njstreetrx7

sorry for caps....i take my fustration out on the key pads...thats why i hate postin my opinion....im dne here ill post resulyts when i geet there

trainwreck517

iTrader: (1)

The 23psi is on a block with GSL-SE rotors, on a GTR35R.. boost measurements taken from the microtech.

Perhaps Rene Franco will chime in, as I know he seems to tune pretty on high on pump gas alot of motors, and I have yet to hear of a failure.. even on his drag car that is boosting 40psi. On a T91, aiwth 1.25 hotside.

But for stock FD motor with high comp rotors, I wouldn't pesonally push more then 18psi on pump.

RotaryEvolution

iTrader: (30)

i still find that hard to believe, i have seen and experienced too many failures to think otherwise unless the octane is increased somehow.

tuning has little to do with it once you start pushing the limits of the build, if he can manage to keep his intake temps icy cold it may sustain for a single run but back to back on the streets is a completely different story and hardly true to real world situations.

GoodfellaFD3S

iTrader: (213)

Hey Wan,

I do run 17 psi on 93 octane, but that is with my water injection system. I typically used to run 15 or so psi on straight pump gas. Back in 2002 or so I briefly ran 17 psi on straight 93 octane, but I decided against that because, quite frankly, pump gas is ****. You never know what you're going to get with it. I popped a motor back in 2003 on a bad tank of supposed 93.

People running 20 psi on pump gas are running on borrowed time---you can be the best tuner in the world, but when that tank of 93 really turns out to be 89.......

RotaryEvolution

iTrader: (30)

or internal temps rise even a tad, most people just are ignorant to what pre-ignition is. in simple it is combustion without a spark from hot spots in the engine, rotaries run hot as hell internally so any of a number of factors can raise internal temps beyond the point of pump gas' handling characteristics when enough boost is added, ask any tuner and they will say the same.

and yeah GoodfellaFD3S i wouldn't doubt there is quite a number of shady gas pump owners who sell 89 and market it as 91 or higher. most cars on the road will not have ill effects on it but if you are tuned for it and don't get the correct octane, well we all know what happens then.

FD3S2005

iTrader: (11)

is there a way to tell if u were cheated gas?? besides the blown motor a couple miles back?? like how the car reacts and such

GoodfellaFD3S

iTrader: (213)

it'll run kind of lumpy/choppy. when I fill up I typically don't go out and starting making redline pulls right away, I'll drive the car easy and boost it slowly to make sure it feels ok. Hell, who I am fooling? lol. Maybe I used to do that, now I don't really worry about it, esp with the water injection.

Cgotto6

iTrader: (8)

Ha, for sure. I used to do the same thing till I got WI. It is definitly fun to light them up after filling up and having some guy ask if "thats a viper?"

njstreetrx7

goodfellas i definately understand ur point u neve know what u can get...or even iof something may go wrong w ur fuel! im not goin the WI way but hopefuly i will have luck at 17 on pump.....Wi requires u to keep it maintained...and i daily my car.lol

njstreetrx7

and lastly i dnt think andybody should run over 15lbs all the time for what?

RotaryEvolution

iTrader: (30)

you mean to tell me after all my thought out posts on what kills these motors you don't even know the real reason why you tried to bitch me out about why it's not safe to push over 15-17PSI on pump fuels?

treceb

i thought the 15 psi limit was cause of the map sensor. and going back to the evos and pistons. alot of times thats their peak hp, which usually goes down a few psi at readline.(dunno if that was mentioned or not)

and wan, stop picking internet fights.lol

RotaryEvolution

iTrader: (30)

the stock map sensor is only part of the problem but that is a good point, the stock map sensor becomes innacurate after those levels since it was never originally inteded to see that much boost. even with an EMS though the limitations on pump octane fuels is still the limiting factor.

treceb

so technically with a 3 bar map sensor and fuel upgrades you can run round 18 psi on pump gas, but youll have to cut back on the timing, making the extra psi not worth it.

