richer for WOT you should be good to go.

Duo · Post by **Duo** » Thu May 31, 2012 2:59 pm

I do have an AFR gauge for a narrowband sensor somewhere, might have to plumb it in and see what happens on WOT, I'm guessing that the methanol cooling would be good but not so easy to set up so might be best to go with a better intercooler first as I'm not going crazy yet, the stock turbo pushes 7psi above 4500rpm as it has dual stage boost, it's still there with the controller on but peaks at 10psi which is safe for the turbo, you can push 11-12psi but thats running right on the edge, over 12psi and the turbo eats itself pretty quick. The extra 3psi makes a lot of difference to my ass dyno and the stock fuelling is insanely rich anyway so it should in theory be fine as the variable inlet cam and variable timing should all bring things in line from sensor readings and have enough give to keep it under control when not reading them.

For now I might just stick to the boosters as the MMT packing ones do have an effect and tbh the 5th gear testing was pretty poor, like the report they did on car waxes. I've seen a good few tests done using the octane testing engine that show about a 2 octane increase on 98ron fuel, it's not subjective either, the engine runs and they lower the head until the compression makes it knock and you get the octane rating from that. The CVL turbo would be my choice but it's not cat friendly and race fuel is crazy expensive and I'd need to work out dilution ratios etc. As long as the engine don't knock it's safe and until it's set up properly I don't intent to run 10psi very much, just too fuel hungry. So the odd £20 on "race formula" booster when I do fancy a squirt on the loud pedal isn't much bother for now but need to get the fuel mapped for stock and higher boost sometime, prefer to wait until I have a new intercooler though, got my eye on a good looking one that requires minimal mods to work and shouldn't cause lag.

judderod · Post by **judderod** » Thu May 31, 2012 4:41 pm

Narrowband sensors are useless at anything other than lambda 1. They basically output one of 3 things. Too rich, too lean, or just right. At WOT if you weren't 'too rich' already, you'd have a melted piston at those kind of pressures!

IDK anything about your car, but on a Prelude/Integra/Civic ECU, most sensors are ignored at above about 66% throttle. Things happen so fast at those kind of RPM's that sensors can't be relied on in a closed loop system, so the ECU defaults to pre-set fuel and ignition tables. Like I said I don't know much about boost but I think it's pretty risky to just increase the octane, increase the boost and hope for the best. If you really want to do it that way, I'd suggest you get a fresh set of spark plugs, pop them in on a hot engine, go for a WOT run and kill the engine as quickly as possible afterwards. Pull the plugs and check for signs of knock. Clean them up and repeat a few times to be sure.

Tuning is the very last thing to get done, once you've got everything exactly as you want it and working perfectly. I built my engine over a year ago and have been driving it on a pretty conservative street tune ever since. Saying that it'll still beat a 300BHP Evo at the moment. I've yet to experience its potential because I have a couple of things left to do. And while driving it a couple of problems have popped up (from non-Honda replacement parts - thanks BLUEPRINT!). Until that's all sorted, I'm holding off either tuning it myself at a local workshop or taking it somewhere to be done. On a modified car, even the slightest change can need a re-tune... Just cleaning my K&N air filter meant I needed a few steps more fuel across the whole map!

Duo · Post by **Duo** » Fri Jun 01, 2012 12:58 pm

I'm thinking more along the lines of the increased octane preventing knock at 10psi, the mapping side would come later, until I can get to Rising Sun and (possibly) have the stock ECU mapped or the fuel piggyback set up I need to be sure the engine is safe, I know the timing is retarded a bit for 99ron already, as I'm not adding too much extra boost and I know on stock fuel it will handle it but runs like a dog I'm guessing it's retarding the timing to a huge degree, certainly in the massive heat we had last week the engine stayed at normal operating temperature even with the higher boost, I was taking it easy though to make sure it was ok and listening very carefully and watching the MAF readings on the R-FIT to see if it was maxing out what the MAF will do.

All seems to be good just not so happy due to timing shift, at a guess an increase in octane would allow the ECU to put the timing back closer to what it should be. Will be at least 2 weeks until the Stagea expert is back off holiday at Rising Sun and I want a little fun this weekend. If I can push 99 to about 100-101ron 10psi should be well within the capabilities of the car from what I've seen on australian and some jap forums, plenty do just run on the 99 with a bigger cooler and all is fine and has been for ages for them. Seems worth a try for now as long as I keep a close eye on things then get to RSP and mapped or tuned asap

One of the guys who has a similar setup to me got the fuel piggyback sorted with more boost and saw about 300bhp which is about 50bhp over stock (250bhp in his case, series 1 RB25, less clever) so fingers crossed with a series 2 Neo engine at 280bhp stock I could and should see over 300bhp all being well, hard to feel in a ~1700kg car though