sentry65

iTrader: (11)

I actually can't think of anyone who has run race gas regularly or mixed in race gas with premium on a regular basis who has blown a stock engine - or runs water/meth injection

I know some people who ran race gas on the stock engine blew their engine because of a missed shift, but otherwise everyone that has blown their engine up that I've ever read about has been on normal premium 91-94 octane pump gas or reved the car way beyond redline often which is something the hardware can't handle a lot of while under boost

My guess is if nissan offered the Z with FI with this engine, they wouldn't be running the compression so high - aside from a bunch of other things that probably would have been changed about the engine. But with a fairly high 10.3 compression ratio and adding in boost on top of that, so far the best solution to prevent detonation has been to pull timing and add in a lot more fuel to richen the mix in order to get away with using the same pump gas that an NA Z would use. Simply using race gas seems like it's the simpler answer if it's available to you, because it would prevent detonation and give you some headroom with running too much timing.

I know of at least two people who were running around 500-520whp on APS TT kits with 101 octane gas for a few months each. I think one person sold his car and haven't heard anything about the new owner. The other person (bigbri?) blew the engine up with a missed shift before building the block.

I get a bunch of PM's each month asking why I'm running the power levels I am on the stock block (which still aren't super high) and they usually all seem baffled when I say I religiously run half race 101 octane race gas and half 91 octane premium (as well as the normal tuning and cooling things) As a side note IMO the HKS ignition amplfier is an awesome thing to use with race gas - which is harder to ignite than pump gas

so who's actually blown their engine running better than pump gas?



something else I've heard is that you don't really want to run less than 1/8 tank - not because the pump can't pick up gas, but because with less gas in the tank, it heats up faster because not only can the tank get hot sitting in the sun if it's hot out, but the pump itself gets hot. With less gas in the tank, the pump can heat it up dramatically faster and the pump itself will actually heat up more if it's not fully submerged in gas. Warmer gas can possibly lead you closer to the detonation threshold. That and taking right severe turns for long periods of time can possibly create fuel starvation. It might all be BS or not a big deal, but it makes some sense

maximumsportZ

iTrader: (25)

I don't daily my Z but when I go out to run it I almost always fill it with 100oct just to keep things safe. I probably only ride around with only 5 gallons of gas at a time. 13k on APS TT no problems.

sugarspunZ

iTrader: (2)

how does higher octane gas make a difference? why is it that guys on the east coast or mid west with 93 octane gas make more power than us guys on the west coast with ****y 91? and why is it that when guys run C16 they make like 80+whp more power.
sorry if this is a silly question. i am trying to learn and understand. i know ocatane makes a huge difference i am just trying to understand how.
thanks.

and... when i was younger i had a buddy who had a built 93 RX7 that was a monster and it ran 89 for top performace. it ran like crap on anything higher than 89.
i know the Rx7 is a totally different motor, just trying to make sense of it all

sentry65

iTrader: (11)

higher octane gas raises the threshold of detonation, so you can run more timing and/or more boost before the engine will detonate and get more power. By itself it won't make more power unless the ECU has a more aggressive timing map available to use with it

91 octane does suck. Everyone on the west coast has it and it sucks. Not sure why the east coast gets 92-94 octane - something to do with the oil refineries available there I think.

C16 is a hardcore leaded race gas and if you have cats, it's bad news because it'll burn them right up. Turbo setups often run test pipes so no problem there. Doubtful you could even dream of passing emissions with that gas though so you'd have to switch back to unleaded (and put on cats) for emissions testing.

side note: If gas sits for long periods of time, its octane levels gradually break down

sugarspunZ

iTrader: (2)

so with higher octane gas and or race gas the tuning can be much more aggresive hench the greater numbers?

sentry65

iTrader: (11)

yeah, it completely raises the threshold of detonation. IMO its the perfect insurance against blowing the stock engine aside from going way beyond what the engine can physically hold under WOT. You can also choose to increase your power up to the new raised detonation threshold, but the closer you get to the detonation threshold, the closer you are to detonating

I know of a few people who ran 450-460whp on 101 octane gas for 1-2 years before electing to build up the engine so they could make even more power - and they still run 101 octane gas for safety

It's expensive though. Premium pump gas here is like $2.39/gal right now and 101 octane unleaded is around $5.99 at the 4 or so gas stations that sell it at the pump and about $5.49/gal if you pick it up in a barrel at the company that directly sells it. You can still probably do long distance road trips to places that don't sell race gas as long as you don't go into boost or run at high rpms

Audible Mayhem

iTrader: (48)

i just blew my headgasket at 22 psi and 125 shot on race gas (c16)


but it was crappy cometics, so not saying much, will be back very soon!!!! with bigger and better stuff...

sentry65

iTrader: (11)

you're not running the stock block though, and 22 psi is a crapload of power btw

failsafe306

iTrader: (38)

I hear it's also bad on O2 sensors.

Bullitproof

iTrader: (3)

i have no cats with the aps st kit. i run 93 octane at the 425whp power level(street map) most the time. occasionally i will mix in a half tank of 100 octane( we have a vp distributor up the street). when i select the race gas map(utec), its tuned for c-16(445whp/420tq). no problems as of yet, knock on wood, but i do want to build the motor and possibly get the aps external wastegate so i can really turn up the boost.

Alberto

iTrader: (14)

I could be wrong but didnt Charles (phunk) run his Greddy TT on stock block at like 440+whp on race gas al the time?-and I know he beat the $hit out of it. I thought when he took it apart to build the ringlands were cracked? Sorry if Im wrong about that Charles, if its not you I know somebody did experience that....

BoOsTedz33TT

iTrader: (1)

c16 leaded will mess up your 02 sensors, i run a mix of half a tank of 93 and mix the rest with sunoco unleaded 110 octane, i could probaly retune it in, and make 500, but 450 is good for now

solidsnake

iTrader: (14)

Im in the process of getting my car tuned., You guys are saying I shoulda make a map specifically for a race gas mix for more power and it will be safe? I heard race gas decreases the chances of detonation.

race4it

iTrader: (1)

We blew a built motor at VIR (road course) running race gas. After 2 days of about 30-40 minute sessions (mostly wide-open-throttle), we blew a built motor with the PE TT kit on it and a good tune.

I think the problem though was that we had some of the earlier custom made JE pistons and based on what happened it seems to me that JE had a problem with the skirts not being strong enough (since every pisiton had hairline cracks on the skirt and one of the piston skirts just came apart).




We've since switched to Arias Exteme Duty pistons and Carrillo H-beam rods and I don't think we'll have any problems.

HoldThisForMe

iTrader: (4)

I always ran some sort of mixture of 100 or 110 with my 93... not to mention i had W/I.

I don't think gas (other that starving off det.) will save your stock block above 450whp. I was putting down 485 when all my rods bent in every direction.

I drove mine everyday at that hp level so maybe thats why mine didnt last as long as others..or maybe just differences in casting of rods but thats a whole other issue...

Russ

Bullitproof

iTrader: (3)

It does decrease the chance of detonation. thats why when we tuned the race gas map, we played around with the timing to get more power. what we found was the car gained 25whp at the same boost level with timing adjustments. we didn't have any major knock counts. we hadnt yet updated the boost control feature on the utec, so we left the boost at 10-11psi. nothing is ever safe when it comes to boosting this motor, but i think my shop tuned my vehicle very well. i like having a race map for the track and some 'night missions'. when i run out of c-16, i just press the button for the street map and dump in some 93 octane. i even have a 3rd map that is tuned for 91 octane in case i'm on a long trip and can't get any 93.