SidewaysR1

As far as the EVO thing I mentioned in my initial post, with the stock ecu, the car does drop the boost level towards redline. But with the reflash, it eliminates this, so it holds full boost till it hits the rev limiter. But along with that reflash, its tuned octane specific. My 2 friends got flashed for 93, so they can get away with the 22-23 psi I suppose. And the ex's 1.8T GTI, i also had a choice between a 91 and 93 reflash, picking the 93 for the extra 20-30 WHP it provided.

And yeah, being on the east coast, i can get 93 octane at any station and 94 at Sunoco. So that might have a bit to do with ppl on the east coast running a bit higher boost. Even though, i would rather be safe than sorry and just stick with 15psi as a good pump gas tune, then up it a bit with some water/methanol injection or have a race gas tune.

RotaryEvolution

iTrader: (30)

i tried to explain what pre-ignition is in my earlier posts but most people don't understand what pre-ignition is. in short you don't need a spark for pre-ignition to happen, it is internal temperature sensative so when internal temps rise enough then the fuel will ignite on it's own prior to the spark plugs igniting the fuel mixture. in pre-ignition cases in a rotary engine it will cause detonation, detonation is very catastrophic in these engines and will break components if there is enough pressure in the chamber when it occurs.

octane is directly related to pre-ignition, higher octane will help prevent pre-ignition from happening. so the truth of the matter is, no matter how safe you tune your ignition maps you still are limited to the internal temps of the engine vs the octane of the fuel at X amount of boost, higher pressures in the combustion chamber(higher boost levels) will increase internal engine temps increasing the chance of pre-ignition.

njstreetrx7

karack i dont undersatnd ur last post..but my point is that 15 psi is NOT our limit on 93-94 octane. i would say our safety margin is still above 15 (16-18) i believe we can run up to about 20 psi on pump w good tuning and proper fuel management w no room for error!.. i beleive anything over 20 is not safe on pump...

RotaryEvolution

iTrader: (30)

you could probably run 18PSI relatively safely on 93 octane if the AFRs are clean, that is dependent on your cooling system and intercooler though. if the engine is operating too hot with improper cooling than even 15PSI can be unsafe on 93 octane fuels, in the right setup you probably could squeeze out 20PSI but that would probably be the limit even with a great intercooler, cooling system and oil cooler.

njstreetrx7

karack i dont undersatnd ur last post..but my point is that 15 psi is NOT our limit on 93-94 octane. i would say our safety margin is still above 15 (16-18) i believe we can run up to about 20 psi on pump w good tuning and proper fuel management w no room for error!.. i beleive anything over 20 is not safe on pump...

njstreetrx7

so i guess we are on the same page now

RotaryEvolution

iTrader: (30)

safe levels are in the setup, most people say 15PSI because alot of people still run stock intercoolers and cooling systems, that is a very big limitation since stock FDs run hot as hell in my opinion. with a lot of money and time invested in the cooling systems you could push those numbers up but not by much. each setup will have different limitations so as a generalization it's good not to tell people it's ok to run the peak because people will believe it and wind up with a 200lb brick sitting in their engine bay.

treceb

so youd have to run colder plugs, very conservative timing and fatten the map a bit to keep temps down. great ill just make same power at 20psi as at 15 just so i can tell ppl im running 20psi on pump.

something like that right?

RotaryEvolution

iTrader: (30)

basically yes there is ways to deter pre-ignition but it is at the cost of power, with the exception of raising the octane level.

Kento

Just to clarify here: Pre-ignition doesn't cause detonation, they are two different problems. Pre-ignition is just that, premature ignition of the intake mixture due to excessive combustion chamber metal temps, "hot spots" like the surface edges in the combustion chamber or components/areas that aren't getting sufficient cooling. Detonation is a premature (and very uncontrolled) ignition of the intake mixture caused by excessive temps in the mixture itself.

ArmitageGVR4

iTrader: (13)

Well that depends a lot on the motor. I routinely run 25 psi on pump gas on my bone stock 188k mile motor. Provided the proper bolt-ons and tuning this is not a problem.