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jkcTN
04-25-2017, 09:18 PM
Anyone run this engine with 87 octane? According to ilmor it is rated for 87 but I've heard from other sources that I should run high test.. The closest marina to me (literally 5 minute idle) only has 100% gas 87.... there is a marina (15 minute boat ride) away that does have high test... I'm just wondering if it's worth the extra drive and cost of high test to run that grade in the boat.

Bottom line I'm looking for people that have real world comparisons in running both grades in the ilmor 7.4 power plant.

lashburn1
04-25-2017, 10:34 PM
87 is fine. Use quality fuel as much as possible
Shell/Chevron/Texaco

sdfoiler
04-25-2017, 10:35 PM
Run 87 anytime I can in my 7.4 - If it's good enough for the Ilmor engineers, it's good enough for me. :)

IBR
04-26-2017, 03:08 PM
I run ethanol free 87 oct. in mine about 90% of the time. I haven't noticed any difference when running 93 octane.

kscrib
04-26-2017, 03:29 PM
I only buy premium gas. Not because of the octane, but because in MO most fuel is ethanol based, but some gas stations sell premium (91 - 93 octane) that is ethanol free.

Is anyone else afraid of ethanol? I am afraid it will pull moisture into the fuel system and cause more expensive repairs than I am paying for the higher priced gas.

If it matters I have a 2015 with 6.2L

hunter991
04-26-2017, 03:32 PM
I only buy premium gas. Not because of the octane, but because in MO most fuel is ethanol based, but some gas stations sell premium (91 - 93 octane) that is ethanol free.

Is anyone else afraid of ethanol? I am afraid it will pull moisture into the fuel system and cause more expensive repairs than I am paying for the higher priced gas.

If it matters I have a 2015 with 6.2L

I am.. i hate the stuff. i put 91 octane only in my 5.7. i won't use ethanol in my snowmobiles, boats, atv's, hell even my lawn mower if i don't have too.

Boats can sit for weeks and it leads to phase separation. If you have too, i add some marine stabil to counter act it. But eth blended fuels are no good for items that sit more than 30 days.

ryancassidy
04-26-2017, 03:44 PM
I was reading (and I can't recall where) and my dealer also recommends just the regular 87 for all the new MC ilmore engines. I used to use only Non-Ethanol fuel previously in my higher strung engines (ie Yamaha jet skiis) but for right now I'm using regular 87 with Marine Stabil.

all my lawn equipment runs Non-ethanol, but it's older and just not built for it.

clrussell
04-26-2017, 05:04 PM
I only buy premium gas. Not because of the octane, but because in MO most fuel is ethanol based, but some gas stations sell premium (91 - 93 octane) that is ethanol free.

Is anyone else afraid of ethanol? I am afraid it will pull moisture into the fuel system and cause more expensive repairs than I am paying for the higher priced gas.

If it matters I have a 2015 with 6.2L

I only run premium in everything.. lawnmower, Prius, boat..

If that tells you anything

Mastercraftdave
04-26-2017, 05:09 PM
I only run premium in everything.. lawnmower, Prius, boat..

If that tells you anything

Im with you. I only run premium in my X23. The manual even says that 93 octane is best for the engine. See below


"Poor-quality or old fuels can cause problems such as loss of performance,
rough idling, hard starting and hesitation. If the engine experiences any of
these symptoms, first try another brand of gasoline and/or replace the old
gasoline with fresh gasoline."

I have the 6.2L in my truck and GM recommends 93 and states that 87 octane may reduce engine performance.

Snipe
04-26-2017, 05:19 PM
I will use ONLY non ethanol. Had issues earlier. Even though It's only a 5.7 :confused:

tkemperdc
04-26-2017, 05:22 PM
I only ran 91 or better in my 7.4. Always ran very well, as well I run non ethanol in most anything and generally high grade 91-93 where and when avail.

jgraham37128
04-26-2017, 08:14 PM
I run 87 in my 6.2l non ethonal.

gsxrjtt
04-27-2017, 07:21 AM
In the 7.4 I highly suggest premium